The Energy Efficient Home

Energy Star Home Certification

I started thinking about making our living space more energy efficient back when I was in college, when I did some volunteer work at a place called Urban Options in East Lansing (now called Michigan Energy Optionslink opens a new window). We only had an apartment in a drafty old Victorian house, but I was still into "green living" well before it was trendy, I guess. When I later moved to a rental house, I did what I could with caulk, insulation, set-back thermostats and such to try and reduce our energy costs (and save money of course). Now that we own a home and are renovating everything in the house, I can finally take some significant steps to improve our homes energy efficiency as I rebuild the entire structure and install new appliances and mechanical equipment. Back in the college days, there really wasn't a definitive answer to what making an energy efficient home actually meant - you just did what you could to stop air leaks and use more efficient heating and cooling practices. Now we've got a much better definition of what an energy efficient home really is.

The good news is, "green building" and "energy efficient home" building techniques are very popular these days, so there's plenty of information available on both subjects, mostly through the Environmental Protection Agency's Energy Starlink opens a new window program web site. Energy Star also has a complete verification list of the specifics to determine if the entire home is Energy Star qualified, so there's no more guessing about what works and what doesn't.

click to magnify At least it's not a negative number.

The bad news is that while I'm taking as many steps as I can to improve our homes efficiency, it's a slow process and the home is performing horribly at the moment. One of the ways to measure our homes energy efficiency is to use the Energy Star Home Energy Yardsticklink opens a new window which provides a rating based on the energy usage data provided and cross-referenced against heating and cooling degree days for the time period in question. On a scale of 1 to 10 (10 being the best), we scored a whopping .5. Sad, but it makes sense given that much of our house remains uninsulated while renovations are being completed.

Unfortunately, there doesn't appear to be a way to make an existing home an Energy Star qualified home under the current guide lines. Qualification only applies to new construction, so despite the fact that I'm essentially re-building every component of the home, I cannot create a true Energy Star qualified home according to the EPA. Even though I'll never get an "official blue sticker" for my electrical panel, there's still nothing that prevents me from going through all of the Energy Star qualification check lists and doing everything right. Even without the sticker, we can still enjoy the benefits of lower energy costs and reduced environmental impact of an Energy Star qualified home. And I haven't given up on that sticker yet either... I'm working with the EPA and an Energy Star rater to determine if I can still receive the appropriate verifications to qualify for the program even though I'm doing all the work myself.

Reducing energy use costs for our house is the main goal of improving the homes energy efficiency, but that means we must do a lot more than just concentrate on weatherization. In order to enjoy a comfortable living space with a minimal ongoing energy budget, we need to address the entire building as a working system. Weatherization is certainly a big part of improving the energy efficiency of the structure, however the additional factors of Indoor Air Quality (IAQ), building moisture and mold prevention, and combustion safety are no less important. Throughout the renovation project, it's been necessary to ensure these factors have always been in mind while making improvements to the building. A little caulk around the windows and a few rolls of fiberglass insulation in the attic when it's all done isn't going to do the job.

Improving Energy Efficiency

Creating a Thermal Barrier
Perhaps one of the most important and cost effective steps in improving heating and cooling efficiency is to prevent air leaks in to and out of the conditioned space. We're paying to heat (or cool) the air inside the home, and the greater the temperature difference between in the air inside the building and the air outside the building, the greater the stack-effect forces driving convective losses through air leaks. The air in the building is warmed by the homes heating system (radiant floor heat in our case), which then makes the air less dense so it wants to rise. In order for the light, warm air to rise and escape through air leaks in the attic, cool, dense air tries to enter the structure through air leaks in the foundation or window and door openings (making the home feel "drafty"). The same thing happens in reverse when cooling the home, in that warm air is drawn in through the attic to replace cool air that's lost through the foundations. If the air leaks are stopped, the stack-effect can be minimized.

Fiberglass insulation, which is what we're using the walls and attic, does nothing to stop air movement - insulation prevents conductive heating and cooling loss, not convective interchanges. In order to stop air leaks we created a sealed envelope between the conditioned space inside the building as the first layer of the thermal barrier, followed by the insulation, then another sealed envelope / moisture barrier outside the building, just below the "weather shell", as the outer layer of the thermal barrier.

Sealing Air Leaks
Because we've been gutting each room to the studs to gain access for new wiring and plumbing as we work through the interior renovation, the process of sealing the interior is relatively straight forward. Once any electrical boxes, wiring and plumbing is in the wall, the next step is to seal any penetrations in the top and bottom plates of the wall with expanding spray foam. Rather than use throw-away cans of Great Stuff™, which pretty much need to be emptied once they're started, I use a Todal Products® link opens a new window Pur Shooter gun and their Pur Fill 1G foam for air sealing any large gaps (see the HVAC section regarding under-floor insulation for more information on the foam gun kit).

Once the big penetrations are sealed with foam, I also go around the perimeter of any electrical boxes with the foam gun, sealing the wiring openings and filling the space between the back of the box and the outer wall sheathing with foam. If the wall has a window in it, I then seal the small gap between the window and the rough opening framing with DAPTex link opens a new window No-Warp® Window & Door Sealant. While DAPTex is in an aerosol can, the nozzle can be removed and cleaned with soap and water between uses so the stuff has a good shelf life. It also doesn't expand like crazy the way polyurethane foam does, so there's no possibility of distorting the window or door casing after it expands.

click to magnify Sealing plumbing and wiring.

Next the wall cavities are filled with unfaced fiberglass insulation (see below), then the entire surface is covered with 4-mil polyethylene plastic sheeting as a vapor barrier. Before installing the poly, I go around the perimeter of the wall (top plate, bottom plate, corner studs, window openings and electrical boxes) with a nice heavy bead of Tremco®link opens a new window Acoustical Sealant, which is a non-hardening, non-skinning synthetic rubber caulk. The stuff is the nastiest, stickiest mess to ever come out of a caulk gun, but it works. I used "regular" acrylic latex caulk to seal the perimeter of the vapor barrier, but the stuff usually skinned over before I got the poly in place and didn't stick very well so I ended up using a lot more caulk than I wanted to in order to get the vapor barrier well sealed to the wall perimeter. The acoustic sealant sticks to the poly (and everything else) like crazy, so it's perfectly suited to the task and allows plenty of work time since it never skins over. Once the poly is up with a couple staples to hold it in place, the sheet is smoothed and tightened over the wall and stapled in place around the perimeter and every 12-inches or so throughout the field.

The final step is to "sweat the small stuff" which means going over the entire wall and seal any remaining penetrations and seams in the vapor barrier with tape. I use 3M™ VentureTape™ Polypropylene HouseWrap Sheathing Tape, which is not cheap, but it very sticky and pretty heavy (compared to plain old packing tape) so it works well. This is the very nit-picky step, since I tape every staple used to hold the poly in place, as well as the seams and big stuff. Once it's done, the result is an air tight, moisture proof surface, ready for the final wall covering (GWB, panelling, etc.).

Insulating the House

click to magnify Wall insulation and vapor barrier (2 photos).

Insulating the Exterior Walls: 2008-2018?
As discussed above, the wall insulation must be installed before completing the interior vapor barrier. For most of the wall insulation I chose John Mansville Formaldehyde-free™ Unfaced FiberGlass link opens a new window R-13 batts (rather than the pink stuff) to reduce bringing more Formaldehyde into the house. I also like it because it's white, and there's often long delays between getting the insulation up and sealed before I get around to applying the final wall covering. It sounds silly, but I can stand looking at white insulation for a while instead of a bunch of pink walls. The JM insulation also comes with a couple Easy-Fit™ batts in each bundle, which are perforated length-wise for when I need to insulate a non-standard width wall cavity.

Unfortunatly, I can only get an R-13 (3-1/2 inches) value for the walls, since I'm not re-framing the entire house with 2 x 6 studs to create the 5-1/2 inch deep cavity required for the recommended R-19 wall insulation value. I suppose if I'd added an inch of rigid foam to the exterior sheathing before I put up the siding I could have hit R-19, but I'm confident that my over-the-top vapor barrier will allow my insulation to perform at its best, so R-13 should do the job. Time will tell.

Most of the exterior walls were insulated and covered with plastic by 2018, although the walk-in closet / laundry room remains un-insulated for now. The living room and bedroom exterior walls also don't have a completely sealed vapor barrier in place — the staples and seams will get taped and any electrical boxes will be caulked when I finally get to installing drywall on those spaces.

Insulating the Floor: 2003-2009
Because the house has a crawl space, rather than a full basement, some consideration must be given to whether to treat the crawl space as conditioned space then insulate and seal the foundation and ground, or treat it as unconditioned space, leaving it ventilated and insulating and sealing the bottom of the floor joists. With radiant floor heat as our heat source, we had little choice but to insulate at the bottom of the floor joists. We also enjoy a very high water table here, so the ground in the crawl space is usually quite damp. Trying to make the crawl space an air-sealed conditioned space would have required installation of an underground drain system with multiple sumps, and since the house is the lowest point of the property, there's really no where to pump the sumps out to. The final solution is actually a combination of both schools of thought (seal and conditioned versus vented and unconditioned crawl space), which I arrived at to balance the need to insulate the radiant heating system as well as deal with the moisture in the crawl space. For details regarding the insulation under the floor, please see the HVAC Floor Insulation section, since the insulation system is an integral part of the heating system. I intend to add rigid board insulation to the crawl space walls, and already have heavy plastic sheeting on the ground under the hosue to help with moisture control. The crawl space is vented as well (for moisture), although the vents are closed in the winter.

click to magnify Under floor insulation.

The interior of the floor still requires air sealing regardless of what's going on with the floor joists and in the crawl space. I don't roll plastic sheeting over all the floors, however the floor still gets a complete perimeter seal with caulk. Before the walls are covered, any space between the wall vapor barrier and the floor is filled with that nasty acoustic sealant, then the sub-floor sheathing is applied - either tongue & groove OSB sub-floor panels (for under the laminate flooring) or cementitious tile backer-board (for under the tile). The OSB or backer-board then forms a seal across the plane of the floor either with sub-floor adhesive under the OSB, or the thinset mortar under the backer-board. The finish floor is also sealed around the perimeter of the room when it's installed. The laminate flooring has a 3mm pre-glued foam backing and is caulked around the entire perimeter with 1/4-inch bead of acrylic latex caulk before baseboard trim in installed. Tile and grout is held away from the wall with a spacer (a 1/4-inch thick strip of plywood) during installation, then the remaining gap is also filled with acrylic latex caulk once the mortar and grout has cured. I use DAP® Alex Plus®link opens a new window siliconized acrylic latex caulk for all the perimeter floor gaps (and everything else that doesn't get the acoustic sealant, for that matter).

Insulating the Attic: 2006-2023?
Heat rises, so lets put lots of insulation in the attic, right? Wrong, mostly… Folks tend to put lots of insulation in the attic because it's easy to get at, not necessarily because of what's going on up there and how it affects the conditioned space below. If the interior is properly air-sealed (which ours is), then there's no chance for convective heat loss or gain through the attic. The problem is there's still an increased chance for conductive heat loss through the ceiling and framing into the attic, since the ceiling surface and framing are naturally warmer than other surfaces inside the house (convective heat transfer is how we all heat the house, remember, so that warm air rises in the home). Even more severe is the chance to reduce interior cooling efficiency in the summer when a super-heated attic conducts heat into the cooler home. So attic insulation is still a big deal, which is why the EPA recommends around 16 to 18 inches of insulation (R-49) for attics in our "Zone 5" area.

Our ceilings are built with 2 x 6 joists, so the easiest place to start in the attic is with some 5-1/2 inch thick fiberglass insulation in all the joist bays. I used Owens-Corning® Pink Fiberglas®link opens a new window R-19 insulation for the first layer of attic insulation. The interior ceiling gets the same vapor barrier / air sealing treatment as the walls, with a little extra fussy attention paid to the recessed lighting fixtures. Recessed lighting is a notorious source of air leaks, so I selected ICAT (insulation contact, air-tight) fixtures, then caulked, taped and foamed even the tiniest openings in the fixtures during installation. The fiberglass insulation is then "fluffed" and carefully placed into every nook and cranny between the ceiling joists and other framing and fixtures in the attic. Another area the requires extra care is the area between the wall top plate and the roof. This critical junction contains a rigid foam vent to allow air flow between the soffit vents and the attic, so the insulation is cut at an angle and placed between the top plate and the vent shield, as well as in any voids between the shield and the framing members. Once all little bits are placed around the top plate, the rest of the insulation is easily rolled out between the joists. Getting the new attic insulation installed has been an ongoing project for many years. The first new stuff went in when the bedroom was enlarged back in 2006 (but only over the new section, not the entire bedroom), and then the offices / boiler room / genkan area was fully insulated as it was put together in 2006 as well (with 5-1/2 inches above the perimeter, and closer to 1-foot of stuff near the peak). The rest of the house has had no attic insulation since we had our first dumpster here for the roof work back in 2006 (and tossed out all the old insulation through the 3-foot vent hole in the gable end). When we finally got the old living room ceiling out in 2017, we just stapled up some plastic sheeting to keep the wind out, but still no attic insulation for most of the house. Sad.

click to magnify Proper attic insulation work begins at last.

With work finally underway on the house interior again in late 2022 (see the Living Room page in the Interior section), I would be able to once more make some progress on insulating the attic — once I finished all the rough carpentry to get the living room ceiling level. That work was completed in late Winter 2023, and after I got the new recessed lights installed and a couple in-ceiling speaker locations worked out, I got up a new vapor barrier, and rolled out a new layer of R-19 unfaced insulation over the entire living room. This is where things in the attic start to get a little complicated…

The next attic insulation step is to add another 10 inches or so (R-30 unfaced fiberglass) of insulation above the new layer of R-19 in the joist bays. The "normal" method of doing this is to just unroll R-30 stuff over the entire attic, perpendicular to the joists, and the job is done with the recommended R-49 insulation thickness. That's a fine idea for attics that are completely open and have no floor. Our attic is certainly not that — half the space has the "sorta truss" boards between the roof rafters and the ceiling joists, there's HRV duct work all around the perimeter, and the area over the bedroom, bathroom, and closet has a floor nailed to the tops of the ceiling joists that is covered with bins and boxes of stuff. We feel we need to keep the ability to have attic storage available, which means we're going to need to keep an attic floor. If we want to achieve that R-49 insulation level in the attic, we determined the only viable solution would be to raise the attic floor, then fill the area beneath the floor (and around the perimeter where there is no floor) with blown-in fiberglass insulation, using the Owens-Corning® AttiCat®link opens a new window insulation system. Rather than attempt to roll out additional fiberglass batts over the top of the joists and trim them to fit everything, the blown-in material will do a superior job of filling any existing voids around the framing members, as well as fill any space around the ventilation ductwork. We'll likely still use a few rolls of the unfaced R-30 stuff for the easier to get at areas (and then fill in any gaps with the shredded stuff from the AttiCat® blower). An additional advantage of the AttiCat® system is that the fiberglass will expand as it's installed, rather than slowly settle like blown-in cellulose insulation. That all sounds good, but that means I need to re-arrange everything in the attic (or bring it all back down, and we have no where to put it), then remove the old flooring, build support for a new floor, then insulate the space and install the new floor. No problem!

Raising the Attic Floor: Early Spring 2023
As mentioned above, I had decided to raise the attic floor in order to maintain storage ability in the space while getting to that R-49 insulation goal. With the bottoms of the ceiling joists for the living room level, I could now figure out how much I needed to raise the attic floor. Starting in the center of the attic at the East end (where the ceiling joist had the smallest thickness of lumber added to the bottom), I measured up a total of 16-inches to get the new attic floor height (R-19 at 5-1/2" plus R-30 at 10-1/4" comes to R-49 at 15-3/4", rounded up to an even 16"). More fun with the 6-foot level, an 8-foot 2x4, and a couple clamps and it worked out that I could use a 10-foot 2x4 as the new floor support, which would give me enough length to attach the 2x4 to the truss board at each end, with a few short 2x4 chunks attached vertically between the top of the ceiling joist and the bottom of the 2x4 along the middle. That would give me a new floor section a little over 5-feet wide in the middle, along with about 2-foot wide sections between the truss boards on each side.

click to magnify The re-built attic floor and first insulation layer (3 photos).

To build the new attic floor I had to get rid of part of the old attic floor, and also get all the stored stuff out of the way. That work had started not long after we removed the flooring underlayment back in late 2021 (see the Bedroom page in the Interior section for more info), which also provided the opportunity to get a bunch of 7/16" OSB sheets loaded into the attic. At that time I managed to remove most of the old attic floorboards over the living room, after moving around the storage boxes and bins, and then stack the eight sheets of OSB on the joists over the living room. The next big supply run in early 2023 (the Vanagon is still out of commission, so I'm at the mercy of a friend with a pick-up truck for Home Depot runs) included 30 2x4s to use for the new living room fusuma door header, tokonoma framing, and then the remaining 20 or so for use in the attic.

When all the rough carpentry for the living room was taken care of, I then turned my attention to making some progress on that attic floor. All the 2x4s were eight feet long, even though I'd determined the new attic floor supports need to be ten feet long (the 8-foot pieces were a lot easier to get into the attic than 10-footers would have been). To get the 10-footers I'd need and to get the little floor support pieces installed, I planned to use a Kreg Jig® HD link opens a new window which I picked up a while ago (and is now discontinued, unfortunately). This thing is built specifically to join 2x stock using pocket screws, so it would work to lengthen the 8-foot pieces to 10-foot pieces, as well as provide a secure method to add each floor support piece to the tops of the ceiling joists.

The new attic floor construction work began by end-joining a 2-foot 2x4 piece to one of the 8-footers with a pocket screw and construction adhesive, then gluing and screwing that 10-foot piece to the gable studs at the end of the attic. I centered the 10-foot length under the roof peak, and leveled it at the 16-inch height above the bottom of the ceiling joist. I then set up the laser level at the other end of the attic with a vertical line cast along the center of the roof and the gable end, and the horizontal line level with the top of the new floor support. That allowed me to work along fairly quickly on each new floor support piece — I'd start installing each support by marking the center line on the 8-footer (5-feet from one end), then clamp it to the truss boards with the top touching the horizontal level line. I could then measure the length for the three support blocks between the 2x4 and the ceiling joist. Next I'd head to the shop and cut the support chunks, then drill a pocket hole in one end. Back to the attic and each block was glued and screwed into place on the ceiling joist, then the 8-footer got a 2-foot piece glued and screwed to the end and that 10-foot piece was then glued and screwed to the support blocks and the truss boards (the two nearest the boiler room actually got a 4-foot piece added to each, to provide a little area to get at the HRV dampers over the boiler room). After a few days of this I had all the new floor supports in place for half the house, and could now get back to adding more insulation and getting the new OSB floor installed — which would allow us to re-arrange all the boxes and bins again, then work on raising the rest of the attic floor and insulating the remainder of the attic.

click to magnify The second layer of attic insulation (4 photos).

More Attic Insulation & A New Floor: Spring 2023
Before screwing down the new OSB for the newly raised half of the attic floor, I needed to get all the insulation in place that the floor would cover (and make inaccessible). As said above, the plan for the insulation under the attic floor was to get that R-19 layer down between the joists (which was done), then get another layer of R-30 down between the new floor supports and fill in all the gaps with the shredded fiberglass stuff from the AttiCat®. The problem was that the rest of the attic was still packed with boxes and bins, so there was no way I was going to rent that AttiCat® machine and try to blow in half the attic with all that stuff up there. I decided the best way to proceed would be to just attempt to shred a couple bales of the AttiCat® material by hand, then blow it into place as I worked along each bay installing the R-30 layer on top of the R-19 stuff. To shred the stuff I grabbed my Lee Valley "hand rakes" from the garden shed and used those to break up the stuff from the insulation bales and spread it around a bit. I also picked up a little 3-hp, 3-gallon shop vac from Harbor Freight that also had an outlet to use as a blower (an electric leaf blower was way too powerful, but this thing was just right). Hand shredding worked pretty well, but it was a lot of work — I don't think I'll be doing that again if I can manage it for the other half of the attic.

Once the entire area for the new floor was well filled with insulation, I then started getting the new OSB flooring in place for half the attic. I started with a full 4 x 8 sheet at the far end, screwed to the new floor supports every 8-inches or so with 1-1/4" square drive screws. I didn't use any sub-floor adhesive on the big sheets, in case someone ever needs to remove this stuff in the future (to get at the wiring or light fixtures for some reason). I then measured and cut the smaller strips of OSB in the shop, and screwed those down next to the full sheets to take care of the center section flooring. These pieces went in with lots of fuss, as none of the truss boards were actually in line with each other. I basically cut a strip that was a little wider than needed, then had to mark and cut a little slot to fit around each truss board to get the piece to lay flat. That also meant I had to add a load of little scraps of 2x2 to the truss boards to support the new floor in between those boards and ensure the new floor was well supported.

click to magnify The first half of the new attic floor is done (5 photos).

For the roughly 2-foot wide sections on each side, I again cut some stock in the shop then laid the piece in place and marked where material needed to be removed for the truss boards (I didn't want to cut up any of the full 4x8 sheets that were already in the attic so I can use those for the other half of the new floor when the time comes). I used the jig saw in the attic to cut the little clearance slots for the truss boards, and eventually got the side strips screwed in place. The last step was to then go over the entire new floor area and fill in all the remaining little spaces between the truss boards and along the end between the gable studs with little pieces of OSB and more 2x2 supports as needed. I basically wanted to ensure there are no little gaps anywhere where something could fall between the floor boards and disappear forever in the insulation below. I then filled any remaining little cracks or spaces with construction adhesive, and with that the first half of the raised attic floor work was completed. Before I filled the new area with boxes and bins, I also added some 1/4-inch OSB strips along the outside edges of the new floor to prevent anything from rolling off the edge, and added some plastic sheeting to the truss boards so the new floor won't get covered with blown in insulation when we eventually get the machine to complete the attic insulation project.

The other half of the attic (over the bedroom and closet) will probably have to wait until Fall for more work, as it's starting to get pretty warm up there on sunny days and it's just too uncomfortable to try and work in that heat. I also need to get the old bedroom ceiling removed and then work out the framing for the new attic entry door. I'll most likely get the details of that work updated to the Bedroom page when the time comes.

More photos and updates to follow as work progresses…

The Expensive Stuff

click to magnify The installed Munchkin™ T80M.

Improving the Heating & Cooling Systems
Upgrading the heating and cooling systems would usally be an expensive proposition that most homeowners don't undertake lightly, but since we had a 50-year old furnace and no air conditioning when we started the renovation, this one's easy — we got to purchase the latest and greatest stuff, and enjoyed sizeable rebates and tax credits in the process. For details of the upgraded heating and cooling equipment we're using, please see the HVAC section. Details of the high-efficiency indirect water heating system can be found in the Plumbing section.

Household Appliances
Household appliances are another area where we've needed to purchase all new units during the renovation, so we've been able to select efficient Energy Star rated appliances for everything (otherwise swapping out perfectly good major appliances for more energy efficient units is a costly endeavor). Our new major kitchen appliances include a microwave/range vent combination unit, a refrigerator, a gas range, and a double-drawer dishwasher. We also recently purchased a new Energy Star front-load washing machine (which automatically adjusts the water level based on the load), and a moisture sensing electric clothes dryer.

click to magnify One of the new windows.

High Efficiency Windows & Doors
All windows and doors were replaced with Marvin Integrity® link opens a new window Wood-Ultrex Energy-Star units (now sold as the Marvin Elevate™ collection). These are fiberglass-clad wood-cased windows and doors, with Low-E II Argon filled double pane insulating glass. Typical thermal specs for the units are U-factor: 0.30; R-value: 3.33; Solar Heat Gain Coefficient: 0.31 and Visible Light Transmittance 0.54 (depending upon the unit style and size, the values vary buy a couple hundredths of a point here and there). Each unit was installed and flashed according to the manufacturer's specifications (for complete installation details, please see the Windows & Doors section.


Moisture & Indoor Air Quality

Dealing with Moisture
With a totally air-sealed, conditioned space inside the home and piles of lofty fiberglass insulation in the walls and ceiling to prevent conductive heat transfer, we're faced with an additional problem of moisture in the walls and attic, which can lead to mold... that's bad. Some moisture in the wall and ceiling insulation is inevitable, since there's always some interchange of warm and cool air within the insulation layer. Condensation appears whenever warm, moist air meets cooler air that cannot hold as much moisture. In order to prevent that condensation from causing problems, the insulation materials should not absorb moisture (fiberglass cannot absorb moisture), and the moisture vapor needs to be removed from the insulation layer. If we encase both sides of the insulation layer in plastic sheeting, any moisture that's within the cavity will be trapped - this is where house wrap comes to the rescue. House wrap is a thin sheet of flashspun high-density polyethylene fibers that keep air and bulk water out of the wall, but allow moisture vapor to escape through microscopic pores in the material. The key to successful application of house wrap is understanding the difference between "bulk water" and "moisture vapor".

click to magnify House wrap on the West side.

House wrap is used to create the exterior layer of the thermal barrier, but it is not the "weather shell" for the building - that consists of the roof and siding materials. In order for house wrap to be effective, it needs to be applied to the building just as carefully as when creating the interior vapor barrier. All seams and penetrations in the material must be sealed with tape and/or caulk in order to prevent air infiltration into the insulation layer. When installing the final finish siding to the building, an additional step is taken to assist with moisture control which is to create a minute air gap between the siding and the house wrap to allow some air flow across the house wrap. This is accomplished by simply adding strips of building felt along the vertical surfaces of all wall framing members before attaching the siding. The top plate and bottom plate of the wall do not get the felt strips, since there has to be a way to get air behind the siding. When the siding is installed, all penetrations and vertical seams are caulked, however the top and bottom edges are left unsealed. The siding and roof overhang prevent bulk water from reaching the house wrap, but because of the small air gap, and moisture in the wall still has a method of escape.

The attic presents a different set of circumstances with regard to ventilation and moisture due to the amount of space between the weather shell (the roof) and the insulation layer (the ceiling) as well as the extreme temperature differentials that occur in the attic. The most practical solution to create a "cold attic" by ventilating the attic with outside air all year. When the attic is super-heated by the Summer sun the warm, moist air within will diffuse moisture vapor into cooler insulation layer at an alarming rate. Fresh air is brought into the attic through soffit and gable vents, and attic air is allowed to escape through a continuous ridge vent which alleviates the super-heating issue. In the Winter, any warm, moisture laden air that makes it into the insulation layer (although that shouldn't really occur with a proper vapor barrier) will be removed from the attic through the same fresh air ventilation system.

Indoor Air Quality
Once the thermal barrier is in place and the house good and tight, we're faced with a new set of problems with regard to indoor air quality and combustion safety. We use a Heat Recovery Ventilator (HRV) to supply fresh air inside the house without compromising our overall energy efficiency. The HRV also ensures combustion air for the gas stove is readily available, as well as to remove combustion pollutants produced by the stove. Combustion air and gases are self contained for the boiler, which employs a direct-vent sealed combustion system. Indoor Air Quality and HRV installation is fully addressed in the HVAC Ventilation section.

Additional Home Energy Improvments

Energy Efficient Lighting
Wherever possible, we install Energy Star lighting fixtures and make use of Compact Fluorescent (CFL) bulbs. Of course, the most used lights in the home are the kitchen overhead lights and bathroom vanity lights, and those are unfortunately using standard incandescent (Halogen) bulbs. The fixtures are Energy Star rated, but for recessed task lighting and seeing your face at 6 am, the current crop of CFLs just don't cut it. We've tried CFLs for the vanity, but they're not bright enough (the fixtures use candelabra-base bulbs, and there's still very few options available for a bulb that will actually fit in there). As for the task lighting in the kitchen, that's currently running PAR20, 50w Halogen bulbs. Other recessed lighting also uses Halogen bulbs, but we generally dim those fixtures by 50% or more, so I can live with that. The dimmable recessed lights in the bathroom do make use of R30 CFLs, and while the dimming performance isn't as nice as incandescent, they function well enough (and provide a better color temperature than incandescent). All other lighting in the house makes use of either cold cathode fluorescent bulbs, compact fluorescent bulbs, or standard bi-pin fluorescent bulbs.

click to magnify The first attempt with LEDs in the engawa.

LED Lighting Update: Fall 2021
It's been over ten years since I wrote the above section regarding "efficient lighting", and much has changed since then: Most significantly has been the impressive improvements in LED bulbs, as well as the significant drop in cost of LED bulbs. We've been steadily upgrading many of the bulbs from CFL to LED (especially as the cost of a replacement Halogen bulb for the recessed lights is nearly twice the cost of the same bulb as an LED). Even with new LEDs however, the dimming performance and color temperature of some of the LEDs we tried was awful. Dimming performance has finally been resolved as we migrate the old switches and dimmers to new Lutron® Caséta® "smart" dimmers and switches (see the wiring page for details), but the various LEDs we tried just didn't have the nice "warm glow" of a dimmed Halogen bulb. As energy costs continue to climb, and as we get closer to making progress on the living room ceiling project (which will add another nine or ten 6-inch recessed fixtures to the mix), I was determined to get the light output from new LEDs lookin' good.

The first lights I started tinkerin' with were the nine outdoor perimeter "downlights" and the six 4-inch recessed fixtures above the engawa. All these lights are on the same dimmer circuit, and we usually have them on every night, dimmed quite low to give the house exterior a nice illuminated effect. The downlights are floodlight fixtures with a G-8 Bi-pin T4 75w Halogen bulb, while the 4-inch cans have a 50w PAR20 Halogen spot bulb. As the downlights started to finally burn out, I was able to find a proper replacement bulb with a 120v, 3w LED with a "warm white" color temperature of 3,000K. These bulbs look very good in the downlights and have no issues when dimmed (and I also found a similar "mini T-4 JCD" replacement LED for the Halogen under-cabinet lights in the kitchen, at 2,700K). The 4-inch recessed lights required a little more work to get right…

I started by replacing the 50w Halogen PAR20 with a 7w GE® LED PAR20 bulb at 2,700K. The color was good and dimming performance was fine, but the bulb stuck out of the fixture about half an inch (the engawa fixtures are "shallow" cans, as there's only 2x4s for rafters in that roof). Knowing I was going to be adding a bunch of new cans elsewhere in the house, I decided to give a "ceiling light retrofit kit" a try. These kits replace the bulb in the recessed fixture with a new trim and lens unit that has an LED built in to the thing behind the lens, and a bulb socket adaptor and plug for power. They run about $10 or $15 each, so basically the same as a decent LED bulb. I also liked the idea of have a sealed surface for these outdoor cans to keep the bugs out of the fixtures. I began with a single 5,000K fixture and a "color selectable" 3,000k - 5,000K fixture to try them out. Even with the one set to the "warmest" temp., it was still way too "cool"/blue for what we were trying to get, especially when dimmed down.

click to magnify Working with the LED recessed light "retrofit kits" (5 photos).

A bit more diggin' around on the 'net led me to information about adding a filter gel to the thing to "warm it up". Apparently I'm not the only one that doesn't like the look of recessed LED lights, and folks are playing with photography lighting filters to try and get things warmed up. I started with a set of Color Temperature Orange (CTO) filters that came as a set with full CTO, ½ CTO, and ¼ CTO gels. I then disassembled the LED retrofit fixture, used the lens to trace a cut line on the gel, and re-assembled the thing with the filter inside. With the LED set to 5,000K, the ¼ CTO gave a nice glow when at full brightness, but when dimmed down it looked like Halloween out there — way too orange! Setting the LED to "warmer" color temps. made it even more orange. This just wasn't working out as I'd like. More diggin' around and I found what looked to be a proper solution from Knight Sound & Lightinglink opens a new window with their Lee® Filters Zircon LED filters. I got their "Warm LED Lighting Pack", which has 12 different 1-foot square gels. I figure I could try them in a couple lights for side-by-side comparisons, then get more of whatever color gel we decided looked best to put in all our recessed fixtures. After lots of cutting and fussin' with fixtures, the #807 "Warm Amber 4" did the job perfectly with the LED set to 5,000K. The engawa fixtures were all fitted with the Halo® retrofit kits and filters, and with that all the exterior perimeter lights were upgraded to LED.

The 4-inch cans for the kitchen task lights were another matter… Even with all the different filters and selectable color temp. LEDs, the side-by-side difference in color with the old 50w Halogen bulbs just never looked right. Some of them were fine at full brightness, but when they dimmed down the color would go way orange, or end up looking sorta grey (which is pretty gross when shed on foodstuffs). As a last resort, I tried one of the PAR20 LEDs that had been in the engawa fixtures and it looked fine! I had a few bulbs available from replacing burned out lights out there, so I went about getting replacements that matched for all the kitchen lights — easier said than done. After a bit of searching, I was able to find the correct match from Bulbs Depotlink opens a new window with the GE® #93360 LED PAR20 bulb (Yes, there are seven different kinds of GE® PAR20 LEDs). We went through the same comparison exercise with a couple 6-inch LED retrofit kits and the other cans in the kitchen, with much the same results. After wasting some bucks on a pair of 6-inch kits, we ended up just replacing the 75w Halogen PAR30 bulbs with 11w Sunco™ Lighting PAR30 bulbs at 2,700K. The color is nice at all dimming levels, and they fit well in the adjustable angle trim cans in the genkan without any problems. We ended up with the 4-inch kits and the two 6-inch kits that we'll never use, but at least I know we won't be getting more 6-inch kits for the rest of the house. I also won't need to monkey around with taking them all apart and painting the trims and baffles. These new LEDs should last many years, and we've certainly noticed a significant change in our monthly electric costs now that many of our light fixtures are equipped with LEDs.

More LED Lighting Changes: Spring 2023
After some good progress on living room and attic renovation work, I spent a little time tinkerin' with a few remaining light fixtures that hadn't been changed to LED, which were the fixtures with regular fluorescent bulbs and ballasts. The attic has four, 4-foot double-tube "shop lights" hung along the ridge board that work okay for occasionally crawling around up there to get something out of storage, but they're pretty old, a couple of the tubes flicker a bit, they make an annoying humming sound when they're on, and they often don't work at all when it's cold up there. I've also got one of these same fixtures out in the garden shed, and it suffers from the same problems (flickers, hums, and rarely works in the Winter). So, the quick solution is to replace the standard T-10, 40w 4-foot fluorescent tube with a "Type-A" LED, right? Nope. I tried that for the garden shed when one of the tubes burned out with an LED retrofit tube from the hardware store, but it just doesn't work (a wasted $20 lesson learned).

click to magnify Changing the 4-foot fluorescents to LED (3 photos).

So here's the deal: T-8/T-10/T-12 retrofit LED tubes come in a few varieties. Type A replacements are "Ballast Compatible" units made to use the existing fluorescent fixture's ballast, so you just remove the fluorescent bulb and pop in the LED and you're done… as long as your fixture has a "compatible" ballast, and is fairly new to ensure the ballast is "good". If it's an old fixture, then this probably won't work. Type B replacements are "Ballast Bypass" units made for direct connection to 120VAC. Also known as "line voltage" lamps, these units have an internal LED driver so they require the fixture to be re-wired to bring line voltage to the lamp holders rather than have power supplied through the fixture's ballast. Type C replacements require an external LED driver/controller that again requires re-wiring to bypass the fixture's ballast (the "magnetic strip" tube replacement kits may be considered Type C replacements, even though they're not tubes). The Type C units usually have impressive dimming, color control options, and long lifespan, but they're also rather expensive compared to the Type A and Type B retrofit options. It would usually make more sense to just replace the entire fixture if the Type C control options are required. Finally, there's the Type A+B (formerly known as Type D) replacements which are both "Ballast Bypass & Compatible" units. These replacements allow you to either leave the ballast connected (assuming it's compatible to begin with), or re-wire the fixture for direct line voltage to the lamp holders. Of course, the Type A+B replacements are more costly then either the Type A or Type B.

While the simplest (and cheapest) route seems to be to just pop in a bunch of new Type A LEDs, the main goal is to enjoy the reduced energy needs of LED compared to fluorescent. Replacing a pair of 40w, 2800-lumen fluorescent tubes with a pair of 14w, 2200-lumen Type A LED tubes obviously drops the fixture's wattage from 80 to 28, but the fixture's ballast will still consume some power (not much, but a few watts at least). It seems much better to me to just bypass the ballast (which will eventually fail) and go with the Type B replacements. But wait, there's more! The Type B units need line voltage wired directly to the lampholder (the little plastic thing at the ends of the fixture, usually referred to as a "tombstone", since that's kinda what it looks like). Lampholder "tombstones" come in a couple of configurations as well, and the lampholder configuration for the fixture must be determined before purchasing the Type B replacements.

To address the lampholder configuration, we need to back track a bit and re-examine the guts of the fluorescent fixture. Assuming we're still talking about a two-lamp, 4-foot fixture, the fixture has four lampholders with two at each end. These are G-13 bi-pin sockets designed to hold T-8, T-10, or T-12 fluorescent tubes. The pins on each end of the tube are the same distance apart: 13mm, hence the name G-13. However the tubes are different diameters, which are a result of how many eights of an inch the model number indicates… So a T-8 tube is eight eighths, or 1" in diameter, a T-10 is ten eighths, or 1-1/4", and a T-12 is twelve eights, or 1-1/2" (there's also the little G-5 bi-pin socket, with pins 5mm apart for the T-5, 5/8" tube). That's not a goofy mix of English and metric measurements at all! What we're really after here though is how each socket is wired to the fixture's ballast. If the fixture has an "instant start" ballast, it will have "shunted" tombstones — this means both contacts in the socket are connected to each other, either internally (which may only be determined with a multimeter), or with a small jumper wire at the base of the socket. Shunted tombstones usually just have one wire from the ballast to the tombstone. The other option would be for the fixture to have a "rapid start" ballast (and sometimes a little "starter" can), which then uses "non-shunted" tombstones. Non-shunted tombstones have isolated contacts with at least two wires going from the ballast to each tombstone. Where this becomes important when considering LED replacement tubes is that the tubes are available either as "single-ended" power or "double-ended" power tubes. Single-ended tubes only require power at one end of the tube, with one pin connected to power/black, and the other pin connected to neutral/white. The other end of a single-ended power LED tube has no wiring connected to the socket, and the socket merely holds the tube in the fixture. Single-ended tubes must be installed with non-shunted tombstones. Double-ended tubes require connections at both ends of the tube, with one end connected to power/black, and the other end connected to neutral/white. Doubled-ended tubes may be installed in either shunted or non-shunted tombstones. Type A and Type A+B replacements always require double-ended power in order to maintain backward compatibility. Type B replacements are usually single-ended power.

click to magnify The last couple fixtures get LEDs (2 photos).

All that blather boils down to my decision to replace my old 4-foot, T-10 fluorescent tubes with Type B, single-ended LED replacement tubes. Because a few of the existing G-13 sockets were missing bits of plastic (even though they still held the old tubes okay), I also picked up a bag of 20 new, non-shunted G-13 tombstones to replace all my old sockets ($14 for the bag, so no biggie). We've been happy with the performance of the Sunco™ LEDs that have gone in all the recessed light fixtures, so I purchased a 10-pack of their Type B, single-ended, 6,000K, 18w frosted T-8s for my fixtures ($80, or $8 per bulb, from Amazon). An afternoon in the attic got all the fixtures up there swapped to LED, and wow what a difference! Most of those fluorescent tubes were many years old, and that 40% luminosity depreciation over the life of the bulb was really noticeable as I got the fixtures upgraded. The LEDs are much brighter, and the 6000K LED color temperature looks great (no hint of the blue-ish "cool-white" tint like early CFLs). Best of all the power required to light up the attic has gone from 320w for the fluorescents and ballasts to 144w for the LED replacements.

With the 4-foot tube fixtures in the attic and garden shed taken care of, all that remained was a flush-mount ceiling light in the kitchen (we call it the "groceries light", since we usually only turn it on if we're putting away groceries in the evening), and 2-foot, double-tube T-10 fluorescent ceiling fixture in the utility room. The kitchen light uses a 22w, T-5 circline fluorescent tube with a 2GX13 quad-pin base, and there really isn't a direct replacement LED tube available for that (basically no such thing as a Type A, ballast compatible, round LED as far as I can tell). There are a few replacement options available that I suppose we could call Type B or Type C, in that they all require re-wiring the fixture for the LED driver, and some even have their own control units for dimming and color temp. I went with a LEDY 33w, 3,630 lumen unit in "warm white". The LED just fit inside the lamp fixture, and even though the LED uses more wattage than the fluorescent (33w versus the 22w for the old tube), the brightness of the LED (3,630 lumen versus 1,900) and warmer color provides much better, more useful lighting for the kitchen. The upgrade for the 2-foot utility room fixture was basically the same as what was done for the 4-footers: remove the T-10, 20w tubes and ballast wiring, re-wire a pair of non-shunted tombstones, and pop in a couple Type B, single-ended power, 9w LED replacements. With the exception of the outdoor floodlights, all other lighting has been upgraded to LED. It's certainly brighter, and time will tell if it makes a noticeable difference in the electric bill.

Extra Attic Ventilation: Fall 2018
Back in 2006 when we built out the new roof framing, I made sure we included plenty of attic ventilation as part of that project. As mentioned above in the Dealing with Moisture section, there is a ridge vent the runs the length of the house, and a soffit vent around the entire perimeter. When working on the siding & trim in 2010, I also added a 36-inch diameter vent to one of the gables, with 16-inch diameter vent in the other, and the entire area under each porch roof is screened for attic ventilation. All this ventilation is an important part of making the insulation in the attic do its job — without adequate ventilation, an un-conditioned attic space will build up warmth during the heating season, likely causing snow and ice on the roof to melt and form ice dams, and also create condensation that can reduce the effectiveness of insulation. During the cooling season, a poorly ventilated attic can get very warm, creating a significant extra burden on air-conditioning equipment.

click to magnify The powered attic gable vent fan.

We have plenty of "passive" ventilation with air moving through the attic from the "stack effect" (which basically just means warm air rises and cool air falls), in through the soffit vents, then up and out the ridge vent. While there hasn't been any insulation in some parts of the attic many years, the thermal barrier and insulation for the kitchen, bathroom, and genkan has been keeping house comfortable with reasonable heating and cooling costs. That changed fairly dramatically when we finally removed the old Homasote® ceiling panels from the living room in the Winter of 2017. We stapled up a temporary plastic vapor barrier to the ceiling joists after the panels were removed, but even that pathetic little 3/4-inch thick Homasote® offered some insulation value compared to a simple plastic sheet. We really noticed the difference the next Summer, when the house would remain very warm well into the evening on hot days, even with the air conditioner running all day. I was in no position to start installing a new ceiling, so as a temporary measure, I investigated adding some "active" ventilation to the attic to get that hot air out of there.

I decided to get an Air Vent® link opens a new window Model #53315 Gable Attic Ventilator through Amazon, and got that installed in the attic at the end of that Summer to see if it would help the situation. The unit I selected has a 14-inch fan blade, so it fit nicely over the 16-inch gable vent where the main attic meets the entry area. It's hardwired in to 120v, and has a small thermostatic control to turn the fan on at whatever temperature you select (we set it to 100°). I also picked up a set of Sorbothane® "anti-vibration" mounting washers to help keep the thing quiet. To get it mounted, I started with a piece of 1/4-inch Oak plywood cut to fit within the framing of the gable end, with a 14-inch hole for the fan at the vent opening. That plywood was given a generous slather of construction adhesive, then I went nuts with the narrow-crown stapler to ensure it was well bonded to the old, uneven, original sheathing boards. The fan housing was then attached with stainless-steel hardware and the anti-vibration washers, then finally wired into a nearby junction box to share power with the attic lighting circuit. It's been working very well at keeping the attic the same temperature as outside, and on even the hottest Summer days it shuts off as soon as the sun moves off the roof. We've also noticed a big difference in how much the air-conditioner is working in the evenings. It's a little loud, but that should change once we actually get some insulation in the living room ceiling.