Owning a 1920's Craftsman Four Square, my energy bills had been taking me to the bank. Literally. The insulation was sloppily installed, and I take full credit for that since I did it myself when I first bought the home over 20 years ago. I also installed the ductwork back then, with, egads, lots of duct tape. And you could actually feel the breeze sitting next to one of my single-pane windows.
There are a multitude of simple tasks a homeowner can do to make their home more energy efficient. I'm systematically going through my home, correcting my mistakes of years ago, and already seeing huge gains.
First, I did a close examination of all my insulation. When I bought the house, there was batt insulation of maybe a maximum R-13 value laid between the ceiling joists in my attic. I had bought rolls of R-19 batt and rolled them perpendicular to the joists, but honestly was not that careful about it, leaving plenty of gaps. So now, I've gone in the attic and rearranged the existing insulation to a tighter pattern, making sure that all edges were snug to the adjacent batt. After that, I purchased additional rolls of R-19 batt and then again laid these perpendicular to the existing upper layer. Now I've got a total of an R-51 in my attic. Easy to do, just make sure you wear gloves, long sleeves and pants, eye protection, and a breathing mask. Oh, and try not to do it in the middle of summer.
Speaking of the attic, one of the best things I did was to create an insulated box cover for my pull down stair. This opening just happened to be right next to my thermostat, so in the summer the heat would just billow down from the attic, causing the cooling system to run non-stop. I had all this insulation everywhere else, but had this huge uninsulated hole where conditioned air could escape and the heat of the attic can penetrate down into the living space. To remedy this problem, I purchased some rigid insulation and built a lightweight box to fit over the stair when it's closed. Constructed of two layers of the rigid insulation on the top and the sides and taped together with foil tape, it's light enough to easily lift off the opening when I need to access the attic. I also installed weather stripping on the bottom edges of the sides, so it seals tightly all around the opening when properly positioned. I've been really amazed at the dramatic difference in the conditioning of my upstairs.
As for the basement, the insulation situation was even worse. (While I'm a huge fan of sealed crawspaces, my basement is really just an oversized crawlspace, five feet to seven feet high, and too large to consider sealing it.) With all the renovation that's occurred during my ownership, the insulation had been pulled away in spots for plumbing and wiring, and in some places had just fallen down. Wearing again the same protection, I've reinstalled the fallen insulation and installed new where there was none. I've also installed new wire supports making sure to adequately support the insulation without compressing the insulation too much (compressing reduces the insulation value of insulation.)
My exterior walls do not have any insulation at all. While there are ways to cut holes in the walls and blow in insulation to the cavity, it's very expensive and, in the region I live, the middle of North Carolina, the savings in energy would take a very long time to justify the cost. I did, however, caulk along all the floors at the exterior wall baseboards with clear caulk (my shoe molding and floors are wood) and installed weather-strip gaskets in all the electrical outlets on the exterior walls. These gaskets are cheap and easy to install. Just take off the outlet plate and the gasket fits snuggly around the outlet, and then reinstall the cover plate. This simple task really helps stop any unwanted and unconditioned air from entering through these openings, especially if there's no insulation in the walls.
In some houses, and certainly in mine, improperly installed or sealed ductwork is a major contributor to energy loss. Especially when the ductwork is run in the attic and/or basement through unconditioned space, you can lose up to 50 percent of the efficiency of the system. In my case, the sheathing on the outside on some of the 20-year-old ductwork had split and cracked, exposed the insulation of the tube. I've systematically replaced each run of the flexible ductwork with the newer and more energy efficient foil ductwork. My biggest find though was in the duct tape that I had originally used to seal the flex to the main trunk and to the duct boots (at the ceiling and floor registers.) All of the "stick" of the tape had long since expired, and the tape was only hanging on out of habit. So, when installing the new flexible ductwork, I pulled back the insulation from the end of the flex insulation, pulled it over the metal connector, and used mastic to seal the joint. I then pulled the insulation back over the joint and used ties to clamp down the ductwork to the connecting metal. The mastic is fun to use – it's easy to apply with a brush and you don't have to make it look pretty! I also used the mastic to seal all the joints in the metal main trunk and at the connection of the trunk to the HVAC unit. Finally, I removed all the floor and ceiling registers, applied mastic on the inside of the "boot" at the joints in the metal, and then reinstalled the registers.
Caulking and Spray Foam Insulation
They say it's the little things that count. Don't underestimate the value of properly sealing openings, even the smallest of ones. Air migrates through the smallest of cracks, so it's really important to pay attention to this detail.
When I was in the attic and basement inspecting my insulation, I noticed light coming from the living space in many locations. Armed with a caulk gun in my holster and a can of spray foam at my side, I systematically attacked all these openings. I was amazed that when I pulled back the insulation around light fixtures and at the ceiling and floor diffusers I could actually see into the house! Clearly if I could see in, conditioned air could escape and unconditioned air can enter where I don't want it. I mostly used the spray foam, going through many cans, to seal around all these openings. Just like the mastic, it doesn't have to be pretty, it just needs to cover all the gaps. Of course, if you want to make it pretty, feel free, but I know for myself anyway that I have other things that need that level of attention.
I also spent the time to seal all the holes where electrical wires and plumbing pipes were run. You may think that was a waste of time, but hear me out. A hole that's not sealed from the attic or crawlspace allows unconditioned air to penetrate the cavity of the wall, even on an interior wall. This air can then enter the house (or conditioned air to leave the house) though electrical outlets or switches, or where plumbing lines enter the house like in a sink cabinet. This air is also unhealthy, coming from your attic or crawlspace.
Doors and Windows
This was probably the easiest and quickest task. I installed weather-stripping at the casing of all my exterior doors and along the bottom of the doors. My single pane windows, being almost 100 years old, did not sit firmly and tightly at the bottom of the lower sash at the sill. And, being a wood to wood connection at the sash to sill and where the sashes overlap, air easily infiltrated. In fact, at some of the windows, if it was breezy outside it could blow out a candle on the inside. I installed simple foam weatherstripping under the bottom of the lower sash and along the back side of the top of the lower sash the seal the joint between the two sashes. Actually, I made my two teenaged sons do it, which will tell you how easy and quick it was.
All of these tasks are all about tightening the envelope of your home, keeping unwanted air out and conditioned air in. They're simple yet offer huge benefits in energy savings. Plus, as an added benefit, they also provide for having healthier indoor air. These tasks do take a little time, but, for me, each task could be attended to when I had time, picking up where I had last left.
Oh, and did I mention that I'm now enjoying much lower energy bills?
As president of TightLines Designs, David Maurer, AIA, LEED-AP, designs small, energy-efficient and sustainable single-family detached homes. He consults with developers, builders and owners on conservation-based community design, green architecture and historic revitalization, and is a frequent contributor at industry conferences.