I love my house. It’s comfortable. It’s warm in the winter and cool in the summer. I continually look for ways to improve the energy systems, the windows (the least efficient part of my house), the heat distribution, but for the most part, the house functions really well and costs me very little or no money to run.
The three elements that make this house comfortable are: Insulation, Low temperature heating system, Air quality. (For details on the renovation, goals, and implementation, click on “78 Main Renovation“)
My house has 12” of dense-packed cellulose in the walls; and 22” in the roof. It also has a fully foamed in basement. Before putting in the cellulose, we filled all the holes in the outside walls and areas around windows and doors with foam to eliminate air infiltration, places where the outside air would try to get in.
It is the amount of insulation and air leakage that determines how much heat (or BTUs) your house will require in the cold months (the heat load). Since most people pay for those BTUs in gallons of oil or propane, or in cords of wood, then keeping the heat load down can make a huge difference on your heating bill. In this house the heat load is low enough that the sun and a seasonal storage tank can provide all the heat required by the house.
Since the insulation is buried in the walls of a house, it is something that may not change for decades. So it is important to get it done right and to the highest standards when you do have an opportunity to build new. Or if you are opening up walls from the inside or outside of an older house, review all the options for insulation and reducing air leakage, look at the best practices, and fill those walls with the best your money can buy. 3 years ago 12″ of dense packed cellulose was considered extreme (super-insulated walls), providing about R40. Today this isn’t extreme anymore.
With a well insulated house, you get a lot of cooling for free as well. Open up the windows when the temperature goes down below 70F and close them up before it starts to rise. You can keep the cool in for days. In a less insulated house, with an outdoor temp of 80F+ it may only take a few hours for the inside temperature to be 80F.
Look for a future blog post to address the heating system and air quality three years later.