by: Paul Kando
The hummingbirds are gone. It's time to think of winter and apply the basics I wrote about last week to our houses. Every house is different. I don't know how easy yours is to heat, but based on over 300 houses my partner and I have audited, it will burn somewhere between 700 and 5,000 gallons of oil (or its equivalent) between now and next spring. That's between 28,500 and 203,700 kilowatt-hours of heat energy. Where will it go? We can calculate how much heat the average house loses through its walls, attic/roof, basement, utilities, windows/doors and through air leaks, but the range between individual houses is very wide:
|Percentage of heat lost through||Average||Median||High||Low|
|Attic and roof||9.0%||7.9%||28.1%||3.2%|
|Utilities (pipes, ducts)||3.0%||1.9%||2.0%||0.1%|
|Windows and doors||14.4%||13.8%||42.1%||-10.2%*|
|Air leaks from structure||35.4%||34.7%||66. %||2.4%|
|* negative consumption = solar heat gain through windows exceed losses|
Only an energy audit can tell you where your house fits in this picture. The audit will also give you a good idea about what you can do to improve things. Understanding the basics can help. Touch the uninsulated basement ceiling: if it is warmer than the basement walls and floor, what you feel is heat conducted through the floor from above. Place your hand near the uninsulated hot air ducts or hot water pipes: the warmth you feel is the product of radiation. If your house is like most, your biggest heat loss is through air leaks - warm air out, cold air in - that's convection. Dampness on the cool underside of your roof up in the attic demonstrates how moisture evaporates, moves with the convecting warm air, condenses - and delivers huge amounts of energy from the heated house to the roof. There it can melt the snow and cause ice dams, in addition to soaking the attic insulation.
It helps to be up to speed on, and learn from, what others have been doing . There are a few builders who build passive houses (PH) here in Maine. Their houses use 90% less energy than conventionally built homes. (Why would anyone build anything else? A passive house more than pays for itself through energy cost savings over a very few years). Seven things PH builders do also provide clues about what can be done to your old homestead: (1) Every PH is designed to meet a predetermined performance standard, rather than some vague "better than" expectation or even a prescriptive building code. (2) Every step and every piece of material in PH construction is pre-planned before anything happens at the building site. It is a lot cheaper to figure things out by computer and on paper than proceed based on tradition, rules of thumb, or by trial and error. This plan guides field workers in (3) super-insulation on top, bottom and all sides, to at least R-45 in our climate. (4) avoiding thermal bridges through framing members (a challenge in an old house). (5) sealing the house air-tight - a no-brainer but in a tight house moisture problems are accentuated since moist air no longer escapes through cracks in the building envelope. (6) Heat recovery ventilation will remove both stale air and excess moisture but no heat. (7) Much improved windows and doors: If you can swing it, buy only the very best, since installation costs will be the same. New -rated windows on the market have R values around 10, while a standard double glazed window offers only R-2. Window inserts you can make yourself are a good beginning in an existing house.
The only way to achieve PH performance in an old house is by literally wrapping it from the outside in an airtight, super-insulated cocoon. My friend, Chris Corson, did this to his own home and anticipates a fabulous 32% return on his fairly significant investment. Short of doing likewise, it is possible to achieve energy efficiency improvements of 50% or more by simple, well-planned energy-saving measures, implemented over several years if need be, financing the improvements from energy cost savings.
Where to get help? To do such things well (and avoid doing more harm than good) takes knowledge and understanding. An energy audit is but a start. After that one needs to plan, acquire skills and tools - or hire a competent contractor. One may also need special financing. And once the job is done, it's time to get off oil altogether. Will it be solar? Wood pellets? Wind? Methane gas reclaimed by the town from organic waste? Something else?
Inspired by communities in Europe - both larger and smaller than ours - that became energy self-sufficient through cooperative effort, a group of us in Damariscotta are thinking of establishing an energy cooperative. We will own and operate it together, without third-party profits to pay. Membership will be open to all. Together we will marshal all the resources we need to succeed in cutting heating costs first, then becoming fully energy self-sufficient. We have a rich tradition to build on. Cooperatives in the U.S. are commonplace - from food coops like Damariscotta's Rising Tide, and buying coops like Ace Hardware to farmer's cooperatives, credit unions, rural electric cooperatives, municipal utilities and more.