Comfort, Cost, Common Sense
What is comfortable? That depends on the season. We want to lose heat on a hot summer day, but in the winter we need the warmth of a heated room. On a hot day it feels good to have a fan blow air toward us, but we certainly don’t want that on a cold day. We sweat on hot days and the moisture we lose cools us as it evaporates. A hot, humid day makes us uncomfortable because saturated air doesn’t absorb our own moisture. But higher humidity in winter keeps us from being chilled by losing moisture. An energy efficient house will deliver year round comfort at a reasonable cost and also provides plenty of clean fresh air.
To make a house comfortable we must, first of all, control the flow of heat, air and moisture and, second, provide external energy as needed for heating, hot water, lights, cooking, and so on. Unfortunately the typical Maine house has it backwards: it relies on once-inexpensive fuels to make up for its failure to control heat, air and moisture flow. Most of our houses are under-insulated and leak air like a sieve.
Moisture moves around a house in the form of vapor until the air that has absorbed it cools. Then the vapor condenses, usually where we do not want it, like inside our walls, on the underside of our roof, on windows and doors, even on the surface of walls and ceilings. Liquid moisture causes mold problems and, over time, rotting of the structure.
Our challenge is to make up for such defects. But how? If all old houses were similar It would be easy to offer general advice. Alas they are not, having been built using one framing system, with maybe additions using another. The average Maine house loses over 1/3 of its heating energy through air leaks alone, but some houses leak more or much less. In some houses it is easy to access trouble spots, in others difficult. Where does your house fit in?
It would be foolish to build any new building but the most efficient — super-insulated, air-tight, without thermal bridges, with heat recovery ventilation and good windows. In existing buildings, the same principles must be tailored to each individual case. For this reason a common sense approach begins with assessing current conditions, followed by lining up what must be done and in what order. Only an energy audit can reliably provide this information, including how the cost of every step to be taken will be paid back from energy cost savings within a reasonable time.
It’s just common sense to treat our current heating bill – say the $2,500 spent on fuel last winter — as our “energy budget”. We can keep spending this budget (or more) on fuel year after year, or spend some part of it on measures that permanently reduce our fuel consumption. The longer we delay to “reprogram” our energy budget in favor of permanent improvements, the more energy and money we waste. Just common sense.