Midcoast Green
Collaborative

Houses without Heating Systems

Part 1

by: Paul Kando

The average Maine family spent five percent of its net income on energy in 1998. By 2008, energy's share has increased to over 20 percent. The forecast for expenditures is estimated to be over 40 percent by 2018. Factor in rising health care costs and the family in 2018 will have less than 25 percent of its income left for all other expenses, like housing, food, clothing, and education.

How is all that energy used? In Maine about 40 percent goes to heat homes. Another 50 percent is guzzled up by cars, and the remaining 10 percent goes for electricity. In addition to fuel for our vehicles, eight out of ten Maine houses rely on oil for winter heating. This makes for a near-total dependency on imported oil, the cost of which is simply removed from the Maine's economy. This is hardly sustainable. Furthermore, to avoid climate catastrophe due to human caused global warming, we must cut energy consumption by about 60 percent across the board.

The irony is that much of the energy we use is actually wasted. Based on the international Human Development Index (HDI), the United States has a standard of living roughly on par with other developed countries, such as Germany, Italy, France and England. Yet to achieve a similar HDI, the Unites States, alone among countries, per capita consumes more than twice the energy.

In other words, we are wasting over half the energy we use for no benefit whatsoever. There are no energy alternatives sufficient to cover such wastefulness. But there is enough renewable energy for mankind to live comfortably if we all cut out the waste. There is between 2 and 4 kWh per square meter of earth surface per year of renewable energy available wherever people live.

The easiest place to cut energy waste is in buildings, where proven, off the shelf technology can reduce consumption by as much as 90 percent, while improving comfort.

Passive house (PH) is an integrated building concept whose goal is to ensure the highest level of comfort using the least amount of energy. Measurements in over 32,000 homes and other buildings in all climates show that fuel consumption of PH is 75 percent to 90 percent lower than that of comparable ordinary buildings.

Their efficient ventilation system doubles as a heating system. No need for a costly boiler or furnace, separate ducts, piping, fans and pumps. Needless to say, using fresh ventilation air for heating will only work in buildings with a minimal heating load.

A PH uses less than 1.5 liters of heating oil per square meter (m2; about 0.039 of a gallon per square foot) of living space per year - far less than a typical low-energy building and about 1/15th of what the typical Maine house uses (similar energy savings have been demonstrated in buildings that require cooling).

Passive houses use energy sources internal to the building. Resident's body heat, waste heat from appliances and solar heat entering the building are captured and redistributed by heat recovery ventilation. Special windows and a highly insulated building shell keep winter warmth in and summer heat out. The ventilation system supplies a constant stream of fresh air, removing excess moisture and providing superior air quality without unpleasant drafts. A highly efficient heat recovery unit captures heat contained in the exhaust air and transfers it to the incoming fresh air.

Appropriate building components ensure consistently high energy savings even as they increase indoor comfort. Compared with a standard double pane, a passive house window reduces heat loss by over 70 percent. Insulation saves up to 90 percent of the heat lost through an external wall. An efficient heat recovery system reduces ventilation heat losses by 75 to 95 percent.

Renewable energy can cost-effectively meet the remaining energy demand, turning a PH into a zero energy structure. An energy balance calculation helps determine the level of insulation required in a given building in a given climate.