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A Glimpse Inside a Super Energy-Efficient Home at Belfast Ecovillage

One year ago, my family joined Belfast Cohousing & Ecovillage in Midcoast Maine and moved into a high performance house, with triple-pane windows and doors, large south-facing windows, lots of insulation from the slab to the attic, and a metal roof. Our home is heated largely by the sun, appliances and occupants, but a modest heating system is available as needed. Our heating bills are 90 percent less than a typical code-built home in the same climate.

It’s rare to have a house with so many energy-efficient features under the same roof. Many people have been curious about our home and asked numerous questions. These are some of the top questions we’ve received.

I’ve heard of mildew and air-quality problems in super energy efficient homes. Has this been an issue?

I’ve heard some concerning stories about super energy efficient houses without ventilation systems, and the mold and air quality issues that occur. Our home however has a Zehnder heat recovery ventilation system, which constantly supplies fresh air while removing stale air from our kitchen and bathroom. By utlizinging a heat recovery ventilation system, intake air is filtered, removing dust and pollen, then preheated from recycled heat from the exhaust air before it exits our home. Although we can boost the speed of our system with a switch in the bathroom or kitchen, the default mode is sufficient the vast majority of the time and we’ve had no mold or moisture issues in our bathroom and elsewhere.

If your house heats itself largely by the sun, appliances, and occupants, won’t it overheat in the summer?

It would seem that a home that stays so warm and cozy in the winter would overheat in the summer, but this is not our experinece. Last summer, the house was cooler than the outside temperature on hot days. For additional cooling, we opened the windows when the outside temperatures dipped at night. The heat recovery ventilation system helps maintain cooler indoor temperatures; when it’s warmer outside in the summer, our ventilation system pre-cools the incoming air from the exhaust air.

Given that Maine has a cold climate, how long is the heating season?

When viewing our home’s electric bills, I was struck by how low our energy usage was from April through October. Although we may experience below-freezing temperatures during April and October, our home typically remains in the upper 60s and low 70s, without supplemental heat. We turned our heat on in November and turned it off in March, trimming two months off.

What is the lighting like in your house?

Because the south-facing living room windows are 5 feet in height, lots of daylight comes into the home. Of course, our north-facing bedrooms get less ldayight. Even during cloudy days, we rarely use lights during the day, especially in the south-facing rooms. When the angle of the sun is lower in the sky during the winter months, sunlight fills the living room and helps keep the winter doldrums away. During the hot summer days, the angle of the sun is higher in the sky and less sunlight enters the home. The only downside to all our south-facing glazing is cleaning all the little fingerprints that appear from my two young children. We also use LED lightbulbs in most of our fixtures to reduce energy use.

What are the heating bills like for your new home?

Our home is all electric, therefore we don’t use wood, propane or natural gas, and receive only one energy bill. Before we installed a photovoltaic solar system, our largest electric bill was $120 for January for nearly 900 kWh of electricity. The summer electric bills were around $50 for nearly 400 kWh, because we don’t need air conditioning. Now that our home is net-zero and we have a solar system that generates all of our energy over the course of the year, we pay $9.75 monthly for the delivery fee.

 

Image Credit: Steve Chiasson