Q&A: A Glimpse Inside a Super Energy-Efficient Home

Reader Contribution by Sarah Lozanova
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Just over a year ago, my family moved to a high-performance house in Belfast Cohousing & Ecovillage in Midcoast Maine. It has triple-pane windows and door, lots of insulation, large south-facing windows and a metal roof. It’s heated largely by appliances and occupants, but has a heating system when needed. Our heating bills are 90 percent lower than a code-built home in the same climate.

It’s rare to have a home that uses so many energy-efficient design elements under the same roof. Many of our friends and family members were curious about our home and bombarded us with questions. Here are some of the top questions we’ve received.

Question 1: Since Maine has a cold climate, how long is your heating season?

When viewing our electric bills, I was struck by how low our energy usage was from April through October. Although we certainly experience below-freezing temperatures during April and October, our home was staying in the upper 60s and low 70s with no supplemental heat. Our heating season began in November and ended in March, trimming a good two months off.

Question 2: I’ve heard of mold and air-quality problems in high-performance homes. Has this been a problem?

I’ve heard some concerning stories about high-efficiency homes without ventilation systems and the mold and air quality issues that ensue. Thankfully, our home has a Zehnder heat recovery ventilation system, which constantly supplies fresh air while removing stale air from the kitchen and bathroom. By incorporating a heat recovery ventilator, intake air is first filtered, removing dust and pollen, then preheated with heat from the exhaust air before it leaves our home. Although we can boost the 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 issues in our bathroom.

Question 3: What is the lighting like in your home?

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

Photos by Steve Chiasson

Question 4: If your home is designed to heat itself largely by the sun, doesn’t it overheat in the summer?

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

Question 5: What are the utility bills in your new home?

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

Sarah Lozanova is an environmental and health journalist with an MBA in sustainable management. She lives in a net-zero house in Belfast Cohousing & Ecovillage in midcoast Maine with her husband and two children.

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