Q+A with Justin McIver of Main Eco Homes

We asked designer and general contractor Justin McIver what he’s learned from building and living in his first net-zero model home in Sweden, Maine.

Photo courtesy Main Eco Homes.

 Q: How do you build a home that uses less energy than it produces?

• Build only what you need.
• Create a tight, well-insulated building envelope with controlled ventilation.
• Site for passive solar, and put living areas in southern exposure and bedrooms in northern.
• Reduce electric loads with an efficient electric heating system, LED lights, and Energy Star appliances.
• Include alternative energy sources such as photovoltaic solar.
• Live a low-impact lifestyle.

Photo courtesy Main Eco Homes.

Q: Which energy-efficient products performed best?
A: We were amazed by the Mitsubishi Mr. Slim mini-split heat pump’s ability to heat a 2,000-square-foot home located on a windy mountain, while using a third of the electricity of a normal baseboard. We were also able to save $10,000 on less expensive R5 triple-glazed windows by adding insulated honeycomb blinds to get to R10.

Photo courtesy Main Eco Homes.

 Q: Anything you’d do differently next time?
A: Instead of the backup baseboard heater I’d like to try connecting an inline electric heater and thermostat to the heat recovery ventilator (HRV). We’ve also found a double wall with recycled cellulose insulation to be a better, cleaner, and less expensive alternative to foam board and spray-foam layers. Lastly, the three floors provide more space than two people need, so the resources for the third floor could be used for a garage instead.

Photo courtesy Main Eco Homes.

Q: What’s next?
A: We’ll find out this year if the 6.8-kilowatt solar array is enough to get us to net zero. Our total energy bill in January was $149 and by May had gone down to $9. We expect to come out even with solar credit over the summer, but if needed, we’ll simply add more panels.

Learn more at Main Eco Homes.