Whenever I travel, I notice a distinct difference between traditional homes and our new high-efficiency home. Because I have lived in older, less-efficient homes for most of my life, it required a bit of adjusting when we first moved in. Our new home is heated primarily from the sun, occupants and household appliances such as the stove, refrigerator and hot water heater. Despite living in Maine, our home has no furnace and just a few baseboard heaters that turn on periodically. After living in the house for over a year, I've picked up a few tips on living in a high-efficiency house.
Our house has a solar orientation and relies on passive solar gains for heating during cool weather. With three very large windows and a door, most of our glazing is south-facing. It’s very important to have the curtains or blinds open to capture this free, clean and abundant heat source, especially during the middle of the day when the sun is strongest. Even during bright cloudy days, our home warms up without using the heaters. The windows also allow daylight to stream in, making supplemental lighting unnecessary most of the time.
Our house is virtually airtight. To maintain the indoor air quality, we rely on mechanical ventilation. Our home has a Zehnder heat recovery ventilation system that brings fresh air into the home and captures the heat before venting stale air out. These systems can recycle up to 95 percent of the heat and run by default, although occupants can boost the system to bring in greater quantities of fresh air when needed.
The intake air on our heat recovery ventilation system is filtered before it enters the home. We vacuum our filters every three months and replace them every six to 12 months. The filters are easy to access, making this a simple task.
Air filters have a minimum efficiency reporting value (MERV rating) between 1 and 16. Higher numbers correspond with a greater percentage of particles being captured through the filter. Ventilation systems that have air filters typically have different MERV rating options.
For people with pollen allergies or who live in areas with considerable air pollution, it’s recommended to use a filter with a higher MERV rating. Our heat recovery ventilation system has a MERV 13 filter available, which can remove auto emission particles, mold, pollen, lead dust and spores.
Many homes rely on exhaust fans to remove odors, moisture and fumes. Although they’re typically effective, they have some drawbacks. One potential issue is that they can create a negative pressure in the home because air leaves without the system, supplying intake air. Makeup air to equalize the pressure enters through cracks, holes and gaps in the building envelope.
In some cases, this can mean back-drafting your woodstove, fireplace and gas hot water heater or furnace. This causes fumes to enter the home, contaminating the indoor air. It’s most common with atmospherically vented combustion appliances. If your gas appliances are vented in this manner, follow these directions to test if it’s properly exhausting fumes.
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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