This is an energy recovery ventilator which runs 24/7/365 to bring fresh air into the house while recovering the energy in the air to essentially pre-heat the fresh air. It uses about as much energy as a CFL light bulb.
Because my heating requirements are so small, my house does not need a central heating system. Instead, we heat only the Great Room using an inexpensive wall-hung heat pump (see the previous blog post), and then use a small ducted fan system to move conditioned air from the Great Room to other rooms. Heating only a single room in a 1,650sf house only works in a house like mine with a highly efficient thermal envelope. A conventionally built American home – even a new one built to meet code – loses so much heat through the exterior walls and ceiling or roof that it can only be kept comfortable by distributing heated air to every room.
Last winter, I used a heat gun to measure surface temperatures all over my house. What I found was that the interior surface temperature of my exterior walls was exactly the same as the air temperature, throughout the house, on both floors. This is possible because of the super-insulation and the air-tight envelope. My European windows get slightly colder than the air but still stay within 7 degrees of the air temperature on a 14 degree winter day. This means that winter-time window condensation is a thing of the past because the glass never gets cold enough to reach the dew point temperature.
Air-tight homes need mechanical ventilation to achieve high indoor air quality. By choosing to ventilate mechanically, we are able to bring exactly the right amount of fresh, filtered air into the house, allowing occupants with allergies or asthma to live symptom-free at home. We built a similar home in Ridgefield for a couple with allergies who described how wonderful it was to come home, shed their allergen-contaminated clothing, take a nice shower, and then enjoy life, symptom-free. There is no secret to doing this. In fact, the first home I built fifteen years ago was an American Lung Association-certified Health House, which pioneered the same strategies.