We don’t use air conditioning much during the summer because we prefer fresh air. During the winter, though, we have to close up and run the heat pump. What are some efficient methods to improve our indoor air quality now?—Mike N.
Rather than opening windows (which will make your heating system run more often), you can bring fresh air into your home in ways that don’t waste energy.
One option is to have your HVAC contractor install a fresh air damper system with a filter in the return section of your existing duct system. A small section of new ductwork leads to the outside. When you’re running the bathroom fan or range hood, the negative pressure created forces the damper open and draws fresh air indoors. When there is no negative pressure, the damper stays closed.
An even more efficient method to bring in filtered fresh air is a heat recovery ventilation system. The outgoing stale air transfers most of its heat (up to 80 percent) to the incoming cold fresh air during the winter, and vice versa during summer. Most models have their own duct system. Window models, similar to a window air conditioner, are effective for a single room, and they can often be controlled by a timer.
Controlling dust and humidity
But adding fresh air isn’t the only thing to do to make your home’s indoor air more pleasant during winter. You’ll also want to control dust and maintain proper humidity levels.
For better indoor air quality you can improve the performance of the air filter on your heat pump by replacing the typical fiberglass filter with a high-quality pleated media filter.
Room-size electronic air cleaners are effective for removing those tiny particles that pop up when you plop down in a chair. They don’t use much electricity and are quiet, so using one in a bedroom at night can be a big help.
You can also save energy and improve indoor air quality when you keep the humidity of the air in your home at the proper levels. This will allow you to set your heat pump thermostat lower by a few degrees and still be comfortable. You can install a heat pump-mounted central humidifier or use several room humidifiers. Both ultrasonic and evaporative types are energy efficient.
Adjust the humidifier dial
Get in the habit of adjusting the settings on your whole-house humidifying system according to changes in the outdoor temperature. As a general rule, the higher the outdoor temperature is the higher relative humidity percentage (30 percent to 35 percent) you’ll want to choose. To prevent condensation on windows as temperatures fall toward zero or below, choose 20 percent or 15 percent humidity levels.
James Dulley from the December 2015 issue.