Whole house ventilation for high performance homes
Back in the good old days, home were so drafty they didn’t need insulation. Air leaked around windows and doors and wall seams. That’s why heavy drapes were used to help block air. Heat came from a coal or oil furnace, or a wood stove or a radiant heat system with a boiler. There was no air conditioning so homes were designed for airflow, and people opened windows and doors.
Fast forward to today’s green homes, where the goal is to build as tight an envelope as possible. With detailed air sealing and effective windows and door, some homes have less than one air change per hour without ventilation.
So if you’re building a new, high-performance home or remodeling your existing home, your building professional should be talking to you about ventilation.
A good quality bath ventilation fan can be a two-for-one solution for both spot and whole-house ventilation needs. Such a fan must be powerful enough to meet both the needs of the bathroom where it is located as well as the provide the level of air movement for the whole house. The amount of cubic feet per minute (CFM) or air volume needed for the whole-house component depends on the square footage and number of bedrooms in the home.
Keep in mind that a whole-house fan will run more often than spot fans, so consider the sound level of the fan, rated in sones. The lower the sones, the quieter the fan is. In fact, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 62.2 standard requires that whole-house fans be rated at 1.0 sones or less. No one likes to be awakened at night by a loud fan running in an otherwise quiet home.
Although choosing an Energy Star-qualified fan is always a good idea, it is even more important for whole-house fans due to their frequency of use. Some of the best fans on the market in terms of overall quality, quiet operation and styling are also the most energy efficient. Energy Star fans use up to 65 percent less energy than standard fans.
There are other options depending on your home such as a balanced ventilation system for the whole house, not just the bathrooms. There are heat recovery (HRV) and energy recovery (ERV) ventilation options to exchange stale indoor air with fresh outdoor air while reclaiming heat to reduce your heating and air-conditioning load.
These whole house solutions can help manage humidity as well, and save energy used for heating and cooling.
If you’re thinking about a high performance home, make sure ventilation is near the top of your list of things to talk about with your building professional.