Choosing Ventilation Wisely
Over the years we’re building tighter houses that offer more comfort and more energy efficiency. Yet by creating a barrier and sealing indoor air in, we’re also creating a problem by sealing in moisture, chemical toxins, and cooking odors too.
Sure, opening a few windows can help in the short run. But what if the temperatures continue to fall well below freezing? Your comfort level is compromised in the process.
Even in houses that are built with the best building materials, careful consideration needs to be made when selecting mechanical ventilation. It’s a prerequisite for healthy occupants and a healthy building.
There are two basic types of mechanical ventilation: spot ventilation and whole house ventilation.
Spot ventilation removes moisture and pollutants at their source. You’ll find spot ventilation used in bathroom exhaust fans and in exhaust fans over the kitchen range. These exhaust fans come in a variety of sizes, styles, and price ranges. They offer control functionality ranging from a simple wall switch to sophisticated timers, sensors, or even humidistats.
Whole house ventilation systems are designed to remove stale air from the building and replace it with a supply of fresh air. These systems are more complicated and costly than spot ventilation system, but are also more effective.
Some whole house ventilation systems use the furnace fan to distribute air around the house. With these systems, the fan speed used for the heating and cooling process is probably too high for ventilation mode. A variable speed instead is more efficient, using less power for the ventilation process.
When designing your home’s ventilation system, a few simple rules apply.
First, your home should be air-sealed effectively, particularly when it comes to basements or garages, or other areas of your home where toxins and pollutants are common.
When selecting new building materials to bring into your home, always check to see their pollutant levels. Select low or no VOCs whenever possible.
Your ducts should also be evaluated from time to time, including if you have a major renovation in your home. The most efficient ducts are smooth, straight, and correctly sized. They are also sealed tightly and provide airflow where it’s desired. Ventilation ducts that pass through unconditioned spaces should be insulated. Duct joints should be properly sealed and evaluated regularly.
Exhaust ducts should always be vented outside, not into crawl spaces, basements, or attics.
How effective is the ventilation process within your home?