Ventilation is very important when it comes to keeping homes cool. While air conditioning units can help to introduce cooler air and fans can help to circulate air, ventilation is needed to remove the warm, stale air from the home. Without this critical step, the air quality in the home will never be ideal and a constant battle must be fought against the warm air in the home that has nowhere to go.
Natural ventilation occurs when air moves into or out of a home through open windows, open doors, air leaks in seals, or passive vents that have been installed. Older homes often have many sources of natural ventilation. Unfortunately, natural ventilation is not easily controlled and air will move either in or out depending on whether there is greater pressure inside or outside of a home. This means that cool air will cycle out along with warm air and outdoor humidity and contaminants will be allowed in.
Spot ventilation helps to keep homes cool by removing heat from areas where a lot of heat is produced. Common examples of spot ventilation are dryer vents, attic vents, and range hoods. DIY spot ventilation can also be created by placing fans in windows. Spot ventilation adds a mechanical element to natural ventilation, which can help to overcome the issue of home pressure and force warm air out of the home. However, contaminants can still enter the home, cool air can still escape with warm air, and humidity is not controlled.
General Indoor Air Quality Ventilation
For homes with tight building envelopes or homes in warmer climates, general indoor air quality ventilation is the best option, as about 35 percent of the air inside of the home is typically dispelled every hour and is replaced by fresh air.
There are several different types of general indoor air quality ventilators, including energy recovery ventilators, ducted central exhaust fans, double-duty fans, and dehumidifying ventilators. General indoor air quality ventilators work best when the building envelope is tight and mechanical cooling methods are in place.
Combining Insulation and Ventilation
Insulating a home can help to prevent heat from leaking through a home building envelope. In the warmer months, this means keeping the hot air outside. While a mechanical ventilation system can help to dispel warm air from a home, that warm air can find its way right back into a home if it is not properly insulated. Combining insulation with mechanical ventilation can more effectively keep warm air out of a home.
Combining Ventilation and Air Conditioning
Running both an air conditioning unit and a ventilation system or a unit that performs both functions can yield much better results than only running one or the other. As ventilation systems remove warm air, air conditioning units cool the existing or incoming air. Using this approach to cool a home can help to save energy, as the air conditioning unit does not have to work as hard to cool the indoor air.