This summer is a good time to consider adding ventilation to your garage. More ventilation will improve air quality since attached garage air is finding its way into your home. Summertime heat often makes your garage a less than ideal place to visit.
Few residential garages are insulated, so they tend to be very hot and humid. Not only is the air hot, but quite often it has a myriad of smells and odors. Quite often it is the storage area for lawn equipment; the lawnmower smells of the last mowing, while fertilizers, weed killers and insecticide add their odors. Pool chemicals, paint, and adhesives are off-gassing in the corner. The cars parked inside add carbon monoxide and other fumes associated with the manufacturing of plastics and rubber.
The garage is perhaps the most contaminated space in your home. We might grow accustomed to the smells of car exhaust and insecticide, but many of the smells mentioned are actually mild to serious environmental emissions, called volatile organic compounds (VOC), which are known to cause cancer.
Installing garage ventilation can be fairly simple, similar to adding a kitchen or bathroom. Each home is different, so you have many options.
If your garage houses a gas water heater or the HVAC system air handler, consult with your HVAC contractor before installing an exhaust fan. While fans are relatively small, they can change the air pressure in the garage, interfering with the HVAC system. It could also cause the gas exhaust to be pulled back into the garage from the water heater stack.