How Does Attic Ventilation Work?North Houston is in Zone 2 of the IECC/IRC Climate Zones map. That means we live in a hot, moist climate, which is no news to any of us! Here in this part of the country, we use attic ventilation to keep our homes cooler. Our homes “expel solar-heated hot air to lessen the building cooling load.”

Up north, the main purpose of attic ventilation is to maintain a cold roof temperature while venting moisture; in fact, the mark of a well-insulated home in northern climates is the amount of snow that remains on the roof. If it melts, you’re losing heat.

True or False: 3 Things You Should Know About Attic Ventilation

Ventilation is all about air circulation. According to, 90% of all homes have “unreasonably high levels of moisture,” another statement that is an understatement in Southeast Texas! Fall/winter is a good time for HVAC (heating, ventilation, air conditioning) maintenance, and it’s important to understand if your attic ventilation is doing its job.

1. More is Better?

False. Your HVAC professional can tell you if you have the right amount of attic ventilation. It depends on the size of your heating/cooling unit, and if you don’t have enough, you’ll deal with decreased energy efficiency and more moisture. If you have too much attic ventilation, you may also have too much “roof penetration,” which can cause blowouts during a hurricane.

2. Attic Vents Are All I Need for Attic Ventilation

False. Certain types of vents actually trap air in the top of your attic.

3. Roof Vents Remove Wintertime’s Heated Air

False. Poor insulation is your most likely culprit if you’re losing warm air during cold snaps.

Unless your roofing system has insulation on the roofing deck and is designed without ventilation, your furnace should not be heating your attic. Worse yet, inadequate insulation is almost surely allowing moisture-laden air into your attic.

Let’s Look at the Air ‘Up There!’

Clean, healthy air circulation is important to all of us. Call Bradbury Brothers Heating and Air Conditioning, 281.651.5484/936.271.2030, for strategies that will enhance ventilation throughout your home and in your attic.