Do we really need roof vents?

The short answer is yes.

Roof vents are a necessary component of a healthy home. All attics require proper ventilation, no matter the season. There is a phrase among today’s builders; “Build tight and ventilate right”.

Soffit vents let air in and vents at the top of the roof let air out

Roof vents help prevent snow from melting on top of the roof, although there are other factors. Those include proper sealing between the house (conditioned area), and the attic (unconditioned area). The key phrase here is “Attic Bypass“. Proper insulation is important too. It is extremely important that the attic hatch is properly insulated, and that the insulation itself is even.

Homes need one square foot of roof vent for every 300 square feet of attic space, but pay attention to the type of vent you use. I never recommend power vents or turbine vents, because they create a vacuum in the attic, which might draw air from the house or exhaust vents such as clothes dryer, kitchen/bathroom fans and furnace exhaust.

Turbine vents, such as this, could create a vacuum in the attic


The best attic/roof vent setup involves roof intake and exhaust vents, working together to remove warm, moist attic air and replacing it with cooler, fresh, drier air. Soffit vents let air in and vents at the top of the roof let air out.

As a home inspector, I often find those soffit vents blocked by paint or dirt, or by insulation that has fallen into the soffit area from inside the attic.

A good spring home maintenance practice includes removing soffit vents and checking to make sure that incoming air can make it to the upper vents. If the space is filled with insulation, you will need to remove it and install (or re-install) air baffles, which are made from cardboard or rigid foam board. They provide a path from the soffit to the upper vents. They are stapled to the roof deck, and sometimes they fall down. This is a task that has to be done from inside the attic.

Replace the vent covers after cleaning them or replace them with new.