Blowing Air In The Attic

Of clearance above the fan.

Blowing air in the attic.

Cellulose blown in ceiling insulation is a good choice for diyers. Put it in an attic full of blown insulation. Attics and heat the condenser in your air conditioner works hard to get rid of heat and pressurize refrigerant for the return trip through your house. Air sealing air leaks are a major cause of losing warm air.

1 the first is out of a white pvc pipe that has an odd section sticking straight up but it s completely open so the cold air is coming out of the top of that. Even if your roof already has ridge vents and plenty of ventilation built in it s a good idea to install gable fans or roof fans to help blow hot humid air out of the attic. A powerful fan draws cooler early morning and evening air through open doors and windows and forces it up through the attic and out the roof vents. Just make sure the ceiling is airtight and fully insulated and the temperature in the attic doesn t matter much.

Blown in cellulose is an environmentally friendly material made from recycled newspaper so it s easier on your skin and lungs. And you can blow it easily and quickly into odd shaped spaces in an attic where access is limited and dragging up batts is tough. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. Use expanding foam or caulking to seal any air leaks in your attic.

However with that understanding that creating negative pressure in the attic can cause all kinds of problems sucking out air from the conditioned space possible back drafting of combustion appliances etc he has come up with the idea to blow air into the attic instead i e creating positive pressure to force the hot air out. As the air leaves it creates negative pressure behind it sucking in cool air from below into the soffits and creating a self repeating ventilation process. Whether it s 110 f or 130 f there s not much difference in the amount of heat flowing from the attic to the living space below. If you have a complex attic with lots of ductwork bathroom fans and ceiling fixtures more air sealing will need to be done.

Handy homeowners can install blown in insulation in the attic. I went up into the attic to investigate and i did notice that in 2 places labeled with red arrows there is ice cold air simply blowing out from the air handler into the attic. These fans are commonly mounted in an upstairs stairwell or hallway ceiling where there s at least 3 ft. Blown in cellulose has a higher r rating and is less expensive than either blown insulation like fiberglass attic insulation or fiberglass batts.

Attic ventilation fans also tend to be quite energy efficient in terms of their own operation. Hot air exhaust vents located at the peak of the roof allow hot air to escape.