This $0 Fix Cools Your Attic by 55°F. Why Don't Roofers Tell You?, by Candlelight Archives on YouTube. 15 min 50 s.
- Video length
- 15 min 50 s
- Time to do it
- 1 hour
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Stand outside and look along the soffits under the eaves. You should see slotted or perforated vent panels every few feet. If there are none, your attic has no intake and cannot breathe.
Go into the attic with a flashlight and check the eaves. Loose-fill or batt insulation is often pushed right against the roof deck, sealing off the soffit vents.
Rake or pull the insulation back about 2 inches from the roof deck at each soffit vent so air can pass up under it. Wear a dust mask and gloves for this.
Slide foam or plastic baffles between the rafters at the eaves. These hold the insulation back permanently and keep a clear channel from the soffit up to the ridge.
Check the ridge vent from outside. The slots should be open along the whole ridge, not covered by shingles, tarps or a badly fitted ridge cap.
Look along the ridge from inside on a sunny day. Daylight showing through means the vent is open. A solid dark line means it is blocked or was never cut.
Measure your vent area. A common rule is 1 square foot of free vent area per 150 square feet of attic floor, split roughly evenly between intake at the soffit and exhaust at the ridge.
Clear gable louvres, static vents and any vents blocked by stored boxes, boards or old insulation. Move stored items away from the airflow path.
Recheck on a hot afternoon. A well vented attic runs close to the outside air temperature. A gap of 30°F or more means air is still not moving through.
Tips and common mistakes
Fix the intake before adding any exhaust fan, or the fan will pull cooled air out of your rooms instead.
Never cover soffit vents with insulation to save a draught, because that traps heat and moisture in the roof structure.
Keep a gap between insulation and the roof deck at the eaves, since a stuffed eave is the most common cause of a hot attic.
Check your shingle warranty wording, as most manufacturers require proper ventilation for the cover to stay valid.
Questions
How do I know if my soffit vents are blocked?
Look under the eaves from outside for visible slots, then check inside the attic at the same spot. If you cannot see daylight through the vent, insulation or a baffle is blocking it.
Will clearing the vents really lower my cooling bill?
It can help, because a cooler attic pulls less heat down through the ceiling. The size of the saving depends on your climate, insulation levels and how blocked the vents were.
Should I add a powered attic fan?
Only after the intake vents are open and sized correctly. A fan in an attic with blocked soffits creates negative pressure and can draw your conditioned air straight out of the house.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
