Symptoms
- One section of wall feels noticeably colder than the rest
- Draft felt when standing close to the wall
- Higher heating bills without an obvious cause
Likely causes
- CommonMissing or thin insulation in that wall cavitySome exterior wall sections, especially around outlets or corners, can have less insulation than the rest.
- CommonAir leak from outsideGaps around outlets, baseboards, or where the wall meets the floor can let outside air in.
- PossibleWall backs directly onto an unheated spaceA wall shared with a garage, attic knee wall, or crawlspace can run colder than interior walls.
What to do
- Feel around the cold area, including near outlets and baseboards, to locate the draft source.
- Add foam gaskets behind outlet and switch covers on that wall.
- Caulk any visible gaps at baseboards or trim along the cold wall.
- Consider a thermal camera or simple hand-check on a windy day to map the cold area more precisely.
- If the wall backs an unheated space, check and add insulation there rather than the interior wall.
- For a wall confirmed to have insufficient insulation, consult a contractor about adding insulation without removing drywall, such as blown-in options.
- Recheck the wall's temperature after improvements during similarly cold weather.
Tools and parts
- Caulk gun
- Foam outlet gaskets
- Flashlight
Outlet insulation gasketsSearch: “foam outlet and switch gaskets”
When to call a pro
Call an insulation contractor if the cold spot is significant and points to missing wall insulation, since blown-in options can add insulation without opening the wall.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.