Insulation 101: Where Your Heat Is Escaping
You can have the most efficient furnace on the market, but if your home leaks like a sieve, you're heating the outdoors. Here's where most homes lose heat — and what to do about it.
The attic is the single biggest source of heat loss in most homes. Heat rises, and if your attic isn't properly insulated, it escapes right through the ceiling. The EPA estimates that adding proper attic insulation can save 15% on heating and cooling costs.
Air sealing is often more impactful than adding insulation. Gaps around pipes, wires, and recessed lights can collectively add up to a hole the size of a basketball in your home's envelope. Sealing these gaps is cheap and highly effective.
Windows and doors are obvious culprits, but the real villain is often the rim joist — the framing at the top of your foundation walls. It's frequently uninsulated and can account for 15–20% of your home's total air leakage.
A professional energy audit uses a blower door test to measure exactly how leaky your home is and pinpoint the worst offenders. It takes the guesswork out of where to invest your insulation dollars.
The average American home has enough air leaks to equal leaving a window open year-round.
- Start with the attic — it's the highest ROI insulation project in most climates
- Caulk and weatherstrip doors and windows every few years
- Check your rim joist in the basement or crawl space
- A blower door test (included in our audit) finds leaks you can't see
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