Basement & Crawl Space Air Leaks: The Hidden Reason Your Upstairs Is Always Hot

May 22nd, 2026 by Marco Campos

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Hot air rises and so does air leakage. When your basement or crawl space leaks, your upstairs becomes hotter and harder to cool.

How Air Leaks in the Lower Levels Affect the Whole Home

AC runs longer
Second floors overheat
Humidity rises
Dust and odors travel upward
Energy bills spike

Why Spray Foam Works

1. Seals Rim Joists

The rim joist is the #1 source of air leakage in most homes.

2. Blocks Moisture From the Ground

Crawl spaces are humidity factories.

3. Prevents Hot Air From Entering the Living Space

Air sealing stops the upward movement of heat.

4. Stabilizes the Entire Home Envelope

Fixing the bottom fixes the top.

Signs Your Basement or Crawl Space Is Causing Problems

Hot upstairs bedrooms
Cold floors
Musty smells
High humidity
Uneven temperatures

The Bottom Line

If your upstairs is hot, the problem is almost always below your feet and spray foam is the fix. Call 1-855-591-2755 to speak with an Insulation Specialist to learn more about how we can keep your home comfortable all while saving you money today!