Air Sealing Tips to Boost HVAC Efficiency This Summer

You can install the most efficient air conditioner on the market—but if your home is leaking air like a screen door on a submarine, you’re still losing money (and cool air).

In the Minnesota summer, where humidity joins the heat party, air sealing is one of the smartest ways to improve comfort and HVAC performance—without upgrading your entire system.
Here’s what homeowners should know about sealing the deal… literally.

Why Air Sealing Matters in the Summer
When warm air sneaks in and cool air leaks out, your AC works overtime. That means:

• Higher electric bills
• Hot spots and uneven temps
• Constant cycling and AC wear

In other words, your system is doing the hard work, but your home isn’t holding up its end of the deal.

Top Air Sealing Tips for Minnesota Homes

1. Focus on the Attic First
Heat rises, but in summer it also floods downward through leaky attic hatches and unsealed can lights. Sealing attic bypasses with spray foam or weatherstripping makes a huge difference.

2. Seal Windows & Doors
Use caulk around window frames and weatherstripping around doors—especially older wood frames that shift with Minnesota’s seasons.

3. Check Basement Rim Joists
In many older Minnesota homes, rim joists are big-time culprits for both winter drafts and summer leaks. Use rigid foam board + spray foam sealant.

4. Insulate and Seal Ducts
If your ducts run through unconditioned spaces like attics or crawlspaces, you’re losing cooled air before it ever reaches your rooms. Use mastic or UL-listed foil tape--not standard duct tape.

5. Schedule a Blower Door Test
Want to find out where your biggest air leaks are? A professional blower door test pinpoints leaks and shows where air sealing will have the biggest impact.

The AC + Air Sealing Combo = Peak Efficiency
Air sealing boosts your system’s performance in summer and helps:

• Keep temps consistent throughout your home
• Improve humidity control
• Extend the life of your air conditioner
• Reduce your cooling bills by up to 20%

And yes--Xcel Energy offers rebates for air sealing and insulation when done as part of an energy audit.

Get More from Your Cooling System This Summer
Air sealing is one of the most cost-effective upgrades you can make—especially before the full force of July hits. It keeps the cool in, the heat out, and your AC from working overtime.

Let’s take a look at your home and see where we can seal things up