Does Attic Insulation Help in Summer? How to Maximize AC Efficiency and Lower Energy Bills

Does Attic Insulation Help in Summer? How to Maximize AC Efficiency and Lower Energy Bills

I was over at a buddy’s house last weekend watching some early season baseball on TV. Now, normally I’d be thinking about things like pitching, batting averages, and whether or not the Giants can make another World Series run this season. That afternoon was a hot one, though, and the temperature in my buddy’s living room was sweltering, even though his air conditioner was running. As an HVAC guy, I had my mind on one thing—the house’s attic. Specifically, I kept thinking about whether my buddy’s air conditioner wasn’t working effectively because of an insulation problem in his attic. Now, you might be wondering: does attic insulation help in the summer? Enough to make a major difference in whether an AC unit can quickly and efficiently cool the air in living spaces like the family room, kitchen, and bedroom? The answer to both questions is a hearty yes. As a responsible homeowner, it benefits you to know why insulation helps to maximize your AC efficiency so you can make an educated decision about whether it’s time to invest in attic insulation before the Sacramento summer sets in.

Does Attic Insulation Actually Help Block the Summer Sun’s Heat?

does attic insulation keep home cool in summerAn attic warmed by the heat of the summer sun beating down on your roof is doing both you and the planet a disservice. 
To understand how attic insulation helps keep your home cool in the summer months, you first have to be aware of the ways a poorly insulated attic can make your house hot. Roofing materials often absorb the sun, especially metal sheeting or asphalt shingles. This heat is then transferred through your wooden beams and into your attic. The heat that is passing freely into your attic will eventually begin to seep into the rooms where you spend your time—and this increase in warmth will mean your air conditioner has to run on overtime to cool your house, burning more energy than necessary. Not maximizing your AC efficiency is bad for the environment, and bad for your wallet. As we’ve discussed in the past, power companies like PG&E are raising energy rates throughout Northern California. An attic warmed by the heat of the summer sun beating down on your roof is doing both you and the planet a disservice. But the proper insulation in your attic can keep the heat out by helping to seal your home’s envelope and preventing temperature gains and air leaks, especially when combined with new windows that aren’t cracked or leaky. Many homes older homes weren’t built with energy efficiency in mind, and houses in the 20 years or older range may have been initially built with a sealed envelope that has since seen breaches. Either way, it’s well worth it for homeowners to invest in better insulation, starting from the top down.

How Insulation Helps Maximize Your AC Efficiency

I had a friend who moved to Northern California in July last year, and he was marveling at how, after two months of living here, he had yet to see a single cloud in the sky. Now, that all changed this winter. I’m sure you all noticed, but we had a few storms that affected sewers, plumbing, and many other parts of Sacramento homes. However, it’s pretty common in the summer months to go weeks on end without a break from direct sunlight around here. We live in a warm summer Mediterranean climate, which makes our summer months hot, dry, and often cloudless. Imagine how your roof feels, stuck in that sun day in and day out. If you guessed really hot, you’d be correct. Statistics from the Environmental Protection Agency suggest that the average homeowner can save as much as 15 percent on heating and cooling costs by investing in insulation. The fact is, there are plenty of benefits of improved insulation homeowners should know about, including:
  1. Decrease heat gains: Insulation can’t protect your roof from the sun, but it can ensure that the heat doesn’t pass into your home.
  2. Keep conditioned air in: Insulation also works to keep the cold air in the lower rooms of your home from escaping out.
  3. Maximize your AC efficiency: When outdoor air stays out, and conditioned air stays in, your air conditioner is able to operate at its peak efficiency.
  4. Lower your energy bill: This probably goes without saying, but if you use your AC less, your monthly power bill is bound to drop as well.
What’s worth learning more about, however, is how to pick the best insulation for your own Sacramento Valley home. A good installation expert is key in this process, but it helps for you, the homeowner, to be educated in the basics as well, so you’re always aware of what you stand to gain from improving your insulation.

Types of Attic Insulation for Hot Climates to Lower Energy Bills

The efficiency of home insulation is a science and so, of course, there’s a numerical system for measuring it. We track a material’s ability to resist heat transfer with something called an R-value. As insulation becomes thicker and more effective, the R-value goes up. Not all insulations, however, are created equal when it comes to lower energy bills—even if they have a solid R-value. Take a look at the two most common types of attic insulation for hot climates:
  • Pink fiberglass insulation: This pink-colored material is the most common type of insulation because of its affordable price and efficient R-values. However, it does have some drawbacks. It tends to settle as it ages, meaning it becomes less efficient over time. It’s also prone to rips and tears so if a critter gets into your attic it could cause leaks and a broken seal.
  • Injection foam insulation: This type of attic insulation is installed via liquid foam pumped into the various spaces of your attic, regardless of shape, hardening after several seconds. Its flexible nature means that there will be no area left unsealed. It’s a bit more expensive than pink fiberglass insulation, but the average lifespan of injection foam insulation is about 80 years, compared to 10 to 25 for fiberglass, which means you’ll spend significantly less money over the life of your home.
There are, of course, other insulation options on the market that may be the right fit, or fill, for your attic, and a trained insulation and HVAC professional can tell you all about them after evaluating your space. Every home is different, but one commonality they all share is that a well-insulated attic will make them easier to cool in the summer. You want your home to be welcoming to guests—especially during baseball season. Better insulation will make sure your house is the cool place to hang out this summer, pun intended. Invite your buddies to stop over and watch a few innings of baseball with you. Now that your AC is working efficiently, it’s your attic, not your guests, that will take the heat. Don’t forget about your attic when prepping for Sacramento Valley summer heat waves. The trained HVAC professionals at Bell Brothers can help you pick the right insulation to cool your home. Image courtesy Unsplash user Tom Thain