Why We Never Recommend Setting Your AC Below 70°F — From the Experts at Golden Rule

At Golden Rule Plumbing, Heating, Cooling & Electrical, we’ve been helping families stay cool during Iowa’s sweltering summers for decades. As HVAC experts, one of the most common questions we get from customers is: “How low can I set my thermostat in the summer?”

Here’s the honest truth: we never recommend setting your AC below 70°F.
And in this blog, we’ll explain exactly why.

1. Your AC Isn’t Built to Go That Low (Especially in Humidity)

Most residential air conditioners are designed to cool indoor air to about 20–25 degrees cooler than the temperature outside. So, if it’s 95°F in Des Moines (which isn’t uncommon in July or August), your AC is going to struggle—hard—to reach temperatures in the 60s.

Trying to push it that far can make your system run nonstop, drive up your energy bill, and create unnecessary wear and tear. We’ve seen it time and again in homes across Ankeny, West Des Moines, and Clive: systems burn out faster because they’re being pushed too hard, too often.

2. Lowering Below 70°F Can Freeze Your Coils ❄️

Another issue we see every summer in service calls across the metro? Frozen evaporator coils.

When your AC runs too long trying to reach an overly ambitious thermostat setting, condensation can freeze on the coils. When that happens, your system can’t cool the air properly. In fact, your home may start getting warmer, even though your system is working overtime.

Frozen coils are one of the most common summer breakdowns we repair—and they’re 100% avoidable.

3. Energy Bills Go Through the Roof

Let’s be real—nobody likes opening their utility bill in the middle of a heat wave. Setting your thermostat too low sends your energy usage soaring. Every degree you drop below 70°F increases your cooling costs significantly.

Instead, we recommend sticking with 72–76°F during the day, especially when you’re home. If you want it a bit cooler while sleeping, try 71–72°F, but keep it realistic. A programmable or smart thermostat can help automate these settings and save you money without sacrificing comfort.

4. You’re Not Getting More Comfort—Just More Problems

It’s easy to think that the lower the temperature, the more comfortable you’ll feel. But in reality, dropping below 70°F often creates the opposite effect. When your AC runs too hard, it short-cycles and doesn’t remove humidity properly—leaving your home feeling cold and clammy.

In Iowa’s humid summer months, dehumidification is key to comfort. A well-maintained AC system running at a moderate setting will do a better job keeping things balanced.

5. Your System Will Wear Out Faster (Trust Us on This One)

As HVAC professionals, we want your system to last as long as possible. But when it’s constantly running full throttle to hit 68°F, it’s going to wear out—fast. Compressors fail. Parts overheat. Air filters clog quicker.

We’ve replaced countless AC systems in Grimes, Johnston, and Pleasant Hill that didn’t even reach their full lifespan—just because they were overworked trying to chase unreasonably low temperatures.

6. The Golden Rule Way: Balance Comfort with Care

We believe in doing the right thing for our customers. That means giving honest advice—even if it’s not what you expected. It’s why we teach our techs not just to fix problems, but to explain them clearly and help homeowners make smart decisions.

Setting your AC at 70°F or higher ensures:

• Better energy efficiency
• Longer equipment life
• Fewer repairs
• More consistent comfort
• Lower humidity levels

And if your home still isn’t cooling properly at 72°F? That’s a sign something else may be going on—and we’re here to help.

Pro Tips from Our Team:

• Schedule routine maintenance. A clean, tuned-up system runs more efficiently and maintains proper temperature and humidity.
• Use ceiling fans. They help circulate cool air and let you set the thermostat a little higher without sacrificing comfort.
• Install a smart thermostat. It learns your schedule and helps balance comfort and savings automatically.
• Check your insulation. Poor insulation or leaky ductwork can undermine your AC’s performance.

Need Help? Call Golden Rule

If your system is struggling to keep up, freezing over, or costing you a fortune in energy bills, don’t sweat it—literally. Our licensed HVAC techs serve the entire Des Moines metro and surrounding communities, and we’re always happy to help.

Whether you need a seasonal tune-up, a system inspection, or a full replacement, you’ll always get honest advice and five-star service. That’s the Golden Rule way—treating you the way we’d want to be treated.

Call us today or book online to get your home summer-ready the smart way.