Skip navigation

Serving The Fresno & Madera Area

70th Anniversary of Purl's Sheet Metal & Air Conditioning

Serving The Fresno & Madera Area


On Call 7 Days a Week


Purl's Sheet Metal & Air Conditioning Blog

Don’t Push Your AC Over Its Limits!

hand-setting-thermostatYou want to avoid HVAC repair in Fresno, CA as much as possible. Even though fall has now officially arrived, the Central Valley is still experiencing blistering hot days that can reach the 90s. Your home’s air conditioning system has hard work ahead, and if you aren’t cautious about running it, you may drive it into the ground and cause an expensive repair or replacement.

Your air conditioner has limits. For example, the AC can’t lower the temperature in your house to the point where water would freeze. (Not that you would want to.) To help you know how best to keep your cooling system running in good shape at the end of the season, we’re going to look at your central air conditioner’s cooling limits.

The 20°F Limit

Q: How much can an AC cool down a house?

A: By 20°F.

This is the way residential air conditioners are manufactured. No matter the cooling tons of an AC, if it’s properly sized for a house the maximum it can lower the indoor temperature is by 20°F. The compressor and refrigerant cannot draw out more thermal energy from the air to cool it lower.

So on a day when the temperature is 92°F, the AC can at the most lower the house to 72°F. This is a comfortable temperature! In fact, it’s lower than the recommended thermostat setting for energy savings, which is 78°F. This doesn’t take into account the house’s insulation, which prevents extra outdoor heat from getting indoors. So even when the temperature is 100°F outside, your indoor temperature will be cooler and the AC can still hit a comfortable target.

What Happens If the AC Is Pushed to Do More?

Imagine you lower the thermostat setting to 60°F (which is the lowest most thermostats will go) when the indoor temperature is more than 20°F higher. The AC cannot cool the temperature to that setting, so it will run continuously—like a person on a treadmill running hard to reach a spot ahead of them they can never reach. The air conditioner will waste energy and pack on the extra strain that can cause it to overheat and fail.

Besides, do you want your home to be 60°F indoors? Most people would find that temperature unpleasant. Aim for the warmest setting you find comfortable to help save energy and lower air conditioning stress.

Can I Get a More Powerful AC?

Not for a house. In fact, you don’t want one that’s more powerful. A residential air conditioner that can exceed the 20°F limit would need to be sending out frigid air. Not only would this drain immense amounts of power, it would make people near to the room vents miserable. You’d have uneven cooling with parts of the house far too cold. You don’t want to force people in the household to put on jackets when the weather outside is in the 90s.

If your air conditioner can’t keep up with your cooling demands, we advise you call our technicians. We can find out if the system needs to be repaired or replaced.

Call Purl’s Sheet Metal & Air Conditioning when you need HVAC repair: “Quality Is the Cornerstone of Our Success” since 1952.

Comments are closed.