A residential air conditioner has a straightforward job: remove heat from a house using refrigerant and release the heat outside, cooling down the air inside the house so it can then be spread through the rooms. This process is called heat transfer, in that it shifts heat from one place to another. A good way to think of it your AC is as a pump that pumps out the heat from your house to make you feel cooler.
But how much heat can an air conditioner pump out? What are the limits on how cool your air conditioner can make your house during a heat wave? You’ve come to right place for an answer, since we are a NATE-certified air conditioning contractor in Katy, TX who work with all types of systems.
The thermostat isn’t a good guideline for AC power
If you look at your thermostat or adjust the settings up and down, you’ll probably find the lowest you can set the thermostat is 60°F. This is too cold for most people! But it’s also not an accurate indication of the cooling power of the air conditioner. Let’s say it’s 100°F outside on a hot and dry day. Can you set the thermostat to 60°F and expect the air conditioner to remove enough heat from the house to make a 40°F change? Don’t expect it—because it can’t happen! This is where we run up against the cooling capacity limits of an air conditioner.
A residential AC can lower the indoor temperature a max of 20°F
The heat transfer capacity of an air conditioner can remove enough heat from a house to drop the temperature by 20°F. It can be set to do less, but it can’t be made to do more. The compressor and refrigerant that carry out heat exchange are unable to pump out the amount of heat necessary to go any colder.
So on that 100°F day, the maximum that AC could lower the temperature is to 80°F. This doesn’t mean you can’t have a cooler house on a day this hot, however: the indoor temperature may already be lower because effective insulation blocking the flow of heat into the house, and covering up windows prevents extra heat from getting in. So even on a 100°F day, you can probably get the AC down to a comfortable temperature of around 78°F. Use an indoor thermometer to tell what the temperature in your home is, and don’t lower the thermostat more than 20°F below that.
If you push your AC to cool beyond its capacity, what will happen is the air conditioner will simply keep running and running as it tries—and fails—to reach that thermostat setting. We advise keeping the thermostat set as high as you find comfortable rather than pushing it lower. This not only lowers strain on the AC and helps save money, it also slows down the movement of heat into the house.
If your current AC cannot keep your house cool enough, it may be time to have a new air conditioner installed. It’s either too small for the house or it’s losing cooling capacity from age. Our technicians can help you find an air conditioner that will maintain your home comfort.
At AC Comfort, your comfort is our business! Call us for any air conditioning service you need.