Do Air Conditioning Units Provide Cooling and Heating?

Most people live in temperate climates which means they need to cool their home in the summer and heat it in the winter. The most common way to achieve these ends is to have a furnace in the basement to heat the home in the winter and to install air conditioning units in the windows during the warmer months to keep things cool. While most everyone knows that it’s possible to install a centralized system that will take care of both jobs a lot of folks wonder if they can use their window unit, split system or even portable air conditioner to generate heat. Below we’ll take a look.

Can an Air Conditioner be a Heater?

The short answer is “Yes”. But, as we said, that’s the short answer. The longer, more complete answer is “Yes, in some cases.” But before we get into a detailed explanation of how such a thing can happen it might be helpful to give a bit of background on the air conditioner. From a purely technical standpoint any device that moves heated air (and just about all air qualifies as “heated” to some degree) from one place to another is considered a “heat pump”. Which means that your humble window air conditioner has been living a secret, second life as a heat pump without telling you. However, standard air conditioners won’t pump out air that’s hotter than the ambient air. They’d need to have a source of warmer air to do that and then some way to deliver that warmer than ambient air to your room. With a central air conditioning system that heat is provided by the boiler. But obviously there’s no room for a boiler in a window unit, split system or portable air conditioner. So where are some air conditioners getting this warmer air?

Turning the Temperature Tide

We’ve already established that some air conditioners can provide warm air in the winter but that there’s no room inside a small air conditioning unit for a boiler. These two facts then beg the question: where does the warm air come from that some units are able to provide? The answer is… the great outdoors. You see, in a common air conditioner air is sucked out of the room, the heat is removed from that air and that heat is expelled into the atmosphere, never to be seen again. The cooled air is then returned to the room. Some (not all) air conditioning units however come with a built in heating mode that, when activated, actually reverses the air conditioner’s mechanical system so that air is drawn in from outside, the heat is removed from that outside air and that heat is then blown into the room while the cooler leftover air is returned to the outdoors never to be seen again. Amazing!

Frigidaire Smart Window


Why Would Anyone Want to Use Their AC This Way?

Good question. Especially when you’re talking about window units. After all, keeping an air conditioner in the window all winter long is not a great idea. Window units don’t exactly fit with a vacuum seal and as a result vast amounts of heat can escape around them into the atmosphere. So unless you can find some way to bulk up the insulation around your window unit (and maybe you can) you might not want to choose this path as you’d essentially just be creating new heat to replace the old heat you’re losing by having the unit in the window. With split systems and small portable ACs however you’re good to go.That said, there are two main benefits of heating your room this way. One is financial, the other environmental, although the two are linked.

● From a financial standpoint you’re not using vast amounts of electricity to heat coils that will warm the room, as is the case with a conventional electric space heater. Nor are you burning expensive heating oil to generate heat. Because of this using an air conditioner with heating mode can be much cheaper than either the conventional space heater or boiler.
● From an environmental standpoint you’re not using vast amounts of electricity to heat coils and you’re not burning fossil fuels that contribute to climate change. Sound an awful lot like the financial reasons don’t they? That’s because the financial benefit and the environmental benefit are inexorably intertwined. You get to save money while saving the planet. Not bad.

Just keep one thing in mind: the air conditioner/heat pump setup will not provide the same level of heat a boiler can. If you come home to a house that’s 38 degrees you can crank up the boiler and be toasty warm in pretty short order. If you try and heat a room that’s less than 45 degrees with your AC unit you’re likely to be disappointed.