Can air conditioning units also heat a room?

We're converting the garage and wondering would a wall-mounted air conditioning unit work as the main heat source in winter as well as cooling in summer?

Asked by Carol on 6th Apr 2026
Expert Trade Answers
"Yes they are hate pump systems they cool and heat very efficiently"
Answered on 6th Apr 2026 - Member since Sep 2024 - report
"Yes, it will be efficient if you have good insulation."
Answered on 6th Apr 2026 - Member since Jul 2025 - report
"Yes they are great and very quick at providing heat"
Answered on 6th Apr 2026 - Member since Nov 2018 - report
"Hi Carol, yes air conditioning units both heat and cool your home. If installed and maintained correctly they are also very efficient way of doing so."
Answered on 6th Apr 2026 - Member since Jan 2026 - report
"Yes. If you do the research it can work out to be half the price of a heat pump. However I do not have any idea about running costs"
Answered on 6th Apr 2026 - Member since Dec 2025 - report
"Yes, a modern wall-mounted air conditioning unit with a heat pump function can work very effectively as the main heat source for a garage conversion, while also providing cooling during summer. These systems are energy efficient and can heat a well-insulated space quickly and economically, making them a popular option for home offices, gyms, or extra living areas created from garages. However, the unit must be correctly sized for the room and the conversion should have good insulation levels, as poor insulation can reduce heating performance and increase running costs in colder weather."
Answered on 20th May 2026 - Member since May 2026 - report
"Yes — a wall-mounted air-to-air heat pump (often sold as air conditioning) can work very well as a main heat source for a garage conversion, as long as the space is properly insulated. They’re efficient for winter heating and give you cooling in summer too.

Main things to check are:

Size the unit correctly for the room
Make sure insulation is good (walls, floor, roof)
Check performance in low outdoor temperatures, though modern units are generally good

A lot of people use them as the primary heat source in garden rooms and conversions."
Answered on 27th Apr 2026 - Member since Aug 2025 - report
"In short yes! An air con can heat a room very efficiently. More so than your heating can sometimes."
Answered on 24th Apr 2026 - Member since Jan 2024 - report
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