How to Heat Your Home With Air Conditioning in Winter

4 min read

Every modern split system is an air-source heat pump, which means the unit on your wall is also one of the cheapest ways to heat a room. Here's how to use it properly when the temperature drops.

Why heat pump heating is cheap

A plug-in electric heater turns 1kW of electricity into 1kW of heat. A heat pump moves heat from outside air instead of generating it, so the same 1kW of electricity delivers 3-4kW of warmth. That efficiency holds up far better than most people expect: modern Daikin units heat effectively down to -15°C outside.

The right winter set point

Aim for 19-21°C in living spaces. As with cooling, cranking the set point higher doesn't heat the room faster, it just overshoots. If the room feels draughty at the right temperature, angle the louvres downward: warm air rises, so sending it low fills the room evenly.

Don't panic about defrost cycles

On cold, damp days the outdoor unit will occasionally pause heating, run in reverse for a few minutes and steam gently. That's a defrost cycle clearing frost from the outdoor coil. It's completely normal, and the room barely notices.

Zone heating: the real money saver

The biggest win is heating only the rooms you're using. Working from home? Heat the office with its unit and leave the central heating off until evening. A single room heated by heat pump typically costs a fraction of firing the whole boiler-and-radiators system for one occupied room.

Want a straight answer about your home?

Free survey, honest advice, fixed prices. No obligation.