Air conditioning vs infrared heating - which is cheaper to run

Infrared heating gets sold as the modern answer to expensive gas. In some situations it is. In most it is not. Air conditioning on heat mode is cheaper to run for the same room, most of the time.

The two technologies

Infrared panels heat objects directly. The panel warms up, it radiates infrared light, the light hits people and furniture and warms them. The air itself does not warm quickly - the room feels warmer only when the objects in it warm up.

Air conditioning on heat mode is a heat pump. It compresses refrigerant, extracts heat from outside air, blows it into the room. The air itself warms up quickly, then everything in the room warms with it.

The running cost gap

A 1 kW infrared panel uses 1 kW of electricity to deliver 1 kW of heat. Simple electric resistance heating.

A 2.5 kW split air con on heat mode uses about 700 W of electricity to deliver 2.5 kW of heat. Coefficient of performance of 3.5.

Per unit of heat, air con is roughly three times cheaper. That gap holds across the entire mild UK autumn and much of a UK winter.

The moment infrared looks better

Infrared has three genuine advantages:

1. Instant warm. The panel is producing radiant heat within a minute. Air con air feels warm within a minute but the room takes longer to reach setpoint. In a room used for 15 minutes at a time, infrared feels warmer faster.
2. Bathroom-shaped. Small rooms with no obvious place to mount a wall split - a downstairs cloakroom, a small bathroom, a workshop - are exactly the shape infrared handles well.
3. No outdoor unit. Flats where the landlord refuses external kit. Listed buildings where planning refuses external kit. Anywhere the outdoor condenser is a non-starter.

Outside those cases, air con wins on running cost.

The install cost catches up

An infrared panel is £150 to £500 depending on wattage and finish. Wire it into a plug or an existing spur and you are done in an hour. Cheap upfront.

A single-room split system is £1,800 to £2,800 fitted. Ten to twenty times the upfront.

The upfront gap closes fast on running cost. A living room heated four hours a night for four cold months:

• Infrared 1 kW panel: about £115 for those four months.
• Air con 2.5 kW split: about £40 for the same four months.

A saving of about £75 per winter for one room. Two rooms, £150. Over a 12-year unit life, that saving pays back the install with plenty left over. And you get summer cooling as a bonus.

When infrared is the right buy

• Rented flat where you cannot fit a split. Buy the panel.
• Occasional room like a garage or workshop. Buy the panel.
• Bathroom you use for 20 minutes at a time. Buy the panel.

When air con is the right buy

• Living room used every evening. Buy the split.
• Master bedroom you sleep in every night. Buy the split.
• Home office you work in eight hours a day. Buy the split.
• Any room where summer cooling matters. Buy the split.

The wrong comparison

Do not compare a full air con install against a single infrared panel. Compare against enough panels to heat the whole room. A living room typically needs 1.5 to 2 kW of infrared to feel warm. That is two panels at £250 each - £500 of infrared kit before wiring.

Once you factor in enough infrared to actually do the job, the running cost gap is what matters, and air con wins.

Get real quotes

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