What Temperature Should You Set Your Air Conditioner? A Room-by-Room Guide

What Temperature Should You Set Your Air Conditioner? A Room-by-Room Guide

Ever found yourself locked in battle over the AC remote - one person craving an Arctic blast, the other happy with a gentle breeze?

You’re not alone.

A 2023 YouGov survey found that 62% of Brits argue over thermostat settings at home.

So, what is the ideal temperature for your air conditioner?

This no-nonsense guide lays out the best settings for each room, backed by UK expert advice - so you can stay cool, save money, and (hopefully) avoid another thermostat standoff.

Let’s get into it…

Key Takeaways:

  • Recommended AC temperature in UK homes: 24–26°C for cooling

  • Lower settings = higher bills (and often less comfort!)

  • Bedrooms: Slightly cooler at night (18–20°C)

  • Smart thermostats: Boost comfort and efficiency

  • Maintenance matters: Regular servicing ensures peak performance

The Ideal Temperature for Cooling

The sweet spot for air conditioning in UK homes is 24–26°C, according to the Energy Saving Trust.

It’s the Goldilocks zone: cool enough to stay comfortable, but efficient enough to keep bills down and humidity in check.

Tempted to crank it lower during a heatwave? Think again.

For every degree below 24°C, your energy use can spike by up to 10%, according to National Grid.

And ironically, setting it too low can leave rooms feeling clammy rather than crisp, as your system struggles to balance temperature and moisture.

Pro tip: Set your AC to 24°C and pair it with a fan. The airflow helps you feel cooler without burning through more energy.

Room-by-Room Breakdown

Not every room needs the same treatment. Here’s how to dial in your AC settings for maximum comfort and efficiency, tailored to each space.

Living Room: 24–25°C

Your living room’s for relaxing, not freezing. A setting of 24–25°C keeps things comfy whether you’re hosting guests or glued to the sofa.

Got south-facing windows? Close curtains during the day to block heat gain.

Bedroom: 18–20°C

Cooler air helps you sleep better. The Sleep Council recommends 18–20°C for bedrooms, especially at night.

If your AC has a sleep mode (common on models from Mitsubishi and Toshiba), switch it on to gradually adjust the temperature as you drift off.

Home Office: 22–24°C

Too cold and you’re distracted. Too warm and you’re nodding off.

Aim for 22–24°C to stay sharp without the midday slump.

Smart thermostats, like those from Bosch, make it easier to hold that perfect range without constant tinkering.

Kitchen: 24–26°C

Kitchens run hot thanks to hobs, ovens, and boiling kettles.

Stick to the higher end of the range - 24–26°C - and position your AC away from direct heat.

How Temperature Affects Your Energy Bills

Dropping your AC by just 1°C can hike your energy use by 8–10%, according to National Grid.

That adds up fast - especially when cooling already makes up around 15% of summer electricity bills for many UK households.

Want to stay cool without burning through your budget? Try this:

  • Use fans to boost airflow and make 24°C feel cooler

  • Keep doors and windows closed while the AC’s running

  • Book regular maintenance to keep your unit running efficiently

Smart habits = lower bills, better comfort.

Using Smart Thermostats and Zoning

Smart thermostats - like those from Toshiba, Mitsubishi, or Bosch - let you control the temperature in each room with precision.

Paired with a zoning system, they go even further by allowing different settings for different areas without overloading your AC unit.

So while your bedroom stays at a sleep-friendly 18°C, your living room can coast at 24°C - all automatically. According to the Energy Saving Trust, systems like these can cut your cooling costs by up to 20%.

Pro tip: Connect your smart thermostat to a mobile app so you can tweak settings on the go - whether you’re in bed or out and about.

“A lot of people crank their AC to 18°C thinking it’ll cool the room faster - it won’t, it’ll just waste energy. Stick to 24°C and let your system do the work.” - Patrick Garner, Gas Safe Engineer at Heatable

When to Call in a Pro

If your AC’s blowing warm air, making strange noises, or struggling to hold the set temperature, it’s not just annoying - it’s a sign something’s off.

Issues like these often point to the need for servicing, recalibration, or even a refrigerant top-up. And the payoff’s worth it: regular maintenance can boost efficiency by up to 15%

Don’t sweat it - call in a pro. Your system (and your summer) will thank you.

Get Cool, Stay Smart

Finding the right AC temperature doesn’t have to be a battle. Stick to 24–26°C for most rooms, tweak for bedrooms and offices, and lean on smart tech to save energy.

Stay cool, Britain!

Next Steps For Your AC Journey:

When planning to install air conditioning for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:

To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos.

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FAQ's

For better sleep, set your bedroom to 18–20°C, as recommended by the Sleep Council.

No. Air conditioners cool at a steady rate regardless of the setting. Lower temperatures just increase energy use, as Patrick Garner notes.

24–26°C strikes the best balance between comfort and efficiency, per Energy Saving Trust guidelines.

Turn it off when you’re out to save energy. Smart thermostats can pre-cool rooms before you return.

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Last updated 25 Jul, 2025

Patrick Garner
Written by Patrick Garner

Patrick Garner, a Gas Safe certified engineer, leads the boiler installations team at Heatable. A wealth of experience, he has successfully overseen the installation of thousands of heating systems.

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