Is air conditioning for a bedroom worth it?

How hot is too hot for a bedroom?

The standard used for new-home design in England is CIBSE TM59. It says a bedroom should not go over 26°C between 10pm and 7am for more than 1% of the hours in a year. The government's 2019 research points out that this limit comes from a small study in the 1970s, so it is a working rule and not a medical line. The same report estimates overheating could cut a good night from eight hours to six or seven. Source: GOV.UK.

What should you try before buying anything?

• Close blinds or curtains on the sunny side during the day.
• Open windows at night, if that is safe and quiet enough.
• Use a fan to move air across the bed.
• Move your bed to a cooler room for the worst nights.

In a study of converted lofts, night-time ventilation cut overheating by 89%. Plenty of people still cannot use it, because the same government research found over half of households sometimes feel unable to open windows, mostly because of security or noise. Sources: Li, Taylor and Symonds; GOV.UK.

Should a bedroom unit be fixed or portable?

Prices are Checkatrade's national figures for 12,000 BTU units. If you sleep lightly and own your home, fixed is the better long-term choice. If you rent, a portable is usually the honest answer. Source: Checkatrade.

What size does a bedroom need?

iHeat suggests 1.5 to 2.0kW for 10 to 15 square metres, and 2.0 to 2.5kW for 15 to 25. Go up if the room is under the roof, faces west or has a big bay window. A tall Leamington bedroom has more air to cool than the table assumes. Avoid buying far too big, as an oversized unit tends to switch on and off more often. The size guide explains why. Source: iHeat.

Will it stop you sleeping?

Set up properly, it should not. Choose a model with a low fan speed and check its quoted sound level at that setting. Mount it where the airflow runs across the room and not onto the bed. Consider your neighbours as well, since the outdoor unit must come in at 37 dB(A) or less at their nearest door or window to count as permitted development, and bedrooms in terraces are often close. Source: Grant UK.

What does a night cost to run?

Using Checkatrade's range of 20p to 60p per hour, eight hours comes to £1.60 to £4.80. Efficient modern units holding a steady temperature are likely to sit at the lower end or below it. At the Energy Saving Trust's typical cooling efficiency of about 7, 2kW of cooling takes about 0.29kW, or about 7.5p per hour at the current price cap rate. Sources: Checkatrade; Energy Saving Trust; Ofgem.