Prepping your home for a heatwave without full air con

You did not book air con this spring. The heatwave forecast is climbing. Here is the maximum cooling you can get without a fitted install, in the order that produces the biggest result.

Step 1 - close every south-facing blind at sunrise

The single biggest effect. UK houses get most of their heat gain from direct sunlight through south and west-facing windows.

Close every south-facing blind or curtain before 8am on any day where the forecast is above 24 degrees. Leave them closed until sunset.

That one change stops about 40% of a summer day’s heat gain. Every other tip is a rounding error compared to it.

Step 2 - open the windows on the north side

The point of closing south-facing blinds is not to make the house dark. The point is to keep the sun out. North-facing windows let in daylight without heat, so open them.

Cross ventilation - a north window open and a south window slightly cracked - moves cool air through the house. Works best early morning and after sunset when outside temperature drops.

Step 3 - stop running heat-producing kit inside

Every internal heat source adds to the load your house has to shed. In a heatwave:

• Do not use the oven. Air-fryer or microwave for anything cooked.
• Do not tumble dry. Line dry outside or in the garage.
• Do not iron. It waits.
• Do not run the dishwasher during the day - run it overnight when it is cool.
• Turn off screens and lights that are not in use.

Cumulative effect: keeps the house 2 to 3 degrees cooler by 6pm.

Step 4 - buy fans that actually move air

Small desk fans do not do much in a hot room. What works:

• Tower fans that move a large volume of air across the room, not blow directly at you.
• Pedestal fans set to oscillate across a seating area.
• Ceiling fans if you have them.

Rough spend: £30 to £60 per fan. Two fans in strategic positions beats one fan on your face.

Step 5 - the wet flannel and ice trick

For sleeping on the hottest nights:

• Damp cotton flannel on the back of the neck. Change out for a cold one every hour.
• Bowl of ice in front of a fan pointed at the bed. Creates evaporative cooling that drops perceived temperature 3 to 4 degrees for the first hour.
• Cotton sheets, no duvet. Even a thin duvet insulates too much on a 25-degree night.

Step 6 - portable air conditioner if you can find one

If the heatwave is going to run more than 5 days, a £400 portable air conditioner for one room (bedroom or living room) is worth it. Not glamorous, not efficient, but it works.

Buy it early. During a heatwave they sell out at Argos and Currys inside three days.

Vent the exhaust hose out of a window with proper window kit sealing - not open sash. An unsealed window lets more heat in than the portable removes.

Step 7 - shade the outside of the house

If the heatwave repeats every year, invest in external shading:

• Awnings over south-facing windows - £200 to £500 per window installed
• Reflective window film - £30 to £60 per window DIY
• Deciduous trees on the south side of the house - free, but takes years to work

External shade is far more effective than internal blinds because it stops the heat before it enters the glass.

What does not work

Two things every article recommends that do not actually help:

1. Placing bowls of water around the room. The water evaporates too slowly to have any cooling effect at UK humidity levels.
2. Spraying water on curtains. Same problem - evaporation rate does not match room heat gain.

The evaporative bowl in front of a fan works because the fan accelerates evaporation. Bowls alone do not.

The other option - book air con for next spring

If this summer feels like a battle every year, an autumn install of a fitted split system in the room you use most (usually a bedroom or living room) transforms the following summer. Prices in October are the same as in April but installer availability is better.

Fill in the quote form with your postcode and rough room count. Three fixed prices from vetted North West installers.

Or check the prices page for a rough bracket first.