The cooling strategies that don't cost £3,000.

Cooling is a stack. Skip the bottom layers and you'll over-spend on the top ones forever. The order matters more than the budget.

• 1. External shading on south and west glass; the single highest-leverage intervention.
• 2. Night purge ventilation; open the house up between 10pm and 7am whenever outside is cooler than inside.
• 3. Ceiling fans in living areas and bedrooms; 10W per fan, makes 26°C feel like 23°C.
• 4. Thermal mass behaviour; keep windows and curtains closed against direct sun during the day.
• 5. Then, and only then, mechanical cooling (split AC) for the rooms that still fail the comfort test.

Solar gain through glass is the dominant summer heat source in most UK homes. Once that energy is inside the glass, internal blinds simply re-radiate it into the room. External shading stops it ever entering; a fundamentally different physics problem.

External roller shutters, brise-soleils, retractable awnings, and even well-placed deciduous planting can reduce solar gain by 70–90%. Internal blinds, by comparison, manage 15–25% on a good day. The cost difference is real, but so is the effectiveness difference.

For listed buildings and conservation areas where external shading isn't permitted, reflective external film on the glass itself is the next best option. Internal blackout blinds are the last resort; they help with glare, not with heat.

A modern DC-motor ceiling fan uses 5–25W on full speed; about the same as a desk lamp. Through the perceived-cooling effect (moving air evaporates skin moisture and disturbs the boundary layer of warm air around the body), a fan makes a 26°C room feel like 22–23°C. That's the entire summer problem solved, for £150–£400 per fan and pennies a day to run.

Bedrooms benefit most. A whisper-quiet DC fan running through the night is the difference between sleeping at 24°C and sleeping at 27°C; far cheaper than the bedroom AC most homes don't actually need.

The reason fans aren't standard in UK homes is historical: we used to need radiators in those ceiling positions, and AC has dominated the recent retrofit conversation. Skip both and a ceiling fan is the simplest comfort upgrade in the house.

Some homes genuinely need mechanical cooling: top-floor flats, west-facing rooms with no external shading option, bedrooms where babies or elderly residents need guaranteed thermal comfort, and any room where opening the window means traffic noise or hay fever.

Before fitting AC, get the passive layers right anyway. AC sized for a shaded, fan-assisted room is half the AC sized for an unshaded room; meaning a smaller unit, quieter operation, lower install cost, lower running cost forever. The passive work pays for itself even in the AC scenario.