How to Prepare a House for a Heatwave

With the extreme heat warning, we give some suggestions for how to keep a house cool:

Short term/Quick/Easy:

• Open windows on the cooler side of the house.

• Vats of cold water near windows, outside or inside, will cool air as it enters.

• Create shade to windows – preferably externally – with an awning.

• Internally – black out blinds in the windows can help, as can white paper which reflects light.

• When external air temp is cooler than indoors, cross ventilate – open windows/doors on two or more sides of the house.

Mid term:

• Trellis to grow climbers up the external walls of the house shades masonry and keeps building cool

• Paint external walls white

• Solar film for windows reflects heat away

• Add shutters to East and West facing woindows and close east facing for the morning, and west for evening. This stops the early sunrise and late sunset from heating up your hosue with solar energy.

• Grow a lawn or wildflower meadow instead of using hard landscaping or astroturf – this is cooler underfoot and retains moisture in the ground

Long term:

• Grow trees and shrubs to create shade.

• Create an eaves projection of at least half a metre as this will shade windows and keep house cool.

• Insulation helps to keep a building cool as well as warm.

Results may depend on your building’s construction. Consult an expert for advice tailored to your specific situation – a PassivHaus qualified architect or engineer is a good start!

Quick Hacks for Hot Houses

 • Shade/Reflect

• Green gardens, walls and roofs

• Ventilate & Insulate

Use shading, reflective materials and colours to deflect light and prevent rooms from heating. Blinds are a quick fix, even white paper can help. Putting coverrings on windows externally is better than internally.

Use greenery, foliage and plants to maintain cool shade on external walls and in garden. Open windows/doors early in morning to get cool breeze, cross ventilate, and lower building temp.

Insulation and ventilation are key – these are dependant on many variables like building fabric, climate and window details.

Passivhaus design examines overhating potential as well as minimising heat demand in the winter, so you stay cool in summer and warm in winter.