A warm spell can turn an uncomfortable room into a health risk. The Government’s current hot-weather guidance says heat can worsen existing conditions and, in some cases, be fatal. Homes do not all respond to heat in the same way: top-floor flats, rooms with windows on only one side, and properties with large sun-facing windows or little shade can be harder to keep cool.
For new homes in England, Part O of the Building Regulations sets requirements to limit overheating. Its scope is specific: it applies to new residential buildings, with technical guidance for designers and builders. It is not a retrofit rule that automatically requires every existing home to have shutters, air conditioning or a heat pump. Buyers and residents should check what was designed and installed in the particular building.
In an existing home, start with the sun. Close curtains, blinds or shutters on sunny windows before direct sunlight warms the room. During the hottest part of the day, opening a window may bring in hotter air; ventilate when the outside air is cooler, often in the evening or overnight, if it is safe to do so. Cross-ventilation can help where the layout allows air to move through the home. A fan can make a person feel cooler by moving air, but it does not reduce the room’s temperature.
For planned improvements, external shading can stop more solar energy reaching the glass than an internal blind. Trees and green spaces can provide shade and improve the local environment, but planting needs space, maintenance and time to mature. Reflective roof finishes may also help in suitable buildings, though owners should check building, lease, planning and heritage constraints before work begins.
Landlords and managing agents should take reports of recurring overheating seriously, especially where residents include people more vulnerable to heat. Keep a record of when and where rooms become hot, what ventilation and shading are available, and any advice already given. If someone becomes unwell in hot weather, follow NHS or public-health advice rather than relying on a property fix.
The practical starting point is to reduce heat entering the room, then release it when conditions allow. Further reading on GOV.UK: Beat the heat: keep cool at home checklist — https://www.gov.uk/government/publications/beat-the-heat-resources-for-hot-weather/beat-the-heat-keep-cool-at-home-checklist — and Approved Document O: Overheating — https://www.gov.uk/government/publications/overheating-approved-document-o.