The Housing Health and Safety Rating System (HHSRS) used in England and Wales describes “excess heat” as a hazard involving threats to health from excessively high indoor air temperatures. The assessment looks at the likelihood of harm over the next 12 months to the age group most vulnerable to that hazard, rather than only the circumstances of the current occupier. This means agents and landlords should treat overheating as a property risk that may need to be assessed and managed, particularly where a home has known defects or features that make high indoor temperatures more likely.
Scotland and Northern Ireland do not have a direct equivalent hazard in their housing fitness standards, although overheating could potentially be considered indirectly where poor ventilation, design, disrepair or other conditions make a home unsafe or unfit to live in.
A growing risk for UK homes
A report from the Resolution Foundation states that, at current summer temperatures, around one-fifth of homes in England overheat. It also found that 36% of homes have attributes that put them at high risk of overheating in future, with poorer households particularly exposed: 54% of the poorest fifth of English families live in homes liable to get too hot, compared with 18% of the richest fifth. The Climate Change Committee has warned that 92% of existing homes could be at risk of overheating by 2050.
Legal and management responsibilities
A property becoming hot during a heatwave would not automatically amount to disrepair, but if excessive heat worsens pre-existing repair issues or property defects, such as broken windows, faulty ventilation, poor ventilation systems or other serious defects, it is important to investigate and arrange appropriate repairs within a reasonable timeframe. A heatwave does not remove a landlord’s responsibility to maintain a rental property and deal with repair issues that affect living conditions.
Agents should ensure repair reports are logged, vulnerable occupiers are identified where appropriate and lawful, contractors are instructed promptly, and landlords are advised where property improvements may be needed to reduce heat risk.
Local authority enforcement
Some local councils carry out proactive inspection programmes, but in most cases an inspection will follow a complaint from a tenant or neighbour, or a referral from agencies such as social services, the police, or a GP.
For Category 2 hazards, councils can decide whether enforcement action is needed. However, if a Category 1 hazard is found, the council is legally required to act. Less serious issues may be dealt with using an Improvement Notice, which formally requires the landlord to carry out work to reduce or remove the hazard within a stated timeframe. The most serious cases could result in emergency orders for remedial work or even the demolition of the property.
The Local Authority also has the discretion to charge a fee to recover costs reasonably incurred in taking enforcement action. The charge can include costs associated with inspection, deciding what action to take, the preparation and service of enforcement notices, and any emergency remedial action.
What causes a home to overheat?
There is no single cause. HHSRS guidance identifies several property-related factors that can contribute to excess heat, including:
- poorly insulated structures
- rooms directly below uninsulated roofs
- lack of ventilation
- high levels of solar heat gain through windows
- inadequate heating controls
- materials with low thermal mass that do not regulate temperature well
Older dwellings and properties with poor thermal insulation may experience higher heat levels in summer, while some modern homes can trap heat because higher insulation and airtightness prevent internal heat and solar gain from escaping.
South- or south-west-facing glazing, skylights, and large areas of glass can increase passive solar gain, especially where shading is limited. Lack of cross-ventilation, faulty ventilation systems, external noise, security concerns, fall risks from open windows, and limited control over heating or hot water in larger buildings can also increase the risk.
Who is most vulnerable?
Hot weather can affect anyone, but the health risks are higher for some occupiers. HHSRS guidance identifies people aged 65 and over as the most vulnerable group for the excess heat hazard.
It also highlights very young children, people with physical or mental health conditions, obese people, those on certain medications, people with mobility difficulties, those with cardiovascular, respiratory or renal disease, people with diabetes, people misusing drugs or alcohol, and those from lower socio-economic groups as being at greater risk. People who spend more time at home, particularly those with limited mobility and those who live alone, may also be more exposed.
The possible consequences are serious. The NHS warns that hot weather can cause dehydration, overheating, heat exhaustion, and heatstroke, and can worsen symptoms for people with heart or breathing problems.
Practical steps to reduce overheating
Agents can signpost tenants to the UK Government’s advice about keeping homes cool for general information on low-cost measures that can help, such as closing windows, curtains, and blinds during the day and opening windows at night when outside temperatures have fallen.
Property-level improvements may include:
- external shutters or awnings
- planting permanent vegetation around the property
- window tinting, deep window reveals, overhangs, brise-soleils,
- green roofs or photovoltaic panels
- lighter-coloured external surfaces,
- improved insulation and better cross-ventilation
- mechanical ventilation or air conditioning where windows are unlikely to be opened because of noise, pollution, security or fall risks.
HHSRS guidance states that passive approaches such as purge ventilation through openable windows and structural insulation should be considered before relying on more energy-intensive solutions.
Once installed, agents and landlords should also ensure ventilation and control systems are maintained in good repair and working order.
