The Future of UK Homes: Overheating Risks, Climate Change, and the Need for High-Performance Windows

As climate change accelerates, UK homes are increasingly vulnerable to extreme weather events, particularly overheating during hot summer months. In recent years, we’ve seen record-breaking temperatures, and experts predict that this will only get worse. While initiatives like the

aim to address energy efficiency, the risk of overheating in existing housing stock remains a significant concern.

Our expert Vasilis Giannopoulos, Passivhaus Designer and Specifications Manager at Internorm UK, shares valuable insights on how climate change will affect UK homes, the associated risks of overheating, and how solutions such as high-performance windows and doors can help mitigate the issue. Drawing from recent studies, including reports from Arup and the Climate Change Committee, as well as key works like Adaptive Thermal Comfort – Principles and Practice by Fergus Nicol, Michael Humphreys, and Susan Roaf, the following explores the challenges and solutions for creating cooler, more comfortable homes.

In the early 2000s, a heatwave in Europe caused nearly 35,000 deaths in countries like France, Italy, and Spain. Fast forward to 2050, and heatwaves of that magnitude could become a bi-annual event for the UK. The Adaptive Thermal Comfort study by Nicol, Humphreys, and Roaf warns that extreme summer heat will soon be the norm, not the exception. What was once a one-in-100-year event will become a regular occurrence, particularly if global warming continues to follow mid-range scenarios.

The UK has experienced record-breaking temperatures in recent years, exceeding 40°C in some regions. With the Met Office predicting that these high temperatures could become average summer conditions by 2035, it’s crucial to understand how this will impact UK homes - especially as most are not designed to cope with such extremes.

A recent report commissioned by the Climate Change Committee and carried out by Arup explored the overheating risk in the UK’s existing housing stock. Through dynamic simulations of over 2,000 dwellings, the study assessed the impact of future climate scenarios on the overheating risk, using current and future weather data to estimate how UK homes will fare under warmer conditions.

Key findings of the report include:

• Current weather conditions: Nearly 55% of homes already fail to meet basic cooling comfort standards, especially in bedrooms.

• 2°C global warming scenario: By 2050, 90% of UK homes could be at risk of overheating, especially in urban areas like London.

• 4°C global warming scenario: This worst-case scenario suggests that all homes will require mitigation measures to cope with extreme temperatures.

In light of these findings, it is clear that urgent action is needed to make homes more resilient to heatwaves and overheating - particularly as smaller homes and flats are at higher risk.

Addressing overheating requires a multi-faceted approach. Key factors that influence overheating risks include wall insulation, roof insulation, and ventilation strategies. Surprisingly, some insulation methods can either exacerbate or mitigate the issue, depending on how well the building allows for natural ventilation.

Here are some common mitigation strategies for managing overheating:

1. Shading and Solar Gains Reduction

   Shading devices, such as external shutters and blinds, are highly effective in reducing solar gains, particularly in urban areas with intense sunlight exposure. However, in bedrooms, the effectiveness of shading during the night is limited due to the lack of solar gains.

2. Increased Ventilation and Purge Cooling

   One of the most effective strategies for reducing night-time overheating is increasing window opening areas to allow for purge ventilation. This process allows cooler air to flow through the home, lowering indoor temperatures. This solution works particularly well in homes with cross-ventilation, where air can naturally flow through multiple openings.

3. Passive and Active Cooling

   While passive cooling measures like ventilation and shading are essential, active cooling systems such as ceiling fans can also provide relief, improving comfort without significantly raising energy costs.

While passive design solutions like ventilation and shading devices are essential, the role of high-performance windows and doors in preventing overheating cannot be overlooked. Internorm windows and doors offer a premium solution for controlling both heat gain in summer and heat loss in winter.

Here’s how Internorm windows support the fight against overheating:

1. Enhanced Thermal Insulation

   Internorm's and windows, French doors, and are designed with advanced thermal insulation technology, reducing the amount of heat entering your home. This is crucial during hot summer months when external temperatures soar. These windows help maintain comfortable indoor temperatures, even when outdoor conditions are extreme.

2. Airtightness and Energy Efficiency

   Internorm windows are engineered for airtightness, preventing warm air from leaking out in winter and cool air from escaping in summer. This reduces the need for artificial cooling in warmer months, helping homes stay comfortable without relying heavily on energy-consuming air conditioning.

3. Solar Control Glazing

   Internorm windows come with solar control glazing, which significantly reduces solar heat gain. This makes them ideal for homes at risk of overheating in the summer, particularly in areas with high sun exposure or urban locations suffering from the urban heat island effect.

4. Sustainability and Comfort

   Internorm windows not only prevent overheating but also contribute to long-term sustainability. Their high energy efficiency reduces the need for active cooling systems, leading to lower energy bills and a smaller carbon footprint. Additionally, they improve overall indoor comfort by reducing draughts, preventing heat loss in winter, and maintaining consistent temperatures year-round.

5. External and Integrated Shading Solutions

   Internorm offers a range of for windows, doors, and large lift & slide doors, designed to enhance comfort, privacy, and energy efficiency. Choose from integrated Venetian or Duette® blinds protected between the panes of glass for a clean, low-maintenance finish, or external Raffstore Venetian blinds for effective solar shading and precise light control. Together, these solutions help reduce overheating, minimise glare, and create a comfortable living environment throughout the year.