17 Aug

How to keep your house cool during a heatwave

Maintaining a cool temperature starts with a building’s design. Known in the architecture world as ‘passive cooling techniques’, there are ways to ensure a home feels comfortable when temperatures become stiflingly high.

During a heatwave, it is tempting to switch on the fans and set the air conditioning units up high. However, when the electricity bills come through the door, and you realize how much energy you’ve used, the need to consider environmentally friendly alternatives becomes apparent. In recent years, temperatures in the UK have been reaching uncomfortable highs, and this extreme heat is sure to have consequences for the way we build our homes. 

Most architects working in warm or tropical climates will adhere to passive cooling strategies when designing a building. Passive cooling is a building design approach that focuses on heat gain control and heat dissipation to improve the indoor thermal comfort without the need for high-energy air conditioning systems. Essentially, the aim is to minimize heat gain and maximize heat loss. 

During a heatwave, buildings are exposed to excessive sunlight during the day, which warms the roof, floors, walls and windows in particular. In principle, it is essential to minimize heat gain through these four elements, which architects can do using several methods. Then, by maximizing heat loss, the building can be cooled down in many ways, like choosing a specific orientation, proper space planning or encouraging active air movement throughout the house. 

Here, we explore some of the different techniques that can help keep a house fresh and avoid the need for energy-intensive air conditioning…

Creating more shade

One of the most effective methods is to shade windows, walls and roofs from direct solar radiation. Add shade with extended overhangs, eaves, slatted or louvred shades in light colours, and recessing windows into the wall. 

When designing the layout, try to position living areas towards the north side of the property. Remember, during the summer, the sun is positioned higher, and sunlight will hit your house in different places than it would during the winter. Additionally, main living spaces can be positioned in parts of the house near tall trees, pergolas, or garden walls, which provide natural shade. 

Making use of natural ventilation

Windows, roof vents and door openings can play a crucial role when it comes to encouraging indoor ventilation. Airflow in buildings is a complex subject, and different concepts will apply for each property. To achieve adequate ventilation, place openings such as doors and windows at different pressure zones (pressure zones are created via numerous air gaps or void spaces in the exterior wall, roof and wall partitions which lead to airflow paths). You can also enhance natural ventilation by including high areas, called stacks or wind towers. 

With openings at the top of the stacks, warm air can escape, and cooler air draws in from openings nearer the ground. Our timber roof lanterns create a similar effect, with thermostatic air vents and increased ceiling height, warm air pulls up and out. 

The courtyard effect

A courtyard is a highly effective way of keeping the inside rooms feeling cold and comfortable. With the main living rooms surrounding an external courtyard, the fresh air from the ground level flows through the openings of the rooms to create an airflow. If the roof surfaces are sloped downwards, towards the internal courtyard, the cooled air sinks into the court and enters the living spaces, with warmer air leaving through openings at a higher level. This arrangement also offers shade, and protection from warm breezes which hit the building at the side. 

Earth air tunnels

At approximately 4m below the ground, the temperature remains cold and constant. Wine cellars and basements are an excellent example of underground spaces colder than the rest of the house. One passive cooling technique is to include an earth air tunnel, which can be in the form of a pipe, embedded at a depth of 4m below the ground. Air flowing through the tunnel and up to the house will often be chilled in the summer, and warm in the winter. 

Using water to encourage evaporative cooling

With evaporative cooling, the heat in the air evaporates water, which reduces the temperature inside the building. It is a particularly useful technique in hot and dry climates, where the atmospheric humidity is low. Sometimes, a body of water such as a nearby pond, lake, or fountain in the garden can provide a similar effect. However, the most used system is a desert cooler, which consists of evaporative pads, a fan and a pump. 

Roof pools and ponds

Rooftop pools can be a rather lavish passive cooling technique that reduces heat gain and makes use of water’s reflective qualities and increased heat capacity. The house is cooled by breezes coming off the water, which are created naturally by temperature variations between the water and the warm building. Large air wells in the roof above the pool can also provide further ventilation.

A home with a pool on the roof helps to reduce the footprint of the developed space, leaving more room on the ground for natural landscaping and plants. Visually, houses with a roof pool look fantastic and have a real wow-factor. 

Choose the proper flooring material

If you don’t want to feel too warm inside your house, it’s best to remove insulating materials such as carpets, rugs and sofa pillows. The best flooring options are marble, sustainable hardwood, and stone tiles, like the products in our Westbury Stone Floors collection.  

Windows with solar reflective glass

During a heatwave, you may find yourself avoiding rooms with a high proportion of glazing. A solar reflective coating on the glazing works by bouncing solar heat off the glass and away from your house, helping things to stay comfortable.  At Westbury Windows and Joinery, we offer Sun Guard coating as an additional option. 

It is a neutral coating that lets in a high level of visible natural light while reflecting 65% of the solar heat, therefore reducing glare and UV inside the room. You can find more information about our energy-efficient windows here.

Westbury Windows and Joinery are specialists in crafting bespoke timber doors, windows, bi-fold doors and roof lanterns. Contact us here or book an appointment to visit our joinery workshop.