As the weather cools and the extreme heat of a few weeks ago dissipates; our second heatwave in the space of a month, you may be wondering whether you need to invest in making your home cooler?
The impact of climate change is only likely to make such extremes a more common occurrence.
Unfortunately, our UK housing stock is not built with the consideration of keeping cool. Usually, our biggest struggle is keeping warm. This is why most focus when it comes to improving the efficiency of our housing stock has been around insulation and more efficient heaters (think condensing boilers and heat pumps).
A quick fix?
Off the shelf portable air conditioners have been popular and are now (relatively) cheap to buy. However, with the cost of energy spiralling and this technology not being known for being cheap to run, is it cost effective to spend money extracting heat from our houses? Would it not be better to keep the heat out to begin with?
As the country tries to move away from fossil fuels, demand for electrical power from the grid will only grow. In reality, mass adoption of air conditioning only serves to further strain that infrastructure and is not a viable solution.
Where does the heat come from?
Most UK houses are built using heavy materials; brick, concrete and tile. These materials have a density which absorbs heat, storing this like a battery which allows heat levels to build during periods of prolonged clear and warm weather. Depending on how your home is constructed, the walls and roof can act as radiators, heating the home even if it is completely sealed to air and light.
Next you have solar gain; that is the radiating heat from the sun’s rays entering through your windows and other glazed surfaces.
Finally, you have airflow. Hot air on the sun facing side of your home can sometimes be warmer than the ambient internal air temperature, meaning opening your windows could be counter-productive.
A continental solution
For inspiration we need to look to countries who more typically have a warmer climate; those in continental Europe and even Australia.
Most European homes, or at least those in warmer countries, have some form of external window shutters. These range from the decorative hinged timber arrangements fitted to older properties to modern metal roller shutters. The latter is probably not all that appealing but certainly effective.
Unfortunately, external shutters will not be practical in most UK applications. There may be planning restrictions and from an aesthetic point of view, they are unlikely to be in keeping with the neighbours. Those familiar with Georgian and some early Victorian houses may be aware that many houses of these eras had built in window shutters. When not in use, these would fold away around the window opening. You can buy modern internal shutters for your non-period home these days too and these are popular and fashionable.
Less obstructive solutions are of course available. Awnings provide shade to windows and patio doors whilst not obstructing light or the view of the outside. They are expensive but certainly a worthwhile consideration for larger glazed areas such as bi-fold doors. If looking for a more contemporary aesthetic, louvred sunshades fixed to the building can also limit the level of sunlight to reach your glazing but again might require planning consent.
A cheaper alternative and something which homeowners could even attempt themselves, is fitting solar film to existing glass. These films allow through most visible light but filter out a high proportion of UV rays which not only reduces the solar heat gain, but can also protect your furniture from fading.
Insulation is still important
With the walls and roof acting as radiators, preventing that heat from radiating internally is equally important. Thermal insulation which is effective at keeping the heat in during colder weather, should be equally good at keeping it out; provided it is properly installed. The same applies to your roof or loft space which is why suggestions on the internet that you should open your loft hatch to give the heat somewhere to go are not to be recommended!
Investing in wall and roof insulation is therefore a great improvement to consider and will have the added benefit of helping with the heating bills over the winter.
Airflow
A final consideration is airflow. Changing the air in your home is good for your health but when the weather is warmer, it can be counterproductive to simply open all windows, as this may simply allow warmer air inside.
Countries such as Australia encourage homes to be designed to promote good airflow; capturing cooler air and driving it through the home.
With our current climate, it probably isn’t worthwhile investing in any substantial ventilation change or system for your existing home, but it is something that new-build developers or self-builders should consider.
For existing homes, a small change to consider is that a well-ventilated roof void can help to reduce heat gains from the loft void, giving the heat somewhere to escape to. It is an improvement which can also protect against condensation and timber decay during colder, wetter periods.
Final thoughts
With the cost of energy only set to increase in the short to medium term, improving the efficiency of your home is becoming more cost effective. Many simple improvements such as ventilation, insulation, and window shutters can be equally valuable during colder periods and help to reduce heat loss. Now is as good a time as any to consider them.
Adam Santos, Regional Chartered Surveyor at SDL Surveying