How to keep your house cool is a primary concern in the long summer months. Image: Shutterstock
The UK heat, as most of us will have noticed, is not like summers we’ve spent abroad. Countries where hot weather is the norm of thought long and hard about how to keep your house cool: air conditioning units, marble flooring and tiling, airy courtyards and other infrastructure all make the heat more bearable.
But Britain’s housing was built to insulate and to trap heat in, given our cold and freezing winters, not to let it out. When the summer then rolls around, many of us struggle to function in the heat.
Unless you’re pretty well off, most of us do not have air conditioning units at home. In fact, a mere 2-3% of Brits have any sort of portable or fixed cooling system in the home according to government data.
With global warming bringing more extreme weather, which includes record-breaking temperatures as witnessed last year when Britain was catapulted to a sizzling 40 degrees, many of us are finding innovative ways to manage in such high temps.
Bar wearing very little clothing, there are some things we can do cool our house and office in these very warm times, from DIY hacks, to more costly measures that will pay off in the long run.
Here’s how to keep your house cool as temperatures soar:
DIY air conditioning
You will have seen this trick do the rounds on social media, but it does help. Putting a shallow bowl or pan of ice in front of a fan means that as the air passes over the ice, it will be chilled and circulate through the room.
For optimal effect, you can use a bottle of iced water, with a damp towel on top, placed in front of the fan. It creates the same chilled effect, but it will have the additional benefit of circulating the moisture from the cold towel.
Close doors and seal gaps
You should close doors to rooms you aren’t using to keep cool air where you need it most. Seal gaps around doors and windows, and use draught excluders to ensure the cool air can’t escape.
But note that evaporative air-conditioners (which cools air through the evaporation of water) will be more effective if you open some doors and windows to increase air flow through the home.
Make sure your ceiling fan is blowing the right way
Those with ceiling fans might feel like it’s just rotating hot air from the room, and it might be the case. Which is why you want to set your ceiling fans to rotate counter-clockwise in summer, to push air straight down, helping to create a cooling effect and clockwise in winter to pull cool air up.
In warmer weather, set the fan speed high and in cooler weather it works best on low.
Change your light bulbs
If it feels like your house is especially warm at night, incandescent light bulbs might be to blame. These lightbulbs produce a lot of heat, so switching to energy-saving bulbs can help cool your home and save on energy costs.
Intuitively, most of us open the windows and doors during the day to let the breeze in. But on very hot days with nary a breeze, we’re just inviting the heat in. Windows are best kept shut.
So why not consider the alternative if you’re thinking about how to keep your house cool: ventilating at night? On cloudless days, such as in summer, the nights are cooler meaning you can open windows and doors to let some of the air in. This will also let you stay cool when you’re sleeping.
If it’s warmer inside than it is outside and you have sash windows, you can use them in a way that means more warm air will escape and let cold air in.
Jess McCabe, an editor at Inside Housing, shared on her Twitter that you can leave a gap at both the top and bottom of windows to let the air in.
She wrote: “Annual hot weather reminder that if you’ve got sash windows and open them equally at top and bottom you can enjoy some Victorian ‘air conditioning’ that ventilates and removes heat.”
And if it’s hotter outside than inside, like on exceptionally hot days, it’s better to keep those windows closed!
Start passive cooling
Adding shading and ventilation — sometimes called passive cooling — means you control how much heat reaches your home. You can do this internally, of course, where you close curtains and blinds, particularly in sun-facing rooms. But you can also consider external options.
Just make sure any external installations are robust enough to survive high winds.
We know to avoid wearing black or dark colours during summer because they absorb heat while lighter colours reflect the sun’s rays. So why not apply this to your home? The darker the surface, the hotter it’s likely to be, so invest in white roofs and/or exteriors for your home if you can.
Dark colours are a huge source of heating, particularly in urban areas such as cities. According to The Yale School of Environment, fresh asphalt reflects only 4% of sunlight compared to as much as 25% for lighter hues such as natural grassland, and up to 90% for a white surface such as fresh snow.
Researchers say that most of the roughly 2% of the earth’s land surface covered in urban development suffers from some level of urban heating. Cities such as New York, or London, which are likely to have less natural shading i.e trees, are found to be hotter compared to their countryside counterparts.
This is where white cover can come in. If we replaced lots of surfaces with white or other light colours, we could cool down cities. The Yale researchers say that “the systematic replacement of dark surfaces with white could lower heat wave maximum temperatures by 2 degrees Celsius or more.”
Invest in and campaign for ‘cool roofs’
While painting things white might be a DIY option for external cooling, you can also use technology that does the work for you. Cool roofs are designed to better reflect light and are a more permanent solution when thinking how to keep your house cool.
There’s also a campaign, the Million Cool Roofs Challenge, to install these in developing countries. They write: “One affordable, sustainable and effective measure that can be taken to improve cooling access is the use of cool roofs – installing coatings and materials on rooftops that reflect the sun’s rays and emit absorbed heat back into the atmosphere.”
Trees are natural solutions
We might not have AC units in the home, but we can still block how much heat gets inside.
According to the Department for Environment and Water in Australia, which deals with warm weather more frequently than the UK, you can: “Plant deciduous trees that cast shade over your home in summer, but still let the sun shine through in winter. If you can, invest in window tinting and top up your ceiling insulation – it’ll help keep the warmth in in winter, too.”
It’s a bit more long term but it’s worth considering if you own your own home or when you’re looking at the area when you rent.
This is the pricier of the options but can pay off in the long run, especially as our summers seem to get hotter thanks to global warming.
Retrofitting ducts, fans, and vents is a privilege that can make British summers much more bearable. But they are costly. According to Checkatrade, on average, the air conditioner installation cost for a small home office is between £1,750 – £3,000. For a double bedroom, you’re looking at an average air conditioner installation cost of £2,250 – £3,000.
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