With the latest extreme heat currently sweeping many parts of the UK, households will be looking for simple and effective ways to keep their homes nice and cool. Whether you are working from the spare room, trying to sleep through a warm night or keeping the living room comfortable during the day, fans, air coolers and portable air conditioning units are likely to be our saving grace and can all make a big difference.
However, a question that often comes up during a period of hot weather is whether you should keep windows and doors open or closed when using them.
The answer depends on the type of cooling appliance you are using. Fans, air coolers and portable air conditioners all work in different ways, so the best setup for one is not always the best setup for another. Online bathroom, heating and kitchen retailer Plumbworld explains more.
The general heatwave rule
During the hottest part of the day, it is usually best to keep windows, curtains and blinds closed if it is warmer outside than it is inside your home. This should help to stop hot air and direct sunlight from heating rooms even further, making that feel really uncomfortable.
In the evening, overnight or early in the morning, when outdoor temperatures are cooler, opening windows can help release trapped heat and allow fresher air to move through the home.
A simple way to think about it is this: if it is hotter outside than inside, keep the heat out. If it is cooler outside than inside, let the cooler air in.
Using a fan
Fans are one of the easiest and most affordable ways to feel cooler in hot weather and there’s plenty on the market to choose from. However, they don’t actually lower the temperature of a room. Instead, they move air around, helping sweat evaporate from your skin and creating a cooling breeze.
During the day, when the air outside is hotter, windows are usually best kept closed while using a fan. Opening them in the middle of a heatwave can let more warm air into the room, making it harder to stay comfortable.
When the temperature drops later in the day, opening a window can help. A fan can then be used to move cooler air around the room or encourage airflow through the home.
Doors depend on what you are trying to achieve. If you want to feel cooler in one room, such as a bedroom or home office, keeping the door closed can help keep the airflow focused. If you are trying to move cooler evening air through the house, leaving internal doors open can help create a better flow.
Using an air cooler
Air coolers, also known as evaporative coolers, work differently from standard fans. They pull warm air through water-soaked pads, which helps cool the air before it is blown back into the room.
Because they use water evaporation, air coolers can add moisture to the air. This means they should not usually be used in a completely sealed room for long periods, particularly if the space already feels humid.
Unlike portable air conditioners, air coolers do not need an exhaust hose going out of a window. However, they often perform best when there is some ventilation.
You don’t need to leave windows wide open during the hottest part of the day, but a window opened slightly can help if the room starts to feel humid or stuffy. This gives warm, moist air somewhere to escape and allows fresher air to enter.
Internal doors are usually best kept closed if you want to keep the cooler air in the room you are using. Just avoid sealing the room completely for too long, as the air can start to feel heavy.
Using a portable air conditioning unit
Portable air conditioning units are the most powerful option because they actively remove heat from the room. Most use an exhaust hose to send warm air outside through a nearby window or vent.
For this reason, windows should be kept closed as much as possible when using a portable air conditioner, apart from the small opening needed for the hose. Any gaps around the hose should also be sealed where possible.
If the window is left wide open, warm air can come straight back into the room. This makes the air conditioner work harder, slows down cooling and can increase your running costs.
Internal doors should also be kept closed. Portable air conditioners work best when cooling one room at a time, such as a bedroom, living room or home office. Leaving doors open allows warm air from hallways and other rooms to enter, which can reduce performance.
The best way to stay cool
In most cases, keeping hot air and sunlight out during the day is one of the easiest ways to stop your home from overheating. Close curtains or blinds when the sun is shining directly through the glass, avoid opening windows at peak heat and use your cooling appliance in the room you are actually using.
Once the temperature outside drops, open windows on opposite sides of the home where possible to create airflow and release built-up heat.
By using the right setup for your fan, air cooler or portable air conditioner, you can stay more comfortable, cool rooms more effectively and avoid wasting energy during the hottest days of the year.
