
Can Air Conditioning Really Heat Your London Home in Winter? Here’s How
You’ll be surprised how air conditioning can warm your home better than gas. Find out what most London homes get wrong and how to fix it.
RightAir Solutions is a company that specialises in commercial air conditioning services.
Most air conditioning systems cool the room by circulating the air already inside. Unless a unit is built with a fresh air intake or linked to a separate ventilation system, it will not pull in air from outside. This means while your room may feel cooler, the air quality might not improve. True ventilation involves moving stale indoor air out and letting fresh air in. That’s what helps with humidity, airborne particles, and that stuffy feeling. Across homes and offices in the UK, many people use AC thinking it’s helping with fresh air when it’s really just cooling down what’s already in the room.
Most air conditioners, whether wall-mounted or portable, are designed to control temperature and moisture. They don’t pull in fresh air. They cool the existing air by removing heat and some moisture, then circulate that same air back into the room. For households across the UK, especially those with more modern insulation, this means the air indoors gets trapped, often for hours.
A lot of people think that because a room feels cooler or smells better after switching on the AC, it must be ventilated. But that freshness usually comes from the built-in filters and the cooling effect, not from actual airflow from outdoors. Without a proper ventilation system, indoor air can become stale, and things like carbon dioxide, dust, and allergens build up.
If you want simple ways to improve airflow at home, check the NHS advice on how to ventilate your home.
Pro Tip: Even modern AC systems can make rooms feel stuffy. Try opening windows early mornings to balance comfort and airflow naturally.
Ventilation is about bringing in clean air from outside and pushing used indoor air out. This exchange helps with pollutants, smells, humidity, and overall air freshness. Air conditioning, on the other hand, cools and dries the air that’s already in the room. Unless it includes a dedicated mechanical ventilation feature, it doesn’t exchange air. So while you feel cooler, the air is not necessarily any cleaner.
Yes, there are. Mixed mode systems use both mechanical ventilation and natural airflow. You might see these in newer office buildings or eco-homes. Some have automatic windows or vents that open when carbon dioxide levels rise. These setups are often linked with demand-controlled ventilation systems that adjust airflow depending on how many people are in the room or what the indoor air quality is like.
The UK’s cooler climate means natural ventilative cooling works well here. Opening windows at night, using high-mounted vents, or setting up passive stack systems can lower indoor temperatures without the need for powered cooling.
For more on legal ventilation requirements, see Approved Document F on gov.uk.
Newer homes and workspaces are starting to use smart ventilation systems. These use sensors to check carbon dioxide levels or humidity, then bring in fresh air when needed. This helps keep indoor air quality healthy without wasting energy.
In cities where space is tight, building design can make a big difference. Some use tall ventilation shafts or narrow gaps in the structure that let warm air rise and escape, pulling in cooler air from below. Others use fixed louvres on the outside to let air in without opening windows too wide. These ideas are helpful where a standard ventilation system is hard to fit.
After COVID, people started paying more attention to indoor air. Hospitals, schools, and workplaces now use extra filters like HEPA and devices like UV lights to reduce germs in the air. More outdoor air is brought inside, even if it means slightly higher heating bills in winter.
Pro Tip: Don’t rely on the cooling sensation alone. Use a carbon dioxide monitor to check if your indoor air is actually being refreshed.
If the air in a room is not exchanged often, carbon dioxide builds up. Rooms with sealed windows and no fresh air can reach levels that make you feel drowsy or foggy. In the UK, studies show that in spaces with AC and no proper ventilation system, levels can rise above 2,000 parts per million. That is well above the level where people start to notice the effects.
Things like household cleaners, cooking fumes, dust, and even furniture can release tiny particles. Without airflow to remove them, they hang around and may trigger allergies or other issues, especially if someone already has asthma or a similar condition.
Try using a carbon dioxide monitor or air quality sensor to see what’s happening in your space. Air purifiers with carbon filters can help, especially if you can’t open a window often. Also, remember to clean or change your AC filters regularly. Dirty filters not only affect cooling but can circulate dust and other pollutants.
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RightAir Solutions
At RightAir Solutions, we provide air conditioning services to domestic and business customers for heating and cooling units. We also supply and fit commercial AC and HVAC services with our insured, qualified and experienced London team of air con engineers.