5 reasons your home feels hot – and how to fix it before summer heatwaves

While a house that always runs hot can be fantastic in winter, they are a nightmare in the summer months, especially when heat waves hit.

This is worse if your home doesn't respond to efforts to cool it down – whether you are using internal AC or trialing some unusual methods for staying cool at home, a building that is constantly hot is usually a sign of more serious issues that need addressing.

Here, contractors and HVAC experts have shared the five reasons your home feels hot all the time and revealed how to fix it before the worst of the weather rolls in.

Reasons your home feels hot

Keeping a home cool in a heatwave should not be hard work if it is properly insulated and you have well-maintained AC systems. If you can’t keep cool indoors in excessive heat, there is likely a mechanical or structural issue to blame, experts begin.

These are the first five things to check.

1. Your AC air filter is clogged

If you have an AC unit and your home still feels hot, the issue could lie in your AC filters, begins Melanie Powers, president at Goodberlet Home Services. If you have not recently cleaned an air conditioning unit or replaced the filters, the likelihood is that they are clogged, preventing the flow of cool air and reducing your unit's efficiency, she explains. This is a simple fix, and can often be done yourself. For more serious servicing, however, call a professional to check over the unit for any signs of serious wear or damage.

2. Your AC is not right for your home

Just because you have an AC unit installed does not mean that it is the best one for your home, warns Melanie Powers, HVAC expert. With so many air conditioning types to pick from, this is an easy mistake to make, she says. A unit that is the wrong size, make, or even age can all have an impact on how hot your home feels:

‘Your unit might be the wrong size. You don't want to go too big because it won't remove the humidity, and you don't want to go too small because it will not adequately cool,’ she explains. An HVAC professional will be able to advise you on the correct style for your home.

Even if your AC is the right size it could simply be too old to be effective, adds Patrick Garner, heating engineer at Heatable:

‘One common culprit could be an old or inefficient air conditioning system. These aging units can struggle to keep up with the summer heat. Regular maintenance, like cleaning filters and checking for refrigerant leaks, can boost efficiency. Yet if homes are still using a very old model, it's probably worth replacing it.

‘In fact, replacing an old inefficient model with a modern energy-efficient one can save you as much as 40% on cooling costs to cut energy bills.’

3. Your home is badly insulated

We usually associate insulation with the winter months and the need to keep a home warm all day. However, it can play a big role in keeping heat out in summer, explains Patrick Garner, heating engineer:

‘Poor insulation is another major cause, with insufficient insulation letting all that lovely cool air escape and inviting the heat in. Homeowners can save an average of 15% on heating and cooling costs by adding insulation in attics, floors over crawl spaces, and accessible basement rim joists.

‘And don’t forget about those sneaky gaps around windows and doors,’ he adds. ‘Unsealed cracks let warm air sneak in and cool air escape. Sealing these with weather stripping, available at Walmart, or caulking can make a big difference with homes willing to seal leaks able to make their homes as much as 20% more energy efficient.'

4. Your air ducts are damaged

If your AC is working, ideally suited to your home, and your insulation is top notch but your home still runs hot, it could be a hidden issue with your vent work to blame, suggests Melanie Powers, HVAC expert.

When cleaning your HVAC system, check the vent work for damage, and ensure that they are not covered up by furniture or window treatments, Melanie suggests. It could be as simple as resituating a sofa or two, but there may be more serious issues that need repairs by a professional.

5. Your home is in direct sunlight all-day

Sometimes, it is not our actual home that is the problem, but its location, Becky Lane, home energy efficiency expert and CEO of Furbnow, points out:

‘Another mistake people make is by not opening up their minds beyond the shell of the home. If you think outside the box – quite literally, you’ll discover that ‘Shadescaping’ - the act of landscaping around your home to shade the property – keeps it cooler while also reducing water and energy consumption,’ she explains.

‘Growing plants and the best trees for close to a house around your property line and by windows can offer the most shade and stop the sun’s rays from beaming inside. An extra benefit is the beautiful dappled effect of pattern cast from shadows too,’ she adds. ‘However, plant them too close and you can risk the roots posing a threat to the property foundations so to shadescape effectively you must consider what these trees and plants will look like and how big their roots are in years to come.'

No matter how good your home cooling system is, it is always a good idea to take note of the expert tips for handling extreme heat at home, especially as the summer temperatures climb year on year. If your home ever becomes uncomfortably hot, it is always best to go somewhere more manageable for the short term, even just the day, to protect your health (especially the health of the very young or elderly) while looking for longer-term solutions.