Heating

Advice on boilers, radiators, central heating systems and keeping your home warm and energy efficient.

Condensation Advice

23rd February 2024

Condensation is the result of water vapour in the air condensing when it comes into contact with a cold surface, which can become an issue. Read our advice.

For most of us, condensation during winter is as normal as endless rain and the occasional storm. However, condensation isn’t necessarily as harmless as it seems.

What is condensation?

Condensation is the result of water vapour in the air condensing when it comes into contact with a cold surface. In the winter, warm air in your house, especially your kitchen or bathroom, can deposit water droplets on cold windows and walls.

How can you reduce condensation?

The best way to avoid condensation is to keep the air moving around your home and reduce the amount of water vapour (humidity) in the air. The easiest way to do this is by ventilating your home properly. This means using your extractor fans when you are cooking or showering and keeping doors and windows open to allow a steady flow through the home. During winter, when your focus is on keeping warm air in, try to keep doors open as much as possible and open windows on warmer, dry days.

Dehumidifiers are an effective way of reducing condensation. There was a time where domestic dehumidifiers were limited to disposable ones or small ones, which aren’t incredibly effective. Now it is possible to buy relatively low-cost, high-volume dehumidifiers that you can keep on in your home all the time. These have the advantage of effectively reducing the moisture content of the air as well as making it easier to heat your home.

Can you prevent condensation?

Condensation prevention depends on its causes. If you are guilty of cooking or showering without using an extractor fan, then prevention may be relatively easy. Tempting as it is to hang your washing on your radiators to dry, this is a serious condensation-causer and can damage your décor, too. If you have to dry your washing inside, use a dehumidifier or invest in a heated, covered drying rack. At the very least, hang your washing in a contained space such as the bathroom with the extractor fan on.

However, if you live in an older house with after-build installed double glazing, you may need to look at a more structural solution, such as installing vents or additional extractors. A builder or damp specialist will be able to advise you of the best course of action.

If you feel as though your condensation is becoming a problem, for example if your walls and windows are always wet to the touch, if you notice damp patches on the walls, or you feel as though you are fighting a losing battle, it is wise to call a damp specialist. They will be able to assess your situation and determine whether you have a more serious damp problem.

Staying on top of home maintenance can be a challenge. At Trust A Trader we do our best to support you by bringing you expert advice and a directory packed with local, trusted traders. Follow us on Facebook or X for more.

Related tags

Looking for more heating advice?

Find clear, practical answers to common heating questions, helping homeowners understand everyday issues, know what checks they can carry out safely, and when it is best to contact a qualified professional.

What is the difference between a combi boiler and a system boiler?

A combi heats water straight from the mains on demand - no cylinder needed, which makes it compact and ideal for smaller homes or flats. A system boiler works with a hot water cylinder, storing a ready supply that can serve multiple taps or showers at once without the pressure dropping - better for larger homes with more bathrooms. There's also the conventional boiler, which needs both a cylinder and a cold water tank in the loft - common in older properties. A heating engineer can help you figure out which suits your home best.
Is an air source heat pump right for my home?

Heat pumps pull warmth from the outside air (even when it's cold) and use it to heat your home and hot water. They work best in well-insulated homes, ideally with underfloor heating or larger radiators that work well at lower temperatures. In draughty or poorly insulated properties, the benefits are more limited. The Boiler Upgrade Scheme currently offers a grant of up to £7,500 towards installation, so it's worth getting a professional assessment to see whether your home is a good fit before committing.
How often should a boiler be serviced?

Once a year, by a Gas Safe registered engineer. It keeps the boiler running safely, catches small issues before they become expensive, and is usually a condition of the manufacturer's warranty. Some home insurance policies require proof of regular servicing too. If you're not sure when yours was last done, book one before winter - better to find out before you're sitting in a cold house!
Why is my radiator cold at the top but warm at the bottom?

This issue is almost always trapped air. Bleeding the radiator - using a radiator key to release the air - usually sorts it, and it's one of the few heating jobs you can safely do yourself. If bleeding it doesn't work, or if several radiators are having the same problem, it might be a pressure or pump issue. Worth getting a heating engineer in to have a look.
What are the signs my boiler needs replacing?

Keep an eye out for: frequent breakdowns, energy bills going up without using more heat, unusual noises (banging, kettling, or whistling), a flame that's yellow or orange instead of blue, and any visible leaks or rust around the unit. If your boiler is over fifteen years old and ticking any of those boxes, replacing it is usually the more economical choice - modern boilers are significantly more efficient.
Is underfloor heating worth it and do I need a professional to install it?

For a new build or a big renovation, underfloor heating is often a great investment - it heats rooms more evenly than radiators and can be more efficient, especially alongside a heat pump. Retrofitting in an existing home is more of a job, and how worthwhile it is depends on your floor types and how much disruption you're happy to deal with. Either way - wet or electric - it has to be installed by a qualified professional.
Why does my boiler keep losing pressure?

Some pressure drop over time is normal, but if you're topping it up regularly there's usually a cause: a small leak in the system (which isn't always easy to spot), a pressure relief valve that's releasing water, or air in the system after bleeding radiators. Topping it up via the filling loop is fine as a short-term fix, but if you're doing it more than a couple of times a year, it's worth getting an engineer to look into why it keeps happening.

Have a question about TrustATrader?

If you have a question in relation to TrustATrader specifically, please check out the TrustATrader FAQs, with separate lists tailored to consumers and tradespeople. Alternatively, get in touch with our team. We're happy to help!

Read FAQs Contact TrustATrader