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Energy at home

Fixing damp and condensation


  • prevent water damage to your home
  • reduce the risk of mould
  • fix leaks in roofs, windows and doors

A build-up of moisture in the home can cause a range of problems and can potentially damage the fabric of the building if allowed to continue. And if mould starts to grow, this can even affect the health of the occupants.

Moisture can get into your home in several ways:

  • Rain can get in through leaking roofs, blocked or damaged guttering, leaky walls and poorly fitting doors and windows.
  • Leaks from plumbing faults, failed appliances and poorly sealed baths and showers can quickly build up, often where you can’t see them.
  • Ground water can rise up through the walls and floor if the damp proof course isn’t working properly.
  • We add moisture to the air all the time just by breathing, as well as from cooking, drying clothes, and from our pets and house plants.

If you have rain water getting in, or any internal leaks or signs of rising damp, then it’s important to get the problem sorted out quickly. You’ll usually need a professional to come in and advise you. Moisture in the air can cause problems too if it leads to too much condensation.

Managing condensation in the home

Moisture in the air will form condensation (droplets of liquid water) when it comes into contact with a cold surface such as a window. We all get condensation on our windows from time to time, but this isn’t necessarily a problem if it clears up quickly.

Problems start if the water builds up to the point where it starts to cause damage. And if it’s building up somewhere other than on the window, you may not notice until the wallpaper starts to peel, or black mould starts to grow. This is most likely to happen in places that are colder than the rest of the house, such as exposed corners or where there is a gap in the insulation, and where the air can’t circulate freely, such as behind furniture.

If you do have mould growing, it’s good to clean it off straight away to minimise any health risk, but you also need to fix the underlying damp problem to stop it coming back. If you don’t have any leaks or rising damp issues, then the problem is almost certainly condensation. There are several things you can do to help avoid problems in the future:

  • Reduce the amount of moisture produced in the first place by keeping lids on pans when cooking, drying clothes outside when possible, and if you use a tumble dryer, making sure it’s vented to the outside.
  • Ventilate so the moist air leaves the house – always use the extractor fan when you’re cooking, showering or bathing, leave any window vents open, and don’t block off any other vents.
  • Make sure air can circulate by leaving gaps between furniture and the wall.
  • Try to avoid cold spots – if there’s a gap between your wall insulation and your loft insulation, for example, try to get this fixed as it will attract condensation and possibly mould.
  • Consider adding more ventilation – this could be a new external vent in a problem corner, a new extractor fan, or even a whole house ventilation system if you need it.
  • Don’t fit any new draught-proofing in a room that already has a condensation problem, and if you’re getting a professional to fit insulation, draught-proofing or new windows or doors, ask them what they have done to check that ventilation will still be adequate.

If you experience condensation dampness in your home, watch our video explaining how you can reduce it.

Last updated: 5 August 2022