Stopping draughts makes a room feel warmer, but the air that leaked out also carried moisture with it. Here is how to seal the house and still let the damp air leave.
Draught-proofing is worth doing, but it removes some of the accidental ventilation that carried moist air out of the house. GOV.UK guidance says energy efficiency work must take account of the extra ventilation needed, otherwise the result can be damp, mould and poor indoor air quality. Seal gaps round doors, windows and pipes, but keep trickle vents open, keep air bricks clear and use extractor fans in the kitchen and bathroom.
The usual story is a cold, draughty house that gets sealed up and then starts to show water on the windows, a musty smell in the bedrooms or mould in the corners that was never there before. Nothing is leaking. What changed is that the moisture from cooking, showering, drying laundry and breathing has fewer ways out.
The Property Care Association says levels of excess moisture in buildings are on the rise and links this partly to tighter, better insulated homes and to draught-proofing. It also lists double or triple glazing and extra insulation as upgrades that can trap airborne moisture indoors. None of that is a reason to leave draughts alone. It is a reason to plan the ventilation at the same time.
Work down the list in order. The first four steps cost almost nothing.
We have not found published figures on draught-proofing or airtightness in Ashford homes, and we will not invent any. The point holds for a draughty period terrace in the town or a sealed newer house on the edge of it: the more airtight the home, the more the moisture depends on the vents and fans you deliberately keep. Before you seal anything, find out where your own home's ventilation comes from: purpose-made vents, or just the gaps you are about to close.
A dehumidifier does not replace a vent you have blocked or a fan that does not extract. It will not fix a leak, a failed gutter or damp rising from the ground, and the water from those sources has to be dealt with first. A Dryzen unit needs a loft to mount in, and it is not suitable for rental properties unless the landlord authorises the changes.
If you have sealed the draughts sensibly and the home still holds too much moisture, a Dryzen system is a loft-mounted dehumidifier with insulated ductwork to the central area or stairway. Each unit covers 150 square metres, extracts 12 litres a day and uses about 20 pounds a year in energy. It helps stop the conditions mould and dust mites need, and the app lets you monitor temperature and humidity. A free survey will tell you honestly whether it would help.
It can if the home loses the air it relied on to carry moisture out. GOV.UK guidance says energy efficiency work must take account of any extra ventilation needed, because some measures reduce overall ventilation rates and can lead to damp and mould. Seal the draughts, then keep trickle vents open and the extractor fans working.
No. GOV.UK guidance says existing air bricks should be kept clear and free of debris and obstruction, because they provide under-floor ventilation. If a draught is coming from a gap around a pipe or skirting, seal that gap instead.
It helps stop the conditions mould and dust mites need by lowering humidity, but it is not a licence to remove every vent. Keep the ventilation your home already has, fix any leak first, and treat the dehumidifier as the last rung, not the first.
Sources: GOV.UK: Understanding and addressing the health risks of damp and mould in the home; Property Care Association: Ventilation and condensation; Property Care Association: Condensation; Property Care Association: Condensation solutions
Last reviewed 2026-10-31. General guidance only; this is not a survey of your home.