How to stop draughts and cut heat loss: doors, windows, curtains and radiators

Find the draughts first

• around external doors, and along the bottom
• window frames and where opening windows meet the frame
• letterboxes and keyholes
• loft hatches
• gaps between floorboards and skirting boards
• unused chimneys
• holes where pipes and cables come through walls

Doors

• Gap at the bottom: fit a brush strip or a rubber-sealed draught excluder to the bottom of the door. A fabric draught snake works as a free stopgap.
• Gaps around the frame: self-adhesive foam or rubber strips stuck to the frame seal the gap when the door closes. Measure the gap first and buy a strip of the right thickness; too thick and the door will not shut.
• Letterbox: fit a letterbox brush or flap on the inside.
• Keyhole: a simple pivoting cover costs very little.

Windows

• Self-adhesive foam strips or rubber seals work for opening casements. Sash windows need brush strips designed for sliding parts, and older wooden sashes are often best left to a specialist.
• Fill gaps between the frame and the wall with a suitable flexible sealant. Rigid filler will crack as the frame moves.
• Secondary glazing film, applied to the inside of the frame and tightened with a hairdryer, is an affordable winter option for single-glazed windows. It is temporary but surprisingly effective.
• Do not seal trickle vents or windows that are meant to provide ventilation.

Curtains and blinds

• Close curtains at dusk to keep heat in, and open them in the day to let sunlight warm rooms.
• Thick or thermal-lined curtains help most. Make them long enough to reach the sill or floor.
• Tuck curtains behind radiators under windows, or shorten them, so they do not funnel warm air behind them and up against cold glass.
• A heavy curtain over an external door can make a big difference in a draughty hallway.

Floors, chimneys and lofts

• Fill gaps between skirting boards and the floor with flexible sealant, and gaps between floorboards with a filler made for the purpose.
• A chimney you never use can be blocked with a removable chimney balloon or draught excluder. Remove it before lighting a fire, and leave some ventilation to prevent damp.
• Fit foam strips around the loft hatch and consider an insulated hatch cover.

Make radiators work better

• Bleed them if they are cold at the top and warm at the bottom, which means trapped air. With the heating off and the system cool, open the bleed valve a quarter turn with a radiator key, holding a cloth underneath. When air stops hissing and water appears, close it.
• Check the boiler pressure afterwards. Many sealed systems should read roughly 1 to 1.5 bar when cold, but check your boiler's manual for the correct range. Top up using the filling loop if needed, following the manual.
• Do not block radiators with sofas.
• Thermostatic radiator valves let you keep rarely used rooms cooler.
• Reflective panels behind radiators on external walls may help a little, especially in older homes with uninsulated walls.

Do not overdo it: ventilation still matters

When to call a professional

• Rotten or badly warped window frames and doors
• Gas appliances, flues and boiler faults: use a qualified, registered engineer
• Cavity wall, loft or floor insulation at scale
• Persistent damp or mould you cannot trace
• Radiators that stay cold after bleeding, or pressure that keeps dropping, which can mean a leak