Windows take more weather than any other part of a house. They face the wind, collect the dust, hold the condensation, and still get blamed when the heating bill climbs. A little attention at the right time of year keeps them working — glass clear, frames sound, sashes sliding — instead of turning every season into a negotiation with a swollen frame or a draught you cannot locate.

What follows is a working checklist arranged by season, with notes for cold, hot-humid, coastal and dry climates. None of it requires special tools. Most of it requires twenty minutes, a rag and a torch.

Spring: Undo the Winter, Then Look for Damage

Spring is for reversing winter, not preparing for the next one. Frost, grit and salt have been sitting in the tracks for months, and the first warm weekend is the right time to get them out before they work their way into the seals.

Start by taking the screens out and washing them flat on the ground with a soft brush and a garden hose. Then vacuum the tracks — a crevice nozzle or an old paintbrush does the job — and finish with a damp cloth. Do not flood the tracks with a hose. Water should leave through the weep holes at the bottom of the sill, and if those are blocked with compacted debris, the next heavy rain will push water into the wall instead of onto the pavement. A bent paperclip is enough to clear them.

• Glass: wash with water and a few drops of dish soap; skip ammonia on tinted film.
• Frames and sills: check for soft wood, bubbling paint or cracks in vinyl and aluminium.
• Glazing putty and seals: press a fingernail in. Chalky, cracked putty needs replacing before it lets water behind it.
• Weep holes: clear them, and confirm water drains outwards, not inwards.
• Hardware: tighten handles, hinges and lock plates that have worked loose over the winter.

Summer: Heat, Sun and a Slow Inspection

Heat makes things move. Vinyl frames expand, aluminium sashes bind, wooden windows dry out and shrink slightly, and a window that opened smoothly in April can suddenly need a shoulder in July. If a sash is sticking, find out why before you force it — a swollen frame, a worn roller or a hinge that has dropped out of alignment all feel similar but need different fixes.

Clean and lubricate sliding tracks with a silicone spray rather than an oil-based product, which attracts grit and turns into a sticky paste. Wipe the surplus off so dust has nothing to cling to. On casement windows, put a drop of light machine oil on the hinge pins.

Summer is also when condensation tells you something. Water on the outside of the glass in the morning is normal. Water on the inside, in a season when the air conditioning is running, usually points to high indoor humidity or a very cold glass surface. Fog or a milky haze between the panes of a sealed double-glazed unit means the seal has failed; no amount of cleaning will help, and the unit will need replacing.

Resist the pressure washer. It drives water past seals and into frames, and it strips the finish from wood. A hose, a bucket and a soft brush clean a window perfectly well.

Autumn: The Sealing Season

This is the most important pass of the year in most climates. A draughty window wastes heat quietly all winter, and the fix is usually cheap and quick if you catch it in October rather than January.

1. Walk the perimeter with a smoke test. On a windy day, hold a lit incense stick or a candle close to each frame, sash edge and sill. A flickering flame shows exactly where air is entering, which is more reliable than feeling with a hand.
2. Weatherstrip the moving parts. Use V-strip for sliding channels, foam or bulb seals for compression gaps on casements. Clean the surface first or nothing will stick.
3. Caulk the fixed joints. Use exterior-grade silicone or a polyurethane sealant outside, and paintable acrylic inside. Fill gaps wider than about 6 mm with backer rod first so the bead can flex instead of tearing.
4. Adjust the latches. A casement that closes but does not compress is still leaking. Nudge the strike plate or the keeper so the sash pulls firmly against its seal.
5. Check exterior flashing and sills. Water should run off, never sit. Re-slope loose sills and replace crumbled mortar under the frame.

Caulk needs dry conditions. Most exterior sealants will not cure properly below roughly 5°C, and painting or caulking over damp wood traps moisture that will come back as rot.

Winter: Cold-Weather Care

Never force a frozen window. Ice in the track means the sash will crack or the hardware will tear before it opens. Warm the frame gently with a hairdryer on a low setting, working along the track, and clear snow from exterior sills so meltwater can drain instead of refreezing.

Heavy condensation on interior glass in winter is a signal, not a nuisance. It means warm moist air is meeting a cold surface. Wiping it is only cosmetic; the real answer is ventilation — run extractor fans when cooking and showering, keep furniture a little clear of radiators, and open a window briefly each day to exchange the air. In a well-sealed house, a short sharp airing beats a permanently cracked window because it clears humidity without chilling the walls. If condensation is appearing on walls and ceilings as well as glass, that is a problem worth raising with a builder or surveyor before mould sets in.

Keep the escape route in mind. Never seal a window permanently shut in a room that relies on it as a fire exit, and keep keys for lockable windows where an adult can reach them quickly.

Climate Notes

Cold continental winters

Priorities are air sealing, insulation around the frame and keeping exterior drainage clear of snow. Frost on the inside of the glass means the surface is losing too much heat — check whether a shutter, curtain or exterior blind can stay open during the coldest hours to keep air moving.

Hot, humid summers

Mould and swelling are the enemies. Keep tracks dry, clear weep holes before the rainy season, and inspect seals on any window facing the prevailing wind. Interior condensation in an air-conditioned room points to excess humidity inside the house.

Coastal and salt-exposed homes

Salt eats hardware. Rinse frames and metal fittings with fresh water every few months, wipe the hinges dry, and apply a silicone or wax-based protectant. Check for white corrosion around screws and replace fixings while they still turn.

Dry, dusty climates

Dust grinds through sliding tracks and abrades seals. Vacuum and wipe tracks more often, blow out window channels rather than washing them, and check that wooden frames are not drying and splitting along the grain.

The Twenty-Minute Habit

Between the seasonal passes, spend twenty minutes once a month walking around the outside of the house with a cloth and a torch. Wipe the tracks, look at the caulk lines, open and close every window one full turn, and note anything that has changed. That small habit catches the cracked bead, the loose hinge and the blocked drain while they are still cheap problems — and it means the big autumn job is a touch-up instead of a rescue.

Photo: Antonius Ferret / Pexels