In winters with thaws followed by hard frosts, moisture from the air seeps into every gap and freezes overnight between the seal and the frame. Windows on the windward side, balcony doors, country cottage windows and car doors and side windows suffer most. Damaged or dried-out seals freeze even harder.
Yanking the sash by force gets you nowhere: you risk tearing the rubber or breaking the handle or hardware. Here is how to open a frozen window without damage and stop it freezing again.
What you will need
Important: Never pour boiling water on glass: the sudden temperature change can crack it. Do not use a hairdryer near water, and do not hold hot air on one spot for long or the plastic may distort.
Step 1
Assess how badly it is frozen
Take a look first. A thin crust of ice round the edge usually gives way to gentle pressure: press the sash softly a few times near the frozen spot before you pull. If the ice is thick or the whole seal is stuck, do not use force; move on to thawing.
Step 2
Thaw it with a hairdryer
Heat works fastest. Aim warm air from a hairdryer where the sash is frozen to the frame and move it slowly along the seal. Keep it at a distance and do not overheat any one spot. The only limit is the need for a nearby socket, so for a balcony or a car you will need an extension lead.
Step 3
Thaw it with warm water
No hairdryer? Warm water does the job too. It runs downwards, so a spray bottle is handier for the top of the frame. Use only warm water, never hot. Dry everything thoroughly straight afterwards, or in a few minutes of frost the water will turn back into ice.
Step 4
Free the sash with a plastic card
Carefully slide an old plastic card between the seal and the sash next to the frozen area, about halfway in. Move it slowly sideways and the ice will gradually break away. Do not use a knife or screwdriver, which cut rubber and scratch the profile.
Step 5
Free the handle and hardware
If the sash is free but the handle or locking points will not move, moisture has got into the mechanism and frozen. Once it has thawed, apply WD-40 Smart Straw into the hardware gaps: it displaces moisture and stops the mechanism seizing again. It works on car locks too.
Step 6
Protect the seals from freezing
The best way to deal with a frozen window is to stop it freezing. In autumn, wash dust and dirt off the frame and seals, dry them and apply a thin coat of WD-40 Specialist Silicone. It repels water, keeps rubber supple and stops ice from bonding firmly. Wipe off the excess and keep it off the glass.
Protect metal hardware and balcony door hinges with WD-40 Multi-Use, which displaces moisture and prevents corrosion.
Tip: If a window freezes in the same place every winter, check whether the seal is torn or the sash has dropped. Replace cracked rubber and adjust the sash, otherwise moisture will keep getting in.
What next
Treat the seals with silicone before the cold sets in and again after heavy thaws. The same WD-40 Specialist Silicone is worth applying to car door and balcony door seals, so they open easily on frosty mornings.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».