⏱ Read time: 7 min | 🌿 Difficulty: Beginner | ⏰ Time: Half a day (4 hrs) | 👷 1 person
Stop the draughts first, then heat the room. Seal gaps around windows, doors and skirting with draught excluder strips and caulk, close the curtains at dusk and use a thermostatically controlled heater sized for the room. Heat only the space you're using, not the whole house, and you'll save energy and save money on energy bills.
Key takeaways
- Draught proofing windows, doors and floors could save around £85 a year, says the Energy Saving Trust.
- Find the draughts before you buy anything. A damp hand on a windy day costs nothing.
- Match the product to the gap: foam strip for small gaps, brush pile for bigger ones.
- An oil-filled radiator with a thermostat gives steady heat for rooms you sit in for hours.
- Never block air bricks, trickle vents or vents that fuel-burning appliances need.
Table of contents
- Why does a draughty room cost so much to heat?
- How can I find draughts in my home?
- How can I draught proof my home step by step?
- What are the cheapest ways to heat up a room?
- Should I hire or buy a heater?
- Worked example: warming up a draughty back room
- Health and safety: what should I watch out for?
- How long does the project take?
- Downloadable project checklist
- FAQs
The heater's on, the thermostat says 20°C and you're still wearing a fleece indoors. Sound familiar? Knowing how to heat a draughty room without wasting energy is mostly about keeping warm air in. Get that right and even a modest heater does a cracking job.
Why does a draughty room cost so much to heat?
Warm air escapes through gaps almost as fast as you make it, so part of what you pay for ends up escaping.
Cold air creeps in under doors and around skirting, and your heater keeps running because the room never reaches temperature. So if you're wondering “how can I not waste energy in a draughty room?”, start with draught proofing, not by using a bigger heater.
How can I find draughts in my home?
The quickest way to find draughts is the damp hand test: on a breezy day, slowly run the back of a damp hand around each likely gap. You’ll feel the cold straight away.
- Switch off extractor fans so they don't skew the results.
- Check windows where the opening part meets the frame, and where the frame meets the wall.
- Check external doors along the bottom and sides, plus the letterbox and keyhole.
- Check skirting boards, loft hatches and fireplaces, then mark each gap with masking tape.
How can I draught proof my home step by step?
The table below matches popular draught proofing products to the gaps they're designed for, so you buy the right thing first time.
Step 1: seal the windows
Clean the frame and let it dry so adhesive strip won't stick to dust or damp. Cut the foam draught excluder to length, peel the backing and press it into the rebate so the closed window squashes it slightly.
Step 2: stop draughts around external doors
Fit a threshold excluder along the bottom and a perimeter seal around the frame, then add a letterbox brush and keyhole cover. Leave internal doors unsealed, as they need a gap for airflow.
Step 4: deal with the loft hatch and chimney
Stick foam or brush strip around the hatch frame, and check your loft insulation while you're up there. A chimney draught excluder in an unused fireplace could save around £60 a year, according to the Energy Saving Trust. It mustn't fully block the flue and must come out before you light a fire.
What are the cheapest ways to heat up a room?
With the draughts sorted, the most cost-effective approach is usually to warm only the room you’re in, only while you’re in it, using a heater with a thermostat.
Standard plug-in electric heaters turn almost all their electricity into heat, so savings come from control, not heater type. Multiply the output in kW by your unit rate. At the Ofgem price cap average of 26.32p per kWh (October to December 2026), a 1.5kW radiator costs up to about 39p an hour on full, or 13p on 500W. There’s more detail in our electric heater running costs guide.
- Oil-filled radiator: best for rooms you sit in for hours. Slow to warm up, but it holds heat after the thermostat clicks off.
- Fan heater: best for short bursts, like a home office first thing. Fast to warm up, but noisier for long sessions.
How do I heat up a room without putting the heating on?
To heat up a room without putting the heating on, stop warm air escaping and let the sun do some of the work:
- Use curtains: open them on sunny days and close them at dusk.
- Shut internal doors: keep warmth in the room you're using.
- Move furniture: a sofa against the radiator soaks up heat.
- Add a rug: bare floorboards feel cold underfoot.
Saving money is great, but not at the expense of your health. The NHS recommends heating the rooms you use regularly to at least 18°C if you can.
Should I hire or buy a heater?
Hire for a short spell, such as a boiler breakdown. Buy if you'll use it every winter.
This table compares hiring an electric heater against buying one outright. Hire prices are the “from” price shown and vary with hire length.
Worked example: warming up a draughty back room
Here’s how the steps above come together in a typical project. The room is a downstairs back room with one casement window and an inward-opening back door. The curtains twitch on windy days, there’s a chill along the skirting, and the radiator never seems to keep up. Prices are from hss.com as of 30 October 2026.
- Window: a 15m roll of Sureseal foam draught excluder (£3.96) seals small gaps up to 3mm around the opening casement. One window uses only a few metres, so there’s plenty left over for the landing loft hatch.
- Back door: a Slikseal around door seal (£7.44) closes gaps up to 7mm around the frame. A CDx threshold excluder (£12.24) stops the draught underneath. It’s 914mm long, so check your door width first.
- Skirting and frame cracks: one 280ml tube of EVO-STIK decorators caulk (£4.56) covers about 10m of 6mm bead. That’s enough for the skirting and the window and door frames in most rooms. Apply it with a skeleton caulking gun (price TBC).
- Heat: an Airmaster 1.5kW oil-filled radiator (£46.45) has 500W, 1000W and 1500W settings and an adjustable thermostat. That’s plenty for a room you sit in all evening.
Total: £74.65 plus the caulking gun. The project takes about half a day for one person.
Running cost: on full power, the radiator uses 6kWh over a four-hour evening. At the Ofgem price cap rate of 26.32p per kWh, that’s up to about £1.58 a night, or £7.90 for five evenings. In practice it costs less, because the thermostat switches the heater off once the room is warm, and a well-sealed room stays warm for longer.
Health and safety: what should I watch out for?
Draught proofing is low risk, but heaters and ventilation need respect. These points come from Electrical Safety First and the Energy Saving Trust.
- Give heaters space: at least one metre from curtains, furniture and paper.
- Plug into the wall: extension leads can easily overload.
- Stay with it: never leave a heater on unattended or while you sleep.
- Keep vents clear: air bricks, trickle vents, extractor fans and vents for gas appliances or open fires.
- Fit alarms: a smoke alarm nearby and a carbon monoxide alarm wherever there's a fuel-burning appliance. Browse our fire safety range.
- Air the room daily: sealed rooms can get condensation. If damp builds up, try our dehumidifier range.
How long does the project take?
It’ll roughly take about half a day for one room, even on your first go.
- Draught hunt: 30 minutes
- Clean and dry frames: 30 minutes
- Fit window strips: 1 hour
- Fit door seals: 1 hour
- Caulk cracks: 45 minutes
- Set up the heater: 15 minutes
Total: 4 hours, one person.
Project checklist
Here is a draughty room project checklist to help keep you on track. Print it, stick it on the fridge and tick as you go.
- ☐ Draught hunt done and gaps marked
- ☐ Vents and air bricks noted, to stay clear
- ☐ Window strips fitted
- ☐ Door seal, threshold excluder, letterbox brush and keyhole cover fitted
- ☐ Cracks caulked
- ☐ Loft hatch sealed
- ☐ Heater with thermostat placed 1m from furniture, plugged into the wall
- ☐ Smoke and CO alarms tested
FAQs
Is a plug-in heater cheaper than central heating?
Not per unit. Gas costs 7.97p per kWh against 26.32p for electricity under the current cap, so a boiler usually wins for the whole house. A plug-in heater makes sense when you only need one room warm for a few hours.
How can I save money on my energy bills without spending anything?
Close curtains at dusk, shut internal doors and only heat rooms you use. We share more free tips in how to make your home more energy efficient.
How can I stop draughts in my home if I rent?
Use removable options like self-adhesive strips and fabric draught excluders. Ask your landlord before fitting anything screwed in.
Does draught proofing cause damp?
Not if you leave intended ventilation alone and air rooms briefly each day.
Can I leave an oil-filled radiator on overnight?
Electrical Safety First doesn't recommend running any heater overnight, but says an oil-filled radiator is the lower-risk choice if you do.
How often should I replace draught excluder strips?
You should change them when they're squashed flat, torn or peeling and repeat the damp hand test each autumn.
Ready to warm up that draughty room?
A draughty room doesn’t need a bigger heater. It needs fewer gaps. Spend an afternoon sealing windows, doors and skirting, then let a thermostat-controlled heater handle the rest. You’ll stop paying to heat the street and start enjoying a room you actually want to sit in, without dreading the next bill.
Keep the warmth going with our guide to insulating your loft before winter.
Everything you need for this project is ready to hire or buy online 24/7, with next day delivery where available. Pick up your draught proofing essentials and a heater to hire or buy in one order. Please note that if your order includes several items, they may arrive separately.
Buy the materials. Hire the tools. One order. All in one place.
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