by Walk into Dunelm or scroll through IKEA and you’ll see two labels that sound like they do the same job: blackout and thermal. If you’re trying to work out blackout vs thermal curtains — which one you actually need — you’re not alone. Plenty of people buy one expecting the benefits of the other, then wonder why their bedroom is still freezing at 2am.
The truth? They solve different problems. Blackout curtains are about darkness; thermal curtains are about temperature. Sometimes one pair does both — but not always. Here’s the honest breakdown, with UK prices.
What Are Blackout Curtains?
Blackout curtains are designed to block out light — as much of it as possible. They use a tightly woven fabric, often with a special blackout lining bonded to the back, that stops sunlight, streetlights and headlights bleeding through.
They’re the go-to for bedrooms — night workers, streetlamps outside, or that 4:30am summer sunrise. A decent pair gets your room properly dark.
What Are Thermal Curtains?
Thermal curtains are all about insulation. They typically have a foam-like or acrylic-coated lining — sometimes two or three layers — that traps air between the curtain and the window, slowing heat loss.
Why does that matter in the UK? Because windows are often the weakest link. In a Victorian terrace with original sash windows, a shocking amount of your heating bill goes straight out of the glass. Thermal curtains won’t fix single glazing, but they noticeably reduce the draught you feel near the window — and take the edge off winter energy bills.
Worth knowing: thermal curtains tend to be heavier and bulkier, and the lining can feel stiff. If you care about how curtains drape, check the different curtain fabrics before you commit.
Blackout vs Thermal Curtains: The Key Differences
Here’s the head-to-head:
| Feature | Blackout Curtains | Thermal Curtains |
|---|---|---|
| Main job | Blocks light | Insulates against heat loss |
| Light blocking | Excellent — up to 99% of light | Good, but not total — depends on the lining |
| Insulation | Mild — the dense weave helps a little | Excellent — designed for it |
| Thickness and weight | Medium — the lining does the work | Heavier and bulkier |
| Noise reduction | Some — dense fabric dampens sound | Better — extra layers absorb more |
| Typical UK cost per window | £25–£80 ready-made | £35–£100 ready-made |
| Best for | Bedrooms, nurseries, shift workers | Draughty rooms, cold hallways, front doors |
The short version: if your problem is light, buy blackout. If your problem is cold, buy thermal. If your problem is both — and in a British winter bedroom, it often is — keep reading.
Can You Get Curtains That Are Both Blackout and Thermal?
Yes — and honestly, this is what most people should buy. Plenty of curtains now come with a combined blackout-and-thermal lining: one coating that blocks light and adds insulation. If you’re still torn in the blackout vs thermal curtains debate, a combined pair removes the dilemma entirely.
You’ll see them as “blackout thermal curtains” at Dunelm, IKEA and John Lewis. They cost a little more than single-purpose pairs, but for a bedroom with a draughty window they’re usually the best value. Just check the product details — “thermal” on the label doesn’t always mean a proper insulating lining.
Blackout vs Thermal Curtains: Which Should You Choose?
It depends on the room:
- Bedroom: blackout first — sleep beats everything. Got a draughty sash window? Go for a combined pair (see our bedroom curtain guide).
- Living room: thermal usually wins — you’re trying to stay warm on the sofa in January, not sleep. See our living room curtains ideas.
- Draughty front door or hallway: thermal, no contest. A heavy thermal curtain — or a proper door curtain — over the front door is one of the cheapest insulation upgrades you can make.
- Nursery: blackout for naps, ideally combined with thermal so the room stays comfortable overnight.
How Much Do They Cost in the UK?
When you’re comparing blackout vs thermal curtains on price, here’s roughly what to expect for a standard window (around 168cm wide, 137cm drop). Prices move around — treat these as typical 2026 ranges:
- Budget ready-made blackout: £20–£40 per pair (supermarkets, IKEA, Amazon)
- Mid-range ready-made blackout: £40–£80 (Dunelm, John Lewis)
- Budget ready-made thermal: £30–£55 per pair
- Mid-range ready-made thermal: £55–£100 per pair
- Combined blackout-thermal: £45–£110 per pair ready-made
- Made-to-measure (either type): typically £120–£300+ per window
Don’t forget the hidden costs: a sturdy pole or track (thermal curtains are heavy — flimsy poles will bow), and possibly longer drops. Floor-length curtains insulate better than ones that stop at the sill.
Practical Tips for Getting the Most Out of Them
Once you’ve picked your pair, a few hanging habits make a surprising difference — especially if insulation is the goal.
- Hang them wide and high. Curtains that extend past the frame on both sides trap warm air instead of letting it spill around the edges.
- Go floor-length for insulation. A gap at the bottom is an escape route for heat.
- Close them at dusk. Thermal curtains only insulate when drawn, so make it a habit as the light fades.
- Watch the radiator trap. Curtains hanging in front of a radiator push warm air behind them. Tuck them behind it, or choose a sill-length pair for that window.
- Check the washing label before you buy. Thermal coatings and blackout linings don’t all survive hot washes — most cope fine at 30°C, but never tumble-dry a coated lining unless the label says you can.
Frequently Asked Questions
Are blackout curtains the same as thermal curtains?
No — they do different jobs. Blackout curtains block light; thermal curtains insulate against heat loss. Many curtains now combine both linings, which is why labels get confusing — but a pure blackout curtain won’t necessarily keep a room warm, and a pure thermal curtain won’t necessarily make it dark.
Do thermal curtains really keep heat in?
Yes, within reason. A good thermal curtain noticeably reduces heat loss — less draught nearby, and rooms stay warmer longer after the heating goes off. It won’t match double glazing or proper insulation, but for draughty period windows it’s one of the cheapest improvements you can make.
Can I get curtains that are both blackout and thermal?
Yes. Most major UK retailers sell combined blackout-thermal curtains with a single lining that does both jobs — ideal for bedrooms with draughty windows. If you can’t find a style you like, layer a blackout roller blind behind a thermal curtain instead.
Do blackout curtains help keep a room cool in summer?
They can help. By blocking sunlight, blackout curtains stop rooms heating up during the day — useful for south-facing bedrooms in a heatwave. Thermal curtains with a reflective backing do it even better. Keep them closed through the hottest hours, and open windows in the evening instead.
Which is better for a child’s bedroom — blackout or thermal?
Blackout usually matters more: darkness protects naps and bedtimes, especially in summer. A combined blackout-thermal pair is the best of both — dark for sleep, warm overnight. Look for machine-washable options, because kids’ rooms and clean curtains rarely stay that way for long.
The Bottom Line
Blackout vs thermal curtains isn’t a contest — it’s about which problem you’re solving. Light? Go blackout. Cold? Go thermal. Both? Buy a combined pair. Either way, it’s one of the simplest, cheapest upgrades for a UK home.
