Nine Ways to Make a Conservatory Warmer
Cheapest first, with a price and an evidence grade against each one. Two cost nothing. One of them ends the conservatory's exemption from the Building Regulations, which is worth knowing before an installer does it for you.
Radiator run off the existing central heating · conservatory · fitted
£300 to £800 the middle rung of nine
Thin evidenceOne publisher, April 2026. Checked 20 August 2026.
How to make a conservatory warmer, and what each fix costs
A conservatory is cold for two reasons at once: heat leaves through a roof that is mostly glazing, and nothing is putting heat back in. Fixing only the second is why people end up heating a room that never gets warm. If the words being used at you are unfamiliar, start with solid, tiled, warm and glass roofs compared.
| The fix | Cost | Evidence | Source |
|---|---|---|---|
| 1. Close the door to the house and keep it sealed | nothing | n/a | Not a priced job |
| 2. Draught-proof the frames and the threshold | no published figure | Gap | Nobody prices this for a conservatory |
| 3. One radiator, supplied and fitted | £150 to £300 each | Thin | One publisher, June 2026 |
| 4. Extend the central heating into the conservatory | £300 to £800 | Thin | One publisher, April 2026 |
| 5. Electric underfloor heating | £500 to £1,200 | Thin | One publisher, April 2026 |
| 6. An insulated ceiling, 3m × 3m, panel finish | from £1,050 | Thin | One publisher, 2 July 2026 |
| 7. A multifoil kit fitted yourself, 3m × 3m | £1,200 to £1,400 | Thin | One publisher, 11 December 2024 |
| 8. Manual roof blinds, fitted | £1,200 to £5,000 | Reasonably | Two publishers, 19 June 2026 |
| 9. Replace the roof with a solid one, 3m × 3m | £6,000 to £11,000 | Well | Four publishers, 1.05x apart on the floor |
All figures installed and including VAT, checked 20 August 2026. Rows 3 to 7 each rest on one publisher, which is why they are graded Thin. Row 9 is the only figure four independent publishers agree on. Row 2 is an absence, not a small number.
The two that cost nothing
1. Close the door to the house, and check it still seals
A conservatory open to the hallway is not a warm conservatory, it is a cold house. The separating door is also doing legal work: retaining it is one of the conditions that keeps the conservatory exempt. Free, and the first thing to test.
2. Draught-proof the frames, the threshold and the trickle vents
Older uPVC frames lose their seals, and a conservatory on a slab often has a gap under the door you can feel with your hand. We hold no published figure for draught-proofing a conservatory, so this rung sits on judgement rather than on a price. What would close the gap: two independent trade sources pricing it by size.
Heating it, and the rule nobody mentions
3. One radiator, supplied and fitted: £150 to £300 each
A single or double panel radiator is £150 to £300 each supplied and fitted. Thin evidence, one publisher, June 2026, checked 20 August 2026. That is the radiator. Getting hot water to it is the next rung, and it carries a consequence.
4. Extend the central heating into the conservatory: £300 to £800
Running a spur off the existing system is £300 to £800. Thin evidence, one publisher, April 2026, checked 20 August 2026. It is the fix most likely to be done without anyone explaining what it changes.
Extending the dwelling's heating system into an exempt conservatory ends the exemption. One of the five conditions in Approved Document L paragraph 0.14 is that the dwelling's heating system is not extended into the conservatory. Extend it and the structure is no longer the thing Schedule 2 Class 7 describes, which brings the whole envelope into scope. Installers do this routinely. Ask before they do, not after.
That is why electric heating keeps appearing in conservatories: a heater or a mat on its own thermostat is not the dwelling's system extended in. It costs more to run and it leaves the exemption alone.
5. Electric underfloor heating: £500 to £1,200, or £60 to £85 per m²
Installed, £500 to £1,200 for a room, or £60 to £85 per square metre as a retrofit. Thin evidence, one publisher for each figure and two different publishers, dated April 2026 and June 2026, checked 20 August 2026. It heats the surface you stand on, and does nothing about the heat leaving through the roof.
Insulate the roof, which is where the heat goes
6. An insulated ceiling, from £1,050 at 3m × 3m
A new ceiling on its own frame, insulated above, finished below. Aluminium panel is £1,050 to £1,200 at 3m × 3m, plastered is £2,200 to £2,750. Thin evidence, one publisher, 2 July 2026, checked 20 August 2026. The method-by-method comparison is on conservatory insulation cost, and how the ceiling is built is on insulated conservatory ceilings.
7. A multifoil kit fitted yourself: £1,200 to £1,400 at 3m × 3m
Thin evidence, one publisher, 11 December 2024, checked 20 August 2026, and the only multifoil-by-size table published in the UK. Note the ordering: a fitted panel ceiling starts below a self-installed kit for the same conservatory. At this size, doing it yourself may save you nothing at all.
8. Blinds, and the figure we will not use
Manual roof blinds fitted are £1,200 to £5,000 depending on size, from 3m × 3m up. Reasonably evidenced, two publishers, one of them dated 19 June 2026. Checked 20 August 2026. They are a shading measure first: they cut glare and some summer solar gain, and do much less in January than the price suggests.
Two other published blinds ranges are excluded from everything on this site and we do not reproduce either figure. One comes from a company that sells insulation rather than blinds, so its blinds price is not a blinds quote. The other sits on a page last updated in May 2024, which makes it the stalest major figure in our research. We publish the exclusions rather than quietly pick the number we like.
See what the top of the ladder costs
Six questions, roof condition first, phone number last. They live on the calculator, not on this page.
work out what your roof will cost
Or have local installers price it and ask each to quote rungs 6 and 9 on the same visit, so the gap between them stops being theoretical.
Check what your roof will cost, or go straight to quotes from local roof installers. We pass your details to vetted installers so they can quote, and we are paid when they do. how we make money.
9. Replace the roof: £6,000 to £11,000 at 3m × 3m
A tiled or solid roof at 3m × 3m is £6,000 to £11,000 installed including VAT. Well evidenced, four publishers agreeing within 1.05x on the floor. Checked 20 August 2026. It is the only fix here that also solves July, because it stops the solar gain arriving rather than managing it afterwards.
It is also the only one that changes the room's legal status. Take the glazing out of the roof and the conservatory stops being exempt: the work becomes notifiable, it goes to building control, and the roof has to meet 0.15 W/m²K under Approved Document L Table 4.2. That is a real cost and a real benefit, and it is why the top rung is roughly six times the one below it.
Which makes the choice simpler than a list of nine suggests. If February is the complaint and August is tolerable, rungs 4 to 6 will do. If both ends of the year are unusable, everything below rung 9 is money spent twice, and the case for putting a solid roof on a conservatory starts there. The full range by size is the cost of a new conservatory roof.
Questions people ask first
What is the cheapest way to make a conservatory warmer?
Can I put a radiator in my conservatory?
Is insulating the roof better than heating the room?
Why is my conservatory colder than the rest of the house?
Every figure here was last checked 20 August 2026, next check due 20 November 2026, with the publisher named on each row. The Conservatory Cost Calculator prices the roof itself.
Find out what yours costs
Six questions, about sixty seconds, and an estimate built from published UK figures with every source shown. Then up to four local installers can quote you, if you want them to.