Six Alternatives to a Conservatory, Costed
Two different people arrive here. One has a conservatory that is unusable half the year and wants out of it for the least money. One has no conservatory and is wondering whether to build something else instead. Both questions are answered below, cheapest route first, with a price band, an evidence grade and a named source against every one of the six.
Six routes · cheapest to dearest · installed inc VAT
£1,050 to £56,000 and the middle is where the data runs out
Mixed gradesInsulating a roof from £1,050, blinds from £1,200, a solid roof £6,000 to £11,000, an orangery £30,000 to £35,000, an extension to £56,000. Grades run Well evidenced to a published gap, row by row below. Checked 20 August 2026.
The six routes at a glance
Read the evidence column as carefully as the price column. Two of these six rest on four or five publishers. Two rest on one. One rests on nothing at all, and says so.
| Route | Low | High | Evidence | Sources |
|---|---|---|---|---|
| Insulate the roof you have, 9 m² | £1,050 | £4,500 | Thin to Reasonably | Two UK cost publishers, Jul and Apr 2026 |
| Blinds, manual then electric | £1,200 | £8,000 | Reasonably to Thin | One UK trades marketplace, 19 Jun 2026 |
| Solid roof on the existing frames, 3m × 3m | £6,000 | £11,000 | Well evidenced | Four UK cost publishers |
| Garden room, detached | no figure | no figure | Gap | We hold no rows. See below |
| Orangery, 16 m² | £30,000 | £35,000 | Reasonably | A national orangery guide Mar 2026, plus two |
| Small single-storey extension | £40,000 | £56,000 | Thin | One publisher's framing line, Oct 2024 |
Checked 20 August 2026. Bands are not like for like on size, and cannot be: the insulation and roof rows are for an existing 9 m² conservatory, the orangery row is 16 m², and the extension row has no size stated at all because its source does not give one. Every row below states its own size and scope.
Insulate the roof you already have
Roof insulation with an internal finish · existing 3m × 3m conservatory · fitted
£1,050 to £4,500 by ceiling finish
Mixed gradesAluminium panel £1,050 to £1,200, uPVC £1,200 to £1,450, plastered £2,200 to £2,750, one publisher, so Thin. A separate guide puts a plastered finish at £2,000 to £4,500, Reasonably evidenced. Two UK cost publishers, 2 July 2026 and April 2026. Checked 20 August 2026.
This is the cheapest thing that changes how the room feels, and it is also the one most often oversold. Insulating the roof you already have does not make it comply with Approved Document L, which limits a replacement roof in England to 0.15 W/m²K, and it does not turn the conservatory into a habitable room. It makes an unbearable room bearable for a fraction of the money, and that is a real answer for a lot of people. What it will not do is buy you the winter, which is what route 3 is for.
Blinds, and the other symptom fixes
Roof blinds fitted · 3m × 3m up to 5m × 4m and above
£1,200 to £5,000 manual, or £2,500 to £8,000 electric
Reasonably evidencedManual roof blinds across two publishers; the electric band is one publisher and is Thin. The freshest and most granular blinds source we found is a UK trades marketplace, 19 June 2026. Fitting labour on its own is £300 to £600. Checked 20 August 2026.
Blinds shade the glass. They do not insulate it, so they help in July far more than in January, and at the top of that band you are within reach of a solid roof that fixes both. One widely quoted set of blinds figures is three to four times higher than the source above, and it is worth knowing why.
That higher set, £3,750 to £6,250 for manual roof blinds at 3m by 3m, comes from a publisher whose own business is selling conservatory insulation rather than blinds, so its blinds number is not a blinds quote. We exclude it from every band on this site and from everything the site calculates, and we name the exclusion rather than dropping it quietly. Checked 20 August 2026.
Swap the roof for a solid one
Tiled or solid replacement roof · existing 3m × 3m conservatory · installed inc VAT
£6,000 to £11,000 typically £8,075
Well evidencedFour UK publishers within 1.05x on the floor, the tightest agreement in our whole register. Their tables are dated 2026, July 2026, December 2024 and undated. Typical is the median of five sourced point estimates. Checked 20 August 2026.
This is the route that actually converts an unusable glasshouse into a room you use in February, and the only one here whose headline clears our Well evidenced bar. It carries two conditional costs no brochure leads with: building control at £200 to £800, Reasonably evidenced but conflicted between two publishers 2.0 times apart, and structural reinforcement at £800 to £4,000 if the existing mullions have no steel in them, also conflicted. We attach no probability to the second, because nobody publishes one. Checked 20 August 2026.
One manufacturer publishes a threshold worth carrying into any quote comparison: a tiled roof quoted below £6,000 is more likely to be a cladover fixed over the existing glazing bars than a true solid roof. Reasonably evidenced, from the system maker, Ultraframe, 1 May 2024, checked 20 August 2026. A warning, not a price.
A garden room instead
A garden room is a separate insulated outbuilding rather than something bolted to the back of the house, which changes the foundations, the planning position and the price. For a lot of people it is the better answer, particularly where the wall you would build against is the only one getting any sun.
We hold no price rows for a garden room, so we publish no figure for it. Our register covers conservatories, roofs, insulation, orangeries, repairs and ancillaries, and a garden room is none of those. Borrowing a conservatory band and putting a garden room heading on it would be the exact substitution this site exists to argue against, so the row above says “no figure” and means it.
What would close it is a UK source publishing a size-banded table against a stated specification. Until then, treat any garden room figure you are shown as unverified unless it names its source and its scope.
An orangery instead
Orangery · 16 m² UK average · installed inc VAT
£30,000 to £35,000 typically £32,500
Reasonably evidencedThree sources, anchored on a national orangery guide, March 2026. All in, the reconciled mid-market rate is £2,000 to £2,500 per m² against £1,500 to £2,000 for a conservatory. Checked 20 August 2026.
Masonry piers, glazing between them, and a mostly flat insulated roof with a glazed lantern set into it. Normally regulated work rather than an exempt structure, so it behaves like an extension on site and on paper, at roughly three times a conservatory. The full side by side is at the difference between a conservatory and an orangery.
A single-storey extension
Small single-storey extension · no size stated by the source · installed
£40,000 to £56,000 one publisher, one line
Thin evidenceA single framing sentence published in October 2024 by one national cost publisher. No size table, no per square metre rate, no regional split, no breakdown. It is the only extension figure our register holds and it is graded Thin everywhere it appears. Checked 20 August 2026.
Fully regulated work, on dug foundations, insulated and heated as part of the house. It is the only route here that reliably adds floor area a surveyor will count. It is also four times a conservatory at the average, and the gap narrows only as you specify a conservatory upwards towards it. The comparison, written from the conservatory side, is at what a conservatory costs against an extension.
There is one more word people use in the same conversation, and it is not a legal category at all. In UK installer marketing it usually just means a conservatory with a solid roof, which is route 3 above under a different name. That is unpicked, with the two honest figures behind it, at sunroom cost.
The middle of the range, where the data runs out
Look at the six rows again and there is an obvious hole. Below the roof band the data is good. Above the orangery band it is thin but it exists. In between, which is exactly the budget most people arrive with, the UK published market has almost nothing.
The only figure we found there is £15,000 to £25,000 for rebuilding an existing conservatory as a full extension, one national cost publisher, May 2024, checked 20 August 2026. It carries no evidence grade, because it is one line with no size, no specification and no second source, so we publish it as an anchor rather than a price. We are not going to interpolate a curve between a roof and an orangery to fill the rest.
Per square metre is the usual way people try to bridge a gap like that and it is the wrong tool here. Rates spread up to ten times across publishers, and the rate falls by roughly 35 per cent from the smallest size band to the largest because fixed costs do not scale with area. The working is in our per square metre price table.
At the small end, if you have nothing yet
If there is no conservatory there to improve, the cheapest route to a room is usually still a small conservatory rather than any of routes 4 to 6. A lean-to at 3m by 3m is £8,000 to £13,000, typically £10,000, Reasonably evidenced from two publishers four months apart which agree exactly on the £8,000 floor, dated July 2026 and April 2026. Checked 20 August 2026. Size band by size band, that is set out at what a small conservatory costs.
Or improve the one you have
Routes 1 to 3 are all versions of one instinct: keep the shell and fix the problem. There are more of them than three, including heating, glazing changes, flooring and ventilation. Every one, cheapest first, is at ways to upgrade a conservatory.
Price your own job
Six questions, about sixty seconds, and an estimate built from the rows above with every source shown.
Which of the six is right for you turns on what you already have, how big it is and where you live. Use price your conservatory to start, or see what yours would cost if the building is already there. The same rows sit behind Conservatory Cost Calculator, and you can get quotes for your roof when you want real numbers against your own frames.
Check what your conservatory will cost
We are paid when an installer quotes you. That is the whole business model, and it is why route 4 on this page says we have no figure instead of guessing one.
Questions people ask first
Is there a cheaper alternative to a conservatory?
Which of the six actually makes the room usable in winter?
Why does one row say you have no figure?
Are blinds worth it, or a false economy?
Why is there so little data in the middle of the range?
Every figure on this page was last checked 20 August 2026, next check due 20 November 2026. One route carries a Well evidenced band, two are Reasonably evidenced, two are Thin, and one is a published gap. That distribution is the honest shape of this market rather than a shortcoming of the page.
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.