Sunroom, Garden Room or Conservatory?
Only one of those three words describes a category that anything official recognises, and it is the third one. The other two are sales language, and in UK installer marketing the first usually means a conservatory with a solid roof on it. That matters because the roof, not the word, is what you are paying for. Start with solid, tiled, warm and glass roofs compared if you want the coverings before the vocabulary.
The product usually sold as a sunroom · solid roof on an existing 3m × 3m conservatory · installed inc VAT
£6,000 to £11,000 typically £8,075
Well evidencedFour UK publishers agree within 1.05x on the floor. No UK source prices a “sunroom” as a product of its own, so this is the nearest honest figure rather than a sunroom price. A whole new build is £9,000 to £25,000. Checked 20 August 2026.
How much does a sunroom cost?
There is no UK published figure for a sunroom, because no UK publisher treats it as a distinct product. Our price register holds 222 rows across conservatories, roofs, insulation, orangeries, repairs and ancillaries. It holds zero sunroom rows. We could invent one by averaging something adjacent. We will not.
What we can do is price the thing the word almost always describes. If you are being sold a sunroom on an existing conservatory, it is a solid roof, and that is £6,000 to £11,000 installed including VAT on a 3m by 3m, typically £8,075. Well evidenced across four independent UK publishers, dated 2026, July 2026, a table updated December 2024 and one undated, with the four publishers agreeing within 1.05 times on where the floor sits. Checked 20 August 2026.
If you are being sold a sunroom as a whole new building, it is a conservatory build, and that is £9,000 to £25,000, typically £15,000, Well evidenced across five independent UK publishers, dated June 2026, 12 May 2024, 28 January 2025, 29 July 2025 and 24 June 2026. Checked 20 August 2026. Which of those two you are actually buying is the whole question, and the quote will usually not answer it in those words.
What installers mean by sunroom
In UK installer marketing the word does a specific commercial job. It signals a room that is comfortable all year, which is a promise a fully glazed conservatory cannot keep, and it does that by describing the same structure with an opaque, insulated roof instead of glass or polycarbonate. Sometimes there is a bit more wall, sometimes there are fewer roof facets. Usually it is the roof and nothing else.
That is why the price question resolves so cleanly: the honest number is a roof number. The decision, the size bands and the three prices it turns on are on swapping to a solid roof. Nothing about the word changes the physics, the weight on your frames, or the fact that going opaque can take the structure outside its Building Regulations exemption.
The word is not a specification. Ask for the roof build-up and the calculated U-value in W/m²K, the weight in kg/m², and who is signing the work off. Two quotes both headed “sunroom” can be a lightweight cladover and a full insulated system with nothing in common but the heading.
One row per word
Five words, one row each, with the nearest figure we genuinely hold against each one. Where we hold nothing, the row says so rather than borrowing from the row above it.
| Word | What it usually means here | A recognised category? | Nearest figure we hold | Evidence and source |
|---|---|---|---|---|
| Conservatory | Mostly glazed walls, its own roof, on a light base | Yes. Named in Schedule 2 Class 7 of the Building Regulations 2010 as an exempt structure, subject to conditions | £9,000 to £25,000, typical £15,000 | Well evidenced, five publishers, latest dated Jun 2026 |
| Sunroom | A conservatory with a solid, opaque, insulated roof. Occasionally a bit more wall | No. A marketing term with no legal or technical definition | £6,000 to £11,000 for the roof on an existing 3m by 3m | Well evidenced as a roof, four independent UK publishers |
| Garden room | Usually a separate insulated outbuilding, not attached to the house at all | No. Covers everything from a garden office to a summerhouse | No figure | Gap We hold no garden room rows and will not borrow conservatory ones |
| Orangery | Masonry piers with glazing between them and a glazed lantern in a mostly flat roof | No formal definition, but treated as an extension in practice | £30,000 to £35,000 at 16 m², typical £32,500 | Reasonably evidenced, three sources, one dated Mar 2026 |
| Extension | Masonry walls, tiled or flat roof, dug foundations, heated | Yes, and it has no exemption route at all | £40,000 to £56,000, small single storey | Thin evidence, one publisher framing line, Oct 2024 |
Checked 20 August 2026. Only the conservatory row and the roof figure behind the sunroom row clear our Well evidenced bar. The garden room row is a published gap: the search demand for that word exists, the price data does not, and importing conservatory figures into it would be exactly the substitution this page exists to warn about.
Why there is no price table here
Every other comparison page on this site carries a size table. This one does not, and the reason is worth stating plainly rather than filling the space. A price table needs a product definition to hang on: a size, a specification, a stated scope of works. “Sunroom” has none of those. Two quotes under that heading can differ by a factor of two and both be honest, because they are pricing different buildings.
So this page does the job the query actually needs. It tells you which product you are being sold, points you at the priced page for that product, and refuses to publish a headline number that would only be an average of two unrelated things. If a UK publisher starts pricing sunrooms against a stated specification, we will add the rows and grade them like everything else.
The same discipline applies to the word garden room. There is real search demand behind it and there is no price data behind it in our register, so we name the word in the table above, say what it usually describes, and stop. We are not going to quote you a conservatory figure under a garden room heading.
If you already have one
Most people arriving at this word already own a conservatory that is unusable for four months of the year, and are being offered a sunroom as the cure. The cure is a roof, and it is the single most consequential thing you can spend money on here. What a whole roof replacement involves, what it costs across every covering, and what it does to the room, is at what a new conservatory roof costs.
Two things change when the roof goes opaque, and neither of them appears in the sales word. The structure can stop being an exempt conservatory, which pulls the work into the Building Regulations and means it has to reach 0.15 W/m²K in England. And the frames have to carry more weight than they were built for, which is a survey question rather than a brochure question. Both are priced work, and both are easier to raise before you sign than after.
Price the real product
Six questions, about sixty seconds, and an estimate built from the rows above with every source shown.
Whichever word is on the quote, the estimate turns on the same three things: what you have now, how big it is, and where you live. Use work out what a conservatory costs for a new build, read conservatory prices for the whole-market bands, or compare local conservatory roof installers if the roof is the job.
Check what your roof will cost
We are paid when an installer quotes you. It is also why we would rather tell you that a word has no price than attach a number to it.
The heavier words, and the cheaper routes
Two more words get used in the same breath and they do describe genuinely different buildings at genuinely different money. One is masonry piers with a lantern, at £30,000 to £35,000 for 16 m², Reasonably evidenced from three sources, checked 20 August 2026, and it is set out at conservatory vs orangery. The other is a full masonry room at £40,000 to £56,000, Thin evidence, one publisher, October 2024, and that comparison is at conservatory or extension.
And if the point of the exercise is simply to make an existing room usable for less than the price of a new roof, there are cheaper routes that sit well below it, each with its own range, source and evidence grade. They are all costed at the alternatives to a conservatory.
Questions people ask first
Is a sunroom the same as a conservatory?
Why will you not give me a single sunroom figure?
Is a sunroom warmer than a conservatory?
Do I need building regulations approval for one?
What about a garden room?
Every figure on this page was last checked 20 August 2026, next check due 20 November 2026. Two of the five words in the table above have no price data behind them anywhere we looked, and those rows say so rather than borrowing a neighbour's number.
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.