Orangery vs conservatory vs garden room extension
All three are glazed rooms on the back of a house. They differ in how much of the roof is glass, whether the room is part of the heated house, and which rules apply. Those three things decide how often you will sit in it.
Get a quoteThe three side by side
| Feature | Garden room extension | Orangery | Conservatory |
|---|---|---|---|
| Roof | Solid and insulated | Flat, with a glass lantern | Glass or polycarbonate |
| Walls | Insulated, with wide glazed doors | Brick piers between tall windows | Glazed frames on a low wall |
| Share of glass | Lowest. One or two glazed walls and a roof light | Middle. Glazed walls and a lantern, solid roof edge | Highest. Glass on three sides and overhead |
| Open to the house | Yes | Usually | No, the doors stay |
| Heating | On the house system, radiators or underfloor | On the house system in most cases | Its own heater, kept apart from the house system |
| Winter and summer | Holds a steady temperature all year | Good all year if the lantern glass is well chosen | Swings with the weather unless the roof is high-performance glass |
| Building regulations | Apply in full | Apply in full | Often exempt under 30 m² |
| Planning | Same limits as any extension | Same limits as any extension | Same limits as any extension |
| Typical time on site | 10 to 14 weeks | 8 to 12 weeks | 3 to 5 weeks |
| Guide price with VAT | £1,800 to £3,000 per m² | £1,600 to £3,000 per m² | £1,100 to £1,800 per m² |
| Suits | A kitchen, dining or living room in daily use | A dining or sitting room where the ceiling is the feature | A sunny spare room for part of the year |
Prices are national guides with VAT, not quotes. Times assume a room of about 16 to 20 m².
Conservatory
A glazed frame, in uPVC, aluminium or timber, on a low wall or straight off the floor, under a glass or polycarbonate roof. It goes up in a few weeks and costs the least.
The price of all that glass is comfort. Heat leaves quickly on a winter night and builds quickly on a July afternoon. Modern roof glass narrows the swing but does not remove it, and the room must stay shut off from the house by doors.
Orangery
Named after the buildings where grand houses wintered their citrus trees. Today it means masonry piers, tall windows between them, and a flat roof with a glazed lantern rising from the middle.
You get a plastered ceiling round the edge for downlights, daylight falling into the centre of the room, and a building that is insulated and heated like the rest of the house.
Garden room extension
An extension designed around its view. The roof is solid, pitched or flat, and the glass goes where it earns its keep: full-height doors to the garden, perhaps a gable window or a roof light.
It has the least glass of the three and the steadiest temperature. It is the one to choose for a kitchen or any room in daily use.
The rules are where they really part
For planning, the three are treated alike. Each is a single-storey extension, and in England each can be permitted development within the same depth and height limits. One small difference: a conservatory is excused from the condition that outside materials match the house.
Building regulations are another matter. A conservatory can be exempt if it is at ground level, under 30 m² in floor area, glazed with safety glass where needed, separated from the house by walls, windows or doors of outside quality, and kept off the house heating system. Take away any one of those and it is no longer exempt.
An orangery or garden room extension is built to the regulations from the start: foundations inspected, walls and roof insulated to set values, glazing counted against a limit, structure calculated. That is why it can open straight onto the kitchen. It is also the reason for the gap in price. In Scotland all three generally need a building warrant, with a narrow exemption for very small conservatories.
How to choose
Start with how you will use the room in January.
- Every day, as part of the kitchen or living room: a garden room extension. Nothing else stays comfortable enough.
- Most days, as a dining or sitting room, and you want the ceiling to be the feature: an orangery.
- On bright days, as a spare room, with a firm budget: a conservatory with the best roof glass you can afford.
Then look at which way the back of the house faces. South and west walls take the afternoon sun, so the more glass overhead, the more shading and ventilation you need. A north-facing garden is the one case where a lantern or a glass roof gives light a solid roof cannot.
Last, think about the house. On a Georgian or Victorian front, the piers and cornice of an orangery sit well. On a 1930s semi or a newer house, the plainer lines of a garden room extension usually look more at home.
What each costs
For a 16 m² room with VAT, allow £17,500 to £29,000 for a conservatory, £25,500 to £48,000 for an orangery and £29,000 to £48,000 for a garden room extension. The cost calculator prices any size and shows whether the depth you want fits permitted development.
If you already have a conservatory and are weighing an upgrade, read conservatory to extension first.
Still undecided? A builder can price two options at one visit.
Get a quoteOrangery, conservatory and garden room questions
What is the difference between an orangery and a conservatory?
The roof and the walls. A conservatory is mostly glass, roof included, on a light frame. An orangery has solid brick or rendered piers and a flat roof around the edge, with a glazed lantern in the middle. An orangery is built and insulated like an extension; a conservatory usually is not.
Is a garden room the same as a conservatory?
No. A garden room extension has a solid, insulated roof and is built to full building regulations, so it works as a normal room all year. Some sellers call a conservatory with a tiled roof a garden room, which is why it pays to ask what the roof and walls are made of.
Is an orangery warmer than a conservatory?
Yes, as a rule. It has less glass, insulated walls and an insulated roof edge, and it is normally heated from the house. A conservatory with modern solar-control roof glass is far better than an old one, but it still has more glass to lose heat through.
Which is cheapest?
A conservatory, at £1,100 to £1,800 per m². An orangery runs £1,600 to £3,000 per m² and a garden room extension £1,800 to £3,000 per m². All three figures include VAT and are national guides, not quotes.
Do orangeries and garden rooms need building regulations approval?
Yes. Both are extensions in the eyes of the regulations. Only a conservatory that is under 30 m², at ground level, closed off from the house by outside-grade doors and not on the house heating can be exempt, and even then its glazing and electrics must comply.
Which adds the most value?
No trustworthy national figure exists. What can be said is that a room built to building regulations counts as living space when the house is measured and valued, and an exempt conservatory often does not.
Sources
- Conservatories: building regulations (Planning Portal)
- Conservatories: planning permission (Planning Portal)
- The Building Regulations 2010, Schedule 2: exempt buildings and work (legislation.gov.uk)
- Approved Document L: conservation of fuel and power (GOV.UK)
- Permitted development rights for householders: technical guidance (GOV.UK)
- Building warrants (mygov.scot)
- Conservatory costs: roof replacement, upgrades and extensions (Federation of Master Builders)
Get a quote for your garden room extension
Postcode first, then four quick questions about the room, then your contact details. It takes about a minute and costs nothing.
We are not a builder. We look for a firm that builds this kind of room near you and tell you its name. Nothing is passed on until you say so.
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- We look for a firm that builds glazed extensions around your postcode, then email or phone you with its name.
- If you are happy with that firm, we send your enquiry across. If not, it goes nowhere.
- The firm measures up at the house and gives you its price. You will not hear from us about anything else.