How Much Does an Orangery Extension Cost? An Architect's UK Guide
- Feb 28, 2025
- 7 min read
Most orangery extensions in the UK cost between £30,000 and £80,000, with a typical mid-range project landing around £40,000 to £60,000. Per square metre, expect £2,500 to £4,000 for a quality build. Bespoke hardwood orangeries sit at the upper end. uPVC and aluminium options come in lower but compromise on appearance and longevity.
An orangery is one of the most considered home improvements you can make. It changes how a property feels to live in, adds genuinely usable space, and (done well) lifts the value of the house. But the price range is wide, and quotes from different installers can vary by a factor of three for what looks, on paper, like the same job. Understanding what drives the cost makes the difference between a confident decision and a guess.
What follows is the architect's view of what an orangery extension actually costs in the UK, what causes the variance between quotes, and how to plan a budget that holds up over the long term.
Average orangery extension cost in the UK
The honest answer to "how much does an orangery cost" depends on what you're comparing.
At the modest end, a small uPVC or aluminium orangery can be delivered for around £20,000 to £30,000. These are entry-level structures, usually with standard glazing, basic foundations and minimal internal finishing. They work for some homeowners, but they don't compete on appearance, thermal performance or long-term durability with higher-spec builds.
The mid-range, where most quality orangeries sit, runs from £40,000 to £80,000. This covers larger footprints, better glazing specifications, hardwood or premium aluminium framing, and proper roof lanterns rather than basic flat glazing. A well-designed orangery in this bracket should last decades and add visible value to the property.
The premium end, which is where most of our work sits at Glass House Architecture, runs from £80,000 to £200,000 and beyond for very large or highly bespoke projects. Hardwood frames in oak, sapele or accoya, structural glazing, integrated heating and lighting, period detailing matched to a listed property: these specifications drive the budget but produce a structure that feels like a permanent part of the house.
Orangery extension cost per square metre
For budgeting, cost per square metre is the most useful figure because it lets you adjust for the size of your project.
In the UK, orangery extensions typically range from £2,500 to £5,000 per m², depending on materials, glazing and complexity. uPVC and standard aluminium builds fall at the lower end. Hardwood and high-specification glazing push toward the upper end. Listed properties, bespoke detailing and complex sites can exceed it.
As a rough sense-check:
A 3m x 3m orangery (9 m²): £22,500 to £45,000
A 4m x 4m orangery (16 m²): £40,000 to £80,000
A 6m x 4m orangery (24 m²): £60,000 to £120,000
These ranges assume a quality build with proper foundations and finishes. Stripped-back uPVC builds can come in under, and premium hardwood or listed-property work can come in above.
What drives the cost of an orangery extension
Seven factors do most of the work in shaping a final orangery quote.
Size and structural complexity
Larger orangeries cost more, but not in a straight line. Doubling the floor area doesn't double the price: it changes the roof span, the structural requirements, the volume of heating and glazing, and often the planning route. A 24 m² orangery can be significantly more than twice the cost of a 12 m² version when the structural and thermal implications stack up.
Frame material
The frame is one of the single biggest cost variables.
uPVC is the cheapest option. Suitable for some homes, but it doesn't carry the look of a quality orangery and tends to age badly.
Aluminium sits in the middle. Slim profiles, modern appearance, strong structural performance. A reasonable choice for contemporary properties.
Hardwood is the premium option. Oak, sapele, accoya or similar. More expensive upfront, but the look, feel and longevity are in a different category. Suits period properties especially well.
Roof design
A flat roof with a glazed lantern is the orangery's defining architectural feature. The size of the lantern, the quality of the glazing in it, and the proportions of the surrounding flat roof all affect cost. A full glass roof costs more again and demands a high thermal spec to be usable through winter.
Glazing specification
Standard double glazing is the baseline. Most quality orangeries now use upgraded double or triple glazing with low-emissivity coatings and inert gas filling. Solar-control glass, self-cleaning glass and acoustic glass are common upgrades, each adding to the cost but improving comfort and reducing running costs.
Site conditions and groundworks
What happens below ground level catches people out. Poor ground conditions, high water tables, awkward access, drainage runs or services that need diverting can all add tens of thousands to a project before the first frame is delivered. A proper site survey before quoting is essential.
Internal finishes and fit-out
The orangery shell is one cost. The fit-out is another. Underfloor heating, premium flooring (stone, oak, polished concrete), bespoke cabinetry, lighting design, plastering and decoration can comfortably add £15,000 to £40,000 on top of the structural cost. Some of this depends on how the orangery is used: a kitchen orangery costs significantly more than a sitting-room orangery once cabinetry and appliances are factored in.
Planning, design and consents
For projects requiring full planning permission, Listed Building Consent or a Larger Home Extension prior approval, the design and consents stage adds professional fees and time. Architectural drawings, planning applications, structural engineering and building control fees together typically run to several thousand pounds.
Lean-to orangeries: a lower-cost option
Not every orangery needs to be a full standalone structure. A lean to orangery extension shares one wall with the existing house and uses a sloping roof rather than a flat roof with a lantern. The build is simpler, the structural demands are lower, and the cost typically comes in below an equivalent-sized full orangery.
It's a sensible option for homes where the budget doesn't stretch to a full orangery but the homeowner still wants a glazed, light-filled extension that performs better than a basic conservatory.
Orangery vs conservatory: which costs more?
An orangery generally costs more than a conservatory of the same footprint. The extra cost comes from the brick or stone piers between the glazed sections, the flat roof with lantern (rather than a fully glazed pitched roof), and the higher thermal specifications that orangeries usually carry.
The trade-off is that orangeries tend to feel more like a permanent part of the house, perform better year-round, and add more value at resale. A conservatory can feel like a glazed lean-to in winter. An orangery, designed properly, doesn't.
For most clients who can comfortably afford the difference, the orangery is the better long-term decision.
Orangery vs traditional extension cost
A standard brick-built single-storey extension can sometimes cost less than an orangery of the same size, particularly at the budget end of the market. At the premium end, the comparison narrows: a high-specification extension with quality glazing, roof lights and finishes can match or exceed an orangery of equivalent size.
What you get is different. An extension prioritises wall space, privacy and storage. An orangery prioritises light, garden connection and architectural feature. Which is right depends on how you want the new space to feel, not just what it costs.
Hidden costs and extras to budget for
A few costs aren't always visible in the headline quote.
VAT. Quotes from VAT-registered contractors are usually inclusive, but check. On a £60,000 project, VAT is the difference between budgeted and unbudgeted by £12,000.
Building regulations fees. Application and inspection fees are modest but real.
Connecting services. Extending heating, electrics and drainage from the existing house adds cost, especially if the supply needs upgrading.
Decoration and finishing. Some quotes stop at plastering, leaving the homeowner to decorate. Confirm what's included.
Landscaping reinstatement. Building works disrupt gardens. Restoring paths, planting and lawns is usually outside the build contract.
A 10 to 15% contingency on top of the build cost is sensible. Even well-planned projects produce one or two surprises during construction.
Does an orangery extension add value to your home?
A well-designed, well-built orangery typically adds value at resale, though the exact figure depends on local market conditions, the original property value and the quality of the build.
What we'd say with confidence: orangeries add more value than equivalent-sized conservatories, particularly on period properties where the build sympathetically matches the existing architecture. They open up dark interiors, create the kind of light-filled spaces buyers respond to, and feel like a permanent feature of the home rather than a bolt-on. A budget uPVC structure rarely adds value at resale. A quality hardwood orangery extension on a well-proportioned house often more than recovers its cost.
The structures that add the most value are the ones that look like they've always been there.
How to plan your orangery budget
Three practical points before you commit to a build.
First, set the budget before the brief. Knowing what you want to spend shapes the design conversation in useful ways. A good architect or designer will work with the budget rather than around it.
Second, get detailed itemised quotes from at least two qualified specialists. Headline figures hide the differences in specification. The quote that looks cheaper often excludes things the higher quote includes: foundations, glazing upgrades, internal finishing, building control fees, VAT.
Third, allow a 10 to 15% contingency over the contract price. This isn't pessimism, it's standard practice in any construction project. Sites reveal things during the build, briefs evolve, and an unspent contingency at the end is a much better outcome than a surprise mid-project.
Talking through the numbers for your project
The ranges in this guide are realistic but generic. Every property is different, and the only quote that matters is the one written against your specific brief, on your specific site, with the specification you actually want.
If you're at the early stage of planning an orangery and want a clear sense of what your project might cost before committing to drawings, we'd be glad to talk it through. Initial consultations are unrushed and there's no obligation. Get in touch with the studio for a conversation about your property and what you have in mind.
