Orangery or conservatory: which is which, and does it matter?

An orangery and a conservatory are both single-storey glazed rooms added to a house. A conservatory has at least 75% of its roof and 50% of its walls in glass, and an orangery has less, with a solid roof edge and brick piers. That split decides how the room is built, whether building regulations apply and what it costs. We cover the difference, 2026 prices, the rules in England and what changes elsewhere in the UK.

What is the difference between an orangery and a conservatory?

The difference is how much of the room is glass. A conservatory is glazed on at least 75% of its roof and 50% of its walls. An orangery falls below both marks, with a solid roof edge, often round a glass lantern, and brick piers or insulated columns between the windows and doors.

What is a conservatory?

A conservatory is a mostly glass room with a glazed or polycarbonate roof, built as a lean-to against the house or in the pitched Victorian, Edwardian and Georgian shapes. It is the cheapest way to add a room, but its glass lets heat out in winter and in during summer.

What is an orangery?

An orangery is a heavier build, with brick piers or columns between tall windows and a flat, insulated roof round a glass lantern. It feels like part of the house rather than a glass box, and it takes more trades and more money to build.

Orangery vs conservatory cost

An orangery costs more than a conservatory of the same size. The gap depends less on the style than on how each room is built, so every figure below says what it covers.

Why the orangery costs more

Brick piers and a solid roof bring in a bricklayer, a roofer and a plasterer as well as the frame installer. Built as an extension, an orangery sits on footings at least 1 metre deep, or 1.5 metres in clay, and is insulated to extension standards. Built to the same standard as a conservatory, it still starts higher at every frame material.

The cheap end of the price table is a lighter build: a frame and roof on a base, kept apart from the house by its existing doors, with no building regulations approval to pay for. That, not the glass, is most of the gap between a £15,000 conservatory and a £60,000 orangery.

Do orangeries and conservatories need building regulations approval?

A conservatory in England needs no building regulations approval if it meets every condition below, and Approved Document L exempts it from the energy efficiency standards on the same terms:

• It is single storey and built at ground level.
• Its floor area is no more than 30 m².
• The wall, door or window between it and the house stays, or is replaced with another wall, door or window.
• The house's heating does not extend into it, and any heater has its own temperature and on/off controls.
• Its glazing meets the safety requirements of Part K.

Approved Document L does not set a glass share for a conservatory. The test applied to the exemption is at least 75% of the roof and 50% of the new walls glazed, so a typical orangery falls outside it and is approved as an extension.

What turns either room into an extension

An exempt room needs approval once any of these happen:

• The doors between the room and the house come out, or a new structural opening is made in the back wall.
• A radiator or wet underfloor heating is run in from the house boiler.
• A solid roof replaces the glazed one, taking it below the 75% glazed roof mark.
• The floor area grows past 30 m².

Losing the separation or extending the heating makes the room an extension in Approved Document L terms. A room over 30 m² that stays separated needs approval too, but its glass area is not capped.

The 25% glazing rule for orangeries built as extensions

As an extension, the room's windows, rooflights and doors can total no more than 25% of its floor area, plus the area of any house windows and doors it covers. New elements must meet the extension U-values: 0.15 for the roof, 0.18 for walls and floor, 1.4 for windows and 2.2 for rooflights.

Bifold doors and a lantern add up quickly, so most orangeries break the 25% limit on paper. A 4 × 4 m orangery on the back of a semi shows how:

This design is 3.3 m² over, and it can still pass in one of two ways. An area-weighted U-value calculation can show the room performs no worse than a compliant one, usually by adding insulation to the walls, roof and floor. Or a SAP calculation can compare the house plus this orangery with the house plus a compliant one.

Building regulations from March 2027

A new edition of Approved Document L takes effect in England on 24 March 2027. It keeps the same five exemption conditions, the same extension treatment when the separation goes, and the 25% glazing rule.

Do you need planning permission for an orangery?

Usually not. In England an orangery is judged against the same limits that decide planning permission for a conservatory, because both are single-storey extensions:

• Depth: 3 m beyond the original rear wall of a semi or terrace, 4 m on a detached house.
• Height: 4 m at most, with eaves no higher than the house's, and no more than 3 m within 2 m of a boundary.
• Side and front: no wider than half the original house, and nothing beyond the front wall or a side wall facing a road.

On a semi or terrace the footings often run close to a neighbour's wall, and in England and Wales that can need a party wall agreement, with a surveyor at £800 to £2,000 per neighbour.

Prior approval takes a rear orangery to 6 m, or 8 m on a detached house, for a £249 fee and a 42-day neighbour consultation. Beyond that, or on a flat or a house whose rights have been removed, a householder application costs £548. A lawful development certificate, at £274, confirms in writing that a permitted development orangery is lawful.

Is an orangery warmer than a conservatory?

An orangery is usually warmer, because less of it is glass and its solid roof is insulated. As an extension its roof must reach a U-value of 0.15, while a rooflight is allowed 2.2, so a square metre of glass roof can lose around 15 times the heat of a square metre of solid roof. An exempt conservatory has no energy standard to meet at all.

An exempt conservatory needs its own heater, with its own thermostat and switch. An orangery built as an extension can run radiators or underfloor heating off the boiler and work as an everyday room all year.

Orangery or extension: which to build?

Built as an extension, an orangery costs about what an extension does. Single-storey extension costs per square metre run £1,900 to £3,300 before VAT, against £2,400 to £2,800, also before VAT, for a fully built orangery, so the choice is more glass or more wall rather than cheap or dear.

An orangery suits a kitchen or family room, where the lantern lights the middle of a deep room. Fitting a new kitchen in it adds £16,000 to £38,000, and means approval as an extension from the start, because a kitchen open to the house removes the separation.

Where the orangery is part of a wider renovation, build it before the new kitchen and floors go in. Knocking through, moving drains and running heating are structural and services work, and that comes before the finishes.

Can you turn a conservatory into an orangery?

Yes, usually with a new roof. A solid or tiled roof costs £8,000 to £15,000, against about £4,000 for a new polycarbonate roof and £6,000 to £12,000 for a new glass one.

A like-for-like replacement roof usually needs no planning permission, but one that raises the height can. A mostly solid roof takes the room below the 75% glazed mark, so it needs building regulations approval and has to reach a roof U-value of 0.15.

Which to choose: orangery or conservatory

A conservatory is the better buy when:

• The budget is under about £20,000, which covers an installed lean-to or Georgian conservatory but not an orangery.
• The room is for spring and summer, as a garden room or a place for plants.
• The doors to the house can stay, keeping the exemption and the lower price.

An orangery is the better buy when:

• It will open into the kitchen or living room and be used every day of the year.
• It will be heated from the house system, with radiators or underfloor heating.
• Privacy matters next to a neighbour's garden, where brick piers block the view in.

Where the usual pick goes wrong:

• A conservatory later knocked through to become the family room, which makes it an extension that was never built to extension standards.
• An orangery chosen for the look on a tight budget, where a conservatory with its own heating gives the same light for much less.

Orangery and conservatory rules in Wales, Scotland and Northern Ireland

Everything above is the England system. Wales, Scotland and Northern Ireland set their own exemptions and planning limits.

Wales has run its own planning system since 2016 and has its own Approved Documents. Schedule 2 of the Building Regulations 2010 covers Wales as well as England, so a ground-level conservatory of up to 30 m² is exempt there too if its glazing meets the Welsh requirements.

Scotland is far tighter. Under Schedule 1 of the Building (Scotland) Regulations 2004, an attached conservatory needs no building warrant only if it is 8 m² or less, at least 1 m from a boundary, and has no flue, combustion appliance or sanitary facility. An orangery of any usable size needs a warrant, and neither room has permitted development rights in a conservation area or on a flat.

In Northern Ireland, Schedule 2 of the Building Regulations (Northern Ireland) 2012 exempts a ground-level conservatory of up to 30 m² if the heating is not extended into it, it has no fixed combustion appliance and its glazing meets Part V. Work at a listed building, in a conservation area or in an area of outstanding natural beauty needs a planning application.