Do You Need Heating in an Orangery?
The short answer
A properly built orangery needs no more heating than any other room in your house. The question of whether an orangery needs heating is really a question about how the orangery is built — and a well-constructed orangery, using a warm deck roof system, high-performance glazing, and correctly insulated walls and floor, will maintain comfortable temperatures year-round with a standard central heating connection or underfloor heating system.
The reputation for cold, unusable orangeries comes largely from older conservatories and poorly built extensions — not from properly specified modern orangeries. Understanding the difference between the two matters before you commit to any project.
Why a Modern Orangery Is Thermally Different from a Conservatory
The fundamental thermal challenge of a conservatory is its fully glazed roof. Glass transmits heat in both directions — outward in winter, inward in summer — at a rate that solid construction cannot match, regardless of how good the glazing specification is. Even the best triple-glazed conservatory roof will lose heat far more rapidly on a cold night than an insulated solid structure.
An orangery is built differently. Its solid roof perimeter — typically constructed using a warm deck system — provides a continuous insulated thermal envelope around the perimeter of the room. In a warm deck roof, rigid insulation sits above the structural deck, keeping the entire structural assembly within the warm zone of the building. This eliminates thermal bridging at the eaves — one of the most common sources of heat loss in older conservatory-style structures.
The glazed lantern at the centre of the roof is double or triple glazed with a thermally broken aluminium frame. It admits light from above without the disproportionate heat loss of a fully glazed roof. The ratio of solid insulated perimeter to glazed lantern in a typical Surrey Orangery build means the overall thermal performance of the roof is comparable to a well-insulated traditional extension.
Insulation in the Walls and Floor
Thermal performance in an orangery is determined by three elements — the roof, the walls, and the floor. Surrey Orangery builds all three to current Building Regulations standards as a minimum, with enhanced specifications available where the client requires exceptional thermal performance.
The masonry pillars and infill panels between the glazing sections are built using insulated cavity wall construction, achieving U-values that meet or exceed Part L of the Building Regulations. The glazing itself is supplied with thermally broken frames and double or triple glazed units as standard, with solar control glass available as an upgrade for south or west-facing elevations.
The floor construction depends on the project — most Surrey Orangery builds use an insulated concrete slab or beam-and-block floor, with rigid insulation beneath. Underfloor heating is laid within or above this slab and connected to the central heating system. This is the preferred heating approach for orangeries because it delivers even, radiant warmth across the entire floor area without requiring radiators that interrupt the glazed wall lines.
Heating Options for a Surrey Orangery
| Heating Option | Best For | Considerations |
|---|---|---|
| Underfloor heating (wet) | Best overall. Even radiant warmth, no radiators needed. Works with combi boiler or heat pump. Preferred on all new-build orangeries. | Higher upfront cost; requires correct screed depth |
| Underfloor heating (electric) | Good for smaller orangeries or retrofits. Lower install cost, higher running cost. | Less efficient on larger spaces |
| Radiators (wet system) | Straightforward extension of existing central heating. Lower install cost. | Radiators interrupt glazed wall lines; less even heat distribution |
| Infrared panels | Effective supplementary heat, particularly for occasional use spaces. | Not suitable as sole heat source in larger orangeries |
| Air source heat pump | Low carbon, highly efficient when paired with underfloor heating. | Higher install cost; requires outdoor unit space |
Will an Orangery Be Cold in Winter?
A Surrey Orangery build will not be cold in winter if it has been properly specified and connected to an appropriate heating system. The combination of warm deck insulation, thermally broken glazing and underfloor heating creates a room that is warm, comfortable and usable every day of the year — not a seasonal space that is closed off from November to March.
The most common reasons an orangery feels cold are: an inadequately insulated roof (particularly older conservatory roof conversions where the insulation has not been correctly detailed at the eaves), glazing with poor thermal performance or non-thermally-broken frames, and an undersized or incorrectly zoned heating system.
Surrey Orangery specifies all insulation and glazing to ensure the heating load is correctly calculated before installation. We work with heating engineers to ensure the underfloor system is correctly zoned and sized for the space, so the room performs as intended from day one.
Will an Orangery Overheat in Summer?
Overheating in summer is primarily a glazing and orientation issue. A south or west-facing orangery with clear glass and no solar control will experience significant solar gain on hot days. The mitigation is straightforward: solar control glass, which reduces heat transmission while maintaining visible light levels, is standard on south and west-facing elevations in Surrey Orangery builds.
The solid roof perimeter also helps significantly. Because the majority of the roof is solid and insulated rather than glazed, the solar gain through the roof is minimal compared to a conservatory. The lantern can be fitted with opening vents to allow warm air to escape, and the glazed wall sections can be designed to open as bifold or sliding doors to the garden, creating natural cross-ventilation.
A well-specified Surrey Orangery is comfortable in summer without air conditioning — a significant advantage over a conservatory, which often requires mechanical cooling or cannot be used at all on the warmest days.
Frequently Asked Questions
How much does it cost to heat an orangery?
The running cost of heating a properly insulated orangery is comparable to any other well-built room of the same size. With underfloor heating connected to a modern condensing boiler, a 25 square metre orangery in Surrey typically costs no more to heat than a similar-sized room in the main house.
Is underfloor heating essential in an orangery?
Not essential, but strongly recommended. Underfloor heating provides even, radiant warmth without requiring radiators that interrupt the glazed wall lines. It is the most elegant and effective heating solution for an orangery and Surrey Orangery installs it as standard on all new builds where the client approves the specification.
Can I add heating to an existing orangery?
Yes. Retrofitting underfloor heating to an existing orangery is possible but more disruptive, as it requires lifting the existing floor finish. Electric underfloor heating mats can be laid under new floor tiles or engineered wood without excavating the slab, making them a practical retrofit option. Surrey Orangery can advise on the best approach for your specific structure.
Does a warm deck roof make a significant difference?
Yes — it is the single most important factor in orangery thermal performance. The warm deck system keeps all structural elements within the insulated envelope, eliminating the thermal bridging that makes older conservatory-style roofs cold. Surrey Orangery uses warm deck construction on all orangery roofs as standard.
