Conservatory roof insulation and insulated roof panels

Conservatory roof insulation comes in two forms that keep your existing roof frame. Insulated panels replace the polycarbonate or glass in the glazing bars. An internal insulated ceiling is fitted underneath the existing roof, from inside. Both usually take about a day, cost a fraction of a new tiled roof and take the edge off the heat, cold and rain noise. Neither reaches the insulation of a full warm roof, and both shut out the light from above.

Does conservatory roof insulation work?

It works better for comfort than for bills. MoneySavingExpert users who fitted panels reported a more usable room but negligible energy savings. One internal insulation firm claims savings of £300 to £400 a year without saying how it worked that out, so treat savings claims with care: the Advertising Standards Authority ruled in 2023 that a spray foam insulation firm’s claim of cutting heat loss by “up to 58%” was unsubstantiated.

On the numbers, 75mm panels are quoted at 0.29 W/m²K, far better than polycarbonate at 1.2 to 2.4, but roughly double the 0.15 that Approved Document L sets for a new solid roof. If you are cold in winter, our page on a conservatory that is too cold covers the walls, floor and heating too.

The main types of conservatory roof insulation

Type	How it works	Published figures	Examples
Insulated roof panels	Foam-cored panels with aluminium skins replace the sheets in the existing bars	0.29 at the centre of a 75mm panel (makers’ claims)	Thermotec, Superior Conservatory Panels, Green Space
Internal insulated ceiling	Timber sub-frame under the existing rafters, multifoil quilt, uPVC cladding or plaster	0.17 to 0.18 claimed for the quilt alone	CI Group, Conservatory Insulations UK, Conservatory Roof Insulation Ltd, Comfy Conservatories, TCIC Living
New warm roof	Old roof removed and a new insulated roof built	0.12 to 0.15 (makers’ claims)	See tiled conservatory roofs

Insulated roof panels: how they fit and what to check

The installer lifts out the old sheets one bay at a time and fits panels cut to size into the same glazing bars. The ridge, bars and gutters stay. A review of Thermotec says a typical installation takes one day and quotes a 10-year guarantee; Superior Conservatory Panels publishes testimonials of fitting within four hours. Green Space quotes a 10-year guarantee on its panels but only a 1-year workmanship warranty, so read what each guarantee covers.

Thickness matters. PanelX, which makes thinner panels to replace individual sheets, quotes 0.98 for 25mm and 0.75 for 35mm, two to three times the heat loss claimed for a 75mm panel.

The U-value is also measured at the panel’s thickest point. Bryant & Cairns, a firm that sells solid roofs and so competes with panels, argues that heat still escapes through the existing bars and ridge, that aluminium skins without a thermal break can cold-bridge and cause condensation, and that guarantees often cover only the panels themselves. It is a competitor’s view, but the questions are fair ones to put to any panel seller.

Internal insulated ceilings: how they fit

An internal ceiling leaves the old roof in place. The fitter fixes a timber sub-frame to the existing rafters, lays a multifoil insulation quilt (products such as SuperFOIL SF19 or YBS SuperQuilt), and finishes it with white uPVC tongue-and-groove or shiplap cladding. TCIC Living and Comfy Conservatories also offer a plaster finish. CI Group says its system takes about two inches off the ceiling height.

This is the cheapest professional option with published prices. Conservatory Roof Insulation Ltd starts from £1,590 and Conservatory Insulations UK from £1,699, neither with a size stated. Comfy Conservatories lists prices from £1,680 for 12m² and gives a 5-year guarantee where several rivals offer 10. The U-values some firms quote are for the quilt alone, not the whole roof.

Because the old roof stays outside, it must still keep the rain out. A Trustpilot reviewer of CI Group reported a roof that leaked months after installation, with saturated insulation and roof ventilation that had not been fitted correctly.

Building regulations: the claims conflict

Some sellers say insulated panels need no building regulations approval. LABC’s guidance takes a different view: products that “underdraw or overclad” an existing polycarbonate roof, and any work that significantly reduces the glazing or translucence of the roof, end the conservatory’s exemption. There is no official ruling specific to lining kits, so treat that as LABC’s position rather than settled law. In Scotland, insulation work does not need a building warrant but must still meet the standards, and an opaque ceiling can take the structure outside the Scottish definition of a conservatory. Ask for the seller’s position in writing, and see our building regulations guide.

Condensation, weight and light

Ultraframe, which makes full replacement roofs, warns that fixing battens and insulation under a glazed roof can damage the glazing bars, adds weight, traps heat and cuts light. One lining firm’s own wording, that its cross ventilation “eliminates the majority of possible future condensation”, concedes some risk remains in the gap above the ceiling. Insulation Superstore advises watching blinds and curtains for mould in conservatories.

Paperwork matters too. Since 6 August 2026, EPC assessors record a conservatory with a false ceiling as an extension, with the insulation recorded as none unless there is visual or documentary evidence. Keep the specification sheet and any building control certificate.

Who roof insulation suits, and who it does not

Insulation suits you if the roof frame is sound and not leaking, you have a polycarbonate roof you are tired of, and you want a quieter, more even room for well under the cost of a tiled roof.

It suits less well if the bars, ridge or gutters leak (insulation keeps the old roof), if you want a room at house temperature all winter, or if you rely on the roof for daylight. Our comparisons of internal insulation kits vs a new roof and a tiled roof vs insulated panels set out the trade-offs.

Questions to ask before you sign

When you get quotes, ask each installer:

1. Is the U-value for the whole roof, or only the centre of the panel or the quilt?
2. How thick is the panel core, and do the aluminium skins have a thermal break?
3. What happens to the existing bars, top caps, seals and gutters? Are any replaced?
4. How is condensation handled, and is any ventilation added?
5. Does the guarantee cover leaks and workmanship or only the panels, how long is it, and is it insurance backed?
6. What is your building regulations position, in writing?
7. How is VAT charged? HMRC zero-rates installed insulation until 31 March 2027, but insulation fitted as part of a wider building job is standard rated.

The insulated panel cost guide shows typical prices by size.