TL;DR: The best conservatory roof insulation brand depends on your priorities. For a fast, no-structural-change upgrade, CosyPanels and ThermoPanels are the stronger contenders. For maximum thermal performance, the LEKA System delivers U-values as low as 0.10 W/m²K backed by a 40-year warranty. For a tiled warm roof with strong UK trade availability, Eurocell Equinox achieves U-values as low as 0.15 W/m²K. This guide breaks down the technical specs, trade-offs, and best-fit scenarios across all five systems so you can make a well-informed decision.
Choosing between conservatory roof insulation brands doesn’t need to be overwhelming. But with several different systems available, comparing them fairly takes more than reading a handful of brochures — each one serves a slightly different need, and the right choice depends on your existing structure, your budget, and how you want to use the space.
This guide covers five of the most widely discussed conservatory roof insulation brands in the UK: CosyPanels, Eurocell Equinox, LEKA Systems, Renolit ThermoPanels, and Stadur FB-1. For each one, the technical data that actually matters to a homeowner is laid out — U-values, panel composition, weight, warranty terms, and roof compatibility.
Where specifications aren’t publicly available, that is stated clearly. Those gaps can be just as telling as the numbers themselves.
What Does a U-Value Mean for Your Conservatory?
Before comparing brands, it helps to understand what you’re measuring. A U-value quantifies how much heat passes through a material per square metre, per degree of temperature difference between inside and outside. The lower the figure, the better the insulation performs.
BRE’s BR 443 provides the standard UK methodology for calculating U-values in roof constructions. It underpins Building Regulations Part L, which sets minimum thermal performance thresholds for dwellings. Comparing brands using this framework ensures like-for-like accuracy.
For real-world context:
- A single-glazed conservatory roof typically has a U-value around 5.0 W/m²K
- A standard polycarbonate roof sits around 1.8–2.0 W/m²K
- A well-insulated warm roof can reach 0.10–0.18 W/m²K
The practical difference is significant. A conservatory with a U-value of 0.10 retains heat far more effectively than one at 2.0 — the gap translates directly into lower heating bills and a more comfortable room during winter.
At-a-Glance Comparison Matrix
Use this matrix as a starting point. Detailed analysis of each factor follows below.
| Factor | CosyPanels | Eurocell Equinox | LEKA System | ThermoPanels | Stadur FB-1 |
|---|---|---|---|---|---|
| System type | Insulated panel overlay | Tiled warm roof | Composite warm roof | Insulated panel overlay | PVC sandwich panel |
| Best U-value | Not publicly disclosed | 0.15 W/m²K | 0.10 W/m²K | Not disclosed (XPS λ: 0.034) | 0.62 W/m²K (44mm) |
| Max insulation thickness | Up to 50mm foam | Part of full warm roof build-up | PIR-core system | 35mm standard | 44mm standard |
| Structural change required? | No | Yes — full replacement | Yes — full replacement | No | No |
| Typical installation time | 1 day | 2 days | A few days | DIY-accessible | DIY-accessible |
| Warranty | 10-year product / 2-year IBG | 10-year | 40-year | Not disclosed | 5-year UV on PVC facings |
| Building Regs compliant | Not stated | Yes — Part L | Yes — MFA certified | Not stated | Not stated |
| Approx. panel weight | Lightweight | Not disclosed | Lightweight | Not disclosed | ~5.0 kg/m² at 44mm |
| Colour/finish options | Colour+ range | 16 tile styles; 8 fascia colours | Range of tile colours | Renolit film colour range | White (RAL 9016) standard |
Thermal Performance: How Do These Brands Compare on U-Values?
What U-value does the LEKA System achieve?
The LEKA System achieves U-values as low as 0.10 W/m²K — the strongest result in this comparison. That figure comes from its composite construction: GRP (Glass Reinforced Plastic) rafters, PIR (polyisocyanurate) insulation sheets, and load-bearing external boards made from high-grade plastic and XPS foam. An ECO variant uses EPS polystyrene in place of PIR. According to LEKA’s system page, the GRP frame also eliminates the condensation and thermal bridging problems common in aluminium or steel-framed systems.
What U-value does Eurocell Equinox achieve?
Eurocell Equinox is a tiled warm roof system that achieves U-values as low as 0.15 W/m²K, driven by high-performance styrene insulation within the roof build-up. The aluminium rafters are separated from the 18mm OSB timber deck, creating an air gap that reduces condensation risk as well as heat transfer. The Equinox product page details both the thermal specification and the structural design.
What U-value does Stadur FB-1 achieve?
Stadur FB-1 is a PVC-faced XPS-core sandwich panel with declared U-values published in its technical datasheet. At 44mm — the maximum standard thickness — the best-case U-value is 0.62 W/m²K using the lower-conductivity XPS core (λD 0.029). With the standard core (λD 0.033), the same panel gives 0.70 W/m²K. A 32mm panel sits at 0.84 W/m²K. These figures represent a clear improvement over polycarbonate, but fall short of the warm roof systems above.
What U-values do CosyPanels and ThermoPanels achieve?
Neither CosyPanels nor ThermoPanels publish declared U-values on their main product pages. CosyPanels uses up to 50mm of high-density foam insulation; ThermoPanels specifies an XPS core with a thermal conductivity of λ: 0.034 W/mK, as detailed in the ThermoPanels brochure. For either system, request the declared U-value for the full assembly in writing before committing.
Panel Composition and Thickness
CosyPanels
CosyPanels are precision-manufactured insulated panels that fit directly over an existing conservatory roof framework. Each panel contains up to 50mm of high-density foam insulation and slots into the glazing bars without any structural modification. The system keeps warmth in during winter and heat out during summer — and fits your current framework without alteration.
Eurocell Equinox
Equinox is a full warm roof replacement. The build-up layers a structural ring beam, aluminium rafters, an 18mm OSB deck, and styrene insulation — finished with a tiled outer surface. The system is manufactured from 75% recycled content and carries full Part L Building Regulations compliance. Sixteen tile styles are available across steel, composite slate, and GRP ranges.
LEKA System
The LEKA warm roof is built in four layers: GRP rafters onto the ring beam, PIR insulation sheets, load-bearing outer boards, and a tiled weatherproof finish. GRP avoids the moisture absorption of timber and the thermal bridging of metal. It also has a higher tensile strength than steel, which matters for long-term structural performance.
Renolit ThermoPanels
ThermoPanels are composite insulated panels with a PVC outer layer and an XPS foam core (density ≥33 kg/m³). Standard panel sizes are 3,000 × 1,000mm and 4,000 × 1,000mm, at thicknesses of 25mm and 35mm. Narrower panels (2,000 × 1,000mm) are also available at 28mm and 32mm. The outer surface comes in standard white (RAL 9016, RAL 9003, or RAL 9001) or a premium Renolit film colour finish applied on HPL — a wider colour range for those wanting a more personalised result.
Stadur FB-1
Stadur FB-1 panels consist of an XPS foam core bonded to hard PVC facings on both sides, available in 1.0mm, 1.3mm, 1.5mm, or 2.0mm facing thickness. The panels are humidity-resistant, high-impact resistant, and carry a 5-year UV guarantee on the PVC facings. They’re German-manufactured and widely used across construction applications, adapted for conservatory use by specialist installers.
Weight and Load Considerations
Weight directly affects whether your existing conservatory frame can support the new roof — and the answer varies significantly by system type.
- CosyPanels: Lightweight panels over the existing glazing bars. No structural modification required.
- Eurocell Equinox: A complete roof replacement. Frame suitability should be confirmed before installation.
- LEKA System: Engineered to be lightweight, but LEKA advises that installers must check existing windows, doors, and glazing can support the roof weight.
- ThermoPanels: Lightweight. Individual panel weights are not published, but the XPS core keeps mass low.
Comparison Methodology and Editorial Process
The article’s conclusions derive from a systematic comparison using authoritative U-value methodologies outlined in BRE’s BR 443, ensuring consistent thermal performance metrics. Information was sourced from primary brand technical pages and brochures, allowing direct verification of claims such as U-values, materials, warranties, and installation details. Where data was unavailable, the article transparently noted this, avoiding unsupported assertions. This approach enables an accurate, balanced evaluation for readers considering conservatory roof insulation options.