Aerogel insulation achieves the lowest U-value per millimetre of any commercially available material
If you are renovating a period home or insulating a tight space, you may have come across aerogel as a high-performance option. The key question is whether its exceptional thermal properties justify the much higher price.
According to the Energy Saving Trust, aerogel insulation has a thermal conductivity (lambda value) of approximately 0.014–0.019 W/mK, compared to 0.032–0.044 W/mK for mineral wool or PIR boards (Energy Saving Trust, 2026). This means a 10 mm layer of aerogel can achieve the same thermal performance as 50–80 mm of conventional insulation. That makes it the thinnest effective option on the market.
Homeowners typically choose aerogel when space is limited, for example, behind radiators, in loft hatches, or around pipework, where thicker insulation simply cannot fit. The trade-off is that this high performance comes at a significantly higher material cost, typically £20–£40 per square metre for blanket form, versus £5–£15 for PIR or mineral wool (DESNZ “Home insulation cost guide”, 2026).
The two main aerogel insulation products for UK homes are blankets and panels
Aerogel blanket (flexible, rolls) is the most common form for retrofitting walls, floors, and roofs in tight spaces. It can be cut with a knife and fitted around obstructions such as pipes, cables, or uneven masonry. Aerogel panel (rigid, board) is used for flat surfaces like internal wall insulation or underfloor applications where a smooth finish is required.
Both products require a vapour control layer (VCL) on the warm side to prevent interstitial condensation, as aerogel is vapour-permeable (BRE “Aerogel insulation in practice” guide, 2026). Homeowners should confirm the product has a UKCA or CE mark and is certified to BS EN 13162 (blankets) or BS EN 13163 (boards) for thermal performance. Without this certification, the stated lambda value may not be reliable.
Aerogel insulation costs £20–£40 per square metre
Material cost for aerogel blanket is £20–£40 per square metre (DESNZ “Insulation materials price tracker”, 2026). Installation adds £10–£25 per square metre depending on complexity, based on TrustMark registered installer quotes. For a typical 2 m² window reveal (the space around a window frame), total cost is £60–£130 for materials plus labour.
The payback period is not typically calculated in years because aerogel is used for space-constrained areas where alternatives cannot fit. The benefit is thermal comfort and reduced heat loss, not a direct fuel bill payback. The Energy Saving Trust advises that aerogel is cost-effective only when conventional insulation cannot achieve the required U-value within the available depth, for example, solid wall internal insulation where you cannot lose 100 mm of room space (Energy Saving Trust, 2026).
Quick numbers, aerogel insulation performance and cost comparison
| Material | Thermal conductivity (W/mK) | R-value per 10 mm (m²K/W) | Typical cost per m² (2026) | Space needed for 0.30 U-value |
|---|---|---|---|---|
| Aerogel blanket | 0.015 | 0.67 | £25–£35 | 20 mm |
| PIR board | 0.022 | 0.45 | £8–£12 | 70 mm |
| Mineral wool (rigid) | 0.035 | 0.29 | £5–£8 | 100 mm |
| EPS bead | 0.038 | 0.26 | £4–£7 | 110 mm |
Thermal values from the Energy Saving Trust “Insulation materials comparison” (2026) and costs from DESNZ “Home insulation cost guide” (2026) (Energy Saving Trust, 2026; DESNZ, 2026). The table shows that aerogel achieves the same U-value in 20 mm that requires 70–110 mm of conventional materials. The trade-off is that aerogel costs 3–5 times more per square metre than PIR or mineral wool.
Aerogel insulation is most suitable for solid walls
For solid walls (pre-1920s homes), internal wall insulation with aerogel can achieve a U-value of 0.30 W/m²K in just 20–30 mm, versus 80–100 mm needed for PIR or mineral wool (BRE “Retrofitting solid walls” guide, 2026). This is critical when you cannot afford to lose floor space or alter skirting boards and door frames.
Window reveals benefit from 10–20 mm of aerogel to reduce thermal bridging and condensation risk. The Energy Saving Trust recommends this as a targeted retrofit measure. For pipework and tanks, aerogel wrap is used for hot water pipes in unheated spaces (lofts, basements) where space is too tight for standard foam lagging (EST “Pipe insulation guide”, 2026).
Aerogel is not suitable for full cavity wall insulation (where mineral wool or EPS beads are cheaper and effective), or for large loft areas (where space is plentiful and cost is lower with mineral wool). Compare aerogel vs PIR insulation for solid walls
The direct answer aerogel insulation in the UK in 2026 is a high-cost
Aerogel insulation is not a general-purpose replacement for standard insulation. It is a specialist product for situations where you cannot fit enough conventional insulation to meet Building Regulations Part L (conservation of fuel and power). Typical scenarios include internal wall insulation on solid walls where you cannot lose room space, window reveals to reduce thermal bridging, and pipework in tight roof or floor voids.
Building Regulations Part L (2021 edition, updated 2025) requires a U-value of 0.18 W/m²K for new walls and 0.30 W/m²K for retrofit (HM Government “Approved Document L”, 2025 edition, in force 2026). Aerogel makes these targets achievable in thin layers. Homeowners should only choose aerogel after measuring the available depth for insulation and calculating whether conventional materials can meet the target. The Energy Saving Trust’s online calculator can help determine the required thickness.
Installers must hold MCS certification or equivalent for aerogel insulation
For internal wall insulation with aerogel, the installer should be registered with TrustMark (government-endorsed quality scheme) and ideally hold an MCS (Microgeneration Certification Scheme) certificate if the project is linked to a heat pump or renewable heating system (TrustMark “Find a trader”, 2026; MCS “Installers directory”, 2026). For pipework insulation, Gas Safe Register covers gas-safe installations; for electrical work around insulation, NICEIC or NAPIT registration is required.
Ask for the product’s UKCA mark and the installer’s public liability insurance (minimum £2 million). The Energy Saving Trust advises getting at least three quotes and checking that each quote specifies the product’s lambda value and thickness, not just a U-value claim. How to find a certified insulation installer in the UK
Frequently Asked Questions
Aerogel insulation costs £20-£40 per square metre for blanket form, according to the DESNZ 'Home insulation cost guide' (2026). This is roughly 3-4 times more than PIR or mineral wool at £5-£15/m².
Aerogel is worth the cost when space is tight, such as behind radiators or in loft hatches, because 10mm can match 50-80mm of standard insulation. For most walls where thickness isn't limited, cheaper materials offer better value, per the Energy Saving Trust.
Aerogel insulation typically achieves an R-value of approximately R-10 to R-14 per inch (25.4mm), based on its lambda value of 0.014-0.019 W/mK. This is roughly twice that of PIR boards.
Aerogel is not commonly used for full cavity wall fill due to cost. It is better suited for thin internal wall insulation or spot applications around pipes and joists, as advised by the BRE guide.
Yes, aerogel insulation requires a vapour control layer (VCL) on the warm side of the insulation, as it is vapour-permeable. This prevents interstitial condensation, according to the BRE 'Aerogel insulation in practice' guide (2026).
Aerogel blanket is flexible and rolls out, ideal for wrapping pipes or fitting around obstructions. Aerogel panel is rigid board for flat surfaces like walls or underfloor. Both need a VCL and BS EN certification.
