External wall insulation plays a crucial role in improving energy efficiency and comfort in homes and commercial buildings. It helps reduce heat loss, lower energy bills, and minimise carbon emissions, all essential as energy prices continue to rise.
While standard insulation materials like EPS and mineral wool are commonly used for large wall areas, some parts of a building can be difficult to treat with standard methods. That’s where aerogel insulation proves useful. Originally developed for the aerospace industry, aerogel is a lightweight, ultra-thin material with excellent thermal performance.
In this blog, we’ll take a closer look at aerogel insulation, how it works, and where it’s most effectively used in UK properties.
Content Page
- Aerogel Insulation: Smart Choice for Hard-to-Insulate Areas
- Key Benefits of Aerogel Insulation
- Applications of Aerogel Insulation
- Frequently Asked Questions
Aerogel Insulation: Smart Choice for Hard-to-Insulate Areas
Aerogel is a very lightweight and highly efficient insulation material made by removing the liquid from a gel, leaving behind a solid structure that contains up to 99.8% air. This results in excellent thermal performance within a very thin layer.
In the construction industry, aerogel is typically used in hard-to-insulate areas such as window reveals, door frames, gas meter boxes, and balcony junctions. These areas are prone to thermal bridging and often lack the space needed for traditional insulation materials.
Silica aerogel is the most commonly used type in building applications. It is valued for its low thermal conductivity, water resistance, and slim profile. Aerogel helps improve the overall insulation of a property by addressing problem areas where standard materials may not be effective.
Key Benefits of Aerogel Insulation
- Ultra-thin, high performance
A 10–20 mm layer of silica aerogel (λ ≈ 0.013 W/m·K) offers exceptional thermal performance in a fraction of the space required by traditional insulation materials, making it ideal for tight or detailed areas where bulkier solutions aren’t practical.
- Targeted thermal-bridge control
Aerogel is available in flexible blankets and pre-cut boards that can be installed behind gas-meter boxes, around steel lintels, window and door reveals, and other thermal weak points.
- Moisture-safe yet vapour-open
Silica aerogel is hydrophobic, it repels liquid water, preventing moisture ingress from wind-driven rain. At the same time, it remains vapour-permeable, supporting breathability and reducing the risk of interstitial condensation and mould.
- Verified fire protection
Silica aerogel insulation is classified as Euroclass A2-s1,d0 under the European fire rating system, which is widely used in the UK. This means it offers limited combustibility, produces little or no smoke, and does not drip when exposed to high temperatures, making it a safe choice for improving fire performance in buildings.
- Extremely lightweight
Made up of up to 99% air, aerogel is extremely lightweight. It adds minimal structural load, making it ideal for use on timber frames, old masonry, or heritage buildings where mass is a concern.
These five advantages make aerogel a niche but powerful option for upgrading hard-to-insulate areas while keeping fabric, aesthetics and internal space intact.
Applications of Aerogel Insulation
- Precision Application in Modern Builds
Aerogel’s unique properties make it a valuable asset in new construction, particularly when dealing with challenging junctions or design details where standard insulation materials can’t be accommodated. Its minimal thickness allows architects and contractors to maintain clean lines and meet energy targets without compromising usable space.
For period homes and listed buildings, insulation retrofits often face restrictions on altering façades or damaging original finishes. Thanks to its slim profile and vapour permeability, aerogel enables discreet internal upgrades that preserve external appearances and support building breathability, a key factor in conservation settings.
- Eliminating Hidden Thermal Weak Points
Rather than serving as a primary insulation layer, aerogel is typically used to treat cold spots and thermal bridges. It’s ideal for detailing around structural junctions, service penetrations, and areas with limited space, supporting full-system thermal continuity without bulky build-ups.
Frequently Asked Questions
- What areas benefit most from aerogel insulation?
Aerogel is perfect for narrow cavities and junctions where standard materials won’t fit, such as behind meter boxes, around window and door reveals, and at balcony junctions.
- Is aerogel insulation cost-effective?
While aerogel costs more per m² than EPS or mineral wool, its performance in tight spots can save you having to redesign details or lose interior space. It’s particularly valuable for eliminating thermal bridges, rather than as a full-wall solution.
- Who installs aerogel?
Choose specialist insulation contractors with experience in advanced materials. Proper handling, fixing, and detailing are key to getting the full benefits of aerogel.
- How long does aerogel insulation last?
When correctly installed, high-quality aerogel insulation can retain performance for 25+ years with minimal degradation.
- Can I apply aerogel insulation myself?
We wouldn’t recommend it. Aerogel is fragile and requires precise fixing, professional installation is strongly recommended to avoid performance loss.
Ready to Improve Your House Insulation?
Whether you’re dealing with cold spots, planning a renovation, or simply looking to make your home more energy-efficient, we’re here to help. As experienced external wall insulation installers, we can walk you through the best options for your property. Feel free to get in touch for a friendly chat about your project.
