Super-insulating solid may soon help historical homes reach net-zero goals

The construction of a new, super‑insulating material has attracted the attention of historians, architects and environmental scientists alike, all of whom are eager to see whether it can help the vast majority of heritage properties in the UK and across Europe meet ambitious net‑zero targets. The material in question is a class of aerogels, a form of silica derived from a gel that has had its liquid component replaced with air, leaving a structure that is both lightweight and highly insulating.Historically significant buildings are often subject to a range of constraints that make conventional retrofit techniques difficult. Many of these properties are listed, meaning that any alteration must preserve the character and integrity of the structure, and owners are frequently restricted in the types of interventions they can implement..

The energy performance of many of these buildings remains far below contemporary standards, and the UK government has set a national net‑zero target of 2050, with a legal requirement for all new buildings to be carbon neutral from 2030. While new construction can be designed for zero emissions, the challenge lies in bringing existing heritage assets up to the same level of performance.Enter aerogel technology, which has been developed by a number of small companies in the last decade. The material is prized for its ultra‑low thermal conductivity and negligible mass, which translates to a significant reduction in heat loss without the need for thick insulation panels..

Because the product can be applied in thin layers, it can fit within the tight confines of historic walls and windows, reducing the visual impact that traditional insulating materials might have.One of the companies leading the charge is British aerogel producer Aerocel, which has worked closely with the Historic England advisory group to develop a bespoke formulation that is compatible with a range of historic masonry types. According to a recent press release, the aerogel can be sprayed or applied as a paste, then cured at room temperature, which eliminates the need for high‑temperature processes that might damage age‑worn stone or plaster. Early trials in a Grade I listed building in London have shown that the new insulation reduced heat loss by up to 30 percent, while also maintaining the breathable characteristics of the wall fabric.The environmental benefits of aerogels extend beyond improved energy efficiency..

Because the material contains little moisture and is fire‑resistant, it reduces the risk of mould and damp – a persistent problem in older buildings that can lead to structural degradation and health issues for occupants. Moreover, the aerogel’s production process, which relies on a sol‑gel method that consumes less energy than traditional insulation manufacturing, is expected to produce a lower embodied carbon footprint. This means that the life‑cycle emissions associated with the building are reduced, not just the operational emissions from heating and cooling.Despite these advantages, sceptics point to cost and availability..

Current production volumes are modest, and the unit price of aerogel is still higher than conventional foams and mineral wools. However, the initial investment could be offset by the long‑term savings on heating bills and the potential for government incentives aimed at preserving heritage while improving energy performance. The UK government’s Energy Savings Opportunity Scheme (ESOS) could be a vehicle for such support, with recent updates indicating an expansion of eligible technologies, including advanced insulation materials.Another consideration is the durability of aerogels over the long term..

While the material is robust in laboratory settings, real‑world performance over decades remains to be fully documented. The industry is addressing this through extensive testing in controlled environments, but heritage buildings are subject to fluctuating humidity, temperature swings, and sometimes the presence of biological growth. Early field trials suggest that the aerogel maintains its properties for at least ten years, but further monitoring is needed before it can be recommended for widespread use.The potential for aerogel to help historic homes achieve net‑zero is not limited to walls and roofs..

It can also be used in window cavities, attic spaces and even under floorboards, where space is often at a premium. In one pilot project in Bath, the material was used to seal the cavity behind a timber sash window, reducing draughts without the need for bulk insulation that would interfere with the building’s historic fabric. The result was a measurable increase in indoor comfort and a reduction in energy consumption, all while preserving the visual character of the building.Policy makers are taking note..

The Department for Energy Security and Net Zero has indicated that it is reviewing the eligibility of aerogel for inclusion in the Green Homes Grant, a scheme that has already supported a wide range of retrofits. If approved, the grant could cover up to 80 per cent of the cost of the aerogel, making it more accessible to owners of older homes who might otherwise struggle with the upfront expense. The Department is also working with local authorities to develop guidance on the appropriate use of aerogel in listed buildings, ensuring that heritage conservation requirements are met.For many owners and custodians of historic properties, the promise of a material that can deliver substantial energy savings without compromising architectural integrity is a compelling one..

As the technology matures and the supply chain scales, the aerogel could become a staple of the conservation toolkit, helping to bridge the gap between preservation and sustainability. The transition to a net‑zero future will require a portfolio of solutions, but the introduction of a high‑performance, low‑impact insulation material may well be a critical piece of the puzzle, especially where the aesthetic and regulatory constraints of heritage buildings have traditionally limited the options available..