Energy saving

The right energy efficient building material

This sponsored content article is provided by H+H

Thirty percent of all the energy consumed in the UK is used to heat homes, which is a huge issue when it comes to tackling climate change. Choosing the right building materials can help you maximise energy efficiency, resulting in a more comfortable home or office that is cheaper to run.

Regardless of building regulations, energy, or thermal, efficiency should always be built into the fabric of a house. This way the effect remains consistent for the lifetime of the building, regardless of home owner behaviour. Insulation experts H+H refer to this approach as ‘fabric first’.

Using a durable material such as aircrete for one or both leaves of a cavity wall will make a significant contribution to the thermal efficiency of the building.

What are fabric U-values?

Simply put, a U-value is the measure of how much heat is conducted through a material: the lower the number, the better the insulation. U-values describe the rate of heat flow in watts (w) through an area of 1 square metre (sq m) for a temperature difference across the structure of 1⁰C or Kelvin (K), and are expressed in W/m2K. A properly insulated aircrete wall, for example, can have a U-value of as low as 1.8 W/m2K, while building regulations only require a performance of around 3 W/m2K.

What is aircrete?

Aircrete – or aerated concrete – is manufactured in a process that captures thousands of small insulating air pockets throughout each block. The result is a material that combines the strength of masonry with inherent insulation built in.

When combined with modern methods of construction, like the Thin-Joint System (external link), efficiencies can be even further enhanced.

Aircrete, combined with thin-joint mortar, provides a hugely airtight wall structure, with the airtightness reducing heat loss still further. What’s more, when aircrete is used as part of a thin-joint solution, it has the additional benefit of speeding up construction as the load-bearing walls can be built extremely fast, giving a weatherproof structure quickly. The interior trades can then get on with fitting out the inside at the same time as the brick outer walls are being finished.

The thermal mass effect

Building regulations in the UK focus on keeping buildings warm as efficiently as possible, but summer comfort is also important and as we experience periods of very hot weather, overheating is becoming an issue.

One way to tackle this is to use materials with a high thermal mass. Materials that have a high thermal mass (such as masonry) will take a long time to heat up. On a hot summer’s day, a masonry wall will heat very slowly, allowing the temperature inside to stay comfortable. Heat absorbed by the masonry during the day will then be released slowly during the night – keeping a relatively constant temperature inside the house throughout the 24 hour cycle.

Lightweight building materials, on the other hand, will heat up and cool down very fast, contributing to significant temperature fluctuations inside the building. 

Find out more about the thermal efficiency of aircrete buildings.