What is Thermal Bridging and How to Stop it

Thermal bridging occurs when heat travels through a material in your home that’s more conductive than the surrounding materials. The thermal bridge acts as a path of least resistance for heat flow, meaning greater heat gain in summer and greater heat loss in winter – even if you have insulation installed. Thermal bridging can significantly reduce the energy efficiency of your home and make it harder to keep indoor temperatures at a comfortable level. In this guide, we explain what thermal bridging is, how it can negatively impact your home’s energy efficiency and what to do about it.

What is thermal bridging?

Heat or thermal energy always flows from areas of high thermal energy to areas of low thermal energy through the path of least resistance. A thermal bridge is an area of the building envelope where heat flow is higher than the surrounding areas. In other words, a thermal bridge is an easy pathway for heat to flow in and out of your home. For example, a steel-framed house with glasswool insulation in the walls may have thermal bridges if the steel frame touches the inside and outside of the house surfaces. In these areas, the steel will act as a thermal bridge since steel is a more conductive material compared to the surrounding insulation layers. A timber house frame can also act as a thermal bridge. Thermal bridging might also occur where there is a gap between insulation materials, for example, if a window is not sealed properly or if gaps are left between insulation batts during installation. The result of thermal bridging is an overall reduction in insulating efficiency. One of the best examples for thermal insulation can be found in ceiling. You can find out more about our ceiling insulation and purchase it on our website.

Types of thermal bridging

Thermal bridges can often be classified as either repeating, linear or point thermal bridges.

Repeating thermal bridges

Repeating thermal bridges occur at regular intervals across an entire section of the building envelope. Examples include wall studs where insulation is installed between the studs and ceiling rafters where insulation is installed between rafters.

Linear or non-repeating thermal bridges

Linear thermal bridges occur where two elements of the building structure meet. For example, where the floor meets the wall or where walls meet windows and door openings.

Point thermal bridges

Point thermal bridges occur at a single point in the building envelope. Examples include penetrations for electric cables and mounting brackets.

When is thermal bridging a problem?

Where thermal bridging occurs, heat flow will bypass your insulation reducing its overall effectiveness. By providing a direct path for heat to travel in and out of your home, thermal bridges lead to greater heat loss during winter and greater heat gain throughout summer. This can have a significant impact on indoor comfort levels and energy consumption for heating and cooling. Homes with thermal bridging problems use more energy to regulate temperatures inside the home. What’s more, thermal bridges can lead to condensation build-up and moisture issues inside the home. When warmer temperatures along the surface of the thermal bridge come in contact with a cold surface, the moisture in the air condenses into water droplets. Moisture issues, including mould and mildew, can negatively impact indoor air quality and may have health impacts. Moisture issues can also cause building materials to deteriorate faster.

How to reduce thermal bridging

Avoiding thermal bridges starts at the design phase. The design, construction techniques and materials used when building, renovating and installing insulation can all help. The following strategies can help reduce thermal bridging and improve the energy efficiency of your home:

Install insulation without air gaps

When installing insulation, aim for a snug fit without leaving any unnecessary air gaps for heat to escape through.

Avoid compressing bulk insulation

Avoid compressing bulk insulation (batts and rolls) when you install it. Compressed insulation has a higher thermal conductivity compared to insulation that is installed properly.

Seal around doors and windows

Seal up air gaps around doors and windows to prevent heat loss and gain at these points. Also, consider using double-glazed windows and insulated doors on your exterior walls.

Use a thermal break

A thermal break is an element with low thermal conductivity. The thermal break is placed where it will interrupt the heat flow path, disrupting the connection between the air inside and outside your home.

Install two layers of insulation

Consider installing insulation in two layers to reduce heat transfer and improve thermal performance. For example, install one layer between the ceiling joists, and the second layer cross-ways over the top of the first layer.

Need more information?

Insulation is one of the best and most effective ways to improve energy efficiency and thermal comfort in your home year-round. To ensure you get the most out of your insulation investment and avoid issues with thermal bridging, it’s important to follow installation best practices. Check out our DIY installation guides or create a budget for your project with our guide to how much it costs to insulate a house in Australia. If you need expert advice about your project, call our team of insulation specialists on 1300 729 639.