The consequences of thermal bridges include:
- Uncomfortable internal temperature of your home
- Increased heating and cooling costs
- Condensation and mould issues
- Structural damage and premature rot
Unfortunately, few people (even experienced designers and builders) understand the importance of eliminating thermal bridges, especially when building an airtight home.
One of the most common thermal bridges occurs around windows – particularly when they are made from aluminium. Aluminium is an efficient conductor of heat. When the weather is cold outside, an aluminium window will feel cold on the inside. Not only will this compromise your efforts to heat your home, but it could also cause condensation to form as the cold aluminium reacts with the warm air inside your home. While you can simply wipe the condensation off the surface of your window frame, you can’t dry the condensation that you don’t see inside the wall cavity. This condensation provides the perfect environment for mould to grow (dark and damp). Other common thermal bridges occur in external corners of rooms. If insulation is not fitted properly, a thermal bridge can cause a temperature differential where the cold from outside meets the warmth from inside and forms moisture. That’s why so many homes develop mould in the corners of rooms. And the problem is, the mould you see is just like the small part of an iceberg poking above the surface – the majority remains invisible behind the walls and ceiling, dangerously affecting the health of your home. Mould will not only cause your home to rot prematurely, but it can also compromise the health of the people living in the home. Symptoms may be as mild as a runny or blocked nose, irritation of the eyes and skin, and wheezing. For others (particularly over time), the consequences can include serious asthma and even mould infection in the lungs. Eliminating thermal bridges at the design and construction stage of building is straightforward and efficient. It’s simply a matter of knowledge and attention to detail. Correcting thermal bridges after construction is far more difficult and costly. And once they are identified, the consequences of thermal bridges (to the home and its occupants) will have already taken effect. For more information about how to avoid thermal bridges when building your custom home we invite you to download our guide on the 5 Key Skills of an Energy Efficient builder where you can learn the key skills your builder needs to have to actually build you a healthy home.Frequently Asked Questions
What is a thermal bridge?
A thermal bridge is a conductive pathway that lets heat transfer from inside your home to outside and vice versa, the same way a frypan heats up from the stove element. Internal parts of your home like windows and walls are affected by conduction from the external building materials.
Why are thermal bridges a problem?
They cause an uncomfortable internal temperature, higher heating and cooling costs, condensation and mould, and structural damage and premature rot. Few people, even experienced designers and builders, understand how important it is to eliminate them, especially in an airtight home.
Where do thermal bridges most commonly occur?
Around windows, particularly aluminium ones, which conduct heat and feel cold inside when it is cold out, causing condensation. They also occur in the external corners of rooms where insulation is not fitted properly, which is why so many homes develop mould in the corners.
How do thermal bridges cause mould?
A cold surface meeting warm internal air forms condensation. Inside a wall cavity you cannot wipe it away, so the dark, damp space grows mould, and what you see is only the tip; most stays hidden behind the walls and ceiling, affecting the health of the home and the people in it.
Can thermal bridges be fixed after the home is built?
Eliminating them at the design and construction stage is straightforward, a matter of knowledge and attention to detail. Correcting them after construction is far more difficult and costly, and by the time they are found, the consequences to the home and its occupants have usually already taken effect.
