The energy efficiency of any home is dictated by a whole host of factors both inside and out.
From the type and quality of the gadgets and appliances used in the home to the very fixtures and methods that the house itself is made with, it is a combination of all of these changes both large and small that contribute to achieving a “green home”.
Whether or not you actually want a green home, making it energy efficient is still generally nice to have. And when you’re constructing or renovating any home for better energy efficiency, thermal bridging is something you and your contractor should be both aware and wary of.
How Thermal Bridging Works
So what is thermal bridging, anyway? Simply put, it is a thing (or lack thereof) within a wall’s structure that allows a faster than normal rate of heat transfer. If you know your thermodynamics, you can skip on ahead to the solutions section, but for those that don’t, we will be breaking it down for you.
To better understand how thermal bridging works, we can use the concept of electricity as a parallel. When electricity powers something like your oven, it has to travel from an electrical outlet to your oven through a wire. That wire is made of a metal core (usually copper) that is wrapped by a plastic sheath.
Now, there are two reasons why the electricity doesn’t just zap anything it touches when it passes through the wire. The first reason is that electrical energy likes to travel the easiest and shortest path across two points.
The second reason is that the copper core of the wire (compared to the plastic sheath) gives electricity that short and easy path because of its conductivity.
In the case of temperature, the principles stay mostly the same. Heat energy likes to travel down the easiest and shortest path, and there are materials that have more thermal conductivity than others, allowing for this faster travel path.
Why Thermal Bridging Matters
All of this matters because of the way thermal energy works. Unlike electrical energy, thermal energy is always on the move and tends towards thermal equilibrium—in other words, it wants to balance out the heat energy throughout a given area.
Since heat has higher energy than cold, the heat from hotter areas will want to move to the colder areas to balance out the temperature.
In the case of your home, this means that the warmth in your house will want to escape on cold days and the heat of the summer will want to enter into your cooled home.
Thermal bridging is exactly this unwanted heat transfer, as we mentioned, and having even one in your home can put a serious damper on your home’s ability to maintain its desired temperature and, in turn, affect its energy efficiency as you will want to push the heater or AC harder to maintain its temperature.
In addition, a thermal bridge can also cause unwanted condensation in some areas as warm air in your home comes into contact with a cold surface. The condensation produces moisture accumulation, which can then cause mold and mildew to form.
Signs of Thermal Bridging
One of the difficulties in solving thermal bridging problems is that they can be very difficult to detect if you don’t know where to look.
The easiest way to do this would be to purchase a thermal camera that can visualize the exact areas where there is unwanted thermal transfer—in fact, this is the method that is used by inspectors for commercial buildings and high-rises. For the average homeowner, however, this might not be so feasible.
As such, we’ve made a handy list below of some of the common signs of thermal bridging happening on your home.
However, we do want to make clear that this will only cover the thermal bridges that you can observe with a visual inspection; as we noted earlier, there can be various other thermal bridges in your home that could be caused by internal wall structures that can’t be seen without the right tools.
- Ice dams could be caused by a thermal bridge as escaping heat from the inside of the house could melt some snow on the roof that freezes again when it reaches the edge.
- Ice or snow stripes on your roof is another sign of a thermal bridge, which is typically caused by a gap or inconsistent thickness in your attic’s insulation. These gaps can cause the warmth from inside to transfer to the roof, melting snow in some areas but not others.
- Mold and mildew formation could be caused by a thermal bridge if your home is located in a region with a large difference between the outside temperature and the desired inside temperature. Such large temperature gradients could cause condensation through the thermal bridge, which creates the perfect breeding ground for these fungi.
- Panel gaps in your home are a textbook example of a thermal bridge, allowing not only thermal transfer but also wind and weather to flow in from the outside. Small gaps might not look like much, but their impact on your home’s energy efficiency—and your energy bill—is nothing to scoff at.
Solutions for Thermal Bridging
From a whole-home standpoint, the most effective solution to thermal bridging really comes down to two things: good insulation and proper construction. Although these two solutions are generally separate things, it is preferable to implement both at the same time.
In the case of insulation, the general idea to reduce the incidence of thermal bridges in your home is to ensure that the layer of insulation in your home is completely continuous with no breaks or gaps. Foam board insulation is one of the most popular ways of going about this, as they can be easily installed and sealed with insulating tape.
As for construction, though, the possibilities and potential solutions are about as complex as the home itself. Those looking to build a new home may want to consider implementing measures like double-glazed windows and ensure proper insulation throughout the house (which could be achieved with newer construction methods like insulated concrete forms).