What is Thermal Bridging?…
To put it simply, thermal bridging is what we call the movement of heat across an object that is more conductive than the objects surrounding it. This conductive material creates a path of minimal resistance for heat. Thermal bridging can create an increased amount of lost energy, which can result in a spike in your home’s utility bills.
Thermal bridging can result in increased energy required to heat or cool a conditioned space due to winter heat loss and summer heat gain. At interior locations near thermal bridges, occupants may experience thermal discomfort due to the difference in temperature. Additionally, when the temperature difference between indoor and outdoor space is large and there is warm and humid air indoors, such as the conditions experienced in the winter, there is a risk of condensation in the building envelope due to the cooler temperature on the interior surface at thermal bridge locations.
Condensation can ultimately result in mold growth with consequent poor indoor air quality and insulation degradation, reducing the insulation performance and causing the insulation to perform inconsistently throughout the thermal envelope.
In the images below taken during a thermographic home inspection, the thermal images show the framing on the exterior wall/roof due to the framing being cooling as a result of thermal bridging to the exterior.
In the construction of a residential home, a pretty sizable thermal bridge can be sparked by the studs inside of the walls. Traditionally, homes were built with 2×4 wooden studs with 16” spacing on center, with added fiberglass insulation to the empty space. The wooden studs are more conductive than the fiberglass insulation they are surrounded by, so even though the insulation does help to reduce energy loss through the wall itself, it does nothing to prevent energy loss across the thermal bridge.
Now consider that almost 25% of a home’s wall is made up of those wooden studs. Even with the fiberglass insulation inserted in the empty space, this 25% of wood studs add up to an entire wall inside of your home with zero insulation working against you. In the summer, the unwanted heat from outside will squeeze its way inside your comfortably air-conditioned home, and in the winter all of the heat you’re paying a pretty penny for will slip into the cold outside air.
Now, how to solve this problem, and quit allowing your money to slip through the cracks?
The best way to go about this is to ensure the studs themselves inside your home’s walls are entirely covered with insulation. When a home is first constructed, it is easy to add insulation to the wall’s construction to break a thermal bridge. In a home that is already built and is in the process of being remodelled, a layer of insulation can only be added from the home’s inside or outside. Adding insulation to the interior way is always particularly difficult and expensive, especially as it calls for a complete remodel to replace drywall, trim, and any other interior finishes.
By far, the easiest way to add a layer of continuous insulation to a finished home is underneath new siding on the outside of the home. By following this method, you are both breaking the thermal bridge and helping to increase your home’s energy efficiency, but you are also able to leave your home’s interior unbothered.
Almost 35% of a home’s energy loss is through the sidewalls of the home. This is more than windows, doors, foundation, and even the roof! This is why it is important to break your home’s thermal bridge with continuous insulation to reduce this energy loss and, subsequently, your utility bill! The most cost-effective time to add a layer of continuous insulation to your already standing home is when you are installing new siding.