Conquering the Thermal Bridge
With today’s new construction standards, increased insulation effectiveness, higher quality windows, etc. it is important to stay focused on the details to ensure your project is as efficient as possible. One sure way to lose valuable heating or cooling energy (Btu’s) is to lose sight of the “Thermal Bridge”. A thermal bridge essentially allows heat to short circuit insulation. By definition a thermal bridge is an area or component of an object that has a higher thermal conductivity than the surrounding materials, thus creating a path of least resistance for heat transfer. This path results in a reduction of thermal resistance of the object or assembly thus creating a situation of higher heat gain / loss to a space. Thermal bridges also can cause the unanticipated expansion or contraction of the building components along with thermal drafts, and condensation on the assembly.
Often a thermal bridge occurs in construction around windows, floor to wall junctions, patios or balconies that tie back into the structure, door to wall junctions, areas with gaps or poorly installed insulation. Curtain walls can experience significantly increases in U-Factors due to their construction of highly conductive aluminum. It is important to design, specify and construct the building to minimize the thermal bridge.
There are several methods that have been proven to reduce thermal bridging:
Ensure continuous thermal insulation installation between walls and floors with rigid foam board.
Lapping of insulation where direct continuity is not possible.
Installing windows with thermally broken frames made of low conductivity material.
Installing double or triple pane windows with gas filler and low emissivity coating.
Verify insulation installation without voids or compressed insulation.
Identifying the thermal bridge can be difficult. Infrared thermography of buildings can allow the thermal signatures of that detect heat loss / gain to be located.
ASHRAE Standard 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings addresses thermal bridging in walls, floors, and roof assemblies.
Concerned about thermal bridging? Contact Engineering Solutions, LLC to provide a Infrared Thermal Imaging investigation of your building.
