A thermal break or thermal barrier is an element of low thermal conductivity placed in an assembly to reduce or prevent the flow of thermal energy between conductive materials.
In architecture and building construction some examples include the following:
a thermal break is also a load-bearing thermal insulation system used in reinforced concrete structures to form a thermal break between cantilever structures and internal floor.
Insulated glazing – the air or gas between the panes stops the conductive thermal energy from passing through the glass.
Metal window or curtain wall framing – a separator material is used between the inner and outer frames to prevent the temperature transfer through the frame and condensation on the inside frame.
Concrete work – a single row of concrete masonry units (CMU block) is commonly set between the inner concrete slab and exterior concrete work to prevent the transfer of heat or cold through the slab.
Garage doors – in some doors that have high R-rating insulation, a vinyl thermal break is used along the edges of each segment instead of rolled steel.
Metal and wood framed buildings - an insulation material installed on the roof, walls and floor prevents thermal short circuit creating the heat transfer through the framing material and controls when desired (winter/summer)resulting in energy savings.
Metal windows and doors - separating the frame into two separate interior and exterior pieces joined with a less conductive material reduces temperature transfer. Thermal breaks (made of substantially rigid, low thermal conductive polyamide or polyurethane which is mechanically locked in aluminum window framing can be more than a thousand times less conductive than aluminum and a hundred times less than steel.
Windows and doors - separating the frame into 2 separate interior and exterior pieces joined with a less conductive material between reduces temperature transfer. In addition thermal breaks can have the added benefit of reducing sound transmittance by dampening vibration.