What is a Thermal Break?
Metal windows and Doors (be it Aluminum, Steel or Bronze) have a number of advantages over wood – they are stronger (in particular the steel and bronze ones), and because of their structural strength, you can make narrower profiles from them, increasing the amount “glass to frame” ratio. They are also very low maintenance, it won’t rot or require re-sealing and treating. But, as any owner of old steel windows might tell you they also have down sides: the principal one is their energy efficiency. Metal conducts heat (energy) easily and that means that on a hot day a solid metal frame will act like a radiator in your room, and likewise, on a cold day, you will be losing heat outdoors through your frames far more than through the glass. If your room is also humid (a kitchen or bathroom, for example) then many homeowners experience condensation on the windows.
In order to solve this problems window and door manufacturers are introducing an insulating barrier between the inside and outside of the window frame. This barrier is what is called “thermal break’
In this example the white material is high density polyurethane resin but it can be reinforced also with fiberglass, another good insulator. The role of the thermal break is twofold – it must be a very poor heat conductor, blocking heat from moving from inside the house to outside and vice versa. Its other job is structural, inasmuch as it holds the two metal profiles together.
The result is a frame that stands shoulder to shoulder, in energy efficiency terms, with frames made in wood.
However there is another, lesser known advantage of a thermal break – that of sound absorption. Just like metal conducts heat it also conducts sound and just like the insulating material blocks heat from passing it also dampens sound vibrations very effectively making for better sound insulation from outside noise.