Don’t waste your money on good windows.

More to the point, make sure the good windows that you purchased are performing to their full potential.

As I mentioned in a previous post about insulation, a good quality thermally efficient product will only perform adequately if is installed properly as part of a well considered system. A high-end window with a quality double or triple glazed IGU (insulated glass unit) is wasted if it is installed in a leaky, poorly insulated house.

Windows are an important component of the building envelope. A thermally advanced window with a low Air Infiltration rate is an excellent choice for a high performance result. If you are going invest your money specifying such a unit in your new house, it makes financial sense to make sure that you are installing the component in a house system of high performance integrity. (Formula One teams don’t develop high performance engines then run them in a Model T Ford).

House performance relies on a system of components that interact with each other. These components must not be treated in isolation. Each component and its connection with other components must be understood. A High performance window must be installed in relation to the water, air, and vapour control layers of the wall system. The detailing of these connections must be thought through and implemented properly to ensure an optimum result. To not do this leads to a poor return on your investment.

LESSON: Don’t waste your money on good windows. If you are paying for high performance, make sure you get high performance. In order to do this, make sure the windows are part of a good ‘whole-house’ system.


The image below is of a thermally broken aluminium framed window. Aluminium is a highly conductive material. The polyamide strip, (indicated in green) interrupts the heat transfer through the frame. This is called a thermal break.

In winter the thermal break significantly reduced the cold temperature transferring from outside to inside through the frame. In summer it does the same by significantly reducing the hot temperature transferring from outside to inside through the frame.

Click here to learn more about thermal breaks.

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