It’s been a long summer for much of New Zealand, but nights are turning colder and thicker duvets are coming out of the closet. The change of seasons is a timely reminder to think carefully about the place of energy efficient windows and doors in your plans for a new home.

In the average New Zealand home, space heating accounts for about a third of total energy use. So potential savings through better conservation can be significant – not to mention the increased comfort levels and health benefits of a warmer home.

There are several window and door upgrades that take energy efficiency to a high level. They come with an extra cost, but the investment can be a smart move, especially in colder parts of the country.

Thermally broken windows and doors offer a significant thermal upgrade. APL Window Solutions has a mainstream residential range of thermally broken ThermalHEART products in its three brands of Altherm, First and Vantage. These brands are used by G.J. Gardner around the country. Customers therefore have the opportunity to step up another level if they choose.

The extra cost over and above standard residential product that is double glazed is in the vicinity of 15-20% for a whole house of ThermalHEART windows and doors. For this premium, you can expect enhanced thermal performance of around 30%. 

Thermally broken technology addresses the high conductivity of aluminium window frames and can almost be seen as the metal’s equivalent of double glazing. A nylon thermal insulator is inserted in window and door profiles to ensure that cold transfer is minimised and interior warmth is retained. There is less condensation on interior aluminium surfaces.

Another powerful enhancement is Low-E Glass. This simple yet sophisticated glass coating can make a significant improvement to the thermal efficiency of double glazed window units (also described as IGU’s – insulated glass units).

Low-E is an abbreviation of ‘Low Emissivity’ and is a coating that cuts down on long wave radiation through the glass from inside or outside the house. This means that heat transfer is reduced, solar heat build-up is cut down and less heat escapes from the inside.

In addition to the positive impacts on interior comfort and power bills, Low-E double-glazing keeps the internal glass temperature warmer and thereby reduces condensation on the inside of the glass.