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How to create an energy-efficient home

August 24, 2018
  Energy Efficiency


Energy-efficiency, and creating a warm, welcoming and comfortable home, are some of the most important factors for those building or renovating their dream house.

A lot of your home’s heat can be lost through its windows and doors, especially if you already have well insulated ceilings, floors and walls. Choosing your windows and doors is one of the most important design decisions you are going to make during your build project, so it’s worth doing your research. But, how do you ensure you choose the right solutions that’ll deliver the goods?

In this blog, we’ve laid out three common energy-efficient window options, along with information on how you can measure the thermal performance of the windows you want to buy.

Double glazing

Double glazing is made up of two glass panes with a sealed air space between them, creating an insulating layer between the two panes (triple glazing has three glass panes). This sealed air space can be filled with a layer of air or an insulating gas such as argon. Double or triple-glazed windows allow as much sunlight into your home as single-glazed windows, but they’re a much more effective way of holding in the heat.

According to the Energy Efficiency and Conservation Authority (EECA), double glazing can halve heat loss in your home, and can reduce both condensation and external noise. On top of that, double glazing reduces glare and fading of furnishings by sunlight, and increases security at your property.

If you're building a new home, your builder or architect will specify double-glazed windows as standard, to ensure your home complies with the New Zealand Building Code. However, if you are replacing/repairing windows in your existing home, then double glazing is still well worth considering.

If budget is an issue, Smarter Homes recommends you concentrate on south facing windows initially as these get very little sun, so lose far more heat than they gain.

Quality thermally-improved aluminium frames

Obviously, your window frames are important to how your windows perform in terms of energy-efficiency. Aluminium is the most commonly used material in New Zealand due to it being lightweight, strong and durable. However, it’s not a great insulator, so for optimal energy-efficiency, you should consider quality New Zealand-made windows and doors that feature thermal break technology.

Thermal breaks are created when insulation is placed between the interior and exterior part of the frame. This clever design feature ensures the aluminium is more robust to changes in temperature with up to 73% improvement in thermal efficiency.


Having thermal breaks within your window frames will mean you can enjoy the comforts of a drier, warmer home in winter, reduced heat in summer, and lower heating and cooling bills throughout the year. For more information, you may download the brochure for the Fairview Thermal range of windows and doors here.

Low-emissivity (low-e) glass

Quality aluminium frames with insulated glazing can definitely help boost the energy-efficiency of your home. When they're combined with a high performance glass solution, like low-e (low-emissivity), the benefits are even greater.

Low-e glass has an almost invisible coating contained on the inside pane of an insulated glass unit (IGU). This coating allows the sun’s light into your home and reflects heat back indoors, forming a shield against the cold which results in saving energy. In warmer climates low-e glass can also be used to keep the heat out.

This glass cuts down heat loss through your windows by about 20-30% compared to double-glazed glass alone. You can take the efficiency a step further by combining low-e glass with an insulating gas like argon.

Thermal performance measurements

The Building Code requirements for house insulation says that “homes in New Zealand must have adequate insulation”, so you need to make sure your property will have the right level of thermal resistance - know as an R-value -  for their location. Thermal performance of windows and doors (measured as an R-value), is the thermal resistance of the entire system, not just the glass. The higher the R-value, the less heat is lost through the system, and the better the insulation will be.

BRANZ is an independent and impartial research, testing and consulting organisation inspiring the building and construction industry to provide better buildings for New Zealanders. In conjunction with the Window & Glass Association (WGANZ), they’ve developed the Window Energy Efficiency Rating System (WEERS), which gives a verified six star rating on the energy efficiency of new residential windows.

The combination of R-value and the WEERS star rating delivers a more complete view of the thermal performance of your window and door solution. By looking at these results together, you will be better placed to make your decision when choosing energy efficient products. Fairview provides instant R-value and WEERS star ratings with every quote. We are the only window and door supplier who can provide this at the click of a button (and you can also get comparisons across different product options too).

If you’re interested in finding out more about the energy efficiency of Fairview’s product ranges you can contact your local manufacturer here.

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