Create a comfortable home environment year-round with thermally-efficient windows and doors

Designed by Mason & Wales, this secluded Queenstown home has full-height glazing supplied by E13 Performance Windows.

When designing a home for comfort, one might consider a calm, neutral colour palette or an abundance of soft furnishings. Plush carpets, ergonomic appliances, and good water pressure might also be considerations. And then, of course, there’s the home’s thermal environment.

There are a number of factors that play into a home’s thermal performance, including insulation, glazing, and heating systems. Conversations around thermal performance often focus on a home’s insulation, yet, without adequate glazing and window joinery, the home still stands to lose a significant amount of heat through the windows and doors.

How doors and windows impact your home’s thermal and energy efficiency

Doors and windows make holes in your home’s thermal envelope, and as these holes can’t be filled by insulation, they impact how warm your home can be. While we need the benefits of doors and windows — access, natural light, ventilation, and views of the outdoors — we also need to consider the impact they have on the building envelope.

To avoid significant heat loss, you can specify doors and windows that are designed with thermal performance in mind. This means prioritising air tightness, naturally insulating materials, and double glazing, or higher, for any glass elements.

The New Zealand Building Code now states that all new homes must be fitted with double glazing as a minimum, but for houses subject to extreme climate conditions, or those with a large amount of glazing, double glazing may not be enough.

With two air layers, triple glazed windows are extremely efficient insulators. Home designed by Mason & Wales.

This Central Otago home is protected from the region’s fluctuating temperatures with triple glazing featuring double Low E and double argon gas.

Creating an ideal internal environment with triple glazing and air-tight joinery

With origins in Vistalite Otago, a long-standing family business dealing in high-quality joinery, E13 Performance Windows was born from the expertise and experience gained by Michael and Kathryn Brenssell during their two-decade tenure. Focusing on thermal performance and design-led solutions, E13 Performance Windows are now leaders in the supply of triple glazing — a pursuit that aligns perfectly with the beautiful views and harsh climate of their Otago locale.

Like double glazing, triple glazing consists of a layer of air trapped between two panes of glass, however, as the name suggests, triple-glazed windows have three panes of glass and two layers of trapped air. Because air is a poor conductor of heat, the trapped air layers mean less heat is lost through the glass. With two air layers, triple-glazed windows are extremely effective insulators. Triple-glazed windows also have thermally efficient window frames to reduce heat loss through the joinery and can be paired with a Low-E coating or argon gas filling for added efficiency.

The benefits of triple-glazed windows are significant, particularly in parts of the country with drastic temperature fluctuations. With the added layer of glass and air, homes stay warmer in winter and cooler in summer, lowering power bills year-round. Triple-glazing also offers acoustic benefits, reducing noise transfer from outside. While the external climate does play a role in insulation decisions, E13 Performance Windows’ Jamie Waller says it’s also about having better control over the thermal environment inside your home.

“Triple glazing provides both insulation and solar control (with an added Low-E coating), making it easier for you to control your internal environment while using the least amount of energy,” Waller says.

In addition to heat lost through glazing, up to 20% of heat in the home can be lost through air leakage. Air leakage is felt as draughts, when warm air is lost through gaps in a building and cold air rushes back in. With this air movement, you are constantly wasting energy either reheating or cooling your home.

“E13 Performance Windows has been pioneering airtight thermally broken joinery for a decade, and we’ve seen industry-leading results. After all, what’s the point of having such great thermally performing joinery and glazing, if you’re just letting draughts undo all of your good work,” Waller says.

This Wanaka home was designed for air-tightness, subjected to a blow door test to ensure no air would escape through the joinery and doors.

Low-E coatings can reduce heat loss by as much as 50%, providing long term energy savings in homes with a large amount of glazing like this Queenstown property designed by Mason & Wales.

Improving the thermal performance of triple-glazing with Low-E and argon gas

A Low Emissivity or Low-E coating is made from invisible layers of metallic oxide, designed to be added onto one or more panes of glass in a double or triple-glazed window. This coating allows natural light to enter the home while reflecting UV rays and infrared light back into the environment. Low-E coatings can reduce heat loss by as much as 50%, providing long-term energy savings for your home — and as the coating is applied to the inner layers of glass, there is no chance of the coating rubbing or wearing off over time.

“Low-E coatings are great, as you gain both heat retention and solar control. With solar control, less heat comes through the glazing, meaning you’ll spend less energy cooling your internal environment in the summer months,” Waller explains.

Argon gas is an inert, non-toxic gas that is denser than oxygen and therefore a greater barrier to heat loss. Placed between glass panes in a double or triple-glazed window, argon gas can increase a window’s thermal performance by roughly 15%.

E13 Performance Windows offers the option to add both Low-E and argon gas to your double or triple-glazed windows to increase thermal performance and energy efficiency.

Learn more about E13 Performance Windows.