What are thermally-broken windows and do they cost more?

 

The windows and doors are some of the weakest points in your home’s thermal envelope. Fortunately, thermally broken windows provide an effective solution, enhancing energy efficiency and ensuring daily comfort. 

In this article, we explain what thermally broken windows are and how they differ from standard windows. We also explain how much these windows cost so you can make an informed decision for your project. 

What are thermally broken windows?

Aluminium window frames are highly conductive, even with Low-E double glazing. To reduce heat loss, a low-conductivity thermal break made of polyamide can be incorporated into the frame. This interrupts the heat transfer in and out, achieving a comfortable temperature all year. 

How do thermal breaks work?

When window frames contain a thermal break, the polyamide bar forms a barrier and slows energy transfer. This bar creates a continuous barrier wrapping around the entire frame, meaning the windows as a unit offer better thermal resistance. 

 

How much do thermally broken windows cost?

The cost of a thermally broken frame varies depending on the configuration and frame material. However, as a general rule, upgrading your residential quote from standard cold frames to ThermalHEART costs approximately 15% more to upgrade.

Thermal windows vs standard windows — Are thermally broken windows worth it?

In most houses, windows are the weakest point in the thermal barrier. Fortunately, by including thermal barriers in the frames, in conjunction with Low-E glass, you can greatly improve this. While they come at a higher upfront cost, thermally broken frames provide a few advantages compared to standard frames. 

Improved insulation

While standard aluminium frames, your home may be prone to significant heat loss. However, thermally broken frames will reduce this significantly when paired with double-glazed Low-E glass. This makes it far easier to maintain a comfortable indoor temperature no matter the season.

Lower energy bills 

With thermally broken frames, you can significantly lower the amount of energy needed to heat or cool your home. This will reduce your energy bills and save you significant amounts of money all year. 

Reduce condensation

When indoor air comes into contact with the cold surface of aluminium frames, the moisture condenses and builds up. Fortunately, thermally broken frames keep the interior portion of the frame warm, reducing the temperature difference between the indoor air and the window. This lowers the likelihood of condensation, keeping your home dry and healthy. 

 

Building Code Compliance and H1 Requirements

The H1 regulations in the New Zealand Building Code relate specifically to energy efficiency and thermal performance. The higher the R-value of your specified windows, the more likely you are to gain compliance.

Fortunately, you can achieve this by including Low-E glass and thermally broken frames. This not only helps towards Building Code compliance but also reduces heat loss and lowers your energy bills. 

To learn more, read our full article about which windows and doors to use for H1 compliance or download our free Guide to Specifying Windows and Doors.
 

How to balance energy efficiency with aesthetic design

Window and door selection affects your home's natural light, temperature, and style. So what are the best ways to maximise thermal performance without compromising the design of the home? Fortunately, we answer that question in our valuable guide, including advice on the following:

• What to consider when specifying different joinery configurations
• H1 regulations for windows and doors
• Choosing materials for energy-efficiency
• Our favourite design pairings
• Project inspiration

 

We also showcase our series of energy-efficient windows and doors, including the ThermalHeart+ range and Klima series. 

Klima® series — uPVC windows

The Klima® Series is designed for New Zealand conditions, with uPVC frames and Low-E double glazing. The series is rated at 6 Energy Stars under the Window Energy Efficiency Rating System, far surpassing the R-Values required in current building standards.

ThermalHeart+ Suite — Thermally broken windows NZ

The ThermalHeart+ Series of thermally broken frames and AGP System™ glass almost doubles the thermal performance of standard aluminium joinery. This specialised series includes Residential, Metro, and Architectural suites that offer a variety of specifications for every design style. 

Centrafix™

The Centrafix™ installation method involves recessing the joinery into the wall to align with the other insulation elements. Combined with our ThermalHeart+ Metro suite, this offers an additional 21.6% improvement in thermal performance. 



At DuCo we love creating spaces you love to be in, so for more product recommendations, download our free Thermal Specification Guide.