Improving new build energy efficiency without compromising on design

By incorporating design elements with good thermal performance, you can lower your energy use, save on bills, and maintain a healthy home all year round. The question is — how can you do this without compromising on design? 

In this article, we discuss the various window and door designs you can use to improve your home’s energy efficiency. With our advice and product recommendations, you can ensure your home has the ideal blend of style, functionality, and comfort.

H1 standards for energy efficient homes

In the New Zealand building code, the H1 regulations relate to energy efficiency and thermal performance requirements. Meeting these standards is critical for compliance but also for ensuring your home is well-insulated and energy-efficient. 

The H1 standards were recently updated to deliver warmer, drier, and more energy-efficient homes for New Zealanders. All new building work is required to comply with these changes, whether building consent is required or not. This will also reduce your energy consumption and long-term costs.

You can achieve the required thermal performance for your home by selecting materials with the appropriate R-values. To simplify the process, we can provide you with the average R-values for your window joinery. 

When selecting your windows and doors, the most impactful options for thermal performance include Low-E coatings, minimal mullions and transoms, and large panel sliding doors. For more information, read our recent article about H1 compliance or download our free Guide to Specifying Windows and Doors.

Thermally efficient window designs NZ

When specifying your new windows, you don’t have to sacrifice visual appeal for thermal performance — you can have both with the right technology. At DuCo, we recommend opting for the ThermalHEART® or Klima® ranges, designed to maintain energy efficiency and complement a range of architectural styles. 

Klima® series

The Klima® Series is inspired by European designs but has been designed and manufactured to suit New Zealand conditions. Klima® is made with uPVC, an exceptional insulator with low conductivity. What’s more, uPVC is highly durable, resistant to harsh sunlight, and noise-reducing. 

Unlike other common uPVC products in New Zealand, Klima® comes with an aluminium cover, providing superior durability and your choice of colour finish. This is the only uPVC suite in New Zealand that conforms with the standard E2/AS1 installation methods, guaranteeing a simple consenting and installation process. 

ThermalHEART® and Centrafix™ 

ThermalHEART® is an innovative series of aluminium windows and doors, designed to almost double the thermal performance of your home. With the innovative Centrafix™ installation method, all insulation elements are aligned to prevent cold air from circulating the frames, a further 20% increase in thermal performance. 

At DuCo, we offer four full ranges of ThermalHEART® suites, including:

1. Residential ThermalHEART®
   The Residential Series offers an economical option for mainstream windows and doors. The recommended door height is 2.1 metres, though this may be increased depending on your site conditions.
   
   
2. Metro ThermalHEART®
   The Metro Series is suitable for both residential and architectural projects, featuring clean lines, a contemporary look, and heavy-duty engineering. The recommended door height is 2.4 metres, though this can potentially be higher depending on site conditions. 
   
   
3. Metro ThermalHEART® with Centrafix™
   With all the advantages and features of the standard Metro Series, you can also opt for the BRANZ Appraised and Codemark Certified Centrafix™ installation method. This alternative solution recesses the units into the building wall, aligning all the insulation elements and improving thermal performance even further. 
   
   
4. Architectural Series ThermalHEART®
   The high-performance Architectural Series is designed for architectural homes and apartments, featuring square edges and flush surfaces. The recommended door height is 2.7 metres, however, they can be increased in certain site conditions. 
   
   This means we can offer versatility and flair across the full spectrum of design, all while maintaining exceptional thermal performance.

Can large windows be energy efficient? 

Large windows are an impressive feature of a home that can magnify sunlight and views, but can also let out heat during winter or cause overheating during summer. If you want to install large windows as an impressive design statement, you’ll also want to mitigate the loss of thermal efficiency with a combination of technological innovations and design considerations, such as: 

Double or triple-paned glass

As a minimum standard for new build homes, all windows must be at least double-glazed. In some climates, homes feature triple glazing for even better thermal performance. 

Low-E Glass

• Solux Low-E — Keeps your home at a comfortable temperature all year round. 
• Solux Ultra Low-E — Specifically designed for hotter climates to reduce solar heating.
  
  

For more information, read our article explaining everything about energy efficient Low-E glass.

Minimise mullions and transoms

In all windows, the frame accounts for a substantial portion of the thermal barrier. Double glazed glass units with Low E have better insulation properties than any aluminium frames. Choosing window configurations with minimal frames and less internal mullions and transoms will deliver higher thermal performance.  

Strategic window orientations

• North-facing windows will receive sunlight at all times of the day. 
• East-facing windows capture sunlight in the morning.
• West-facing windows capture sunlight in the afternoon and early evening. 
• South-facing windows will not receive any direct sunlight during winter but may receive small amounts during summer. 

For inspiration, check out one of our projects we worked on in Lake Karapiro, complete with a full architectural suite of windows designed for thermal performance. 

DuCo was commissioned by Rob May Builders to deliver all the exterior joinery for this award-winning Cambridge home, including expansive windows and doors facing the lake. To maximise thermal performance while also complementing the stunning architectural design, the following features and products were employed:

• 35mm & 40mm Architectural Suite
• Green Double Glazing
• Glass 1-Lite Pivot Entry Door
• Aluminium Louvres
• Custom Patio Screen