Just beginning to hear about passive home builders? Not sure what they are? Passive homes could be the next big step for the NZ building industry, especially because New Zealand has a reputation for cold, damp houses. While most European countries with a similar climate to ours have central heating as the norm for all homes, New Zealand doesn’t, and that means there’s an opening for a newer way to design and build--passive houses. Read on to find out more.
What Is a Passive House?
First designed in Germany in the 60s, passive houses are airtight structures that are insulated adequately, have limited thermal bridges that might allow heat to escape (like window frames), and have excellent indoor air quality.
All these factors make passive houses extremely low consumers of energy. This is mainly achieved through investing properly in insulation and the addition of a whole-home ventilation system designed to distribute air evenly. Using energy-efficient appliances can push down this energy consumption even further.
Over the past few years, passive house projects have become easier and easier to carry out in NZ, due to the increasing availability of the high-quality building materials that passive houses need. These can include thermally broken windows and doors, and air-tight membranes that can help control the interior environment.
Another important part of constructing a passive house is the use of local climate data. Having local climate data is an important part of designing the home. For example, building a passive home in Auckland is a different type of project to building one in Queenstown.
Passive Houses Guarantee Excellent Air Tightness
Air tightness in passive houses is tested with the blower door test, a process first developed in Sweden. During construction, this test is used to pressurise the house, using special equipment, and measure how much air leaks out. If there are any issues with air leakage, the issue can be fixed at this stage. Once construction is complete, this test is then repeated to provide verification that the air tightness of the home meets Passive House standards.
You may be wondering what having an airtight home will do for the air quality. Don’t worry! The ventilation system used for passive houses is designed to suck moist, warm air out, and use it to heat fresh, filtered being drawn in from outside. The air-tight design and ventilation system work together to ensure that only warm, dry air makes its way into the home. Many find that they don’t need to open windows for fresh air at all once they’ve moved into a passive home.
Passive Houses are Certified
Real passive houses come with a certification that proves they are legitimate. There’s a difference between just anyone building what they call a ‘passive house’ and getting a certified passive house. The Passivhaus Institute in Germany has historically set the standards that need to be met in order to obtain certification. Within New Zealand, there are increasing numbers of certified professionals, including architects, engineers and builders, that can help you achieve the rigorous Passive House standard.
Passive House Certification also works well alongside the Homestar certification, which is a New Zealand based rating tool, which covers a broad range of sustainability features.
Passive Housing in a Nutshell
Here at Craft Homes, we’re seeing a continued increase in interest for passive homes, and it’s not hard to understand why. They’re sustainable, energy-efficient, can be highly cost-effective, and are continuing to be recognised worldwide as a new benchmark for low-energy consumption buildings. To learn more, get in contact with the team here at Craft Homes today!
Toby and Cat Tilsley