Passive House Approach
High performance homes often follow the Passive House approach and are usually designed by architects using a combination of systems to achieve a higher performing energy efficient home.
High performance homes are becoming more common in New Zealand for a number of reasons. Immigrants from colder climates such as North America or Europe are experiencing our poor housing stock, and many have quoted they’ve never been as cold in their life before living in a traditional New Zealand home. These immigrants are bringing ideas and building systems from overseas to build higher performance homes for their families. Kiwi’s are getting sick and tired of asthma, crying windows, mold, and damp energy hungry homes – and are pushing architects and designers to embrace new improved design and construction methods. It is readily accepted that the Building Code is a minimum, not a target, and for a warm comfortable home you need to make a number of improvements.
One of the more popular recent construction methods are homes certified under the “Passive House” standard, initially started in Germany but now a building performance standard used in tens of thousands of homes world-wide. A Passive House (not to be confused with a home designed for passive solar gain) is carefully designed to ensure the home only uses around 20% of the energy a typical home would consume. It is then much easier to bridge the remaining 20% gap with local renewable power, and the next logical step is a “Zero Energy” home. Zero energy homes consume as much power as they produce, and are often grid-tied and feed and draw power from the general electricity network. The heart of a Passive House is design, high levels of insulation, air-tightness, and balanced ventilation. Before adding on renewable energy generation, the first priority is to reduce the base load of demand. That way – you need a much smaller and cheaper system.
An average home will lose or gain up to 35 per cent of heat through ceilings, up to 25 per cent through the walls and 14 per cent through the floors. Increasing the R-Value of insulation at the initial stages of your build is more economical, increases the comfort levels and will future proof your home.
Homestar
Homestar® is New Zealand’s environmental and energy rating for both new and existing homes, which is administered by the New Zealand Green Building Council (NZGBC). The aim of Homestar is to improve the performance and reduce the environmental impact of new and existing homes in New Zealand, making them warmer, healthier, and more comfortable places to live. Homestar encourages homeowners to make informed decisions that will improve the performance and comfort of their home. Homestar covers a wide range of topics including energy efficiency, water harvesting and efficiency, sustainable building materials, design, renewables, waste management and site usage such as native plantings and permeability. Qualified Homestar Assessors work with homeowners and designers to first complete a Design Rating for the home, which then gets confirmed as a Built Rating once the project has been completed to plan.
Earthwool® glasswool is the only product in New Zealand with GreenTag Level “A” rating, and qualifies for points under the Materials section of Homestar. It can also be used in Greenstar rated projects, which is the rating tool for commercial buildings such as office blocks.