In 2021 the Ministry of Business, Innovation and Employment (MBIE) proposed changes to the building code, specifically around the Acceptable Solutions for H1 Energy Efficiency, with the goal to improve the thermal performance of new homes and buildings to make them warmer, drier and healthier. The changes released in November 2021 are the most significant in a decade. The new Acceptable Solutions come into effect for new homes consented from November this year.
Changes to Climate Zones
To ensure New Zealand homes are fit for purpose, they must have adequate insulation for their location. The requirements vary for different parts of the country, with more insulation required for houses in colder climates. Traditionally, New Zealand has been divided into three climate zones with minimum R-values for each zone.
The zones have been reviewed and from November, the country will now be broken up into six separate zones that better reflect the climate for those areas.
Thermal Performance and Insulation
One way the level of insulation in any building material is measured or rated is in terms of its thermal resistance, or R-Value. To achieve good thermal performance in an entire home, the R-Value of each part of the home needs to be considered. The new acceptable solutions will require increasing minimum R-Values in the roof, walls, floor and windows of new homes and buildings.
What will be required is different in different parts of the country. We explore some of these changes below.
For trussed roofs, the ceiling is one of the simplest and most cost-effective ways to increase insulation. Skillion roofs as featured in many Lockwood homes are a bit trickier. From November, all zones in New Zealand will require R6.6 roof insulation, at least double what has previously been required.
Floors of new dwellings will now have different standards depending on the type of construction. Concrete slabs will require insulation around the perimeter to achieve R1.7 and underfloor insulation in other types of construction, such as timber piles, will now require up to R3.0 for South Island homes.
Windows represent the largest source of heat loss in a home. The minimum insulation level for windows across the country will increase. The roll-out of the changes will be in stages, starting with the colder climate zones. By the end of 2023, all parts of the country will have to achieve an R-value of at least R0.46.
Because both the window frames and type of glass used can significantly affect the way a window performs, there are many options available to achieve the required R-values; however, standard double-glazing will no longer acceptable.
By November 2022, Zones 3 & 4 will require R0.46, with zones 1 & 2 in a transition period to reach the same level from November 2023. For most parts of New Zealand, the new standards will require either thermally broken aluminium joinery, timber joinery, or UPVC joinery paired with high performance glass.
Wall insulation will experience the smallest degree of change due to the complexity and material costs involved in increasing insulation. From November, all parts of the country will require R2.0 insulation in the walls.
What will this cost?
Additional insulation and the new requirements for windows will increase the construction cost of your project. While the initial investment will be higher, it’s essential to keep in mind the benefits that will come as a result. MBIE has said the changes will reduce the power required to heat and cool a home by up to 40%, reducing ongoing power bills by about $200 a year, and contributing to better health and well-being of the people living in the home.
What does this mean for your project?
The update to the code means significant changes for all parts of the construction sector, but we have it covered! Lockwood has always delivered high-performance homes that meet and often exceed minimum building code requirements; these new changes are no exception.
Lockwood homes currently in early design phases will include the additional ceiling and underfloor insulation details. Our team will work through joinery and window options that best meet the requirements for your zone, and you have the opportunity to choose higher specifications if desired.
The Lockwood building system already meets the requirement for R2.0 insulation in the walls, with our insulated 107mm board offering R2.1. The solid nature of the Lockwood board means this R2.1 is consistent at any part of the wall, where conventional, timber-framed buildings lose heat through uninsulated corners and areas of timber framing.
If you have questions or concerns about the Building Code changes and how they impact your home building plans, please get in touch. Our knowledgeable team are happy to help.