Energy efficiency is a wonderful thing. After all, who wants to waste money on power and fuel that isn’t necessary?
And of course there is the knock on effect on New Zealand’s ability to maintain energy security for the future and the impact on the planet.
Wouldn’t we all like our home to be part of this success story? For many of us, who live in houses, application of Clause H1 of the Building Code ensures that our homes are built to meet an energy efficiency standard. For others who choose an apartment as home, the story is more variable. The problem is embedded in our history where individual houses were where people lived and larger buildings were classed as commercial buildings.
4218 or 4243
H1 splits these into houses and buildings of under 300m², and commercial buildings (not housing) over 300m². So where do the apartment dwellers sit? It seems that at present that depends on which council consenting office your dwelling falls under, or even in some cases which consenting officer is assigned to the project.
The old way was to treat apartment buildings as commercial buildings and use NZS 4243 to test their energy efficiency as an entire building. A mid step is to use the entire building envelope still, but to use the residential standard NZS 4218 for the calculations; a more stringent test. There are those who say that this step is sufficient; however InsideOut believes differently.
If you live in an apartment wouldn’t you expect a dwelling as energy efficient as a house? So shouldn’t we apply the residential test to each apartment? If we just calculate for the whole building then we allow the apartments that get too cold in Winter to average out the ones that get too warm in Summer. The building looks on average to be energy efficient enough to comply with Code but for the occupants their apartment can be very expensive to run.
Take a look at how we approached one of our projects in this case study of the Il Casino Apartments project.
It’s not difficult to calculate energy efficiency for apartments. InsideOut does it all the time. We just have to remember that it’s not just a calculation, it’s a home.
Author: Ruth Williams – Principal, Buildings That Work InsideOut Ltd