Why setting building minimums doesn’t work and why Passive House can help affordability.
This year, as we enter the Autumn season suddenly, along with the cost of living so high, I suspect power bills will be on some peoples mind more than before.
Our homes here in New Zealand aren’t well designed to preform year-round. Even the newest ones. The real issue is that the cheapest and most effective place to reduce power bills is in the design. And that design has been so undervalued and undertaken often with those not skilled or trained in the area of creating good performance homes. Simply viewing a design as sketching a floor plan means design performance happens accidentally with the perception that a building standard will make up for the lack of consideration.
It never ceases to amaze me at the perception by the general public that our New Zealand Building Code will create a healthy comfortable home for them. We are great at talking about housing affordability. On a side note, housing affordability is not a new thing, nor is it limited to New Zealand.
When H1 Energy Efficiency in our NZBC was first opened for public consultation for minimum improvements a couple of years ago, the push back by some major housing providers and group home builders was largely based on an argument of affordability. Yet affordability is not simply limited to the size of the loan or cost to build. Anyone saving for a deposit to buy, renovate or build new will tell you that their monthly bills need to get paid first, and savings for a loan deposit comes after. So only seeing affordability in the build space is a limited misconception to encourage status quo and focus only on one aspect of the big picture. There is a real disconnect between the people who make design decisions and the people who get to experience the impacts of those decisions on a daily basis over the lifespan of that building.
H1 Energy Efficiency is not simply insulation, but our minimum building code doesn’t set out minimum requirements for the energy use (yet, bring on 2026), simply the reduction of heat loss from a building. Having travelled to hot places like Cuba, I can assure you that heat loss was the last thing on my mind. In a country where we obsess about insulation, push back on increasing it, complain about the high levels of it and then boast about over insulating, it seems ironic that some still think Passive House only belongs in cold climates.
For those unfamiliar with Passive House, it is a world standard of building performance assets by Energy modelling and not limited to building methodology. It has also been around since 1992 with buildings including homes all around the world.
Our building code has a current pathway to Energy Efficiency, its called the verification method and uses energy modelling which is the basis of Passive House. It’s a little used pathway but has been available to be used for many years now. However due to its additional fees and requirement of expert knowledge and software, its largely ignored until the glazing conditions of the building demand it under the Code. It seems whilst we boast of quality and innovation, the actual pathways to innovation are ignored to reduce design costs. Yet those decisions at the design stage stay with the life of the building. And that impacts life cycle costs.
Our building code sets out the minimum legal requirements. That is effectively the worst preforming building legally allowed to be built. If the schedule method or calculation method are being used for your consent approval to prove compliance with H1 then its highly likely that your build is exactly that. The worst preforming building legally able to be built with Energy Efficiency evaluation only based on heat loss.
I suspect that easily 95% of the new buildings currently consented and constructed today are exactly that. Meanwhile the general public truly believe they are getting a good quality home.
Passive House sets out caps for energy use. It doesn’t specify the way to achieve it, that space is open for innovation. These caps effectively are easily 75% higher preforming that our assumed levels under the minimum standard. This means at least a 75% reduction in operating power bills.
That is designing for affordability. And the bonus, these strict requirements also ensure that what is created meet world health organisation recommendations of a minimum temperature of 18 degrees indoors (ideally 20 degrees)
That’s the quality my clients deserve.
As we talk insulation, housing affordability and how it is getting chilly in the coming months, lets include Passive House and Energy Efficient Design into that conversation.
Because claiming quality and high performance are great for marketing, but its only when design is evaluated, and numbers revealed that can unveil the true performance of the design.
New Zealanders deserve better.