Bob Burnett Architecture is currently working on three certified Passive House standard Superhomes.
So, what is Passive House standard? And how can it help you get the best design and also help solve the climate crisis.
The good news is designing to Passive House standard doesn’t necessarily exclude quality architecture and stunning aesthetics. The Passive House approach is primarily about putting the fabric of the building first to ensure that it only needs a very small amount of heating or cooling to maintain a comfortable temperature. This involves super-insulated walls, floor and roof, while also eliminating thermal bridging and air leakage through the fabric of the building. A high-level of attention to detail is required when considering everything from the form and orientation of the building to proper installation of correctly proportioned high-performance windows. Careful planning is critical to integrate essential services, like a balanced mechanical ventilation heat recovery system (MVHR) within the thermal envelope of the building. Sometimes, during the technical design process, other aspects of the design that have an important influence on the look and feel of a finished home can be lost; such as the treatment of light, spatial awareness or flow, and connection to the outdoors. Bob Burnett Architecture looks to balance thermal performance requirements with the other aspects that create an appealing feel and architectural form.
Although not all clients wish to go to the extent of certifying to Passive House standard, all Bob Burnett Architecture homes are designed with these considerations and always to Superhome Movement criteria. BBA homes for example often meet or exceed the Passive House airtightness standard of 0.6 air changes per hour, which is confirmed by a blower door air test. This air leakage test is also a good indication of build quality. Certifying and monitoring the finished buildings further validates the performance. It is critical to have the right dedicated team of designers, engineers, builders and tradespeople onboard and communicating well to ensure Passive House targets are achieved.
Passive House will not meet every budget as there is an increased cost to reach this level of specification and construction. Recent research has indicated Passive House costs about 15% more but it is not clear what standard of building was being compared. An innovative architectural home will also cost more than a building company standard home built to building code minimums. When things are new and less common they can cost more, but this will change in time when better standards are normalised. To suit varied budgets, Bob Burnett Architecture has three levels of specification for a residential project; good, better and best with best being Passive House level and good still far exceeding building code minimums. With certified Passive House projects currently under way it was found that the BBA general methodology and best level of specification was already about 98% of the way to achieving certified Passive House. However, certain shapes and sizes are inherently easier to certify than others so this can influence the complexity and specification required for each individual project.
Last year saw heightened awareness around climate change and a recent study by BRANZ identified that new homes produce five times the amount of carbon as required to meet the Paris Agreement. Low-carbon building includes the reduction of both operational and embodied carbon. Passive House can reduce operational carbon while BRANZ has released a Life Cycle Assessment tool called LCA Quick which enables assessment of embodied carbon to help reduce the impact of the building process. The combination of these and other tools gives the potential to solve carbon emissions created by the built environment. Another useful rating tool for sustainable housing is Homestar. Bob Burnett has been a Homestar assessor since 2012 and was responsible for NZ’s first 10 star home in 2015. Rating tools are helping to create awareness about important considerations but don’t go far enough. There is no substitute for careful integrated design thinking. The uptake of various certification schemes has been slow but hopefully will get a boost as ANZ bank has recently introduced a Healthy Home Loans Package for Homestar rated homes offering up to 1% off your mortgage rate.
A Bob Burnett Architecture home provides the best of both worlds. The best possible living experience in an attractive, unique feeling space while incorporating award-winning sustainable design thinking, optimum health, comfort and earthquake resilience providing peace of mind that you are future-proofed for our changing climate.