Quake resilient and environmentally sound eco-homes
Bob Burnett, of Bob Burnett Architecture and Eversun Homes, has a longstanding passion for eco-friendly design and has recently created and overseen the completion of two innovative and affordable eco-homes that are also quake resilient.
They far exceed code requirements and have been designed to achieve Homestar 8 star ratings, making them among the most energy efficient and environmentally sound homes in the country. Burnett previously designed New Zealand’s first 7 star Homestar rated house in 2011.
The two homes are very different construction types. One is a modest sized timber frame home of only 113 square metres, which has a “spatially aware and efficient layout”. With four bedrooms and two bathrooms, variations in ceiling heights provide a perception of space that feels much greater than you would assume given the size of the footprint.
The homes also have a very small ecological footprint. Bob says they are targeting zero energy use through excellent thermal design and the use of PV solar panels to provide more than enough power.
The second, two storey home, measures just in excess of 152 square metres. Insulated precast concrete panel thermomass construction has been carefully detailed to eliminate thermal leakage. It, too, features PV solar and high performance glazing and has a solar wall collector to pre-warm fresh air, which is then fed into an energy recovery ventilation system (ERV).
“The timber homes that we’re designing have thicker walls as standard. These are multipurpose – they are better for getting more insulation into the walls, so better thermally and they also make for a stronger house in an earthquake.
“We’re wrapping the house with ecoply barrier so that it’s really well braced, targeting about 200 percent of code.
It’s solid and unlikely to be damaged and gives you a warmer more airtight house too.
“The idea behind Eversun Homes is to draw on some of the innovations I’ve developed in my architectural practice over the last 12 years and filter them into a range of not-so-big homes that are affordable and accessible to more people,” he says.
“People are starting to realise they can get something much better than the standard Kiwi home, that has poor performance, without it costing a lot more. The obvious compelling benefits of a sunny, warm, dry, more healthy and comfortable energy efficient home are now being seen as essential and more attainable; particularly when ongoing cost savings that can help pay off the mortgage faster are considered; it makes complete sense.”
However, Burnett warns homeowners still need to be aware of pitfalls when going down the energy efficiency route. “There is a lot of ‘greenwash’ out there and the right advice is critical.
“There is a fine line between getting energy efficient designs right – and not. All our homes are homestar rated, not just the best selected projects. It is about walking the walk and not just talking the talk.”
He says the whole house should be considered as a system, because its not about just adding energy efficient features to any house design, as ideas need to be incorporated correctly and be complementary or they simply won’t work.
“The key is to take an integrated design approach from the earliest conceptual stage when around 90 percent of the important decisions need to be made. People are often surprised that careful design, as opposed to incorporating a whole lot of expensive technology, is the most essential element of an energy efficient home.”
Bob Burnett Architecture uses 3D computer thermal modelling to analyse the home’s solar gain and heat losses for different months of the year. This process provides credence to designs and the solid data allows the new home’s future power bill to be assessed at design stage. Previously, designs were created just through experience of what works in practice.
“Once built, the real proof of a home’s energy efficiency is the power bill. That’s why people should always think about their new homes as having two prices – the price to build it and the annual running costs. A lot of money can be spent on big houses that don’t necessarily perform well.
“As a certified Homestar practitioner and assessor myself, I’m particularly enthusiastic that Homestar becomes recognised in New Zealand, leading to not only better buildings, but also future-proofed homes with high ratings which will have increased value.
It’s not only about high performance specifications and rating, the homes must be appealing designs which are ‘chic’ and eye-catching and appeal to New Zealanders.”
Bob says most New Zealand houses are built to only three to four stars and don’t use modern earthquake resilient design principles. “Generally Kiwi homes have been viewed by people from overseas with dismay and are seen as notoriously poor performers, often cold, damp and even unhealthy. Better knowledge and higher building standards mean immigrants from Europe, the United States and Japan recognise and seek better homes that are better than a standard New Zealand house.”
“Highly rated Homestar homes will be construction milestones as well as being of great public interest; particularly if they are affordable and designed to be quake-resilient. We know from research and work in Japan that we can design and construct buildings that will withstand impacts much better than our current earthquake prone buildings.”
Bob Burnett and co-founder Don Holden had the idea for Quakestar. An easily understandable five star rating, for a buildings earthquake performance. The system has widespread support from public, industry and local and national authorities and will rate not only safety but also damage and cost and time to recover.
More information: Bob Burnett Architecture, (03) 33 88 303, Eversun Homes 0800 002 674