Simply put, an ‘eco-house’ is an environmentally low-impact home designed and built using materials and technology that reduces its carbon footprint and lowers its energy needs, creating a legacy of environmental responsibility rather than disregard.

Sounds easy enough. Just head off to the Eco house yard and buy one. Delivered in a week saving you money on your power bill in three. Everyone should have one. Just sign on the dotted line of the recycled A4 contract.

Unfortunately the building industry is neither as clever or as sexy as the automobile industry. Henry Ford, grandfather of mass production, sent the Model T down the assembly line, creating unforeseen manufacturing efficiencies, and inspiring architects of the time to imagine what if we could do the same with housing. Factory-produced housing had been around for a while; the colonies were built from mail order, your Victorian villa included, but Ford’s thinking put the idea on steroids. The 20th century is littered with well-intentioned factory-produced housing schemes.

The car companies have continued to innovate. They realize to stay in business they have to push the green envelope. Safer, faster and more economical, taking advantage of all the latest in gadgetry, sensors and logic boards, shrinking carbon footprints and growing efficiency.

Meanwhile, in the housing market, technology remains very last century, treated 4 x 2 and a 24-ounce hammer … she’ll be right mate.

As a consumer I can easily procure a petrol-sipping miser, green lean and mean fresh off an optimized low-energy robotic production line from any of the big auto manufacturers. Meanwhile my house remains barely insulated, let alone with individually controlled and zoned environmental comfort like on offer in the car yards.

Our housing stock generally leaks energy like a sieve, creates masses of landfill through an antiquated construction process, causes more hospital admissions of children than monkey bars, and costs us an unaffordable portion of our incomes, as well as generally being aesthetically deficient.

What gives? Is there a ‘green’ housing option available for the average consumer looking to house their average-sized family on an average-sized income? What kind of driveway will my Prius look its most awesome in?

Eco-building in Hawke’s Bay

With the building sector contributing 25% of our landfill waste and using 40-50% of our energy, what opportunities are there for innovation and lowering the energy and carbon footprint of homes in the Bay?

The Best Home project – a Hastings District Council (HDC) initiative in partnership with Beacon Pathways and Hovarth Homes, a local volume-housing supplier – has recently brought a new product to market.

HDC tasked Horvath Homes to participate in the building of a show home in Havelock North that would “exceed current building regulations to achieve a minimum six stars on the Homestar energy efficiency rating tool for no more than 5% additional cost of a standard build”.

The Council seeks to leverage this partnership as ground breaking and innovative, creating new intellectual property and value for the local community. However, it is unclear whether the approximately $220,000 invested thus far has actually created any new knowledge. For example, Homestar already provides a rating tool.

The show home incorporates the basics of sustainable building practice such as passive solar design, water recycling and onsite power generation. The key elements of passive design are:

  • Building orientation to sun
  • Insulation over and above the building code minimum
  • Double-glazing as minimum
  • Allowance of natural heating and cooling via controlled seasonal access to direct solar radiation
  • Provision of thermal mass (ample material to store heat energy)
  • Have glazing correctly placed and sized to aid with passive heating and cooling and natural ventilation
  • Include appropriate shading provided by overhangs and screens

The house is standard fare to look at – 187 sqm, two bathrooms, two-car garaging, four bedrooms. Its $500,000 price tag is unaffordable to the majority of the district’s population, relative to incomes.

Is a house of this size and type sustainable in the first place?

The trend in NZ, Australia and US over the last 25 years has been towards obesity of home size. A super-sizing not dissimilar to the fast food industry. Do we need to be building large or do we need to put our homes on a diet to achieve the first principle in sustainability – economy. We need to be thinking smart, not necessarily big.

The innovation the Best Home project provides is not in product but in process. When it comes to gaining a building consent, the ‘green tape’ route proposed, rather than red tape, is welcome relief for anyone requiring a building consent.

The Hovarth model is been further tested in partnership with the council on the site of the former HDC Nursery on Fitzroy Street in Hastings, which is being touted as a model medium density development. It will be interesting to see what a higher density model will mean for the Best Home.

It seems the new green is really the old green with some marketing speak around it. Perhaps the development of green building should be left to the experts and the market to sort out. Best practice examples and data are a mouse click away.

A ‘best practice’ eco house in Hawke’s Bay will:

  • Be site dependent
  • Be design-lead so key sustainable prin-ciples are incorporated at the front end
  • Be aligned with principles of passive solar design outlined above
  • Provide rainwater harvesting and storage capacity
  • Use a grey water recycling system
  • Generate power via photovoltaic or wind, with ability to feed back to grid
  • Heat water via solar roof top installation
  • Be built to an efficient module that doesn’t create excessive waste
  • Be flexible in use to accommodate variable patterns of occupation over time
  • Use local sustainably-forested timber
  • Have the capacity to collect and monitor environmental and energy-use data
  • Use 21st century technology where it can, including off-site fabrication technology
  • Be of a size and form related to comfort, efficiency and economics

Eco-building affordability

The simplest and most cost-effective eco-measures are those that align with a ‘passive solar’ strategy as outlined above. There is no additional cost to orientating a building to the sun and very little cost in additional insulation. It is eco through design and careful consideration at the front end.

It is the hard engineering technology where additional cost lies. If the project is designed correctly in the first place, however, then eco technology can be aligned to a customized upgrade programme as capital becomes available.

Obviously the paybacks in energy savings and carbon reduction get greater as energy costs increase and the initial capital costs required decline.

The good news is that a global push towards future-proofing against energy cost spikes in a post peak-oil world is driving research and consumer demand for greener buildings as well as cars. The trickle down has already started.

Photovoltaics have experienced massive increase in efficient generation capacity as well as cost cutting as a result of manufacturing efficiencies and technology. Payback times are decreasing rapidly. The future holds the capacity of every house to be a micro-generator feeding the grid. For the Bay, a golden opportunity.

Subsidies via tax rebates and low interest loans have been useful ways to stimulate the market elsewhere and could be replicated here. Kiwibank has moved in this direction by offering Sustainable Energy Loans as a top up to Home Loans where they will contribute $4,000 over four years towards cost of a system. Home insulation funding up to $1,300 has been available through EECA for some time and has been widely used.

Straw bales and mud bricks?

Eco-building has been talked about at least since the 60s when the hippies brought ideas into popular cultures with long beards and DIY muddy fingers. Current developments are an outgrowth of that culture of growing environmental awareness. The market perception is still somewhat that ‘eco’ equals ‘hippy dippy’, but it’s not actually like that.

There are great examples of the more traditional methods of eco-building like strawbales and mudbricks for individual projects, but the opportunity we need to consider is the wider housing market and the large-scale greening of our housing stock and building industry.

Technology has moved on, but we have yet to download the full value of knowledge and technology into our home building culture. As the traditional suburban stand-alone house becomes less a sustainable dream, building our housing on smaller more affordable lots, closer to community infrastructure, transportation and place of business, is the trend we need to advance … a design-led trend that can create inherently more sustainable housing infrastructure in our cities.

Eco-building brings economic benefits to individual homeowners. However, the broader social benefit is stimulating the ‘green economy’. This is widely considered to be the next tech-induced economic boom, and is where NZ Inc and Hawke’s Bay needs to be investing, one rooftop at a time.

There is a massive market out there needing and looking for innovation … no reason why Hawke’s Bay couldn’t have a piece of that pie.

Anthony Vile, a regular contributor to Architecture NZ, is a designer and urbanist. His work ranges from residential architecture, public art and urban design to urban planning and cultural analysis. Completed formal architecture and urban design education in New York. Has taught design at Univ of Auckland School of Architecture and Planning and Unitec.

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