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A Winter's Tale

by Rhys Taylor

www.sustainablehouseholds.org.nz

This article was first published on Impact E-magazine.

We shifted our household within Christchurch just in time for our traditional mid-winter dinner with friends, held to mark the solstice and Matariki. The move took a whole day with large van and a hired team of muscle in support. There are still dozens of boxes to unpack, a week later. We clearly have acquired too much stuff. One batch has already been donated for re-use to a garage sale. Boxes more of paper are off to recycling.

The good news is that a roast turkey, chestnut stuffing and assorted home grown organic vegetables were served to our guests in a comfortably warm room, whilst sleet fell outside. The experience was so different from a week earlier, when it was equally cold outside, but our home had felt cold and damp inside too.

Why move in mid-winter, with short daylight and snowfalls to frustrate our efforts? Our previous landlords had decided to 'test the market', and found that they sold their tenanted house quickly. Anne and I had to find a new place within a few weeks and took this as a prompt to seek improved comfort and lower electricity costs, while accepting that a higher rent was inevitable. The search proved depressing at first. We were shown several older wooden houses, cold and ill-equipped, then some traffic-assailed sunless city centre town houses with tiny rooms and single-glazed windows. Then we found, from a newspaper advert, this six month old terraced house. Its two levels have double glazed windows, get winter sunshine and are warmed by heat pump. We gritted our teeth at the cost and immediately rented it for a year!

It has thermal insulation to meet the current Building Code standard, as improved in recent years (See Consumer Build website: http://www.consumerbuild.org.nz/publish/materials/materials-insulation.php )

Electric power consumption, for the final week before we moved was 414 units (KiloWattHours) and for the first week here was 285 units, providing a saving worth $24 a week and a tangible increase in comfort. Electric water heating cost and water use will have been similar in both houses, so this gain is from insulation plus more- efficient heating. Despite seeing ice outside during both weeks, we have felt no cold draughts, less chilling (feeling heat being radiated from our skin to colder windows and walls) and noticed less condensation on windows and none on walls.

The low angle winter sunshine, although often cloud-obscured, reaches into the lounge and my study, aiding the passive solar gain for which any new home should be designed. Eaves provided here will shade the hottest high angle sun in the summer, as well as keeping out water. Our previous house lounge got no useful winter sunshine as it was orientated the wrong way. It was set parallel to the road, square within its section instead of being angled to face the North. However there's no sign yet of a City Plan rule alteration to require developers to orientate their sub-divisions and new buildings to the North, ready for passive solar gain, and too few do this spontaneously.

Why do so many New Zealand Mainland houses have such abysmal heat gain and retention? Are we such hardy folks that we'd rather wear thermals sitting in bed to watch TV, than be comfortable; or that we like burning wood and coal inefficiently in open fireplaces to create urban smog (Christchurch has recorded over a dozen smog pollution nights by mid-winter: http://www.ecan.govt.nz/Our+Environment/Air/Air+monitoring/Air+Pollution+Today.htm and there are some grant and loan incentives available in Canterbury to encourage conversion of inefficient, polluting open fires into 'clean heat' using heat pumps plus ceiling insulation: http://www.ecan.govt.nz/Our+Environment/Air/Home+Heating/Clean+Heat+Project/

Existing building technologies can take the wooden houses being built today up to reasonable comfort and efficiency levels, as shown by the Beacon NOW demonstration home in New Lynn: http://www.nowhome.co.nz/the+criteria.aspx, but to get really impressive thermal performance you need to use passive solar gain plus storage of that warmth within the building structure, in floor and walls kept snug by exterior insulation. Concrete floors and stone, concrete block, re-inforced brick or earth interior walls can achieve this best, as they have more thermal mass than timber and gypsum-board. Our rented house only comes part way towards this standard as it is insulated but still low in thermal mass, which is why a heat pump, efficiently warming the air is a good heating option here.

The first stage of our architect-designed house Geraldine, to be built in 2007, will be concrete, using these 'passive solar gain plus thermal mass storage' principles. It will still need some winter heating top-up, from Thermofloor electrical tape heating under floor tiles, for comfortable radiant heat that does not require such warm air (http://www.homeideas.co.nz/brochure/index.asp?cat=9 ) and active Thermocell solar water heating on the roof (http://www.thermocell.co.nz/ ) to keep down power bills.

We will also be experimenting, firstly with solar pre-heating of incoming ventilation air and secondly by taking surplus collected solar heat, once the water cylinder is hot, to a wall radiator. This will help us to get best value from the uninterrupted Northern aspect on that site.

Local builders are providing competitive quotes for the Geraldine project this month, enthused by sustainability themes presented by speakers from Beacon and BRANZ at their recent NZ Master Builders national conference: http://www.branz.co.nz/sustainablefoundations/files/Events2.htm. They have sensed that times are changing, noted the sustainable development requirements of the 2004 Building Act, the tighter Code standards coming in from 2007 and they are getting ready for a growing market, of which Impact's readers are clearly a part.

Why does it matter? Because buildings consume 40% of the world's energy resources and 55% of the timber harvested, and because we spend the great majority of our time indoors and the quality of that environment matters. Be more comfortable and healthy while reducing your impact on the planet - the marketers call that a lifestyle of health and sustainability. Read more about actions you can take at home, whether or not you are building or shifting soon, at http://www.sustainablehouseholds.org.nz/

Rhys Taylor is national coordinator of the NZ Sustainable Living Programme.

Email: coordinator@sustainablehouseholds.org.nz

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