The Green Superhome with $6/month power bill June 3rd 2021 : Stuff
When Vicky Jones received her first power bill for her new home, she thought there must be a mistake – the total was $6.
That was in November last year. The following two summer bills were $3 and $5. “Ridiculous,” says Jones.
She and her husband demolished a rental property – that was “rat-infested, affected by rising damp” and “full of asbestos” – to make way for the ultra energy-efficient new build in Riccarton, Christchurch, last year.
Data from the Ministry of Business, Innovation and Employment shows the average New Zealand household spent a total $2067 on power in the year to March 2020. That is a bill of $188.92 per month, when averaged over the year.
Jones’ build was only completed late last year, so the home has not been lived in over winter yet – and admittedly the bills may go up a touch in the coldest months.
But Jones is confident it will be easy to maintain the current indoor temperature of 22 degrees Celsius.
She says the new house has a lovely “hush” kind of atmosphere, no doubt thanks to its airtightness (with one full air change an hour) and a mechanical heat recovery ventilation (MHRV) system.
Her son lives in the Rata St home and he tracks its power usage via a smartphone app.
The 12 solar panels feed power back to the grid if it is not being used but as the power company pays only one-third of what it charges for power, it is best to use it as you make it.
Jones says she is impressed at how far energy-efficient building technology has come in the 12 years since she last built.
“We look at this as a forever home, so it is best to build it as well as you can. When you build a home, you hope it won’t need too many tweaks to keep it modern. We have tried to future-proof it.”
Jones drives an electric car, as does her husband, but she says she is not a greeny.
“It is just in the back of our minds. Throughout bringing up children, it was not centre and front – you are too busy.
“But now that we have the time and money, it is good to be able to do it.”
REDUCING YOUR FOOTPRINT
Architectural designer Bob Burnett says the Rata St house is built to Superhome standards, which look at both the efficiency of the building and also the sustainability of the materials used to build it.
“Timber structure has been prioritised over steel to help reduce the carbon footprint and the single steel portal frame required has been positioned inside the thermal envelope to eliminate thermal bridging,” he says.
“The recessed, thermally-broken windows have argon filled low-E Xtreme glass, which is a new, ultra-high performance double glazing that further improves the energy efficiency of the windows which are always the weakest point thermally in a dwelling.”
The way the house is laid out is also in keeping with green design principles. A study on the lower floor, for instance, is set back to minimise overheating from the afternoon sun.