The cost of a ‘green’ home
Falling temperatures make for rising power costs, and leave many people keen to ‘‘green up’’ their homes to ensure greater energy efficiency.
But while there is a growing trend towards building sustainable homes in New Zealand, many people are wary of the expenditure involved in making an existing home ‘‘greener’’.
‘‘Greening’’ a home can involve insulation, double-glazing, heat pumps, home ventilation systems, solar energy systems, rainwater tanks, thermal insulated curtains, low-flow water fixtures and even smart technology systems.
They all have costs, but there is also a payoff. Here’s what some of them cost, and what homeowners stand to save, and gain.
Solar panel systems
Harrisons Solar spokesperson Mitchell Grant said the company had seen a significant increase in demand for solar energy systems between the first quarter of last year and the first quarter of this year.
Solar panels were getting cheaper but were more efficient, while power prices were rising and sustainability was becoming more important to people.
The company’s most popular system cost $9940 for a standard Kiwi home, he said.
‘‘A ‘typical’ solar system might have a net system cost of $10,000, but it will provide an estimated net power bill savings of $40,129 over the 25-year life of the system.’’
Going solar allowed people to take control of their power, so if they had a home battery installed and there was a power cut the power would stay on, and the systems also added to resale value, Grant said.
Rainwater tanks
Rainwater tanks are necessary in rural areas with no town water supply, but drought-related water restrictions have led to increased interest in rainwater tanks in other areas too.
Auckland Council has scrapped the resource consent requirement, resulting in a saving of between $500 and $4000.
Think Water Auckland director Claudia Knarston said the costs involved varied widely as tanks ranged from 500 litres to 25,000 litres in size, and there were different types of pumps and filtering systems.
A basic tank and pump would cost between $7000 and $9000 depending on tank size. A filtering system would cost $3000 on top of that.
Harvested water can be used for watering the garden, washing the car, flushing toilets and washing clothes, and with a good filtration system it can be used for drinking water and bathing, she said.
Thermal curtains and blinds
Even in an insulated house, upwards of 45% of the heat can be lost through the windows, but using thermal insulated curtains and blinds could make a big difference.
Grant said they could reduce window heat loss by up to 60% when closed
Thermacell blinds cost from $450 per window, and thermal-lined curtains cost from $300 per window. Both created an effective barrier against cold windows and draughts.
‘‘But light-filtering insulated blinds are also estimated to save 26.1% more energy, while roomdarkening ones are estimated to save 34.1% more energy.’’
Smart home technology
Schneider Electric home solutions consultant Rob Knight said being able to turn off lights and appliances, such as heat pumps and heated towel rails, automatically or on a schedule made for a greener, more energy-efficient home.
‘‘Our smart home solutions offer a starting point for everyone, regardless of budget. It could be as simple as a bluetooth dimmer for a couple of hundred dollars.
‘‘But it could range through to a full high-end system customised to meet specific requirements, where the pricing can range from $20,000 to $100,000.’’
A large Gulf Harbour house, with a heated swimming pool, underfloor heating and lots of electronics was an example of how much could be saved, he said.
The house used to have a monthly $1000 power bill, but the smart technology system ensured the high demand appliances operated only when electricity was at off-peak rates, and it cut the bill to around $300.
Financial help was available for people who wanted to increase the energy efficiency of their home.
ANZ recently launched a ‘‘good energy’’ home loan top-up which allowed customers to borrow up to $80,000 at a three-year fixed rate of 1%.
It could be used to upgrade homes with solar panels, heating, insulation, double glazing, ventilation systems and rain water tanks.