KEY POINTS:
Heat pumps are great things but need to be used wisely to avoid power bills blowing out, says the Energy Efficiency and Conservation Authority (EECA).
The number of heat pumps in New Zealand has more than doubled from around 35,500 in 2004 to nearly 80,000 last year, and
is still rising.
As the numbers have increased, so has concern about the cost of running the pumps.
Slome users have complained to power companies about unexpected big increases in their electricity bills.
Some South Island consumers' bills have more than doubled from last year. But they have been told by power suppliers there is nothing wrong with their metering or billing.
They are being told they are seeing the effects of new heat pumps installed since last winter.
Estimated bills are based on last season's power consumption, and when a current reading is made, there is a "catch-up" to be accounted for in the bill.
Contact Energy and Trustpower have told customers that heat pumps can cost between $5 and $7 a day to run - which has come as a shock to people who invested in pumps because they thought the running costs were low.
The EECA yesterday issued a list of tips on how to get the best out of the latest heating trend without breaking the bank.
They include:
* Don't leave the heat pump running 24 hours a day. Use the timer and don't set the temperature higher than you need it.
* Choose an "energy star" heat pump - the star assures customers they have bought an energy-efficient.
* Buy the right-sized heat pump for the space you want to heat.
* Insulate your home.
* Choose a heat pump that is tested for colder climates if you live in a place where the temperature often falls below zero degrees.
* Avoid using the heat pump as an air-conditioner unless you really need to do so.
EECA chief executive Mike Underhill said heat pumps were one of the most efficient types of electric home, heating but had to be used wisely.
Leaving the heat pump running 24 hours a day would clearly push the power bill up.
In June, Consumer magazine told concerned subscribers that a considerable amount could be saved in heating costs if people kept their homes at about the same temperature as before they installed the heat pump.
If they wanted their houses warmer than before, their heating bills wouldn't drop by much and it would be difficult to achieve the goal of the heat pump paying for itself in 10 years, Consumer said.
- NZPA