Heat Pumps

A heat pump works by extracting heat from the air outside your house and bringing it indoors. It’s like a refrigerator in reverse. By trying to cool the world, it can extract heat. Or vice versa. Older styles of reverse-cycle heat pumps have only two operating modes - the pump either works at 100 percent capacity, or not at all.

The newer inverter-system pumps can operate at various levels up to their maximum capacity. They remain switched on and adjust their working capacity in order to maintain the room temperature. Their manufacturers claim this makes them more energy-efficient than non-inverters. And they usually have three or more fan speeds to match. On some units the fan can be used as a fan on its own, to provide cooling when the heat is not extreme.

How heat pumps work

Use an old-style bicycle pump for a while and it will get hot. That’s because gas (air) is being compressed. Spray an aerosol can and the valve area will become cold. That’s because the compressed gas in the aerosol can is expanding.

Heat pumps (like refrigerators) have a system of pipes containing gas (refrigerant) that is continuously expanding in one part of the system and compressing in another. When the gas is being compressed, it gets hot. A heat pump’s exterior unit compresses the gas, then pumps it to the interior unit where the gas runs over a series of finned coils, giving off its heat.

The gas is then returned to the outside unit, where it expands and runs through another set of finned coils, which become cold. The cold gas is then recompressed and the cycle continues. For summer cooling, the refrigerant flow is reversed, so the interior unit becomes cool, while the exterior hot.

Heat pumps shift more heat than the electrical energy consumed in compressing the refrigerant and running the fans, making them highly-efficient methods of heating - up to three times as much in the right conditions.

Heat pumps are basically space heaters. The simplest versions are designed for a single room; the most complex, for a whole house. It takes 3 to 5 minutes to bring a room up to temperature, after which the level will be maintained within one or two degrees.

Reverse cycle heat pumps

This type of pump can heat the room or cool it at the touch of a button. This is achieved by reversing the flow of refrigerant, allowing heat to be pumped in or out of the room.

Inverter/constant speed types

Inverter systems are one of the big technical breakthroughs of the last few years. They use a variable-speed electric motor which slows down and speeds up as needed to hold a chosen temperature.

Before inverter technology arrived, heat pumps used single-speed motors that were either on or off (like a fan heater that turns off when the desired temperature is reached and then switches on when the temperature drops a bit).

Inverter models are more efficient, and electricity companies like them because they don’t create surges in the demand for electricity. We strongly recommend inverter systems, if you can afford them.

How to choose a Heat Pump / Air Conditioner

Here's a simple checklist to help you find the heat pump / air conditioner to suit you best:

• How many rooms do you want heated?

You can buy a single heat pump to heat a single area or room, a `multi-system' to heat 2, 3 or 4 areas, or a fully ducted system if you wish to heat your whole home.

Many people start with a single unit, and later, when they see just how convenient and comfortable heat pumps can be, go on to buy more units for other rooms.

• What you should expect from your Heat Pump

Today's heat pumps come with a variety of features. However, there are some basic requirements that are important:

Quality
It is important to choose a brand you can trust. Fujitsu, for example, offer the longest warranty in New Zealand - 6 Years full parts and labour warranty when you choose a Fujitsu Accredited Installer, or 5 years if you choose a non-accredited installer.

Energy Efficiency
Efficiency means lower running cost, and a healthier environment. By their very nature, heat pumps are the most efficient form of heating there is. But different brands also have different levels of efficiency too - check to see the brand you are purchasing has the Energy Star logo, and the ratings from EECA. Efficiency has always been a priority with Fujitsu.

Quiet Operation
Most heat pumps are quiet indoors, as the only sound comes from the fan. The decibel levels of our heat pumps are shown in the brochure specifications. Fujitsu's improved fan design and `quiet mode' on many models means that you simply cannot buy a quieter heat pump anywhere.