Heat Pump Efficiency - Giving You Savings

If you are trying to select a new hot water system, then heat pump efficiency and how heat pumps work will be important to understand for you to be able to compare them with the other hot water systems available.  

A Heat Pump Is Like an Energy Multiplier

A heat pump uses electricity to drive the compressor and the fan instead of using electricity to heat the water directly.

A heat pump transfers the abundant heat energy in the surrounding air to the water in the storage tank. It's similar to an air conditioner on the heating cycle, but instead of heating the air, it heats the water in the tank - and they are highly efficient.

The heat transferred is dependent on the temperature of the air surrounding the heat pump unit, known as the ambient air temperature.

For example, when the outside temperature is 15°C and the required water temperature for the household is 60°C, the heat transferred into the water tank can be 3 times as much as the electrical energy used by the fan and compressor. On a 30°C day, the heat energy transferred to the water is over 4 times the energy used by the system. That’s a performance efficiency of 400%. (This performance measure is known as the Co-Efficient of Performance or "COP")

An electric hot water system which uses an element to directly heat the water has a theoretical maximum performance efficiency of 100% (usually around 98% in practice).

Taking the heat abundant in the air means far lower usage of electricity to provide you with your hot water needs.

heat pump efficiency

A specification sheet for a heat pump will contain a table showing the COP (Co-efficient Of Performance) for that model at a variety of ambient air temperatures (and humidity levels). Also, as the humidity level increases, so does the performance of the heat pump.

coefficient of performance for heat pumps

It's important to choose the right model which meets your needs and one which is best suited to the climate where you live.

If you are living in an area which experiences occasional frost or short periods of cold weather, we recommend  a model with built-in frost protection.

Call a Veraahdy advisor on 1800 420 600 and find out today how the remarkable heat pump efficiency benefits could be saving you up to 75% off your water heating costs.

Do Heat Pumps Work In Cold Weather?

Domestic air source heat pump systems are suitable for use in most weather conditions found in Australia.  Some systems are designed to operate correctly in cold climates with winter temperatures well below 0C, some as low as -10C.

Heat pump systems operate by extracting the heat contained in the air. Air is composed of various gases and water vapour. Latent heat (stored heat) is contained in both. 

They absorb heat from moisture contained in the air, as well as heat stored in the air itself. In the mornings and on cold days when the relative humidity is generally high,  these conditions can actually improve the heat pump's efficiency. (see the Table above)

For example, even though the ambient air temperature in the morning is usually colder than later in the day, the higher humidity level in the morning means that a heat pump system still working with high efficiency producing plenty of hot water.

These maps Courtesy of the Bureau of Meteorology clearly show how morning humidity levels are, on average, much higher in the mornings when it's cooler - and that improves heat pump efficiency - which means re-heatings times are shortened.

australian humidity morning
australian humidity afternoon

The Australian Government’s Clean Energy Regulator has recently revised the number of STC’s allocated to manufacturer’s heat pump models to better reflect the performance of heat pumps in cooler climates in areas like Canberra and Hobart which are prone to frosts.  These regions now are categorized as Climate Zone 5 areas.

climate zones STCs

Pick the wrong model for your climate zone, and not only might you run out of hot water when you shouldn't, but your upfront cash discount will be lower as you will receive less STC's than you would selecting a model designed for colder climates! More about available Government Incentives..

Your Veraahdy advisor can recommend the right model for any climate zone in Australia or New Zealand, just have your postcode information when you call.

Why Are Running Costs So Low?

High heat pump efficiency is achieved because the system does not use electricity to heat water, thus it only requires minimal electricity to run. This is the major point of difference to electric and solar systems. See the comparison chart..

In a heat pump system the air heats the refrigerant liquid, converting it to gas, which is then compressed, increasing its temperature. It is this superheated/compressed refrigerant gas that goes through the condenser coil heating the water.

The water tank is highly insulated, so much so that it does not require a booster and you will not run out of hot water, whether you are a family household, or a hotel or resort with high demand water usage requirements.

Want to know more? Speak with one of our friendly heat pump specialists today.

Call Veraadhy on 1800 420 600

Optimal Output from a Heat Pump System

Depending on the design of the specific hot water heat pump, there are specific conditions that give optimal heat pump efficiency and output.

Some heat pumps are designed so the litres per hour water heating rate never changes with the ambient air temperature - the compressor just works harder in cold weather. Other systems have a variable reheating rate which is dependent upon the ambient air temperature, but a larger storage tank. Some are designed to operate on off-peak electricity tariffs, others works just fine on standard tariffs.

The technology is now so advanced after decades of refinement and low ozone CO2 (R744) refrigerants are being used and a few systems run much more quietly than an air-conditioner.

But all systems have the following requirements:

  • Be installed in a location with free air movement around the unit (or  a min of 250 cubic m air volume if indoors)
  • The expelled air from the heat pump unit is cold and dry
  • They only run when powered up
  • Best located away from bedrooms and neighbours

For commercial applications the heat pump system can be located near a plant room which produces heat, thus makes the running costs of the heat pump lower by improving the heat pump efficiency.

Cal Veraahdy today if you have questions about installing a heat pump system.

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