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Running Cost Considerations

The heart of your central heating system is a highly efficient Daikin Altherma heat pump. A correctly specified, installed and setup heat pump is an economic alternative to traditional fossil fuelled heat sources.

If you are experiencing actual or perceived high running costs this could be due to many factors. This page helps you understand common influences and, if necessary, help identify information required for further investigation.

Outdoor unit, extracts heat from the air automatically and there is no adjustment requirements. Efficiency can be reduced if air circulation through the unit is restricted by fencing, leaves, plants, other debris, etc. Keep the unit clear at all times to allow unrestricted air circulation and maintain efficient operation.

Indoor unit, if fitted, distributes hot water around the heating and hot water system. The control settings are essential to maintain optimum efficiency of the heat pump. During the initial setup and commissioning the installer will aim to provide comfort conditions at the lowest water temperature and therefore maximise the system efficiency. If these initial settings have been adjusted it can directly impact the running costs of the system.

Scheduling, like other heat sources, e.g. gas boilers, the programming of the heating periods is required to reduce running times and reduce costs. Has an appropriate heating schedule been set? Short heating periods and/or low setback temperatures make the heat pump work harder and reduces efficiency.

Seasonal, during colder periods your heat pump will work harder to extract the heat from the outside air. It’s important to review your annual running costs rather than a winter period alone.

Utility costs, unlike a gas boiler your heat pump uses electricity to operate. Your energy costs should be compared against the combined electric and gas costs if the heat pump has replaced a gas boiler installation.

Energy costs, gas and electric prices fluctuate and comparisons should be made against energy usage and not actual costs. This will help determine if more energy is used rather than a higher running cost.

Climate, no two heating seasons will be the same, likewise no two annual energy usage will be the same.

Room temperature setpoint, efficiency comparisons can only be made if the desired room temperature remains constant. Often, the indoor air temperature is increased and this  will ‘off-set’ efficiency gains using a heat pump. Similarly, when potentially more efficient heat emitters are installed the tendency is to increase the indoor air temperature, e.g. underfloor heating. Consider whether or not your perception of efficiency has changed your comfort setting conditions.

Heat emitters, heat pump efficiencies are greatly affected by the heating system water temperature setpoint. Heat emitters should be designed to operate at the minimum water temperature to satisfy the building heat load and your comfort levels. If the water temperature has been adjusted it will directly affect the energy usage and running costs.

Running cost software, all estimated energy usage is based on historical climate data and assumed heating usage patterns. Actual usage will always differ based on individual site conditions and personal preferences.

Building fabric, improved thermal efficiency of the building will reduce the heat load on the heat pump. Has all the building work been completed or has the buildings thermal efficiency been changed?

Heat load, has the building heat load changed due to an additional heated space? An increased heat load will decrease the heat pump efficiency and increase energy usage.

Heat emitters, is the system working correctly, e.g. radiator valves operating and set correctly, underfloor heating balanced correctly and controls set correctly. Has a heat emitter been removed or altered to cause the water temperature to increase.

Heated spaces, are all unused/unoccupied rooms heated? Adjacent heated rooms maybe losing heat to cold rooms and making the heat emitter/heat pump work harder to compensate for the increased heat load of used rooms. Heat loads are calculated based on adjacent rooms being heated.

Soft furnishings, has the output of the heat emitter been restricted? Thick carpets and rugs will increase the water temperature required for underfloor heating and reduce the heat pump efficiency; what floor finishes were included in the design? Similarly, radiator cabinets and furniture placement may adversely affect the radiator system performance.