Standard vs heaterless heat pumps:
What distinguishes heaterless systems from the rest is that heaterless heat pumps don’t rely on a power-hungry heating element to function under normal conditions.
Many heat pumps do not incorporate an electrical heater within their own product specifications. However, many of these do require the inclusion of a heating element in the system they are to be part of.
As a result, these heat pumps misleadingly appear to be very efficient while the required additional heater would decrease overall energy efficiency to a significant extent. Their requirement to include a heater in the system design increases the total cost of ownership by means of higher energy consumption. Unfortunately, this isn’t obvious to the buyer that may be enticed by a lower sticker price since the heat pump is under-powered for their needs.
Heaterless heat pumps produce the total power requirement solely via the heat pump and don’t require an electrical heater, integrated or otherwise. They are slightly costlier to buy since they are designed to match the exact capacities needed for a given project – but they are much more economical in the long-term.
In this post we’ll examine the facts, costs and savings for these two systems to determine which is best and why.
So, what exactly are heaterless heat pumps?
Heaterless heat pumps are designed to perform reliably without the need for an electrical heater. This makes heaterless units much more efficient allowing them to maintain a higher COP, therefore a much better return on investment over the heat pump’s lifespan.
Successfully installing a heaterless heat pump however demands technical experience as the system must be sized, designed and installed properly.
Where specifications demand, or in the case additional heating redundancy is required, an optional electric heater module can be added to such a system to boost heating capacity further but at the cost of economy. Of course, this additional electric heater could be operated manually to ensure that it is only used in an emergency.
How much more efficient are heaterless heat pumps?
To better understand how much more efficient a heaterless unit is, we compared data between a 11.2kW heaterless heat pump system and a typical 14kW system comprised of an 8kW heat pump system with a 6kW electrical heater.
The 11.2kW heaterless system and the 14kW standard system are equally matched in terms of heating capacity – the 14kW standard system (8kW HP+ 6kW heater) just consumes more energy to produce the same amount of heat as the heaterless unit.
Assuming a kW/h cost of €0.16 (Average EU kW/h cost) and a SCOP of 4.0 (for both heat pumps) we examined a rather typical case of a building needing 34,655 kWh of heating per year based on a pretty common heating scenario using the EN14825:2018 standard.
Results and conclusion:
|Unit||Puchase Cost||KWh per year||Cost per year||Total cost after 25 years|
The heaterless heat pump could heat this building by consuming a total of 8,664 kWh per year costing the owner €1,386 per year at an investment cost of €6,950.
The standard heat pump could heat the same building by consuming a total of 10,257.5 kWh per year. Of this annual 10,257.5 kWh consumption, 2,125 kWh would be consumed by the heater with 8,132.5 being used by the heat pump itself. This would cost €1,641.2 per year at an investment cost of €5,897.
The savings of using a heaterless heat pump amount to €255 per year – a significant impact on total savings over time.
Although the standard heat pump costs €1,053 less, that initial difference would be paid back in roughly four years for an owner that would choose a heaterless unit. More importantly, the heaterless unit would have cost €5,100 less to run over a 20-year lifespan, or €6,375 less over a 25-year lifespan. If energy costs rise during this period the heaterless unit will make even greater financial sense.
Of course, a good system design would consider such issues and ensure the proper heat pump selection in the first place as this is after all a system sizing mismatch. Nevertheless, system designers should strive to use heaterless heat pumps for at the very least 90% (ideally 100%) of the load requirements by matching the HP’s capacity to realistic scenarios. This will ensure maximum economy over the duration of the heat pump’s lifetime.