Should you fit a heat pump?

As part of the government’s climate action plan, there is a target to fit 400,000 heat pumps in Irish homes to meet our 2030 targets for the reduction of green house gases . Most heat pumps warm  your home by producing hot water which is fed radiators or underfloor heating, similar to an oil or gas boiler, but at lower temperatures. They use electricity to do this, harnessing outside air or ground temperature which is pushed through a refrigeration cycle by a compressor, giving off a large amount of heat in the process. The beauty of the system is the efficiency, for every unit of electricity used roughly 3-4 units of heat are given off, so up to 300-400% efficiency.  So is a heat pump the best option for your home energy upgrade?

To investigate this further, we have a case study 150sqm, 1900s stone farm house with an existing BER rating of G. A typical upgrade of the building fabric is planned; external wall insulation, tripled glazed windows and doors, roof insulation, airtightness and ventilation.  Using the DEAP software we have looked at the impact of different heating systems, aiming to achieve a B2 BER rating or better as required by the SEAI One Stop Shop Scheme. These are shown below.

The graph above shows the BER rating achieved when the building fabric upgrade is combined with different heating systems. Electric heaters (e.g. convector heaters or infrared) only archives a C1, an oil boiler just scrapes into the B2 category and an air source heat pump gets to an A3. To get the electric heater option to the B2 target would require adding solar PV, while adding the same PV system to the heat pump option gets to an A1. Its also worth looking at the CO2 emissions for each option, shown above as kilograms per year. The oil boiler has the highest emissions, followed by the electric heater option and even the electric heater option with PV is still higher than either heat pump option. Estimated annual fuel bills are lowest with the heat pump options, and the electric heater option by far the most expensive at €3,780 per year!

Although it probably has the highest initial investment cost, on this particular property, with the insulation upgrades already planned, the heat pump option achieves the best BER rating, lowest CO2 emissions and running costs. More widely speaking, if you are completing a home energy upgrade, at the moment, in most cases, a heat pump is probably the best option, provided the house is well enough insulated, (this should be varied with a technical or home energy assessment), the system is designed and installed correctly.

Feel free to get in touch if you are planning an upgrade and would like to discuss any of our services.

* All modelling of the energy upgrades has been completed using the DEAP software, following the BER methodology and latest SEAI published average fuel costs.

Heat pump