FAQ
Are heat pumps and solar PV right for everybody?
This page contains answers to the most common concerns around heat pumps, solar PV, and some retrofit case studies from Shipbourne and Plaxtol.
Heat pump FAQs
Don’t heat pumps need warm or moderate weather to work?
Modern heat pumps are designed to work efficiently all year round, even in freezing temperatures. They extract heat from the air, so they can still provide warmth when it’s cold outside. They work well down to temperatures about -25°C. Around two-thirds of Norwegian households have a heat pump, despite being a much colder country than the UK. In fact Sweden, Finland and Norway have some of the coldest climates in Europe and yet these three countries have the highest heat pump sales in the continent.
Are heat pumps more expensive than gas boilers?
The upfront cost of a heat pump is generally higher than a gas boiler, but they’re cheaper to run and maintain over time. This is because heat pumps are about four times more efficient than gas boilers, which means that they are better at keeping your home warm and can save you money on bills. With government grants and lower energy bills, most households see savings in the long run.
Do I have to install new radiators and insulation before buying a heat pump?
Not necessarily. Good insulation and bigger radiators help any heating system work better, but many homes only need minor adjustments. During a home assessment, experts can check whether your existing radiators and insulation are suitable. We have heard it often makes sense to install a heat pump and try it out for a winter before deciding on any major adjustments.
Will a heat pump be enough to keep me warm?
A properly sized and installed heat pump will comfortably heat your home, just as effectively as a traditional boiler, but using cleaner energy. There are steps you can take to improve the efficiency of your heat pump, outlined here by the Energy Saving Trust.
Will my heat pump offset the carbon emissions resulting from its production?
Analysis by Carbon Brief shows that, even with conservative assumptions, a typical heat pump would take about 13 months to offset the carbon emissions resulting from its manufacture.
Will a heat pump devalue my house?
A study by ScottishPower and WWF in 2022 showed that an air-source heat pump could increase the sales value of a home by around £5,000-£8,000.
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Further information is available from Carbon Brief: "Factcheck: 18 misleading myths about heat pumps."
Solar PV FAQs
Will my solar array still generate electricity when its cloudy outside?
Solar panels still produce electricity in cloudy weather, though output is slightly lower. They don’t need direct sunlight to generate power. Rain can actually improve the function of your solar array by washing away debris. And if paired with a battery, extra energy created on the sunniest hours of the day can be stored for the night.
Are solar installations too much hassle and cost for little payoff?
If you choose the right installers, the process is quick, low-maintenance, and supported by grants or finance options. With rising energy prices, most solar arrays pay for themselves within a few years and continue generating free electricity for decades. To get an idea of how much Solar PV would cost you, and how much you could save, try the Energy Saving Trust’s calculator.
Local retrofit case studies
Plaxtol case study: Installing solar PV and switching from an oil boiler to an air source heat pump
Photovoltaic panels: We have a 4 kW solar photovoltaic system which was installed in 2011 on a south facing roof and to date this has generated over 55,000 kWh of electricity. Since installation, the panels and system have run without issue. The only caveat to that is that no electricity has been generated when the panels have been covered with snow or when it is foggy.
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Air source heat pump: In 2022 we replaced a 35 year old oil boiler with an air source heat pump as a retrofit which included an upgrade of all the radiators and the hot water tank. There were issues on installation, and the system sprang two leaks, the first caused by possible damage to a radiator pipe and the second was identified to have been caused by a previous plumbing repair in which a substandard joint had been used. Since both issues were resolved (in the first couple of weeks), the system has run without issue. It took a while to adjust to having warm rather than hot radiators after a lifetime of cold houses with oil fired heating systems with just a couple of hours of hot radiators a day. The entire house is now maintained at an even temperature (our preference is between 15°C and 18°C) whereas previously the lesser used rooms would have had the radiators switched off in the winter and those rooms were very cold. The increased airflow from keeping all the internal doors open has meant that no cold or damp areas in the house have been noted since installation.
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Verdict: The photovoltaic system is brilliant. The air source heat pump works well. When the outside temperature drops below zero, you can see the increased demand for electricity on the smart meter and at this point we choose to use a couple of mobile stand-alone radiators to boost the heat in the rooms which are most frequented.
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If we were to start again: We would add a storage battery on installation of the photovoltaic panels (this was not an option when our system was installed) so that evening electricity use was provided by our system rather than having to buy from the grid when the sun has gone down. As for the air source heat pump system, we would remove the radiators and have the system installed as underfloor heating.
