A solar assisted heat pump (SAHP) is a renewable heating system that combines solar energy with heat pump technology to produce hot water efficiently.
It draws warmth from both sunlight and the surrounding air, meaning it can operate reliably throughout the year, including during Scotland’s cloudier and colder months.
What Is a Solar Assisted Heat Pump?
A solar assisted heat pump works by capturing heat from the sun and the surrounding air through a panel or solar collector, then using that energy to heat your home’s hot water supply. The system includes a heat pump unit, a solar collector or photovoltaic panels depending on the type, and a hot water cylinder.
Because it sources energy from both sunlight and ambient air rather than relying entirely on grid electricity, a SAHP uses significantly less electricity than a conventional electric water heater. It is designed to provide consistent hot water across all seasons, not just in summer.
Our guide on heat pump vs solar panels ca also help you decide if a SAHP is a good option or just one of the two seperately.
How Does a Solar Assisted Heat Pump Work?
The system works in a straightforward loop. A solar collector or evaporator panel absorbs warmth from the sun and the surrounding air. Inside the panel is a heat transfer fluid that absorbs this energy and carries it to the heat pump. The heat pump then raises the temperature further and transfers the heat into a hot water cylinder for household use.
The result is a steady, reliable supply of hot water that uses far less electricity than a standard immersion heater or boiler-fed hot water system. Because the solar element pre-warms the fluid entering the heat pump, the heat pump does not have to work as hard to reach the desired temperature, which reduces energy consumption and wear on the system over time.
Types of Solar Assisted Heat Pumps
There are two main system types, and the right one depends on how you want to use solar energy and what infrastructure your property already has.
Solar thermal-assisted heat pumps
Solar thermal assisted heat pumps collect heat directly from the sun and surrounding air through flat thermodynamic panels or solar collectors. This heat is transferred directly to the heat pump via a fluid loop, pre-warming the water before the pump raises it to the final temperature. Because the fluid enters the system already warm, the heat pump uses less energy and runs more efficiently.
Solar PV-assisted heat pumps
Solar PV-assisted heat pumps use photovoltaic solar panels to generate electricity, which then powers the heat pump. The heat pump draws warmth from the outside air in the usual way, but relies on self-generated solar electricity rather than the grid to do so. This type is a natural fit if you already have solar panels installed or are planning a combined solar and heating upgrade.
Both system types aim to reduce reliance on grid electricity. The main difference is whether solar energy is being used to directly heat the fluid entering the pump, or to generate the electricity that powers the pump itself.
Benefits of Solar Assisted Heat Pumps
Lower energy bills
By drawing on free energy from the sun and the air, a SAHP significantly reduces the electricity needed to heat your water compared to conventional heating methods. Running costs are lower on a day-to-day basis and the savings compound over time.
Reduced carbon footprint
Because the system relies on renewable energy sources rather than burning fuel, carbon emissions from your hot water heating are cut considerably. This makes a SAHP a meaningful step toward a lower-carbon home.
Reliable hot water throughout the year
A common concern with solar systems is whether they work in poor weather. A SAHP continues to function effectively in cooler and overcast conditions because it draws on ambient air heat as well as sunlight. For Scottish homes, this year-round reliability is one of the most important practical advantages.
Low maintenance
Once installed, a solar assisted heat pump requires minimal day-to-day attention. The system runs automatically and is built to be durable. Annual servicing by a qualified engineer is generally sufficient to keep the system running efficiently across its lifespan.
Potential property value uplift
Renewable heating systems are increasingly attractive to buyers, and an energy-efficient hot water system can contribute positively to a property’s energy performance rating and market appeal.
Drawbacks of Solar Assisted Heat Pumps
Higher upfront cost.
Because a SAHP combines two systems, the initial cost is higher than installing a standard heat pump or boiler alone. Government grant support can help reduce this, but the upfront investment is a genuine consideration.
Space requirements.
The system needs space for the solar collector or PV panels, the heat pump unit, and a hot water cylinder. Homes with limited roof access, significant shading, or restricted internal space may face installation challenges.
Slower hot water recovery.
A SAHP heats water gradually and to a steady volume rather than instantly or in large quantities. After periods of heavy hot water use, the cylinder may take some time to fully reheat. Households with high demand should factor this into the system design and cylinder size.
Efficiency depends on conditions.
While the system works year-round, solar contribution does reduce on heavily overcast days and in colder months. In those periods, more of the load falls on grid electricity. In Scotland this is a real consideration, and expectations should be set accordingly. The system will still operate effectively, but will not always match the performance of peak-summer output.
How Efficient Are Solar Assisted Heat Pumps?
The efficiency of a SAHP depends on a combination of factors: solar radiation levels, ambient air temperature, the desired water temperature, and system design. Under favourable conditions, where the panels receive good sunlight and the air temperature is reasonable, the system can deliver hot water with very low electricity input.
In colder or cloudier conditions, the solar contribution is lower and the heat pump works harder. In practical terms for a Scottish home, this means the system will never be as efficient in January as it is in June, but it remains a substantially more efficient way to heat water than a conventional electric heater throughout the year.
For the best long-term performance, the system should be sized and configured based on your household’s actual hot water demand rather than on an ideal-conditions calculation.
How Much Does a Solar Assisted Heat Pump Cost?
The cost of a solar assisted heat pump varies based on home size, system type, installation complexity, and whether a new hot water cylinder is needed. A typical solar PV assisted system with a heat pump installed system in the UK currently costs in the region of £6,000 to £10,000 for solar panels and £5,000 for a heat pump installation after the BUS grant depending on specification.
However if you live in Scotland the grants are far better and you can get a heatpump from as little as £1,000 on average making them a great option.
Key factors that affect the final price include:
- Home size and daily hot water demand.
- Whether a solar thermal or solar PV-assisted system is chosen.
- Number and quality of panels required.
- Complexity of the installation and existing plumbing setup.
- Whether a new hot water cylinder is needed.
- Available roof or wall space for panels.
- Access to grant funding.
Government grant support is available in Scotland that can reduce the upfront cost significantly. The Home Energy Scotland grant scheme offers support for qualifying renewable heating systems, and it is worth exploring eligibility before committing to installation. Factoring in the reduction in monthly energy bills, the long-term cost of ownership is typically lower than continuing with a conventional water heating system.
Is a Solar Assisted Heat Pump Right for Your Scottish Home?
A SAHP is most suitable for households whose primary goal is efficient, low-cost hot water production, particularly where reducing running costs and carbon emissions are the main drivers. It works best in homes that have suitable roof or wall space for the collector panels, a reasonable daily hot water demand, and some willingness to wait for the cylinder to reheat after heavy use.
If your goal is to heat both your home and your hot water, a standard air source heat pump combined with solar PV panels may be the more flexible and widely applicable solution. The SAHP is specifically oriented toward hot water production rather than full space heating. For Scottish homeowners who need both, a full solar-plus-heat-pump setup is worth discussing with an installer.
At The Edinburgh Boiler Company, we install heat pumps and solar systems across Scotland. As one of Scotland’s highest rated renewable energy installers, MCS and NAPIT certified, we can assess your property and advise on whether a solar assisted heat pump or a combined solar and heat pump system is the right fit for your home and budget.
FAQs
What is the difference between a solar thermal-assisted and a solar PV-assisted heat pump?
A solar thermal-assisted system captures heat directly from the sun and surrounding air through thermodynamic panels and uses it to pre-warm the fluid entering the heat pump.
A solar PV-assisted system uses photovoltaic panels to generate electricity, which then powers the heat pump. Both reduce grid electricity use, but they do so in different ways. If you already have solar PV panels or are planning a wider solar installation, a PV-assisted system usually integrates more naturally.
Do I need a hot water cylinder for a solar assisted heat pump?
Yes. Most solar assisted heat pump systems require a hot water cylinder to store the heated water. The cylinder size should be matched to your household’s typical daily demand. Many modern systems come with an integrated cylinder, which can help with space constraints in smaller properties.
Does a solar assisted heat pump work in winter in Scotland?
Yes, it continues to function in winter, but efficiency is lower than in summer. The system draws on ambient air heat as well as sunlight, so it does not shut down in cold or overcast conditions. That said, Scottish homeowners should expect reduced solar contribution in winter months and a greater share of the energy load being met by electricity. The system will still be more efficient than a conventional electric heater in those conditions.
Can a solar assisted heat pump be combined with battery storage?
Yes. If the system is solar PV-assisted, pairing it with a battery storage system such as Tesla Powerwall, Fox ESS, or Duracell Energy allows surplus daytime solar generation to be stored and used to power the heat pump in the evenings or during overcast periods. This improves the overall economics of the system and reduces grid dependence further.
Interested in a solar assisted heat pump or a solar and heat pump combination for your Scottish home?
The Edinburgh Boiler Company installs solar panels, heat pumps, and battery storage systems across Scotland. Get in touch today for honest, expert advice and a tailored quote from one of Scotland’s top-rated MCS and NAPIT certified renewable energy installers.
