You’ve done your research and know an air source heat pump (ASHP) is an excellent way to make your home more energy-efficient, but maybe your needs go beyond what one unit can offer. Maybe you live in a large home or in a region of the UK that experiences particularly cold winters. Or perhaps you simply want a backup for peace of mind.
It’s possible to install a primary and secondary heat pump in your home to share the heating load and provide backup when needed. If your home is larger or experiences colder weather, this is a smart way to ensure your heating is consistent and reliable.
To help you consider your options and understand how two systems can work together, we’ve put together this brief but helpful blog.
For more detailed guidance on installing two ASHPs, please contact Cinergi today. We are renewable energy specialists with over thirty years of heating experience, serving homes and businesses throughout the South Coast.
What are primary and secondary heat pumps?
The primary pump is your home’s main source of heating. It’s the workhorse, running most of the time to meet your home’s heat demand. ASHPs extract warmth from the outside air and deliver it indoors through radiators, underfloor heating, or other systems.
The primary unit is typically designed to supply the bulk of your heating needs, keeping your home comfortable and energy-efficient throughout the year.
A secondary pump can work alongside your primary system to provide additional heating support during peak demand periods or in extremely cold weather. While the primary pump handles most of the work, the secondary unit kicks in when needed, ensuring your home stays warm and the primary system isn’t overworked.
This second pump adds an extra layer of security and efficiency, which is especially useful in large homes or areas with harsh winters.
This approach not only keeps your home at an even temperature but also increases the overall efficiency of the heating system by ensuring both pumps are working optimally and sharing the workload.
For more information on how heat pumps function in the winter, read our blog.
Do I need to have a backup ASHP?
One ASHP is usually sufficient for average-sized homes. However, it’s worth considering if your home has a high heat demand, such as multiple floors or a large floor plan, or if you live in an area prone to harsh winters.
It can ensure that your home stays warm even when temperatures plummet or if your primary unit breaks down or needs maintenance. Many homeowners value this level of security.
How many air source heat pumps can be installed in a house?
There’s no fixed limit on how many ASHPs can be installed in a house, but typically, one or two systems are enough for most homes.
Larger homes or commercial properties with separate zones (such as guest houses, multiple floors, or wings) may benefit from installing additional ASHPs to ensure each area is heated efficiently. The decision will depend on your home’s layout, heat demand, and efficiency goals.
Benefits of a primary and secondary heat pump system
- Efficiency
Sharing the load between two pumps means neither is overworked, leading to better performance and lower energy use. - Reliability
A secondary pump gives you backup in case the first system struggles during cold snaps or when demand is high. - Longevity
Reducing the strain on each system means you can extend the life of both pumps. - Comfort
Dual systems can more consistently heat larger homes or homes with uneven heating needs, resulting in better comfort across the house.
Considerations for installing a primary and secondary heat pump
System compatibility
Think about whether your home’s infrastructure is compatible with a dual system. For example, the pumps would need to sync with your existing radiators/underfloor heating and pipework to avoid major disruption. Also, the control systems need to be able to manage two pumps.
Cost
Clearly, two pumps are more expensive than one. Two external units and a second refrigeration circuit require more materials and installation. However, the long-term energy savings and the extended life of each unit can offset this.
Another option is to combine one outdoor unit with dual indoor units, which can be a more cost-effective solution. This setup makes installation easier and more affordable and offers the benefits of a dual heating zone system, but on the downside, there’s no backup if the external unit fails.
On average, you can expect to pay between £4,000 and £8,000 for a single ASHP (after the BUS voucher is deducted). The total cost will depend on your home’s size and heat demand.
Space
Each ASHP needs its own outdoor unit, so you’ll need to ensure you have enough space on your property to accommodate both. Units are typically 80 to 110 cm in width, 60 to 90 cm in height, and 30 to 50 cm in depth and are usually mounted on an exterior wall.
Size of the heat pumps
The pumps don’t necessarily have to be the same size. The first pump could be the larger of the two as it will handle the majority of the heating load. The second unit can be smaller if it only needs to kick in during peak demand. The size of each pump should be tailored to your home’s specific heating needs so both pumps can operate efficiently without overloading either system.
Looking for advice? Get in touch with Cinergi
If you are considering a dual heat pump system, Cinergi is here to help. Our service includes a thorough consultation to understand your heating needs, an inspection of your home and detailed heat loss calculations. We can then recommend the ideal solution, whether that be one or two ASHPs.
Contact us today for expert advice and a free consultation tailored to your needs.
