The short answer is yes, you can technically install a heat pump in a poorly insulated house. However, there is a big difference between whether a heat pump can work and whether it will work efficiently and effectively for your home, your pocket and the planet.
Making the switch from a traditional gas boiler to a renewable system is one of the biggest steps you can take to green your home. When you replace your boiler with a heat pump, you’re moving away from burning fossil fuels for heat and toward a smarter, more sustainable future. While a boiler provides quick, high-heat bursts, a heat pump works most effectively by maintaining a steady, consistent temperature. This is why getting your air source heat pump insulation right is so important; it ensures that the gentle, efficient warmth created by your new system stays exactly where you want it—inside your home.
We want to make sure your switch to low-carbon heating is a success. While heat pumps are incredibly efficient, often reaching efficiency levels of 300% or more, their performance depends on how well your home holds onto and delivers heat within your rooms. If your home is leaky, your heat pump will have to work much harder, which can lead to higher electricity bills. Equally, if radiators in rooms are undersized, you’ll likely notice cold spots and uneven heating throughout your home.
Another issue with having no insulation, or poor insulation levels, is that the heat loss of your property is naturally greater.
Whilst we’ve covered how insulation helps your home hold onto heat, a greater heat loss means you need a bigger heating source to overcome the losses. In essence, the more heat your home loses, the more heat you need to put in, which requires a larger capacity heat pump. A larger capacity heat pump won’t just cost more to run, it will also cost more upfront.
Understanding what insulation an air source heat pump needs.
When looking into air source heat pump insulation requirements, it’s helpful to think of your home like a thermos flask. A heat pump provides a steady, low-temperature flow of warmth rather than the quick, intense bursts of a traditional gas boiler.
If you have a heat pump in a poorly insulated house, the heat often escapes through the walls and roof faster than the system can replace it. This doesn’t mean the technology has failed, it just means the environment isn't helping the machine do its job.
Think of your home like a fridge, and the heat pump the compressor that keeps it cool. If you leave the fridge door open, the heat loss is too great, therefore the compressor would never be able to keep the fridge at a stable temperature.
Before you commit to a full heating upgrade, we always recommend a fabric first approach. This means making sure your loft, walls, and floors are doing their bit to keep the warmth inside.
Why insulation for a heat pump is the secret to lower bills.
The main goal of insulation for a heat pump is to reduce the heat loss of your property. When your home is well-insulated, your heat pump can run at lower flow temperatures, which leads to:
Lower running costs: The less work the pump has to do, the less electricity it uses.
Consistent comfort: Insulation prevents cold spots and draughts, making your home feel much cosier.
Smaller unit size: A well-insulated home may only need a smaller heat pump unit because the total heat demand is lower. This can often be cheaper to install.
Potentially longer lifespan of key components: Any heating system components whether this is the heat pump itself, or other equipment will likely last longer when it’s not being run at maximum capacity constantly to overcome significant heat loss.
Path 1: Not insulated?
If your home currently lacks proper protection against the cold, it is worth pausing before rushing straight into a heat pump installation. Instead, you should look at the government grants and schemes available.
What insulation do you need for a heat pump?
To get the most out of your green energy transition, you should ideally aim for a combination of the following:
Loft insulation: One of the easiest and most effective ways to stop heat rising out of your roof.
Cavity wall insulation: Essential for modern homes to keep the warmth within the living spaces.
Room in roof insulation: Insulating your loft conversion could help with heat loss.
Flat roof insulation: Can also make your home more cosy and energy efficient.
Path 2: Already insulated? Why a bespoke home survey is your next step.
If your home is already sporting thick loft insulation and cavity wall protection, you’re in a fantastic position to move forward. However, because every home is unique, especially older UK properties, a one-size-fits-all approach doesn't work for renewable energy.
Are heat pumps suitable for old houses?
A common myth is that heat pumps only work in new builds. That isn't true. While heat pumps in old houses require more careful planning, they can be incredibly effective if the radiators are sized correctly and any draughts are managed.
Which houses are not suitable for heat pumps?
Very few houses are truly unsuitable, but some may require significant upgrades before a heat pump becomes cost-effective. For example, a listed building with single-glazed windows and solid stone walls that cannot be insulated might struggle to stay warm with a standard air source heat pump.
Are heat pumps good in very cold climates?
Many people worry about the UK’s damp, chilly winters. You’ll be pleased to know that heat pumps are the primary heating source in Scandinavian countries like Norway and Sweden, where temperatures drop far lower than they do in the UK. As long as your system is designed correctly, it will keep you warm all year round.
One of the biggest hurdles to upgrading your home can be the initial cost, but the good news is that you don't have to go it alone. Through the Boiler Upgrade Scheme, you can access £7,500 heat pump grants to help with the installation of an air source heat pump. This significant government heat pump and insulation subsidy is designed to make renewable energy more accessible, ensuring that the transition to a greener, more efficient home is affordable as well as sustainable.
Why us? Specialists in tailored home heating.
We are specialists in tailored home heating. We don't just drop a box outside your house and hope for the best. Our experts conduct a detailed energy assessment to find the right heat pump size and type for your specific needs.
We look at:
Your home's specific heat loss calculations by room.
The size and heat output of your existing radiators (you might need some larger ones).
Your hot water usage patterns.
Your specific needs and property occupancy levels.
This bespoke home survey ensures that your system is designed for maximum efficiency, so you aren't spending more than you need to on your energy bills.
Take the next step toward a sustainable home.
Whether you are starting from scratch with insulation or you are ready to install the latest air source technology, we are here to guide you.
Already insulated? Get a heat pump quote let our experts design a perfect, tailor-made system for your home.
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