As homeowners across the UK look to replace gas boilers and reduce carbon emissions, two low-carbon heating technologies are gaining attention: heat pumps and heat battery boilers like the ZEB.
Both systems are electric and designed to cut carbon emissions, but they work in very different ways. Understanding these differences can help homeowners choose the right solution for their property, lifestyle, and long-term heating needs.
What Is a Heat Pump?
A heat pump is a low-carbon heating system that extracts heat from the air, ground, or water and upgrades it to heat a home. Rather than generating heat directly, heat pumps use electricity to move heat, which allows them to operate very efficiently under the right conditions.
Pros of heat pumps:
- Use ambient heat from outside the home
- Are very efficient – using a small amount of electricity to deliver a large amount of heat
- Can be cheap to run if installed and used properly, particularly with smart tariffs
- Cut carbon emissions drastically vs fossil fuel heating
- Currently available for a grant under the Boiler Upgrade Scheme
Cons of heat pumps:
- Standard air-to-water heat pumps need to be installed outside in a suitable space
- Efficient operation requires lower flow temperatures, which may involve replacing or upsizing radiators
- Installation typically takes 3–5 days, with more disruption if redesigning heating systems
- While highly efficient in the right homes, heat pumps may not be suitable for every property
What Is a ZEB Heat Battery Boiler?
The ZEB is a type of heat battery. It uses electricity to store heat directly in a thermal core, which is then released on demand to supply a traditional wet heating system, such as radiators or underfloor heating.
Instead of capturing heat from the environment , the ZEB draws power off-peak when electricity prices are low and then delivers heat when it’s needed. Doing this allows the ZEB to charge like a battery, but heat like a traditional boiler.
Pros of the ZEB heat battery:
- Charges using electricity during off-peak periods – cheaper and greener than flat-rate power
- Stores heat with minimal losses over time
- Releases heat on demand at high flow temperatures, replicating gas boiler performance
- Avoids the need to change pipework, radiators, or existing heating controls
- Installed indoors – no outdoor unit or flue required
- Can charge and discharge simultaneously, ensuring a household never runs out of heat
- Now available for a grant under the Boiler Upgrade Scheme, for winter 2026.
Cons of the ZEB heat battery:
- Finite storage – the ZEB holds 40kWh of heat. This is enough for the average UK home, but will need topping up with peak power in larger buildings.
- The ZEB needs to be installed on a solid, level surface. It can be installed on any floor of a building provided there are solid stairs or a lift.
- Best paired with a time-of-use tariff and smart meter for optimal off-peak charging
- Requires an indoor space that is weatherproof and typically heated.
Heat Batteries are a great fit for homes with limited outside space, or where the upgrades needed to make a heat pump possible are simply impractical or expensive.
Installation Differences: Heat Pump vs ZEB
Installation is one of the most significant differences between heat pumps and heat battery boilers.
Heat pumps are typically suited to:
- Homes with good insulation (or homes where low flow temperature heating works effectively)
- Properties with space for an outdoor unit
- Homeowners able & willing to undertake a system redesign
- Projects where installation disruption is acceptable
Heat batteries are designed for:
- A straightforward boiler replacement
- Homes where retrofitting a heat pump may be difficult
- Flats, terraces, or properties with limited outdoor space
- Homeowners looking to decarbonise with minimal disruption
- Properties in conservation areas or listed buildings where making external changes is difficult
One of the key differences between heat pumps and heat-battery boilers is how they are installed, which can influence the type of home and level of disruption involved.
Day-to-Day Use and Heating Control
Heat pumps typically run at lower temperatures and for longer periods, maintaining a consistent indoor climate. This can feel different from the on-demand heating many households are used to and may require changes in how heating is managed – including replacing your heating controls.
The ZEB, by contrast, behaves much more like a traditional boiler:
- Heat is delivered when it’s needed
- Existing thermostats and controls can often be retained
- Intelligent heat modulation allows the system to match output to demand
- Homeowners experience a familiar heating pattern to fossil fuels
The way heat is delivered varies between heat pumps and heat-battery boilers, with each offering a different approach to maintaining comfort and managing your home’s heating.
Efficiency and Energy Use
Heat pumps are known for their high efficiency, as they can produce more heat energy than the electricity they consume. However, performance depends on factors such as insulation, system design, and outdoor temperatures.
The ZEB converts electricity directly into heat and focuses on:
- Smart charging during lower-cost or lower-carbon periods
- Reducing peak electricity demand
- Providing predictable performance regardless of weather
- Integrating easily with time-of-use tariffs
Rather than maximising efficiency , heat batteries like the ZEB prioritise flexibility, familiarity, and ease of installation.
Which Low-Carbon Heating System Is Right for You?
Choosing between a heat pump and a heat battery boiler depends on several factors, including:
- Property type and age
- Insulation levels
- Available space
- Budget and appetite for retrofit work
- Preference for how the heating system is used
Heat pumps can be an excellent solution for homes that are well suited to low-temperature heating and system upgrades. The ZEB heat battery boiler offers a compelling alternative for homeowners seeking a low-hassle, like-for-like replacement that fits easily into existing homes – particularly where outside space is limited.
The Future of Low-Carbon Heating
As the UK moves towards net zero, it’s encouraging to see a growing range of low-carbon heating options becoming available. Heat pumps and heat batteries each have an important role to play in decarbonising homes.
We cannot achieve net zero with either solution alone.
By offering different pathways away from fossil fuels, technologies like the ZEB heat battery help ensure that more homes can make the transition to low carbon heating; regardless of the type of home, location, installation complexity, cost or people’s preferences for how they heat their homes.