How the ZEB heat battery boiler and Sunamp Thermino provided a compact, low-carbon heating and hot water solution for apartment living.
The challenge: Restoring heat and hot water in a North London apartment block
After the building could no longer rely on its previous gas heating infrastructure, homeowners needed a new way to restore reliable heating and hot water.
For a busy apartment block, finding the right replacement can be tough. Outdoor space is at a premium, making traditional air source heat pumps or air-to-air systems impractical, there just isn’t room for bulky outdoor units or major external modifications.
The right system had to:
- Remove the need for gas, for good
- Fit within the apartment’s layout, without an outdoor unit
- Connect to the existing radiator system
- Deliver dependable hot water and heating
- Cut down on the high cost of direct electric solutions
- Support a cleaner, low-carbon home
The solution: Compact and practical electric heating and hot water
The homeowners turned to tepeo and Octopus Energy for help finding a practical, long-term answer. Together, we installed a system combining the tepeo ZEB heat battery boiler for heating, and a Sunamp Thermino for domestic hot water.
The ZEB is a British-made heat battery boiler. It charges using off-peak electricity, stores that energy as heat, and releases it directly into the wet radiator system when the home needs it, no gas required, and no need to overhaul the existing heating infrastructure.
For hot water, we paired the ZEB with the Sunamp Thermino: a compact thermal battery that neatly fits where space is limited, removing the need for a large cylinder.
This new solution is entirely indoors, low-carbon, and perfect for apartment living.
The installation: Designed for real homes
The full upgrade was completed in just one week and included:
- Removing the old system
- Installing the ZEB heat battery boiler
- Adding the Sunamp Thermino for hot water
- Flushing the radiator system
- Upgrading to new smart heating controls
Both the ZEB and Sunamp Thermino slotted into the space left by the previous boiler setup, a huge benefit where every inch counts. With no requirement for outside units or flues, we avoided challenges that typically limit low-carbon heating options for apartment blocks.
The result: Warmth – and peace of mind
With the new system in place, the homeowner gained back reliable heating and hot water, without gas. The ZEB now provides consistent warmth through the radiators, while the Sunamp Thermino delivers hot water efficiently and compactly.
This wasn’t just an upgrade, it was a transformation. The home became warmer, more comfortable, and took a confident step away from fossil fuel heating.
Why this solution works for apartments
Decarbonising heat in apartments isn’t easy. Space is tight, planning restrictions are common, and large hot water tanks often don’t fit. But the right technology offers new options:
- No outdoor unit: ZEB and Sunamp fit entirely indoors, making them ideal where traditional heat pumps aren’t viable.
- No gas needed: The system restores heating and hot water without reverting to fossil fuels.
- Works with existing radiators: The ZEB delivers heat through the current wet radiator system (subject to suitability).
- Compact hot water storage: Sunamp Thermino fits even in apartments where a large cylinder won’t.
- Designed for off-peak electricity: The ZEB charges when electricity is cheapest, adding value and sustainability.
- Retrofit-friendly: Both units fit neatly in the boiler cupboard, simplifying installation and minimising disruption.
What this means for the future of apartment heating
We need practical solutions to decarbonise every type of home – not just houses with plenty of space. Converted buildings and urban apartments often face barriers that make traditional systems impossible.
This project shows how heat battery technology and compact thermal storage can bridge the gap – bringing low-carbon heating to places where other options fall short.
Heat pumps will play a key part in the clean heat transition, but every home is different. Scaling up decarbonisation means giving homeowners real choice, including apartment-friendly solutions that work in the real world.
Is the ZEB right for your apartment?
If you’re living in an apartment or converted building and looking for:
- a replacement for your gas boiler
- a low-carbon heating system with no outdoor unit
- an alternative to costly direct electric heating
- a way to keep existing radiators (where suitable)
- a compact, smart heating solution
- a system that works with off-peak electricity tariffs
… then the ZEB may be just what you need. At tepeo, we always begin with a home check to ensure the solution fits your needs, space, and lifestyle.
Get in touch to find out how you can say goodbye to fossil fuels – and hello to a warmer, more comfortable future