Heat pump cylinder with bespoke flexibility
The ECOflow copper unvented heat pump hot water cylinder range provides fantastic benefits the most important of all is ensuring maximum efficiency from your heat pump. The use of copper allows the most efficient heat transfer not only in standard units but also bespoke units, tailored to your size and requirements.
The ECOflow range is built to deliver superior mains pressure simultaneously for showers, sinks and wash hand basins. Since its introduction in 1993, we have developed our unvented cylinder range, concentrating on ease of installation, reliability and a reduction in maintenance.
The bespoke design flexibility of the ECOflow product range overcomes the restrictions of stainless steel alternatives. With a wide range of diameters available to choose from, and the ability to adjust the tapping positions to suit the installation, it has become the perfect choice for installers.
Designed to maximise the performance of heat pumps, the ECOflow copper hot water cylinder heat pump cylinder comes pre-fitted with our high performance double or triple pass finned copper coil to maximise heat transfer, provide higher flow rates and reduce pressure drop from the heat pump.
Our Tank On Tank unit, the first introduced in the UK, combines a buffer vessel situated below the ECOflow cylinder. Where a buffer vessel is required on the system, the unit has only one footprint.
Our operations manager, David Stewart, talks through the fantastic benefits of our ECOflow heat pump cylinder range.
Is the ECOflow not suitable for your installation? Click here to see our complete range of heat pump cylinder solutions.
ECOflow has been developed to meet the growing demand for Heat Pump compatible hot water cylinders and offers:
- Unique bespoke design flexibility to provide an unvented solution to suit any installation requirement
- Slimline models starting from 400mm diameter
- Heat Pump and Heat Pump Solar models
- High heat transfer double or triple pass finned copper coil, maximising heat pump efficiency and reducing running costs
- Standard cylinder or tank on tank with integrated buffer store
- Suitable for all models of air source and ground source heat pumps
- Compression fittings as standard for ease of installation
- Proven reliability with 25 year guarantee
- Available with white case and high density pouring foam insulation or spray foam insulation (50mm or 100mm)
We provide an MCS Umbrella Scheme service which includes free heat pump training for installers.
The course is held in our dedicated training centre at our head office in Glenrothes, Fife. It is specifically designed for plumbers and heating installers looking to enter the rapidly growing heat pump market.
These courses provide hands-on experience of heat pump products, giving participants an in-depth understanding of the installation process, where you will gain:
- In-depth heat pump knowledge
- Learn everything there is to know about installing heat pumps, including both air source and ground source heat pumps
- Hands-on experience from industry experts
- Gain practical skills through interactive training sessions led by industry professionals.
- MCS Accreditation
- Once completed, you’ll gain access to the MCS Umbrella Scheme, through our training partner Alto Energy, which removes the hassle of completing the MCS accreditation & associated paperwork yourself.
- Become an Assured Installer
- Have leads provided and attract customers looking for renewable heating solutions.
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Click here for further details on the training, MCS Umbrella Scheme and register your interest in one of our courses held throughout 2025.
Many heat pump cylinder manufacturers are now insisting on the use of copper cylinders with their products, due to the improved performance copper offers.
- Cheaper running costs
- Copper’s thermal conductivity rating is over 15 times greater than that of stainless steel
- High efficiency finned copper coils, provide one of the most effective heat transfer processes on the market
- Copper has unrivalled bacteria killing properties, even at the lower temperatures achieved by heat pump sources
- Copper is 100% recyclable
A traditional gas boiler operates at 70-80°C, therefore providing a higher kW output through a standard indirect coil than a heat pump, which generally operates at 55°C. As the heat pump is a lower temperature heat source, it is essential to maximise the heat transfer to the water held within the cylinder.
A standard indirect cylinder will not work as efficiently with the heat pump input because the heat exchanger is simply not large enough, or designed correctly, to extract sufficient heat from the lower temperatures supplied. This was highlighted during recent Hot Water Association (HWA) tests, where it was shown that a cylinder with the specially designed heat pump coil reduced the heat up time by more than 30% compared to a standard indirect coil.
Many consulting engineers and even heat pump manufacturers recommend 3m2 surface area of heating coil. Measuring a heat exchanger performance purely by its surface area is inaccurate, especially when comparing coil types, such as a plain, copper integron (finned), or stainless steel corrugated heat exchanger.
The internal coil design in a heat pump cylinder differs from an indirect or solar cylinder, with most heat pump cylinders incorporating either a double or triple pass coil.
What is critical is that the purpose designed heat exchanger provides optimised heat exchange, low pressure drop, and allows higher flow rates to let the heat pump perform most efficiently. This multiple pass coil design has been shown in recent HWA tests to provide 75% extra reheat performance compared to a standard indirect coil.
The cylinder is fitted with an integral immersion heater and thermostat, which raises the stored water temperature to 60°C during its pasteurisation cycle, in line with guidance from the Hot Water Association (HWA), avoiding the risk of Legionella. The thermostat brings the immersion heater on at a temperature just below the heat pump maximum and switches it off at between 60-65°C, maximising the direct energy extracted by the heat pump and ensuring it is safe to use at the tap.
Click here to see the HVP Magazine feature explaining more.
- An optional integrated buffer vessel (sits below the cylinder offering a small footprint ideal for those who have limited space to work with).
- Wide range of capacities and sizes
- Pre-plumbed option
- Extra Coils – Solar, Boiler etc
- Vented Option
- Up to 100mm Lagging – Improved Sap Ratings
- Commercial Units
| Installation | Indirect | Dimensions (mm) |
| 1 bedroom + bath/shower | 150 | 1125 x 550 |
| 2 bedroom + bath/shower | 180 | 1325 x 550 |
| 3 bedroom + bath/shower | 210 | 1525 x 550 |
| 4 bedroom + bath/shower | 250 | 1525 x 600 |
| Larger Properties | 300+ | 1825 x 600 |
Dimensions include insulation
If you are looking to squeeze your hot water cylinder into a tight space, we also offer Slimline versions of our Unvented cylinders.
Typically measuring, an industry leading, 450mm in diameter including the insulation, these slimmer models are manufactured to the same standards and designs as our ECOflow units and come with the full 25 year guarantee.
However thanks to our flexible approach to manufacturing and our use of copper, we can manufacture cylinders as small as 400mm.
We can even place the connections in the best location for the installation, making further savings on installation time and costs.
To find out more about our ECOflow heat pump cylinders and to discuss sizing and dimensions, contact our technical sales team now.
In addition to our unvented hot water cylinder standard sizes we offer a bespoke service creating tailored units so you don’t need to compromise – to discuss your options just contact us on 01592 611123 or contact us online.
