Heat pumps are becoming a popular choice for decarbonising home and business heating to achieve net zero targets. The UK Government has set a target of 600,000 new heat pump installations per year by 2028. However, a critical factor often overlooked is the type of hot water cylinder (HWC) you pair with your heat pump. Spoiler alert: not just any cylinder will do!
What Makes Heat Pumps Different?
Unlike conventional gas or combi boilers, heat pumps extract heat from the air or ground, transferring it into a refrigerant. An electrically powered compressor is then used to compress the refrigerant, significantly raising its temperature. This heat can then be used for building heating and to provide hot water.
Today, air source heat pumps (ASHPs), such as the Mikrofill RenewAIR range, typically provide flow temperatures between 35°C and 55°C, compared to 65-80°C with gas boilers. This slower, gentler process means your hot water cylinder must be specifically designed to suit.
Why a Standard Cylinder Won’t Work with Heat Pumps
Conventional cylinders are designed for quick, high-temperature (fuel-based) input from gas boilers. They assume high heat input over a short period. If you connect a heat pump to a standard cylinder, several issues can arise:
- The coil may be too small, meaning heat transfer is inefficient and the cylinder becomes a limiting factor in the building heating system.
- You could end up using more electricity to top up temperatures with an immersion heater – defeating the purpose of using a heat pump in the first place.
- It could result in higher return temperatures into the heat pump, which could negatively impact the performance of the heat pump.
What Makes a Heat Pump Cylinder (HWC) Different?
Heat pump-optimised hot water cylinders are engineered to match the unique demands of low-temperature, longer-duration heating. Here’s what sets it apart:
- Larger heat exchanger coils: These allow better heat transfer at lower flow temperatures. Always match the cylinder’s coil peak power rating to the heat pump’s output at the intended flow and return temperatures.
- Greater surface area: Helps the cylinder absorb more energy from the heat pump. A standard cylinder with a smaller coil might not efficiently transfer heat, leading to slower heating times and lower water temperatures.
- Enhanced insulation: Maintains temperature to accommodate the slower reheating process.
- Built-in legionella control: Most heat pump HWCs include built-in immersion heaters to periodically raise the water temperature to 60°C+ to kill bacteria.
Benefits of Using the Right Cylinder for Your Heat Pump System
Improved System Efficiency
A correctly specified cylinder allows the heat pump to work at its optimum performance levels. With larger internal coils and better heat exchange design, the system can transfer heat into the water more effectively, even at lower temperatures. That means your heat pump:
- Operates more efficiently, leading to lower electricity usage.
- Maintains steady performance, especially in colder weather when it may already be under more demand.
Lower Energy Bills
When your heat pump and cylinder are working in sync, the entire system becomes much more energy-efficient. This translates into noticeable savings:
- Less reliance on backup electric immersion heaters (which are far more expensive to run).
- Better insulation in modern cylinders reduces heat loss, keeping water warmer for longer.
Over time, this can lead to substantial cost savings, particularly in households with higher hot water demand.
Reliable Hot Water Supply
One of the common worries people have when switching to a heat pump is whether they’ll still have enough hot water. A dedicated, accurately sized heat pump cylinder is designed to meet this need:
- Designed to retain heat better, so there’s always a reserve.
- Often quicker to recover than you’d expect, because the larger coil maximises heat transfer.
In other words, you’ll have hot water when you need it – whether it’s for morning showers, evening baths, or running multiple taps at once.
Explore how a domestic pressure booster set can further ensure reliable hot water supply, complementing your heat pump and hot water cylinder setup.
Reduced Environmental Impact
Pairing a heat pump with the right cylinder helps you get the most from this low-carbon heating system. The result is:
- Lower CO₂ emissions from day-to-day operation, especially if the electricity for the heat pump is generated from renewable sources.
- A meaningful step toward more sustainable, environmentally responsible home heating.
It’s a small change that supports a much bigger climate goal.
Better System Longevity & Fewer Maintenance Issues
When a heat pump struggles to heat a poorly matched cylinder, it works harder than it should, which can lead to:
- Increased wear and tear.
- More frequent faults or breakdowns.
- Shorter overall system lifespan.
A properly matched cylinder reduces strain on your heat pump, protecting your investment and helping it run smoothly for years to come.
Final Thoughts: Why Choosing the Right Hot Water Cylinder Maximises Your Heat Pump Investment
So, if you’re investing in a heat pump, don’t cut corners on the hot water cylinder. The right cylinder isn’t just a nice-to-have, it’s essential for getting the most out of your system.
Speak to Dutypoint today about choosing a heat pump-optimised cylinder that matches your property’s size, water usage, and heating setup.
The Element Eco Range supports the growing demand in the marketplace for a complementary HWC to pair with your Heat Pump.
Contact Dutypoint on 01452 300110, or drop us an email on sales@dutypoint.com for further help, specification or information on Element Eco.
