Is it worth getting a heat pump hot water system?
Is it worth getting a heat pump hot water system? Yes, a heat pump hot water system is well worth considering – especially if you currently rely on direct electricity to heat your domestic hot water. The main reason is because a heat pump water heater uses electricity to transfer heat from the surrounding air into a hot water cylinder, as opposed to having an electric immersion heater do all the work. This can cut down the electricity needed for hot water production by a significant margin. Yet, whether or not it’s worth your while will ultimately depend on various factors such as the purchase price, household hot water demand, installation location, electricity tariff, hot water cylinder size and the efficiency of the specific system you go with.
How Much Electricity Can a Heat Pump Water Heater Really Save?
The main draw for people considering a heat pump hot water system is its energy efficiency. This is in stark contrast to a conventional electric immersion heater, which converts electrical energy directly into heat. In practice, that’s about 1 kWh of electricity being used to heat up 1 kWh of water.
On the other hand, an air source heat pump water heater works in a much more clever way. It extracts low-grade heat from the air using an evaporator and refrigerant circuit, then a compressor kicks in to raise the temperature of the refrigerant before transferring that heat to your domestic hot water.
The efficiency of this process can be measured using the Coefficient of Performance (COP) – with a typical COP of 3 delivering about 3 kWh of heat for every 1 kWh of electricity used. Though, actual performance will vary based on all sorts of factors, including air temperature, cold water inlet temperature, hot water temperature and how often the electric immersion heater has to step in.
For more information about our domestic and commercial hot water solutions, explore these product pages:
Wall mounted heat pump hot water systems
Domestic heat pump hot water systems
Commercial heat pump hot water systems
When is a Heat Pump Hot Water System the Most Worthwhile Investment?
For households that rely mainly on direct electric resistance heating for their hot water, a heat pump water heater can be a pretty attractive option. They can also be useful for anyone who wants to reduce their electricity consumption or make better use of electricity generated by solar PV panels. However, a household with a high daily hot water consumption will tend to get more absolute energy savings than a household that only uses a little hot water. This is where hot water cylinder size comes into play – an unnecessarily large cylinder will increase standing heat losses, while an undersized one might lead to a greater use of supplementary electric heating.
Are There Any Disadvantages to Consider?
The biggest downside is usually the higher initial cost compared with a traditional electric hot water cylinder.
A heat pump water heater is a much more complicated appliance – containing a compressor, fan, evaporator, condenser, refrigerant circuit and electronic controls. This means there are also additional practical installation considerations to take into account. For example, the heat pump needs an adequate supply of air, and it also discharges cooler air after extracting the heat from it. Depending on the appliance, ducting might be used to take air from or discharge it to another location.
There’s also the issue of condensate – so a suitable condensate drainage arrangement will be required. On top of that, there’s the potential for noise – unlike a standard cylinder, a heat pump water heater contains a compressor and fan. Modern units can be relatively quiet, but it’s worth considering the potential for disturbance.
What’s the Hot Water Recovery Time Like?
Heat pump water heaters often have a lower heating output than traditional boilers or large electric immersion heaters, so reheating the entire cylinder can take a bit longer. But that doesn’t necessarily mean that users will run out of hot water. What’s more, a correctly sized hot water cylinder will store enough energy to meet expected demand, allowing the heat pump to gradually recover the cylinder. Many integrated heat pump water heaters come with an immersion heater for supplementary heating, rapid recovery or high-temperature cycles.
Are R290 Heat Pump Water Heaters Worth Looking Into?
An increasing number of heat pump water heaters use R290 refrigerant, which is refrigerant-grade propane. R290 has a very low Global Warming Potential (GWP) and useful properties, making it suitable for heat pump applications. However, R290 is an A3 highly flammable refrigerant, so the appliance must be designed, installed and used in accordance with the manufacturer’s requirements and applicable safety requirements.
Is a Heat Pump Hot Water System a Good Investment?
For many UK properties that currently use direct electric water heating, a heat pump hot water system can be a very worthwhile upgrade. The potential reduction in electricity consumption can offset the higher initial purchase cost over time, especially in homes with regular domestic hot water demand.
When selecting a system, the property is worth considering over and above the quoted COP – as real-world performance is affected by all sorts of conditions, such as cylinder capacity, recovery time, airflow, ambient temperature, condensate drainage, noise and actual household hot water demand. A correctly sized heat pump water heater that’s properly installed will give you a pretty efficient and practical way to get domestic hot water while knocking down your electricity bill by using a heck of a lot less electricity compared to a traditional immersion-system water heater.