Heatopia

When considering heat pumps, one of the main factors to bear in mind is the system’s running costs. Here, the design of the heat pump system plays a crucial role. A poorly designed system, especially one that’s significantly oversized, can cause frequent cycling. Cycling, or short cycling, is when the heat pump repeatedly turns on and off before it’s had enough time to thoroughly heat your home. This typically happens when an oversized heat pump generates more heat than the radiators and underfloor heating can dissipate. If the radiators aren’t upgraded to handle a larger surface area, the problem of heat dissipation only worsens.

So why is it a problem if the heat pump switches on and off frequently? You might wonder, as gas boilers do this all the time. However, heat pumps are most efficient when heating steadily and gradually. The initial start-up phase is less efficient since the pump has to ramp up to generate heat, but once it reaches a stable flow, it ticks along efficiently. Excessive short cycling, where the pump runs briefly, shuts off, and then has to ramp up heavily again, disrupts this efficiency and can lead to higher running costs.

Another consideration is whether you have a time-of-use electricity tariff, perhaps because you already have an electric vehicle (EV) or have chosen a tariff designed for heat pumps, offering cheaper electricity at specific times. Some evidence suggests you might be able to preheat your home slightly during these off-peak times, letting the building materials store some of that heat so the pump can run less during peak hours. Similarly, you could use the off-peak period to heat your water, storing it for later use. If you don’t already have a time-of-use tariff, check with your energy provider to see what options are available. However, not all tariffs will suit your lifestyle: if, for instance, you’re up at 5 am and out by 6 am, preheating during the cheap period wouldn’t be effective. Choose a tariff that fits your routine, and ideally, one that allows for future flexibility.

Finally, consider whether your home has rooms that aren’t frequently used. Perhaps the kids have moved out, leaving a few bedrooms seldom used. In this case, check with your installer to determine the best heat pump settings. Should you keep all rooms at the same temperature, or is it more efficient to lower the temperature in unused rooms? While some experts advise against switching off radiators in individual rooms, you might benefit from setting a lower temperature in certain spaces so the heat pump operates more efficiently at a steady level. If you’re not comfortable adjusting these settings often, especially for infrequent guests, you might consider keeping a few oil-filled or portable heaters on hand instead.

In general, a well-designed heat pump system should help you reduce heating costs, especially if you’re currently using an older, non-condensing gas boiler (a topic we’ll cover in a future post). For now, stay warm and heat smartly!