Homeowner Guide to Your “Open Loop” Heat Pump System

Your heat pump works in a similar way to a traditional boiler, heating both your home and your hot water. However, your open loop system is designed to run more efficiently—helping you save around 30–40% on running costs compared to standard heat pump setups.

How your system works

Your radiators or underfloor heating (UFH) run at lower temperatures than a typical boiler system. The temperature automatically adjusts depending on the weather outside:

• When it’s colder outside, your heating will feel warmer
• When it’s milder, it will run at a lower temperature

This happens automatically to keep your home comfortable while using less energy. At their warmest, radiators and UFH will typically reach 35–45°C.

If you prefer higher, constant temperatures, your installer can adjust this—but it may increase running costs by up to 40%.

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Keeping your home comfortable

Your system is designed to run continuously at low temperatures, rather than turning on and off like a traditional boiler. This keeps your home at a steady, comfortable temperature while staying energy-efficient.

For best performance:

• Leave your heating running at your chosen temperature throughout the day
• Avoid turning the system on and off frequently
• Try not to switch off individual rooms

Turning rooms off or letting your home drop below 17°C can make it much harder (and more expensive) to warm back up, as the heat pump has to work much harder to recover the temperature.

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Room controls

Instead of traditional on/off thermostats, your system uses smart modulating thermostats, which gently adjust the temperature for better efficiency.

These are typically installed in:

• Bedrooms
• Kitchen
• Main living areas

Bathrooms and shared spaces don’t usually need thermostats. While extra thermostats can be added, using too many or frequently switching them can reduce efficiency and increase costs.

Once your home reaches your chosen temperature, the system will maintain it automatically—no overheating or cold spots.

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Heating controls

Your system is designed to be simple to use. You can control your heating and hot water through:

• Your smartphone
• The heat pump controller

Just set your desired temperature and let the system do the rest.

For the best efficiency, it’s usually better to keep the heating running steadily. Turning it off overnight may seem like a good idea, but it often uses more energy in the morning when the system works harder to reheat your home.

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If needed, you can:

• Lower the temperature overnight
• Or switch heating mode off via your phone or controller

The system is also set so it won’t run when your home is above 18°C (this can be adjusted if needed).

You can fine-tune temperatures in key rooms using your thermostats or radiator valves.

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Hot water

Your hot water cylinder is set to 50°C and is automatically maintained by the heat pump, so you’ll always have hot water when you need it—no timers required.

Once a week, the system will heat the water to over 60°C. This is completely normal and part of a safety feature called the legionella cycle, which helps keep your water system clean and safe.

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