Recommended settings for most homes

There isn’t one hot water setting that suits every home. Start with the setup your installer provided, then adjust everyday heating controls only if they don’t meet your routine.

You don’t need to change every setting below. If your hot water is working well, use this guide to understand the options.

Choose how you want heating to be planned

The main choice is whether the tank plans heating for you or you choose the heating times yourself. You use one approach at a time.

• Automatic control: Mixergy Flex learns when you use hot water and plans heating around your routine and energy tariff. Choose Standard as a starting point if you want automatic control. Allow up to two weeks for it to learn.
• Your own schedule: a manual schedule tells the tank when to heat and how much hot water to prepare. This suits homes that want to choose their heating times.

To see your current option, open the Mixergy app and select your tank. Open the menu at the top right and select Mixergy Flex. Standard or Economy means automatic control is active. Off means you need to use a manual schedule.

Use Set schedules and smart control for the setup instructions. If someone else manages your tank, ask them before changing it.

If you use Mixergy Flex

Standard balances energy savings with keeping enough hot water for everyday use. It is the recommended starting option for automatic heating.

Economy prepares a smaller regular amount. Choose it only if your household uses little hot water and that smaller amount meets your needs.

Use hot water normally while Mixergy Flex learns your routine. A Boost is a request to heat extra water when you need more than usual; see Set hot water levels and use Boost for how to request one.

If Economy regularly leaves you short, return to Mixergy Flex in the app and select Standard. If you still regularly run short after the learning period, ask Mixergy Support for help.

If you want to opt out, turn Mixergy Flex off and set a manual schedule instead. Eligible homes stop building up Mixergy Flex Rewards while it is off.

If you use a manual schedule

Start with the schedule and hot water amounts your installer provided. For many homes, heating less than a full tank meets everyday needs. Heat-pump systems can be set up differently, so follow your installer’s advice before reducing their scheduled amount.

Find the gauge, the slim black panel with lights and buttons on the tank. Its red lights show how much hot water is ready.

Look at the red lights before your usual showers or baths, then again afterwards. Each light represents about one tenth of the tank’s usable hot-water capacity. Five red lights mean about half is ready. That can be the whole amount you requested and enough for your needs; it does not mean heating is unfinished.

• More hot water is regularly left than you need: try a small reduction in the scheduled amount, if your installer’s guidance allows it.
• You regularly run short: try a small increase for that scheduled period. Allow enough heating time before you need the water.

Follow Set schedules and smart control to change the schedule. Make one change at a time and compare several similar days.

A light is not a fixed number of showers. Your tank size and shower flow affect how much you need.

Keep the installer’s heat-source setting

The heat-source setting tells the tank which equipment supplies its heat. Keep the option chosen during installation. Changing it can make the tank expect heat from equipment your home does not use.

Don’t select a different option just to test it. If it looks wrong or you’re unsure, check your handover information or ask your installer. If you rent, ask your landlord or housing provider.

Keep energy prices up to date

Your tariff is the price plan you pay for the energy that heats your water. Use a recent bill or supplier account to check the unit prices and any cheaper periods.

Follow Set your energy tariff to enter or update those details. Don’t guess prices or change information managed by someone else.

Keep temperature and safety settings as installed

The amount of hot water you request and its temperature are different settings. Changing a scheduled percentage changes how much water is heated, not the target temperature.

Keep the target temperature your installer chose. Keep the cleansing cycle enabled; it helps control bacteria in stored water. Ask your installer for advice before changing either setting.

If you have solar panels

Keep the solar setup agreed with your installer. Panels only heat the tank if a compatible system is configured to use their spare electricity.

If you want to check whether this is working, follow Is solar PV working with your tank?. Don’t move sensors, alter wiring or change installer settings.

Common questions

Do I need the app?

You can read the red lights and request a Boost using the gauge on your tank without the app. The app is needed to change schedules and other settings. If you do not have access, ask your installer or housing provider who manages those controls.

Should I heat to 100% every day?

Not every home needs a full tank each day. Follow your installer’s advice, especially with a heat pump. The tank also runs a separate cleansing cycle that heats it fully to help control bacteria in stored water. Keep this safety function enabled.

What if Economy doesn’t give me enough hot water?

Use a Boost for an occasional extra need. If you regularly run short, consider Standard rather than repeatedly adding Boosts.

Why did heating happen at another time?

Flex can vary heating times around your routine and energy tariff, including adjustments for Grid Assistance. The separate cleansing cycle and frost protection can also request heating outside your usual schedule. See How Mixergy chooses when to heat for an explanation.

What if I rent?

Keep the settings provided to you. Ask your landlord or housing provider before changing managed controls or the heat source.