WattKeeper

Your home, in step with the sun.

WattKeeper is a set of free tools that help a smart home use sunshine, heat and electricity prices more wisely.

Grid Your car Your home Heat pump Community

An illustration of a typical sunny day. Your own home will differ.

Sun on the roof
Strong
Electricity price
Low
Where the power goes
Car, heat pump and community

The energy transition starts at home.

Solar panels, heat pumps and electric cars are arriving on more roofs and in more garages. They work best together, and when they know what the grid and the electricity community are doing.

WattKeeper teaches a home to do that. It builds on Home Assistant, the free, open-source software that many people use to run their smart home.

A heat pump that listens.

Heat pumps are major players in the transition. WattKeeper lets Home Assistant read how yours is doing and gently steer it, so hot water is made when the sun is out.

Draws on the heat in the air or underground for your home’s energy.

Know when electricity is cheap.

With a dynamic tariff, the price of a kilowatt-hour changes through the day. WattKeeper brings the current Groupe E price into your home, so the dishwasher, the car and the boiler can wait for the cheap hours.

Cheap hoursPricier hours
An example of how a dynamic price can move through one day.

Charge your car at the right moment.

An electric car uses a lot of power, but it is also a great battery. WattKeeper lets Home Assistant run your charging station: it charges with your roof’s surplus, or during cheap hours, up to the level you choose.

Solar surplus Cheap hours
The sun or the cheap hours feed the car.

Share your energy with the electricity community.

A sunny roof often makes more than one household can use. In a local electricity community, that surplus can go to another home that needs it right now, for instance to charge a car. Each home offers its extra power and can reserve another member’s.

Needs power Has extra sun Needs power
One sunny roof, two homes in the community that can use its surplus.

A scenario for every moment of life.

A home does not always live at the same pace. With WattKeeper and Home Assistant, you group your settings into scenarios and switch between them with a single tap. Here are three examples.

  • Comfort

    The house is warm and hot water is always ready. The sun is used first, without giving up anything on your wellbeing.

  • Economy

    Heating, the car and the boiler wait for the sun or for the hours when electricity is cheap.

  • Holiday

    While you are away, the house goes to sleep: heating turned down, hot water off. You wake it up before you come back.

These are only examples: you create and name your own scenarios.

See examples in pictures

Start in three steps.

  1. Run Home Assistant

    It is free software for your smart home and runs on a small computer such as a Raspberry Pi. Find out more at home-assistant.io.

  2. Add a WattKeeper tool

    Pick the tool that fits your home on its page, then add it through HACS, the community store for Home Assistant.

  3. Connect your devices

    Enter the details of your heat pump, tariff or community. Home Assistant shows the numbers and you decide the rules.

A question, an idea?

WattKeeper is a personal project, built in spare time. For a question or an idea, message me on LinkedIn. For a specific problem, open an issue on the GitHub page of the tool concerned, listed below.

Contact me on LinkedInSee the projects on GitHub

Open source, built in the open.

Every WattKeeper tool is published on GitHub, where anyone can read the code, report a problem or suggest an idea.