Frequently asked questions
How do you account for solar irradiance?
Cloud cover from the weather forecast (cloud_cover_pct) reduces the modeled production
by up to 85% compared to a clear sky - the more clouds, the lower the forecast. It's the same principle
as a sunny day giving full output and an overcast day giving a fraction of it, just expressed as a
formula instead of a guess.
How do you build the solar surplus forecast?
The base model is a clear-sky model: a sine curve between sunrise and sunset for the current month, scaled by a monthly efficiency factor and the system's peak output - the same principle as June producing more than December. But as soon as the house has built up its own history, a digital twin takes over: a learned profile of what the roof actually tends to produce per month and hour, built from the house's own logs instead of a generic formula. The longer the system runs, the more accurate the forecast becomes for your specific roof.
Can you choose your own priorities, or is it all fixed?
The order between the different control rules is fixed - it's built so that safety and economics always run in a defined, predictable order, not something every user should have to reason through. What you control are the parameters within that order:
- Comfort temperature during cheap vs. expensive electricity (two separate setpoints)
- Minimum level and time for each EV (e.g. at least 50% by 07:00)
- Manual pause or forced charging, if you want to take over temporarily
That lets you tune comfort against savings without needing to understand or risk disturbing the whole decision logic.
Do I need solar panels or an EV for the system to be useful?
No. A heat pump alone is enough to get started - the heat control (the thermal battery) works regardless. Solar, an EV and a battery add more things the system can optimize against, but aren't a requirement.
How do you make sure the house doesn't get cold while the system saves money?
Price optimization must never come at the cost of basic comfort - minimum levels (for both indoor temperature and EV charging) are a hard limit in the control logic, not a goal the system tries to balance against. The system optimizes within that limit, never by lowering it.