Tesla has launched Heat Pump Optimization, a feature that lets the Powerwall 3 and the three-phase Powerwall 3P tell a compatible heat pump when to run harder — so a home can bank surplus solar energy or cheap grid power as hot water.
Classification: CONFIRMED. The feature is documented on Tesla's support page, was detailed by Electrek, and was summed up by Tesla Energy itself on X: “Heat Pump Optimization allows your Powerwall to boost heating when there's surplus solar or energy is inexpensive.”
How it works is simple: throughout the day, the Powerwall watches electricity prices and solar production and sends the heat pump one of two signals — run normally, or boost. When boosted, the heat pump heats water beyond what the home needs right now, typically into a domestic hot water or buffer tank. That stored heat then carries the house through the expensive hours, when the heat pump can run less.
How the Powerwall decides when to boost
The trigger depends on the operating mode. In Self-Powered mode, boosting only happens when there is surplus solar left after the home's other loads are covered. In Savings mode, it boosts when solar is available or when grid power hits its cheapest price, based on 24-hour tariff forecasts.
The SG-Ready standard and the requirements
There is no cloud integration with heat pump brands here: it is a wire. The feature runs on SG-Ready (Smart Grid Ready), a label introduced in 2012 by the German Heat Pump Association (BWP) with 17 manufacturers, which uses two relay contacts to signal four operating states. Tesla only uses the “normal” and “boosted” recommendations.
The requirements are specific: a Powerwall 3 or Powerwall 3P on firmware 26.26 or later; an SG-Ready-certified heat pump with an accessible SG-2 contact, configured to accept external signals; physical wiring between the Powerwall and the heat pump, installed by a Tesla-certified installer; and the Tesla app on version 4.59.1 or later. The signals are only recommendations — the heat pump's own thermostat can override them —, each signal must be held for at least 10 minutes, and during a power outage the feature drops back to normal to prioritize backup loads. Oddly, there is no on/off toggle in the app: once it is wired up, it is on.
Why a hot water tank is a cheap battery
The math is what makes the feature interesting. A 300-liter hot water tank heated an extra 30°C holds about 10.5 kWh of thermal energy. With a heat pump running at a COP of 3, that takes only around 3.5 kWh of electricity — and leaves the Powerwall's 13.5 kWh free for the loads that cannot be stored as heat.
The market is there too: Germany sold 299,000 heating heat pumps in 2025, up 55% year over year according to BWP, and they made up nearly half of all new heating systems sold in the country for the first time. Tesla is not the first either: sonnen shipped an update in 2023 that lets its home battery run heat pumps off surplus solar. For now, the feature is Europe-only — Tesla has said nothing about bringing it to the United States or Canada, where the SG-Ready standard barely exists.
Read also: Tesla tests Cybercabs in Detroit, newspaper says
Image credit: Electrek / Tesla. The image shows two Tesla Powerwall units mounted outside a home.
Sources: Electrek; Tesla support page on the Heat Pump Optimization feature; Tesla Energy, on X.
Transparency: this article was produced with the help of artificial intelligence, based on public posts on X and sources from the internet. We recommend checking the original sources to verify the information.
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