Two fixes merged into Home Assistant Core on 20 October 2026 make the cost sensors of the Energy dashboard more reliable. One prices the energy used while Home Assistant was stopped, the other handles a meter that changes its unit. Both come from Petar Petrov (MindFreeze), were reviewed by Abílio Costa (abmantis), and went into the dev branch that becomes Home Assistant 2026.11 in early November.
The cost sensor in question is the one Home Assistant creates when you add a price to a meter in the energy settings. It watches the meter, multiplies each increase by the current price and adds the result to a running total. The fixes apply to energy, gas and water meters.
Usage during downtime had no cost
Until now the cost sensor kept its last priced meter reading only in memory. After a restart, the first reading became a new starting point without a price, so whatever the meter counted while Home Assistant was down never got a cost. After a short restart the gap is small. A meter that reports only once a day is a different story: the pull request notes that a whole day of usage could be left out.
The cost sensor now saves its last priced reading in the state Home Assistant stores at shutdown. On the next start it prices the difference between that reading and the new one as a separate cost cycle.
A unit change charged the whole meter again
The second bug appeared when a meter switched units between two readings, for example after changing its display unit from kWh to Wh. The cost sensor subtracted the old reading in kWh from the new one in Wh. The result was charged as if roughly the whole meter reading had been used again, or it was taken as a meter reset.
The previous reading is now converted to the current unit before pricing. When the two units cannot be converted, such as a gas meter that switches between energy and volume, pricing simply continues from the new reading.
Older errors stay
The fixes change how new readings are priced. Cost spikes or gaps left by earlier restarts or unit changes remain in the long-term statistics, and the Statistics tab in Developer tools is still the place to adjust them by hand.