The answer
Which comparison is fair?
Use the first year to learn how the system behaves across seasons, not to judge it from one cold or cloudy week. Track energy and generation alongside comfort, occupancy, weather and any settings changed.
01 / 02
Choose measures you can interpret
For a heat pump, record electricity use, heat delivered if metered, indoor comfort and hot-water availability. For solar, track generation, on-site use and export. Keep the installer forecast and its assumptions beside actual results; a changed tariff or a new EV can alter bills without indicating an equipment fault.
02 / 02
Know when to investigate
Look for persistent trends, alarms or a room that repeatedly misses temperature. Compare similar seasons and note weather and occupancy differences. Record interventions and control changes before altering settings again. A short review after commissioning, then seasonal reviews, makes later troubleshooting much easier.
Where this guidance comes from
Check the original guidance.
These primary sources support the technical or scheme points above. Rules can change; follow the current source before making a commitment.
Apply this to your property
Need help making sense of your energy data?
FLO can help relate performance questions to the installed system and the way your property is being used.