Heat pump experiences: what measurements show

What makes an experience comparable

Look for the building's heat demand and renovation state, heat-pump model, emitters, flow temperature, hot-water use, backup and measurement period. Weather and occupant behaviour can change annual results.

Costs also depend on tariffs, assistance and fixed charges. A neighbour's lower bill is not evidence that the same installation will deliver the same saving in your house.

Metering and the system boundary

A meaningful seasonal factor divides delivered useful heat by electricity within a named boundary. Check whether the readings include resistance backup, source pumps, circulation pumps and hot water.

A catalogue SCOP and a measured field SPF are different indicators. Do not merge them into one ranking or transfer a study's average to a particular model or home.

What field studies can and cannot show

Fraunhofer's work in existing buildings and the UK Electrification of Heat project provide documented operating evidence. Their populations, climate, measurement boundaries and periods differ.

Use their methods and findings in context. They do not guarantee a Slovak household's performance or establish a universal brand ranking.

What to record in your own home

• Separate useful-heat and electricity readings for a defined period.
• The exact system boundary, including backup and hot water.
• Outdoor and flow temperatures, comfort and control settings.
• Tariff version, dates, fixed charges and maintenance.
• Changes to the house or household during the comparison.

How to read reviews

Ask whether problems concern design, installation, controls, maintenance or equipment. A brand name alone does not identify the cause.

Unexpected consumption should prompt a review of readings, settings, backup operation and heat demand with the responsible installer. Do not infer a fault from an unmatched bill comparison alone.