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ASHP efficiency

Air source heat pump efficiency in the real world

Air source heat pump efficiency is shaped by flow temperature, emitter sizing, defrost behaviour, controls, and how honestly the heat loss has been assessed. The numbers only mean something if the inputs are real.

The biggest efficiency mistakes are usually made before install day: optimistic assumptions, weak emitter checks, and a system route that does not really fit the property. · 3 min read

Guide

Efficiency levers that depend on survey quality

What strong looks like

Capture standards

  • Emitter evidence aligned to room-level demand
  • Envelope and infiltration assumptions supported with photos and notes
  • Flow-temperature risks identified before quoting
  • Constraints flagged early so design choices remain realistic
Where time is lost

Where teams lose time

  • Optimistic assumptions with no traceable evidence
  • Inconsistent report structure between jobs
  • Late-stage clarifications that force redesign
Why it helps

What better inputs change

  • Flow temperatures are set against a more believable heat-loss picture
  • Emitter upgrades are easier to spot before install day
  • Weak assumptions are exposed before they distort the quote
  • The quoted performance has a better chance of matching the real property
Related guides
What is an air source heat pump? ASHP running costs UK ASHP survey reports ASHP calculator guide ASHP vs air-to-air Heat loss calculations