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Explainer

Heat loss vs EPC

What’s different, what each is used for, and what evidence helps.

Installers and homeowners often mix these up. Here’s a clear, practical explanation and where to start if you want fast delivery with minimal follow‑ups.

Heat loss page Energy performance certificate guide

Use the EPC evidence checklist if you want the practical survey-day document list.

Differences

At a glance

Exact requirements depend on scope — we confirm what you need before booking.

Heat loss

What it’s for

  • Inputs for sizing and design decisions
  • Clear assumptions (so the result is usable)
  • Fewer installer re-questions
EPC / RdSAP

What it’s for

  • Energy performance assessment
  • Evidence capture can include documents
  • We photograph relevant documents on the day (when applicable)
Evidence

What helps most

Energy performance certificate guide EPC & audit evidence hub EPC evidence checklist FAQs Get pricing