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EPC C → B upgrade for Timber-frame home
Timber-frame construction starts with decent fabric — but adding insulation requires a different approach, and the upgrade path to B usually skips insulation entirely.
Upgrade measure stack
Cheapest-first ordering — calculator stops adding measures once the gap to B closes.
| Measure | Cost | SAP uplift |
|---|---|---|
| Full LED lighting retrofit | £250 | +1.0 |
| Thermostatic radiator valves + controls | £400 | +1.0 |
| Air-source heat pump (BUS-eligible) | £11000 | +10.0 |
| Total | £11650 | to band B |
What's specific about this archetype
Timber-frame walls already have significant insulation between studs. Adding more internally or externally requires specialist detailing to avoid interstitial condensation. For a C → B upgrade, a heat pump swap or solar install is usually a better target than more fabric work.
Model your exact property
The figures above use a reference archetype. Your real floor area, mortgage balance, current energy bill and exact current band will shift the numbers. Use the full EPC upgrade calculator for a customised version, the insulation savings calculator to choose between competing fabric measures, and BUS grant eligibility if a heat pump is on the shortlist.
Other wall-type archetypes
| Archetype | Start → Target | Net cost | Annual saving |
|---|---|---|---|
| Solid-wall terrace | EPC E → C | £22650 | £322/yr |
| Cavity-uninsulated semi | EPC D → C | £5350 | £171/yr |
| Timber-frame home (this page) | EPC C → B | £4150 | £90/yr |