Resources / Checklists

Solar & Heat Pump Planning Checklist

Sequencing, electrics, self-use and grants — for homeowners in Devon & Cornwall deciding what order to do things in.

Independent planning tool from HeatWiseSW — not a payback guarantee.

How to use: Be honest about urgency of heat vs roof opportunity. Solar does not make midwinter heating free. Tick gaps before you sign either quote.

1. Urgency & sequence

  • ☐Is heating urgent (failed boiler, leaving oil this winter)? → heat pump path first
  • ☐Is scaffold/roof work already booked and heating stable? → solar can go first
  • ☐Can we fund a coordinated design this year? → plan both together electrically
  • ☐I accept the winter gap: PV is weakest when heat demand peaks

2. Heat pump side (if in scope)

  • ☐Heat loss will be done — solar will not replace correct kW sizing
  • ☐Emitters / UFH plan at low flow temperature
  • ☐BUS eligibility checked (£7,500 / £9,000 oil-LPG off-gas where rules allow)
  • ☐Outdoor unit siting & noise assessment considered

3. Roof & solar yield

  • ☐Orientation and pitch noted (south / east–west / mixed)
  • ☐Shade from trees, chimneys, neighbours photographed
  • ☐Conservation / listed visibility constraints checked if relevant
  • ☐Roof condition — fixings and remaining life discussed

4. Self-use & money

  • ☐Daytime occupancy / flexible loads (appliances, EV, immersion) noted
  • ☐Payback assumptions: generation kWh, self-use %, import & export rates in writing
  • ☐Battery only if surplus + evening import justify capital (not automatic)
  • ☐Scaffold and electrical upgrade costs included in comparisons

5. Electrics (both technologies)

  • ☐Main fuse / supply capacity to be confirmed
  • ☐Consumer unit space for heat pump ± PV ± EV
  • ☐If solar first: headroom left for future heat pump
  • ☐If heat pump first: cable routes and isolation planned cleanly

6. Fabric (still counts)

  • ☐Easy wins listed (loft, draughts) before oversized plant
  • ☐Ventilation considered if tightening the house

7. Decision lock

  • ☐Chosen sequence written: fabric / HP / solar / battery order
  • ☐One person owns design coordination across trades
  • ☐I will not undersize the heat pump because “solar is coming”

Next step

Run planning numbers for both technologies, then lock sequence from urgency and roof reality.

Combined estimator Solar before or after HP Battery worth it?

HeatWiseSW — independent advice for Devon & Cornwall. Checklists are educational planning aids.

Next step

Get a realistic planning band for your home, then use the checklist when you speak to installers.

Solar estimator Combined estimator View solar checklist