When solar PV is the right measure
Solar earns its place at the end of a fabric-first programme, when the roof is settled and the house's electrical demand is known. It makes particular sense alongside a heat pump — heating becomes an electrical load, and generation offsets it — and after any re-roofing or roof insulation, so the array lands on a roof that will not need touching for decades. If your roof covering is tired, we will tell you plainly: re-roof first, panels second. Fitting solar over a failing roof is buying the same scaffold twice.
How we do it
- Structure verified first. Old roofs were not designed for point loads from panel rails. At St Swithun's House in Kennington, the consulting engineer's structural assessment of the original roof — purlin and hip-plate capacity — was carried out specifically ahead of future solar PV, while our fabric works were being delivered. That is the order of operations: engineer's assessment, then array design.
- Designed into the whole-house plan. Orientation, slope and shading are assessed at survey; the array is sized alongside the heating design rather than sold by the panel. On Howard Street in East Oxford, a 2 kWp array on the south-east roof slope completed the works — the final measure after fabric, ventilation and heat pump.
- Electrics made ready during the rewire. Generation needs provision: at Orchard House the solar-PV controller was relocated to the garage alongside the new consumer unit during the electrical renewal, so the system integrates cleanly rather than being tacked on.
- Installed with our managed certified partners. The certified partner installs and commissions the array within our programme; we coordinate scaffold, roof access and sequencing so it happens once, properly.
Where a whole-house retrofit is phased, solar is designed now and installed when its turn comes — at Church Way in Iffley, solar PV sits in the designed later phase of the retrofit plan, with the insulated re-roof delivered first so the panels will land on a finished roof.
What it pairs with
Solar PV pairs with heat pumps as the load it offsets, with re-roofing and loft and roof insulation as the works that must come first, and with rewiring and electrical for the provision it needs.
Proof
On Howard Street, East Oxford, the 2 kWp south-east array was the closing measure of a whole-house retrofit verified on the public register at EPC B (89) — a house that had started at E (49). Read the full case study.
Questions we're asked
Who installs the solar panels?
The array is designed and coordinated by us and installed with our managed certified partners, as part of our programme. We handle the roof readiness, the electrical provision and the sequencing; the certified partner installs and commissions the system. You hold one contract with one company.
Should solar go on before or after insulation work?
After — or at least, planned alongside. The roof is the natural place to finish, not start: if a re-roof or roof insulation is coming, panels fitted first would come off again. On our projects the array is sequenced as one of the final measures, once the roof build-up and structure are settled.
Is my roof strong enough for solar panels?
That is checked, not assumed. At St Swithun's House in Kennington the project's consulting engineer carried out a structural assessment of the century-old roof — purlin and hip-plate capacity — specifically ahead of future solar PV, as part of the whole-house plan.
Does solar make sense with a heat pump?
They are natural partners: the heat pump turns your heating into an electrical load, and the array offsets part of it. On Howard Street a 2 kWp array on the south-east roof slope completed a retrofit whose heating had just moved from gas to an air source heat pump.