Author: Oliver Wakefield-Smith, Founder Digital Signet. Reviewed against DfE Sustainability Strategy (Mar 2025) and Education Estates Strategy (Feb 2026). Verified 22 June 2026.
£30k to £150k for a typical school DNO connection upgrade when ASHP and rooftop solar are added together. The figure is driven by the local Distribution Network Operator's reinforcement charge rules, not by the school's own works.
£30k to £150k for a typical school DNO connection upgrade when ASHP and rooftop solar are added together. The figure is driven by the local Distribution Network Operator's reinforcement charge rules, not by the school's own works.
A DNO upgrade is generally required where the proposed ASHP plus solar load exceeds the existing supply rating, or where the connected generation exceeds the export ceiling. A connection design enquiry to the DNO is the only definitive answer; ENA's Connection Charging Methodology governs the rules.
ENA budget 9 to 18 months for DNO works in 2026, with longer queues in constrained regions. Salix expects this lead time to be reflected in the PSDS Phase 4 programme plan.
PSDS Phase 4 funding can include the school's contribution to the DNO upgrade but cannot directly fund the DNO's own network reinforcement. Trusts should ring-fence the DNO contingency separately within the bid.