SAP Optimisation | Thunder Energy Services

SAP compliance

When your building fails SAP targets, we design the solar strategy to make it pass.

If performance gaps, DER shortfalls or limited roof space are stopping a dwelling or block from passing Part L, we design a solar-led strategy to close the gap.

Discuss Your Project

MCS certified installation

G98 / G99 DNO handling

3D modelling & PVGIS data

Greater London coverage

The problem

Why buildings fail SAP

Many projects fall short of Part L compliance because solar was treated as an afterthought rather than an engineered solution. The result: the project cannot be signed off for occupation.

Insufficient roof area

Available roof space cannot support required kWp capacity
Shading limits

Surrounding structures reduce effective solar generation
Poor system sizing

System was not optimised for compliance targets
Heat loss issues

Communal heat loss increases energy demand beyond solar offset
PV as afterthought

Solar added too late in the design process to be effective

A solar-led strategy can resolve these issues without structural changes.

Our approach

How we get you to compliance

We can work with your existing SAP assessor or manage the process from the ground up with our own trusted assessor team.

01

Performance gap review

We review the current SAP results or begin a fresh assessment if required. This identifies where the building is falling short and by how much.

02

Assessment and scenario development

If you already have an assessor, we coordinate and refine improvement scenarios. If not, we can appoint and manage a new SAP assessment from scratch.

03

Solar-led optimisation

We design the optimal PV configuration, panel placement, kWp sizing and string layout, designed around your building's constraints and the size of the gap.

04

Compliance delivery

We manage system specification, solar installation and final SAP alignment, and we take responsibility for the compliance result.

Where this applies

Projects we help

New developments

Residential developments struggling to meet SAP targets
Flat conversions

Block conversions with limited roof capacity
Extensions

Extensions requiring updated SAP calculations
Renovations

Renovation projects triggering Part L compliance

Deliverables

What you receive

Solar optimisation strategy

Full strategy tailored to your project’s compliance gap
kWp configuration

Recommended kWp configuration and system layout
Managed SAP pathway

Coordinated SAP pathway, new or existing assessment
Implementation plan

Clear implementation and delivery plan
Coordinated installation

PV installation managed to ensure compliance
Compliance outcome

We take ownership of the SAP compliance result

Case example

North London residential block

A residential block that could not reach its SAP target on the available roof area. A hybrid, distributed solar strategy closed the gap with no structural changes to the building.

Read the full case study