Solar PV vs LED lighting — which delivers a bigger EPC uplift?

The headline answer

For MEES 2030 compliance on UK office buildings, solar PV typically delivers a larger EPC uplift per pound of capex than LED relighting — but the two measures stack rather than compete. Most successful EPC-B compliance pathways combine both.

Typical EPC point gains:

LED relighting alone: 3-7 SAP points
Solar PV alone: 4-12 SAP points
LED + Solar PV combined: 8-18 SAP points

The combined approach is almost always the cost-effective MEES-2030 pathway for offices currently rated C or D. Standalone LED rarely lifts a high-C office into B; standalone solar PV does so only on buildings with very generous roof-to-floor area ratios.

Why the comparison matters

For office portfolio managers approaching MEES 2030, capital deployment decisions need clear comparative data. The temptation is to “start with LED because it’s cheap” — but the headline £10-15/sqm LED cost doesn’t always deliver MEES compliance, and proceeding to solar PV afterwards then needs to absorb the additional capex that LED-only path didn’t avoid.

Working out the right capex sequence requires understanding the EPC arithmetic.

LED relighting in detail

LED relighting of an office building typically costs £10-20 per sqm depending on existing fitting density, ceiling type, and controls strategy. For a 5,000 sqm office, that’s £50-100k.

EPC impact comes through reduced lighting electricity demand in the building’s notional carbon dioxide emissions calculation. The exact point gain depends on:

Existing fitting type. Fluorescent → LED gives bigger gain than older LED → newer LED.
Lighting load proportion. Buildings with high lighting hours (24/7 operation, dim natural light) gain more than buildings with strong daylighting.
Controls retrofit. Adding occupancy sensing, daylight dimming, time switches adds 1-2 points on top of pure fitting replacement.

LED typically tops out at lifting a low-C office into mid-C, or a high-C office into low-B. Lifting a D into B with LED alone is rare.

Solar PV in detail

Solar PV typically costs £700-£1,000 per kWp installed. For a 5,000 sqm office at 75% demand coverage, that’s typically a 450 kWp system costing £350-450k.

EPC impact comes through reduced “purchased electricity” in the SBEM calculation. The relationship between system size and EPC points is roughly:

5 Wp per sqm of floor area: ~2 SAP points
10 Wp per sqm: ~4 SAP points
25 Wp per sqm: ~7 SAP points
50 Wp per sqm: ~10 SAP points
100 Wp per sqm: ~12 SAP points (often the ceiling)

A typical office with 60% usable roof area can fit roughly 60-100 Wp/sqm of floor area. So 10-12 SAP point gain from PV is common.

Stacking the two

For a typical C-rated 5,000 sqm office:

LED upgrade: £75k capex, 5 SAP points, lifts C → low B
Solar PV: £400k capex, 10 SAP points, lifts C → high B
Combined: £475k capex, 14 SAP points, lifts C → A

The combined approach future-proofs the building against any tightening of MEES beyond EPC B (under consultation toward EPC A by 2035) and locks in the strongest tenant proposition.

The capex sequencing question

For multi-year decarbonisation programmes, the question is which measure to deploy first.

The pragmatic answer: deploy LED first if your existing fittings are end-of-life anyway (LED has its own ROI from electricity savings + maintenance reduction), then add solar PV in the following budget year. This sequence:

Spreads capex across two budget cycles
Captures LED savings during the year before PV install completes
Lets you size PV against the post-LED reduced demand baseline (slightly smaller system, slightly cheaper)

Where building lighting is recently upgraded and not due for replacement, lead with solar PV — it delivers the larger MEES uplift per capex pound.

Request a free MEES compliance pathway covering both measures.