During our last four articles, we’ve explored ESOS (Energy Savings Opportunity Scheme) audits and B Corp (Benefit Corporation) audits individually, but factory owners often ask:
“What’s the difference – and why should I care about both?”
The answer lies in how each one serves a different – but complementary – purpose for your business.
1. Compliance vs Voluntary
The first big difference is that ESOS is mandatory for factories that meet the thresholds (250+ staff or £44m+ turnover).
You don’t have a choice – you must carry out the audit every four years to remain compliant with UK law.
If your factory falls below the mandatory threshold – an ESOS audit becomes voluntary.
By contrast, B Corp is voluntary full stop. No government requires it, but many businesses choose it to demonstrate leadership and values.
2. Focus Areas
ESOS is primarily about energy efficiency.
It looks at how much energy your buildings, processes, and transport consume, and highlights opportunities to reduce waste and costs.
B Corp, on the other hand, is holistic.
It includes energy efficiency and emissions but also considers governance, workers, community, and customers. It asks not only how efficient you are, but also – how responsible and sustainable your entire business is.
3. Output & Action
An ESOS audit results in a technical report: data, charts, and specific efficiency recommendations. It’s very practical.
A B Corp audit contributes to your B Impact Assessment, which measures performance across the five categories. Instead of a compliance report, you get a score that determines whether your business qualifies for certification and how you compare with peers.
4. Timeframe
ESOS follows a strict four year cycle with fixed deadlines. Miss them, and you risk fines – if it’s mandatory.
B Corp has no fixed timeline – you can pursue certification whenever your business is ready, though recertification is required every three years to maintain status.
5. Opportunity for Factories
For factories, the sweet spot lies in how these audits overlap.
An ESOS audit will almost always highlight areas where rooftop solar panels could deliver energy efficiency savings.
Installing solar not only cuts grid electricity costs but also feeds directly into your B Corp audit by boosting renewable energy usage and lowering Scope 2 emissions.
That means one smart investment – solar – ticks both boxes: legal compliance and reputational advantage.
Summary:
✅ ESOS = Legal, technical, focused on efficiency and compliance.
✅ B Corp = Voluntary, strategic, focused on values and sustainability.
✅ Together = A compliance obligation transformed into a competitive advantage.
For factories, understanding the differences helps you see the full picture:
ESOS keeps you compliant and cuts costs, while B Corp elevates your brand, attracts talent, and wins new business.
Combine the two with renewable energy like solar, and you’re not just compliant or certified – you’re future ready – including long-term energy efficiency savings
