Before you lease a commercial property in 2026, the Energy Performance Certificate (EPC) is no longer just paperwork — it directly determines whether you can legally rent the building at all.

Under Minimum Energy Efficiency Standards (MEES), most commercial properties must achieve at least an EPC rating of E. If your building is rated F or G, you may be prohibited from granting a new lease and could face enforcement penalties.

The good news: in many cases, improving the rating is faster and cheaper than owners expect.

This guide explains exactly what to upgrade, what to avoid, and how to reach compliance quickly.

Step 1: Understand What Affects a Commercial EPC

An EPC does not measure how a tenant uses energy.
It evaluates the building itself — its construction and fixed systems.

Main scoring factors

  • Heating system efficiency

  • Cooling & ventilation systems

  • Lighting efficiency

  • Insulation levels

  • Windows & glazing

  • Hot water systems

  • Controls & automation

Decoration, furniture, and appliances rarely affect the rating.

Step 2: Book a Pre-Assessment (Most Important Step)

Before spending money, arrange a recommendation survey.

An assessor can calculate:

  • Current rating

  • Target improvements

  • Cheapest path to E

  • Estimated cost vs gain

This avoids overspending — many landlords waste thousands upgrading the wrong things.

Step 3: The Fastest Improvements That Increase EPC Score

1) Upgrade Lighting to LED (Highest Impact)

Typical cost: Low
Improvement: Very high

Replace:

  • Fluorescent tubes

  • Halogen spotlights

  • Incandescent bulbs

Why it works:
Lighting efficiency heavily influences commercial EPC software.

Typical improvement: +5 to +15 points

Often this alone moves a property from F to E.

2) Install Heating Controls

Typical cost: £150–£600
Improvement: High

Add:

  • Programmable timers

  • Zoned thermostats

  • TRVs on radiators

Buildings without controls score poorly because they appear to run constantly.

3) Service or Replace HVAC Systems

Typical cost: Medium
Improvement: High

Provide documentation for:

  • Maintenance servicing

  • Efficiency rating

  • Modern inverter systems

Old air-conditioning units significantly reduce EPC scores.

4) Improve Roof or Ceiling Insulation

Typical cost: Medium
Improvement: Very high

Commercial EPC calculations strongly reward insulation.

Typical improvement: +8 to +20 points

5) Upgrade Hot Water Systems

Typical cost: Low–Medium
Improvement: Medium

Replace:

  • Electric immersion heaters

  • Outdated boilers

Add timers and insulation jackets.

Step 4: Improvements That Usually DON’T Help Much

Many landlords spend money with almost zero EPC impact.

Low-impact upgrades

  • New flooring

  • Decoration

  • Furniture

  • Partition walls

  • Kitchens (non-fixed appliances)

  • Cosmetic renovations

EPC is about efficiency — not appearance.

Step 5: Typical Upgrade Plans by Property Type

Small Retail Shop

Most effective upgrades

  • LED lighting

  • Thermostat

  • Door closer

Typical cost: £400 – £1,200

Office

Most effective upgrades

  • LEDs

  • Insulation top-up

  • HVAC service

Typical cost: £1,200 – £3,500

Restaurant / Café

Most effective upgrades

  • LED lighting

  • Extract ventilation controls

  • Efficient AC system

Typical cost: £1,500 – £5,000

Step 6: Re-Assess the Property

After improvements:

  1. Book a new EPC inspection

  2. Provide invoices/spec sheets

  3. Assessor recalculates rating

  4. New certificate issued (usually within 24 hours)

Your old EPC does not update automatically — you must obtain a new one.

Step 7: If the Building Still Cannot Reach E

You may register a legal exemption if:

  • Upgrade costs exceed savings (7-year payback rule)

  • Listed building restrictions apply

  • Third-party consent denied

Exemptions must be formally registered and expire after 5 years.

Benefits Beyond Legal Compliance

Improving your EPC rating helps more than regulations.

Financial advantages

  • Higher rental value

  • Faster tenant demand

  • Lower vacancy periods

  • Better mortgage acceptance

  • Lower operating costs

Efficient properties now lease significantly faster in competitive markets.

Quick Compliance Checklist

Before advertising your property:

✔ Check current EPC rating
✔ Arrange recommendation survey
✔ Upgrade lighting first
✔ Add heating controls
✔ Improve insulation if required
✔ Replace inefficient HVAC
✔ Re-issue EPC certificate

Final Advice

Most F-rated commercial buildings can reach E with simple upgrades — usually within days and often under a few thousand pounds. Waiting until a tenant is found can delay a lease and create legal risk.

Planning early ensures the property remains lettable, valuable, and compliant in 2026.

EPCRate London