Commercial EPC Levels 3, 4 and 5: Which Does Your Building Need?

Commercial EPC Levels 3, 4 and 5: Which Does Your Building Need?

The level of a commercial EPC is set by the building's heating, ventilation and air conditioning, not by its size or height. Simple heating and small cooling units mean Level 3. Anything more complex means Level 4. Level 5 is used where the assessment is done in a dynamic simulation model.

The level matters because the energy assessor has to be qualified for the type of building. So the level decides who can produce your EPC.

What the levels are

Every commercial EPC is produced in government-approved software: SBEM or a dynamic simulation model (DSM). Level 3 and Level 4 buildings can both be assessed in SBEM. The only difference between them is the building services.

Level 5 buildings are the ones assessed with a dynamic simulation model. The government guidance says this is for cases where the simplified method may not be detailed enough for the building.

Level 3: simple buildings

A building is Level 3 when all its services are on the "frequently occurring" list:

• Simple heating: a boiler system under 100 kW in total. Two linked 75 kW boilers add up to 150 kW, so that building is Level 4. For heating other than boilers, it is each heater that counts.
• Simple ventilation: opening windows, and basic mechanical ventilation that is extract fans only.
• Small comfort cooling: up to 12 kW in total across all units. Split units cooling one room, or one shop and its store cooled by one unit, stay Level 3.

Level 4: complex services

A building is Level 4 if it has any heating, ventilation or air conditioning that is not on the Level 3 list. Examples from the guidance:

• linked boilers totalling more than 100 kW
• multi-split cooling and VRF systems
• central air conditioning: air handling units, all-air and air/water systems, and chillers

One system is enough. An office with radiators and opening windows on four floors and a VRF system on the fifth is a Level 4 building.

Level 5: dynamic simulation

Level 5 is not about the number of floors. It is about the calculation method. A tall office with central plant is Level 4 on its services. It becomes a Level 5 job only when the assessment is done in a dynamic model rather than SBEM.

If your building has unusual features SBEM may not model well, tell us at the start. We'll check the drawings and plant details and tell you straight.

Large warehouses and distribution sheds

A big shed is not Level 4 because it is big. The level follows its services. A shed heated by warm-air heaters of under 100 kW each, with a small office on up to 12 kW of split-unit cooling and extract fans in the toilets, can still be Level 3. Add an office block on VRF, or air handling units in the main space, and it is Level 4.

Some warehouses need no EPC at all. Storage space where the air is not fully heated or cooled can fall under the exemption for industrial sites and workshops with low energy demand. Our guide on how long a commercial EPC lasts covers when a shed is in scope and what happens with shell and core units.

Why the level matters to you

Only an accredited energy assessor who is a member of a government-approved accreditation scheme can produce the EPC, and they must be qualified for the type of building. The EPC itself names the assessor, their employer and their accreditation scheme.

The level also changes how the survey is run. On a Level 3 building the assessor must collect the data personally. On Level 4 and 5 buildings an assessor can be helped by data gatherers, but must still visit and inspect each building and keep a record of who collected what.

Give the full picture when you ask for a quote. If a job is priced as Level 3 and a VRF system turns up on site, the quote has to change.

What we need from you

• Floor plans, or the address and floor area if there are no drawings
• What the building is used for, room by room if it is mixed
• Heating: boiler sizes in kW, or the type and number of heaters
• Cooling and ventilation: the type of system (split, multi-split, VRF, air handling units) and data sheets if you have them
• Lighting details and proof of any insulation or upgrades

Behdad is a Level 4 commercial energy assessor, accredited with Elmhurst Energy (EES/027276), so we cover Level 3 and Level 4 buildings. We have produced more than 2,000 commercial EPCs. Turnaround is 3 working days for small commercial buildings and 5 for larger ones.

Questions we get asked

Does a tall office building need a Level 5 EPC? Not automatically. Height and floor area don't set the level. A tall office with central air conditioning is Level 4 on its services. Level 5 applies only when the building is assessed in a dynamic simulation model.

Is a large warehouse a Level 4 building? Only if its services are. A shed with heaters under 100 kW, extract fans and up to 12 kW of comfort cooling is Level 3, whatever its size. VRF, air handling units or linked boilers over 100 kW make it Level 4.

We have one air conditioning unit in the office. Is that Level 4? Not if it is small. Comfort cooling up to 12 kW in total stays Level 3. Multi-split or VRF systems make it Level 4.

How do I check who produced our EPC? The EPC shows the assessor's name, their employer and their accreditation scheme. The EPC register also lets you check an assessor's accreditation.

More: commercial EPCs, SBEM calculations, how long a commercial EPC lasts, letting a building with an F or G EPC, EPC B by 2031, TM44 inspections.

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