How Much Energy Does an Office Use in the UK?

A typical UK office uses about 95 kWh of electricity and 120 kWh of heating energy per square metre each year. That is roughly 8.8 kWh of electricity and 11.2 kWh of heating per square foot. These are the typical benchmarks for a general office in CIBSE TM46, the benchmarks that Display Energy Certificate ratings are compared against.

In practice, a 300 m² office (about 3,200 sq ft) uses around 28,500 kWh of electricity a year, or 2,375 kWh a month, plus about 36,000 kWh of gas if it has gas heating. At 2026 prices that comes to about £1,108 a month for both fuels, including VAT.

How we researched this guide: energy use comes from the CIBSE TM46 typical benchmark for a general office. Prices come from the government’s quarterly business energy price tables, published by the Department for Energy Security and Net Zero (DESNZ) on 29 September 2026. VAT rules come from HMRC Notice 701/19. We checked every figure on 9 October 2026.

How Much Energy Does an Office Use in the UK?

A general office uses about 95 kWh of electricity and 120 kWh of heating energy per square metre a year, according to the CIBSE TM46 typical benchmark. Multiply those figures by your floor area for a first estimate of your yearly use.

CIBSE is the Chartered Institution of Building Services Engineers. Its TM46 benchmarks give a typical yearly energy use for each type of building, measured per square metre of floor area. Electricity covers lighting, computers, small power and any air conditioning. The heating figure covers fuel burned on site, which for most offices means gas.

These are typical figures, not targets or limits. Your own office could use much more or much less. The best guide to your real use is your last 12 months of business energy bills, which show the kWh you were charged for.

How much energy does an office use per square foot?

On the same benchmark, an office uses about 8.8 kWh of electricity and 11.2 kWh of heating energy per square foot each year. Here is what that means for common office sizes in square feet.

How many kWh does a small business use per month?

For a small office, the benchmark points to about 1,200 kWh of electricity a month at 150 m² and about 2,400 kWh at 300 m². If the office has gas heating, add about 1,500 to 3,000 kWh of gas a month. Gas use is not spread evenly across the year, because most of it goes on heating in the colder months.

How Much Does an Office Spend on Energy Each Month?

A 150 m² office pays about £693 a month for gas and electricity, a 300 m² office about £1,108 and a 500 m² office about £1,917. These estimates use DESNZ Q2 2026 business prices and include VAT.

How we worked these out: we took the yearly use from the table above and applied the DESNZ price for the matching size band, including the Climate Change Levy. Electricity used under 20,000 kWh a year falls in the very small band at 38.36p per kWh. Between 20,000 and 499,000 kWh it falls in the small band at 28.59p. All four offices are in the very small gas band, at 9.31p per kWh.

Electricity carries 20% VAT in every row, because each office uses more than 33 kWh a day. Gas in the two smaller offices carries the 5% reduced rate, because they use under 145 kWh a day. The two larger offices pay 20% on gas. DESNZ prices are fully delivered averages, so the standing charges are already inside the figures.

Notice that the 150 m² office pays a higher price per kWh of electricity than the 300 m² office. It sits in a smaller DESNZ band, and smaller users pay more per unit. For the full price table by business size, see our guide to business electricity prices per kWh. For gas and other building types, see our guide to business energy costs.

What Affects How Much Energy an Office Uses?

Floor area sets the baseline, but how you heat the building, how long it is open and what equipment runs in it decide where your office sits against the benchmark. Two offices of the same size can use very different amounts.

Heating type

The TM46 heating figure assumes the office burns fuel on site, usually gas. An office heated by electric heaters or a heat pump has no gas bill, but its electricity use rises instead. If your office has no gas supply, expect electricity use well above 95 kWh per m².

Opening hours

Lighting, heating and computers run for as long as the office is open. An office used for long shifts or weekends will use more than one open for a standard working week. Equipment left on overnight also adds to the total, even when nobody is in.

Air conditioning and IT

Air conditioning and server rooms both use electricity around the clock. An office with comfort cooling or an on-site server room will usually sit above the typical benchmark for electricity.

The building itself

Insulation, glazing and the age of the heating system all change how much heating energy you need. A draughty older building will need more heat to stay warm than a modern, well-sealed one of the same size.

Is an Office’s Electricity or Gas Bill Bigger?

For most offices with gas heating, the electricity bill is bigger even though gas use is higher. In Q2 2026, the smallest business users paid about four times as much per kWh for electricity as for gas, and the gap is wider for larger users.

Take the 300 m² office above. It uses more gas than electricity, but its electricity costs about £9,778 a year against £3,519 for gas. That is why cutting electricity use usually saves an office the most money. It also means switching off lights and equipment pays back faster than turning the heating down by the same number of kWh.

How to Estimate Your Own Office’s Energy Use

You can estimate your office’s energy use in four steps using your floor area, the TM46 benchmark and a recent bill. It takes a few minutes and tells you whether your office uses more than a typical one.

1. Find your floor area. Your lease, rates bill or floor plan usually shows it. To turn square feet into square metres, divide by 10.764.
2. Work out the typical use. Multiply the floor area in square metres by 95 for electricity and by 120 for heating. That gives a typical yearly figure in kWh.
3. Compare it with your bills. Add up the kWh on your last 12 months of electricity and gas bills. If your real use is well above the typical figure, there is likely room to cut it.
4. Price it. Multiply your kWh by your unit rate, add the standing charge for the year, then add VAT. Our business energy cost calculator can do the sums for you.

If you only have a few months of bills, remember that gas use is much higher in winter. A summer bill on its own will understate your yearly gas use.

How Can an Office Cut Its Energy Use?

Start with what runs when nobody is in the office: lighting, heating and equipment left on overnight and at weekends. Then look at heating controls, lighting and how you buy your energy.

1. Check your bills against the benchmark. Divide your yearly electricity use by your floor area. If it is well above 95 kWh per m², look for equipment and lighting running out of hours.
2. Switch off out of hours. Put lighting, screens and printers on timers or smart plugs, and agree a simple end-of-day routine.
3. Set heating controls to your hours. Heat the building only when it is in use, and check thermostats are not set higher than they need to be.
4. Use efficient lighting. If your office still has older fluorescent or halogen lighting, LED replacements use less electricity for the same light.
5. Get the right contract. Renew before your contract ends to avoid out-of-contract rates, and compare the total yearly cost, standing charge included. Some suppliers offer tariffs with no standing charge, and business energy brokers can compare suppliers for you.
6. Consider generating your own power. Offices with suitable roof space can look at commercial solar panels to cut daytime electricity use.

Last updated: October 2026. Energy use from CIBSE TM46; prices from DESNZ, checked on 9 October 2026.

Tom Reynolds

Business Energy Specialist

Tom focuses on commercial energy, renewable adoption, and sustainability strategy for SMEs. His background with UK energy suppliers helps businesses cut costs while meeting carbon targets.

Reviewed by

Laura Bennet

Home Energy & Sustainability Editor