Office business energy: how small-office bills work

An office looks like a low-energy business: no ovens, no cellar, no machinery. But lights, computers, heating, cooling and the kettle add up, and small-office bills are shaped by a few quirks that catch people out. This guide covers how small-office electricity (and gas, if you have it) is billed and where to look for savings.

What a small office uses energy for

• Heating and cooling. Usually the largest share. Offices are often heated by electric panels, heat pumps or a gas boiler; some have air conditioning for summer.
• Lighting. Often left on after hours in shared or serviced buildings.
• IT and equipment. Desktops, monitors, printers, a server cupboard, a router. Many draw power on standby overnight.
• Kitchenette. Kettle, fridge, microwave and dishwasher.

Unlike a pub or restaurant, an office usually has a clear pattern: busy on weekdays and idle on nights and weekends. That makes base load (what you draw when nobody is there) easy to spot and worth checking.

Hybrid working and occupancy

If staff are in only two or three days a week, many costs stay fixed. The standing charge is payable every day. Heating a half-empty floor still takes much of the energy. The practical response is to match heating, lighting and cooling schedules to the days people really attend, rather than assuming the office is empty or full.

Shared buildings and serviced offices

Many small offices do not have their own supply at all. If energy is bundled into your rent or service charge, you have no contract with a supplier and nothing to switch; the landlord does. If a landlord sub-meters you and bills you for use, that is resale, and the rules say a reseller may charge no more than they pay for the energy, including any standing charges. See our landlord guide. If you do have your own meter, you need your own contract.

Worked example: why a small office can pay a lot less tax

The de minimis rules help the smallest users. If you use no more than about 1,000 kWh of electricity a month on average (33 kWh a day), the supply is treated as domestic: the Climate Change Levy does not apply and VAT is charged at the reduced rate instead of 20%. Compare two offices with an illustrative 27p/kWh unit rate and 60p/day standing charge (example rates, not a quote):

	Office A: 9,000 kWh/year	Office B: 15,000 kWh/year
Average per day	9,000 ÷ 365 = 24.7 kWh	15,000 ÷ 365 = 41.1 kWh
Energy	£2,430.00	£4,050.00
Standing charge (365 × £0.60)	£219.00	£219.00
Climate Change Levy	£0.00 (de minimis)	15,000 × £0.00801 = £120.15
VAT	5% = £132.45	20% = £877.83
Total	£2,781.45	£5,266.98

Office B uses 6,000 kWh more but pays £2,485.53 more, which is 41.4p for every extra kWh. That is a higher effective price per kWh, because the tax treatment changes. Worth knowing before you add a heater. Office A is shown at the normal 5% rate. From 1 October 2026 to 30 June 2027, HMRC's temporary zero rate covers qualifying electricity in Great Britain, including de minimis supplies like Office A's, so its VAT would be £0 during that period and its total £2,649.00. Our VAT and CCL calculator shows how the thresholds work, and HMRC says no certificate is needed for de minimis supplies, though it is worth checking your bill shows the right rate. See the 33 kWh de minimis limit.

Meter type: small offices on half-hourly

Most small offices sit on a standard meter. Larger or higher-demand offices can be on a half-hourly meter, billed on usage by the half hour and sometimes with capacity charges. The market is moving to half-hourly settlement for everyone (see market-wide half-hourly settlement); the programme timetable runs to May 2027, but this does not mean your bill is rewritten overnight. Smart meters give you the usage data to see your base load; see business smart meters.

Practical ways to reduce an office bill

1. Read your overnight base load. Compare a reading at close on Friday with one at opening on Monday. If a weekend of nobody draws a lot of power, find out what is on.
2. Control heating by schedule. Timers and thermostats matched to days of attendance.
3. Switch to LED lighting and sensors for meeting rooms and toilets. See LED lighting for business.
4. Power down equipment. Smart plugs on printers and monitors; a defined shutdown routine.
5. Review the contract. A fixed deal gives certainty; a renewal reminder avoids drifting onto out-of-contract rates. Read business energy renewals.

Check you are not paying for a larger supply than you need. Offices that have downsized sometimes keep capacity they no longer use; see supply capacity.

Contract and protections

Most small offices are microbusinesses, meaning fewer than ten employees and turnover or balance sheet within €2 million, or low enough energy use. You then get clear Principal Terms and limits on rollover (no more than 12 months), and you can use the Energy Ombudsman if a complaint is not resolved. If you are not sure whether you qualify, see what is a microbusiness for energy.

Gas, or all-electric?

Some offices have a gas boiler; others are all-electric. If you have gas, the gas supply has its own meter (identified by an MPRN) and its own standing charge, so you pay two sets of fixed charges. If the building is all-electric, you have one supply, one standing charge and a larger electricity bill. When comparing offices to rent, compare total expected energy cost, not just the rent. A gas-heated unit may be cheaper to run per kWh of heat, because gas costs far less per kWh than electricity, but an electric system can be more efficient per kWh used, so ask for the last 12 months of bills from the previous occupier. Your MPAN and MPRN identify each supply.

Seasonal pattern

Expect winter heating peaks, and a smaller summer bump if you run air conditioning. Estimated bills can hide this: if your supplier is estimating, a surprise correction can arrive later. Sending regular readings stops that; see how to submit a business meter reading.

Next steps

1. Check whether you or your landlord holds the energy contract.
2. Take a meter reading when you leave on Friday and again on Monday morning.
3. Work out your daily average kWh to see which tax treatment applies.
4. If the contract is yours, put the end date in the diary and compare quotes before it arrives.