Garage and MOT centre energy costs: compressors, heating and the winter bill

Why a workshop bill looks the way it does

Most trades buy energy to serve customers inside the building. The motor trade buys it to run machinery in a shed that keeps opening to the street. That explains almost everything about a garage bill: it is winter heavy, it is driven by a handful of large fixed loads rather than by how busy you are, and it barely falls on a quiet day.

Four things do most of the damage. The compressor cycles from the first job to the last, whether an impact gun is in use or sitting on the bench. High bay lighting is on over every ramp and across the forecourt all day, and in a test bay it has to stay on because DVSA requires the bay to be adequately lit. Space heating fights an open shutter door from October to March. And in a bodyshop, a bake cycle burns more energy in an hour than the rest of the workshop uses in a day.

The trading pattern makes it worse. There are around 23,000 MOT test stations in Great Britain, almost all of them owner operated small businesses holding their own supply contracts. The person watching the ramps is the person meant to be watching the contract end date, and there is no point in the day where that happens.

Published UK benchmarks put the main workshop loads at roughly this:

• Air compressor (screw or piston): 7,200 to 26,400 kWh a year, about £1,800 to £6,600.
• Workshop and forecourt lighting: 8,000 to 25,000 kWh, about £2,000 to £6,300.
• Workshop space heating (gas warm air or radiant): 25,000 to 200,000 kWh, about £1,750 to £14,000.
• Spray booth and bake cycles: 27,000 to 96,000 kWh, about £1,900 to £13,200.
• Vehicle lifts, ramps and MOT bay equipment: 2,500 to 9,000 kWh, about £625 to £2,250.
• Jet wash, vacuums and hot water: 4,000 to 18,000 kWh, about £1,000 to £4,500.

Notice what is missing from that list: anything you can simply switch off to save money. That is why the rate you are paying per kWh matters more here than in most sectors.

Typical annual usage and bills by size

These are the figures we publish across our motor trade energy guide: typical, estimated ranges from published UK benchmarks, priced at 25p per kWh for electricity, 7p per kWh for gas and around £365 a year in standing charges. They are not quotes.

The arithmetic is worth seeing. Take a four ramp garage using 45,000 kWh of electricity and 30,000 kWh of gas a year. That is 45,000 at 25p, so £11,250, plus 30,000 at 7p, so £2,100, plus roughly £365 of standing charges. Call it £13,700 a year. At the 30 to 50% businesses typically save when they switch with us, that is roughly £4,100 to £6,850 back, for a change that alters nothing in the workshop.

The four contract traps that matter in the motor trade

1. Deemed and out of contract rates

When a fixed contract lapses and nothing is signed, the supplier does not stop billing you. They move you to a deemed or out of contract rate, which is their default price and typically the most expensive thing on their book. It is unusually common in workshop trades, because the contract quietly ended in a month when the ramps were full. It is also the cheapest thing on this page to fix. Businesses that switch with us save 40% on average, typically 30 to 50%, and more if you are on out of contract or deemed rates. Those are estimates based on typical UK business energy spend and published market rates, not on our customer records, so see how we estimate before you count on a number.

2. Rollover and the renewal window

The other version of the same problem is a contract that renews itself onto terms you did not choose. The window to do something about it is often short, and it opens long before your end date. Most suppliers will let you agree rates several months, and in many cases up to around 12 months, ahead of your end date and hold them. Being in contract is not a reason to wait. It is usually the best time to look.

3. Standing charges and multi-meter sites

Standing charges are billed per meter per day, at around £365 a year for each supply, and they arrive whether you trade or not. Workshop sites collect meters: the main workshop, a separate forecourt or car wash supply, the unit next door taken on when you expanded, a gas meter for the warm air unit. Three electricity meters is three sets of standing charges, three end dates and three chances to be rolled over. Renewing them as one job, on one date, is often worth more than shaving pence off a unit rate.

4. Half-hourly meters and capacity charges

Larger sites, typically those above 100,000 kWh of electricity a year, sit on half-hourly meters. Bodyshops and HGV workshops often qualify. Half-hourly supplies carry capacity and availability charges alongside the unit rate, and agreed capacity is frequently set years ago for plant that has since changed. Paying for headroom you have not drawn in three years is worth reviewing in its own right. The upside is that half-hourly data lets a supplier price your real load shape instead of guessing it, which usually works in favour of a site with a heavy, predictable working day.

Seven things worth doing in the workshop

1. Walk the air line with soapy water. Leaks typically waste 20 to 30% of everything the compressor produces. On the £1,800 to £6,600 a year the benchmarks give a workshop compressor, that is roughly £360 to £1,980 going nowhere. A single 3 mm hole in a ring main runs to about £700 to £1,000 a year on its own.
2. Drop the compressor pressure to what the tools actually need, and fit a variable speed drive if the compressor is due for replacement. Every unnecessary bar adds roughly 7% to compressor energy, so each one is costing you something like £125 to £460 a year on the same band.
3. Move high bays to LED and zone the lighting. Against older fluorescent or metal halide fittings, LED typically cuts lighting energy by half or more, and lighting is usually the largest single electricity load in a workshop. Zone it so you can light two ramps rather than eight, and put sensors over the tyre bay and stores.
4. Deal with the door. In a heated workshop, most of the gas bill walks out with every vehicle. A fast acting or insulated shutter, an air curtain, or strip curtains on an open fronted bay all make a measurable difference.
5. Heat the bay, not the building. Benchmark heating demand for a workshop runs at roughly 180 kWh of fuel per square metre a year, so a 400 square metre unit is around 72,000 kWh, or about £5,000 of gas at 7p. Radiant tube or plaque heaters warm the fitter rather than the volume above them, destratification fans bring the warm air back down in a high roofed building, and a time clock set to your trading hours beats a frost stat left on all week.
6. Put the spray booth into standby properly. Booth suppliers report gas savings of up to about 30% and electricity savings of 20 to 50% where the burner and fans ramp down instead of running flat out between guns. Variable speed drives on the booth fans do the same job through spray and flash off. And batch your bakes: two half full cycles cost close to double one properly loaded one.
7. Kill the overnight load. Emissions analysers, diagnostic rigs and laptops on standby add up over a year in a bay full of electronics. Put forecourt and signage lighting on a photocell and a time clock. If you have added an EV charge point, check your supply capacity and the shape of your tariff, because charging at the wrong time of day can rewrite the bill.

When to switch, and how it works with us

The best moment to look is anywhere from 12 months down to a few weeks before your contract ends. The worst is the week after it lapses, when you are on a deemed rate taking whatever the market happens to be doing. If your end date has already passed, this is worth an hour today.

The process is short. You send us one recent bill, which carries your meter numbers, your unit rate, your standing charge, your annual consumption and your contract end date. We compare 20 plus suppliers on gas and electricity separately, because the best price for each often sits with a different supplier, and we come back with real prices rather than a modelled estimate. If you like one, we handle the paperwork.

Nothing physical changes. Your meters, cables, pipes and network operator stay exactly as they are, there is no interruption to supply, and the switch typically completes within four to six weeks of the paperwork. It can be timed to start the day your current contract ends. There is no fee to you: we are paid a commission by the supplier you choose, and if you are a microbusiness, Ofgem rules require that total third party cost to be shown in the contract's principal terms before you sign. Get a free estimate for your site and we will tell you what you are actually paying.

Questions we get asked

How much does energy cost a typical UK garage each year?

A small one to two bay garage typically uses around 15,000 to 35,000 kWh of electricity and 5,000 to 20,000 kWh of gas a year, which is roughly £4,500 to £10,500 at the rates above. A multi bay workshop with an MOT bay is more like £10,500 to £21,000, and a bodyshop with a spray booth can pass £50,000. These are estimates. Your bill depends on your rates, your building and your hours.

Can you switch me if I only have electricity?

Yes. Plenty of workshops are electricity only and heat with radiant or electric heaters, and plenty run a gas warm air unit. We compare either fuel, or both together, and we can quote a single site or a group of depots on one set of end dates.

Is a spray booth really that expensive to run?

Yes. The bake cycle is the heaviest single energy event in most bodyshops, drawing a large gas or electric heat load in short bursts on top of the extraction fans. How much of the day the booth idles matters as much as how many cars go through it, so standby control is the first thing to look at.

Figures on this page are estimates from published UK benchmarks, modelled at 25p per kWh for electricity, 7p per kWh for gas and around £365 a year in standing charges. They are not quotes. See how we estimate.