Quick Answer
A commercial microwave is rated by output watts and duty cycle, not cavity size. Light duty (1000W) suits under 50 uses a day, medium duty (1500–1800W) up to 150, and heavy duty (1800–3200W) handles continuous service. Expect £340–£1,130. Domestic microwaves are not legal for commercial kitchens under most insurance and EHO conditions.
Caterzone supplies commercial microwaves to UK pubs, cafés, care homes, takeaways, and hotel kitchens, and the commercial microwave is the single most under-specified piece of equipment we see in British kitchens. Operators buy a £120 domestic unit from a high street retailer, run it 80 times a shift, and replace it within four months.
This guide explains the difference between light, medium, and heavy duty ratings, how output watts translate into real reheat times, why commercial cavities are built differently, what the UK legal and insurance position actually is, running costs at current electricity rates, and how to size a microwave against your covers. Browse the commercial ovens and microwaves range as you read.
What makes a microwave "commercial" rather than domestic?
Three things separate a commercial microwave from a domestic one, and only one of them is power.
The first is the magnetron duty rating. A domestic magnetron is designed for roughly 15–20 minutes of cumulative use per day. A commercial magnetron is built for 3–8 hours of cumulative on-time and uses a heavier transformer and forced-air cooling to survive it. This is the component that fails when a domestic unit is used commercially — usually with a burning smell and a dead cavity.
The second is the cavity liner and door. Commercial units use stainless steel cavities with removable ceiling filters and a door rated for tens of thousands of cycles. Domestic units use painted or acrylic liners that chip, and hinges rated for a fraction of that cycle count. A chipped cavity is a food safety failure point because it harbours residue and cannot be properly cleaned.
The third is the control set. Commercial microwaves offer programmable pads — typically 10 to 100 memory positions — so a member of staff presses "jacket potato" rather than entering a time. That removes the single biggest cause of inconsistent reheating in a busy kitchen. Stackability, a metal-clad exterior, and a plug rated for continuous load complete the picture.
What do light, medium, and heavy duty actually mean?
Duty rating describes how many heating cycles per day the unit is engineered for, and it is the specification that determines whether your microwave lasts one year or seven.
Light duty units are rated at roughly 1000W output and are designed for under 50 uses a day. They suit a small café warming a few paninis and soups, a staff room, or a bed and breakfast. They typically hold a 25–26 litre cavity and use manual or simple digital timers.
Medium duty units run 1400–1800W output and are engineered for around 100–150 uses a day. This is the correct rating for most UK pubs serving food, care home kitchens, and mid-volume takeaways. Programmable memory pads become standard at this level, along with a stainless cavity and a ceiling-mounted air filter that you can pull and wash.
Heavy duty units run 1800–3200W and are built for continuous service — 200 uses a day and upwards. They use two magnetrons or an inverter drive, a heavier door, and often a stirrer system instead of a turntable so you can fit a full-width tray. They are the right choice for hospital catering, contract catering, and any site where the microwave is on the critical path at service.
Buying a rating below your actual usage is the most expensive mistake available here. A light duty unit run at medium duty volume typically fails in three to six months and carries no warranty cover, because misuse against the duty rating voids most manufacturer warranties.
How does output wattage change reheat times?
Output wattage is the microwave energy delivered into the food, and it scales close to linearly for a given load.
As a working guide for a 350g chilled portion taken from an 3°C fridge to a core temperature of 75°C — the UK reheat standard for food served hot:
- 1000W: roughly 3 minutes 30 seconds
- 1500W: roughly 2 minutes 20 seconds
- 1800W: roughly 2 minutes
- 3200W: roughly 65–75 seconds
Note the difference this makes across a service. At 60 covers with one reheat each, a 1000W unit spends about 3 hours 30 minutes of on-time; a 1800W unit spends about 2 hours. If your microwave is the bottleneck at 12:30pm, that gap is the difference between food going out and orders backing up. Conversely, a heavy duty 3200W unit in a 30-cover café is capital you did not need to spend.
Be careful reading advertised figures. Some manufacturers quote input power (what the unit draws from the socket) rather than output power (what reaches the food), and input is typically 1.5–1.8× higher. Always confirm you are comparing output watts to output watts.
Commercial microwave comparison: which duty rating do you need?
| Duty rating | Output | Uses per day | Typical cavity | Best for | Price range |
|---|---|---|---|---|---|
| Light duty | 1000W | Up to 50 | 25–26 L | Small café, B&B, staff room | £340–£420 |
| Medium duty | 1400–1800W | 50–150 | 26–34 L | Pub kitchen, care home, takeaway | £380–£960 |
| Heavy duty | 1800–2100W | 150–250 | 30–34 L | Hotel, contract catering, hospital | £950–£1,100 |
| Heavy duty programmable | 3200W | 250+ | 34 L+ | High-volume, continuous service | £1,100–£1,400 |
| Combination (microwave + convection) | 1000–1500W + grill | Varies | 25–34 L | Browning, finishing, small sites | £700–£1,800 |
Are domestic microwaves legal in a UK commercial kitchen?
There is no single statute that says "domestic microwaves are banned", but in practice three separate obligations make using one a serious risk.
First, the Provision and Use of Work Equipment Regulations 1998 (PUWER) requires equipment to be suitable for the purpose for which it is used. A microwave that the manufacturer rates for domestic duty, used at commercial volume, fails that test on its face — and the manufacturer's own manual is the evidence against you.
Second, commercial insurance. Most UK catering policies require electrical equipment to be commercially rated and PAT tested at the interval set by your risk assessment — typically every 12 months for portable kitchen appliances, or 6 months in a heavy-use wet environment. If a domestic microwave causes a fire, expect the loss adjuster to look at the appliance rating first.
Third, the EHO and your HACCP plan. Under Regulation (EC) 852/2004 as retained in UK law, food premises equipment must be constructed so it can be kept clean and does not risk contamination. A chipped painted cavity does not meet that standard, and an inspector who sees one will note it. It is also far harder to demonstrate consistent reheat to 75°C on a domestic unit with no programmable memory.
The practical position: a commercial microwave from £340 removes all three problems, and the price difference against a decent domestic unit is roughly £200.
How much does a commercial microwave cost to run in the UK?
Running cost is driven by input power and on-time, not output power, so a more powerful unit is often cheaper per portion because it finishes faster.
At a typical UK commercial electricity rate of 26p per kWh:
- 1000W output (≈1.55kW input): 3 min 30 s per portion = 0.090 kWh = 2.35p per portion
- 1800W output (≈2.9kW input): 2 min per portion = 0.097 kWh = 2.51p per portion
- 3200W output (≈5.2kW input): 70 s per portion = 0.101 kWh = 2.63p per portion
The per-portion cost is remarkably flat — under 0.3p between the smallest and largest unit. That means running cost should almost never drive the buying decision; duty rating and throughput should. Over 100 portions a day, 300 days a year, the difference between the cheapest and dearest to run is about £84 a year, while a wrongly specified light duty unit failing twice will cost you £680 in replacements plus the lost service.
Check your circuit before buying a 3200W unit. At 5.2kW input it draws roughly 22A and will need a dedicated commercial supply — a standard 13A socket will not carry it. A 1800W output unit at around 2.9kW input draws roughly 12.6A and sits at the top of what a 13A plug should be asked to do continuously.
How do you size a microwave for your covers?
Work backwards from your peak 30 minutes, not your daily total, because that is where the queue forms.
Estimate the proportion of your menu that passes through the microwave. In a typical UK pub kitchen with a fresh-cook main menu, that is often 15–25% of dishes — sauces, sides, vegetables, jacket potatoes, and desserts. In a care home or hospital regeneration kitchen it can be 90%.
Then apply this rule: peak covers × microwave share × reheat time ÷ 30 minutes = number of cavities needed.
Worked example — a 90-cover pub, peak 60 covers in 30 minutes, 20% microwave share, 1800W unit at 2 minutes per portion: 60 × 0.20 × 2 = 24 minutes of demand in a 30-minute window. One medium duty unit copes, but with almost no headroom. Add a second cavity if you plan to grow or if a single failure would stop service.
Worked example — a 40-bed care home regenerating 40 lunches in 45 minutes: 40 × 0.9 × 2 = 72 minutes of demand in 45 minutes. That needs two heavy duty cavities, or one heavy duty unit paired with a regeneration oven.
Two smaller units almost always beat one large one for resilience. When your only microwave dies mid-service, the service stops.
Where should the microwave go, and how do you maintain it?
Placement affects both lifespan and hygiene score, and it is usually decided badly.
A commercial microwave needs clear air at the cooling vents — normally 75mm at the sides and 150mm above. Boxing one into a cabinet is the second most common cause of magnetron failure after duty-rating mismatch. A dedicated stainless wall shelf at 1,400–1,500mm from the floor puts the cavity at safe working height, keeps the unit off valuable bench space, and lets you clean underneath it, which an EHO will check.
Never site a microwave directly above or beside a fryer or chargrill. Grease-laden air pulled through the cooling fan coats the magnetron and the internal PCB, and that failure is not covered by warranty.
Maintenance is short but non-negotiable. Wash the ceiling air filter weekly in hot detergent — a blocked filter raises internal temperature and shortens magnetron life measurably. Wipe the cavity and door seal after every service; a damaged or dirty door seal can allow microwave leakage and must be tested at PAT. Replace the cavity ceiling liner (a cheap consumable on most commercial units) as soon as it discolours or cracks, and keep the PAT certificate with your HACCP paperwork.
Frequently asked questions
How many watts should a commercial microwave be?
Match watts to volume, not cavity size. Choose 1000W for under 50 uses a day, 1500–1800W for 50–150 uses, and 1800–3200W for continuous service above 150 uses. A 1800W unit reheats a 350g chilled portion to 75°C in about two minutes, against three and a half minutes at 1000W.
Can I use a domestic microwave in my restaurant?
It is strongly inadvisable. A domestic magnetron is rated for roughly 15–20 minutes of daily use and typically fails within months at commercial volume, voiding its warranty. It also creates problems under PUWER, your insurance conditions, and food hygiene rules on cleanable equipment surfaces. A commercial unit starts at around £340.
What temperature must reheated food reach in the UK?
Food reheated for hot service must reach a core temperature of 75°C in England, Wales, and Northern Ireland, and 82°C in Scotland. Hold at 63°C or above thereafter. Probe the thickest part after standing time, as microwave heating is uneven, and record the reading in your HACCP diary.
How long does a commercial microwave last?
A correctly specified commercial microwave typically lasts five to seven years in a UK kitchen. Lifespan depends almost entirely on matching duty rating to actual use, keeping the air filter clean, and siting the unit away from fryer and grill vapour. Under-specified units commonly fail within a year.
Do commercial microwaves need a special electrical supply?
Light and medium duty units up to about 1800W output run on a standard 13A socket. Heavy duty 3200W units draw roughly 22A at around 5.2kW input and require a dedicated commercial supply installed by a qualified electrician. Confirm the input rating on the data plate before ordering.
Should I buy a combination microwave?
Buy a combination microwave only if you genuinely need browning or crisping and have no separate oven or salamander. They cost roughly twice a straight microwave, are slower on plain reheats, and have more to go wrong. In most kitchens a straight commercial microwave plus a salamander is the better split of budget.
Where to buy commercial microwaves in the UK
Caterzone stocks light, medium, and heavy duty commercial microwaves alongside the wall shelving to mount them properly. Browse the commercial ovens and microwaves collection, or start with the 1000W light duty commercial microwave at £340.00 for a small café, step up to the 1800W heavy duty commercial microwave at £956.00 for a pub or care home line, and for continuous service specify the 3200W programmable commercial microwave at £1,127.90. Pair any of them with a heavy duty stainless microwave wall shelf at £133.95 to free up bench space and keep the vents clear.
For the rest of the reheat and hot-service line, read our commercial bain marie buyer's guide and our contact grill and panini press guide. To match a duty rating to your covers, call Caterzone on +44 7787 069044 or email info@thecaterzone.co.uk.
