Class B, S, or N? What size? Tap water or distilled? New or renewed? Here’s everything you need to know before you spend a penny.
Buying an autoclave is one of the biggest equipment decisions your practice will make. Get it right and you’ll have a reliable, compliant sterilisation process for years. Get it wrong and you’ll be dealing with failed cycles, compliance gaps, instrument damage, and an expensive replacement sooner than you’d like.
The problem is that most of the information out there is written by manufacturers trying to sell you something, or by suppliers who list features without explaining what actually matters. This guide is different. It’s written by the engineers who service, validate, and repair autoclaves every day across dental, veterinary, and podiatry practices in the UK. We know what breaks, what lasts, and what features genuinely make a difference to your daily workflow.
Before you look at brands, sizes, or prices, you need to understand autoclave classifications. This is the single most important factor in your decision, because the wrong class means your autoclave physically cannot sterilise some of the instruments you’re putting into it.
The European Standard BS EN 13060 defines three classes of small steam steriliser, each named for what it can handle:
Class N (naked) autoclaves use gravity displacement to remove air from the chamber. Steam enters from the top and pushes air downwards and out through a drain. This is the simplest and cheapest approach, but it only works reliably for solid, unwrapped, non-porous instruments placed loose in the chamber. Class N machines cannot reliably sterilise pouched instruments, hollow instruments like handpieces, porous materials, or anything where air can become trapped. The gravity displacement method simply leaves too many residual air pockets for steam to reach all surfaces. If you’re using sterilisation pouches, storing instruments for later use, or processing anything with a lumen or cavity, Class N is not suitable for your practice.
Class S (specified) autoclaves sit in the middle. They may include a simple vacuum stage, but they’re only validated to sterilise the specific load types declared by the manufacturer. The catch is that capabilities vary significantly between models. One Class S machine might handle certain wrapped loads; another might not. You have to cross-reference the manufacturer’s documentation against every instrument type you process. If your range changes or expands, you may find your autoclave is no longer validated for what you’re sterilising.
Class B (big steriliser performance) autoclaves use a vacuum pump to actively remove air before steam is introduced. This is done through a series of pressure and vacuum pulses, called fractionated pre-vacuum air removal, that extract more than 99% of the air from the chamber, including from inside hollow instruments, wrapped packs, and porous materials. After sterilisation, the vacuum pump provides a post-vacuum drying phase that removes residual moisture from the load. This matters because wet packs are not considered sterile: moisture can wick bacteria through packaging material, compromising the sterile barrier.
Class B is the only class validated for the full range of instruments used in dental, veterinary, and podiatry practice, from solid hand instruments to pouched surgical kits to hollow handpieces.
The short version: if your practice performs surgical or invasive procedures, uses sterilisation pouches, processes handpieces, or stores sterile instruments for later use, you need a Class B autoclave. A Class N or Class S machine processing loads it isn’t designed for is not just inefficient; it’s a sterilisation failure waiting to happen.
Once you’ve established that you need a Class B machine, the next question is chamber size. Benchtop autoclaves typically come in 17, 22, and 28 litre options, and the right choice depends on your daily instrument volume and how you want your workflow to run.
A 17 litre chamber suits smaller practices with moderate throughput, solo practitioners, or as a second autoclave alongside a larger unit. It will typically handle 3 to 4 standard instrument trays per cycle.
A 22 litre chamber is the most popular choice for busy single or two-practitioner practices. It strikes a good balance between capacity and cycle time, handling larger loads without the extended drying times of the biggest chambers.
A 28 litre chamber is built for high-throughput environments: multi-chair dental practices, busy veterinary surgeries, or any setting running multiple cycles daily with large or numerous instrument sets.
Two mistakes come up repeatedly. The first is buying the smallest (cheapest) autoclave and then running it flat out all day to keep up. Overworking a machine shortens its lifespan, increases the risk of cycle failures, and creates workflow bottlenecks. Buy slightly more capacity than you think you need and leave yourself headroom for busy days.
The second is relying on a single autoclave with no backup. If your only machine breaks down, your sterilisation capability stops entirely until it’s repaired. Some practices choose to run two smaller autoclaves rather than one large one, giving them built-in redundancy. It’s worth considering, particularly if you can’t afford any downtime.
This is the issue that causes the most avoidable damage to autoclaves, and the one that most practice owners only learn about after something goes wrong.
BS EN 13060 specifies maximum permissible contaminant limits for the water used in small steam sterilisers, including a conductivity threshold of 15 microsiemens per centimetre or below, neutral pH, and zero hardness. Tap water in most parts of the UK doesn’t come close to meeting these requirements. It’s full of dissolved minerals, primarily calcium and magnesium, that deposit as scale inside the chamber, on heating elements, and within pipework every time the autoclave runs a cycle.
Over months and years, this scale reduces heating efficiency, increases cycle times, causes wet packs (which means your instruments aren’t coming out sterile), and eventually leads to component failure. It also leaves visible residue on instruments. We see the consequences of poor water quality on service visits more often than almost any other problem.
Practices have traditionally dealt with this in two ways. The first is buying distilled or deionised water in bottles or containers. It works, but it’s inconvenient: you need to store the water, manage deliveries, and physically fill the reservoir by hand every day. The second is installing a reverse osmosis (RO) system that filters incoming mains water. RO systems produce water on demand, but they need plumbing, take up space, require regular filter changes, and the water quality drifts if maintenance is neglected.
There’s now a third option that solves most of these problems: a built-in demineralisation filter integrated directly into the autoclave’s water reservoir. You fill the machine from the tap, the filter strips out the dissolved minerals, and the autoclave runs on clean water without any external system. No RO plumbing, no bottles of distilled water, no separate storage. The filter needs replacing periodically, but that’s straightforward and far less disruptive than maintaining a standalone water treatment setup.
If you’re choosing a new autoclave in 2026, built-in water filtration should be high on your list of priorities. It’s one of the most practical advances in autoclave design in recent years.
Manufacturers list dozens of features. Here’s what actually makes a difference when you’re the one using the machine every day:
Automatic cycle recording is essential, not optional. Your autoclave should save a record of every sterilisation cycle with time, temperature, and pressure data. Modern machines store this internally and let you download via USB or Wi-Fi, which saves you from filing cabinets full of thermal printouts.
A clear touchscreen interface reduces training time and operator error. The best displays guide the user through each step with on-screen instructions rather than expecting you to memorise button sequences.
Modular drying adjusts the drying phase to match the actual load, saving time on smaller loads without compromising larger ones. Fixed-length drying cycles waste time when you’ve only loaded half a chamber.
Wi-Fi and network connectivity allows remote technical support (your service engineer can diagnose issues without a site visit), cloud-based cycle data storage, and app-based monitoring. Increasingly useful, particularly for multi-site practices.
Shared printer capability means one printer serves multiple autoclaves on the same network. Saves money and worktop space compared to buying a printer for each machine.
Consistent external dimensions across chamber sizes means you can start with a 17 litre and upgrade to 22 or 28 litres later without rearranging your decontamination area. Not every manufacturer offers this, but it’s a smart piece of future-proofing.
What’s not worth paying a premium for? Flashy colour schemes, proprietary consumables that lock you into a single supplier, or features you’ll never use. Focus on reliability, ease of use, and the quality of after-sales support.
A quality renewed (refurbished) autoclave from a reputable supplier can be a sensible choice, particularly for practices on a tighter budget or those looking for a backup machine. A properly renewed autoclave should be fully stripped, inspected, fitted with new seals and wear parts, functionally tested, and validated before delivery. It should come with a warranty and access to ongoing servicing.
Before buying renewed, ask: who did the refurbishment? What parts were replaced? Is there a warranty? Can you get it serviced and validated by the same supplier? If the answers are vague, walk away.
For a practice’s primary sterilisation unit, buying new is usually the better long-term investment. You get the full manufacturer’s warranty, the latest technology, and the longest expected lifespan. And if the upfront cost is a concern, leasing or finance can spread it into manageable monthly payments with servicing and validation included.
We service autoclaves from every major manufacturer. We see what works, what breaks, and what keeps running year after year with minimal trouble. When it came to choosing a manufacturer to partner with for equipment supply, we chose MOCOM, and here’s why.
MOCOM is part of the Cefla group, an Italian cooperative with decades of experience in sterilisation equipment. Italian engineering has a well-deserved reputation in this field: precision manufacturing, high-quality materials, and attention to the details that determine whether a machine is still running smoothly at year five or costing you money in repairs. MOCOM’s autoclaves are designed and manufactured in Italy, and it shows in the build quality.
The machine we recommend most is the MOCOM Futura B. It’s a Class B vacuum autoclave available in 17, 22, and 28 litre chambers, all sharing the same external footprint. It was the first autoclave in its class to incorporate a built-in demineralisation filter that lets you run the machine on ordinary tap water, which alone eliminates one of the biggest day-to-day headaches in autoclave management. The 5-inch colour touchscreen is intuitive enough that staff can be trained on it quickly, and the built-in video tutorials mean the user manual isn’t something that gets lost in a drawer and never looked at again.
Wi-Fi and Ethernet connectivity come as standard, with MOCOM’s EasyCheck remote support system allowing our engineers to run diagnostics remotely if an issue arises. Cycle data saves automatically to internal memory and can be downloaded via USB, the MOCOM sterilconnect app, or cloud storage. An optional printer can be shared across multiple Futura units on the same network.
But the reason we chose MOCOM isn’t really about any single feature. It’s about what we see on service visits. MOCOM machines hold up. The chambers stay clean. The vacuum pumps keep performing. The electronics don’t give trouble. When you’re the company that has to fix these machines, you develop strong opinions about which ones are built to last. MOCOM is at the top of that list.
Every MOCOM Futura B comes with a 3-year or 3,000-cycle warranty covering parts and labour, whether you buy or lease.
For practices that want to spread the cost, we offer all-inclusive 3-year lease packages that bundle the machine with annual servicing, Pressure Vessel Inspection, validation, and parts warranty in a single fixed monthly payment. No surprise bills. No separate contracts for servicing and equipment. Read our full guide to autoclave leasing here.
Do you process hollow instruments (handpieces, cannulas)? You need Class B.
Do you pouch or wrap instruments for storage? You need Class B.
Do you run more than 4 to 5 cycles per day? Consider 22L or 28L.
Are you a solo practitioner with moderate throughput? 17L may be sufficient.
Do you want to avoid the hassle of distilled water or an RO system? Look for a built-in demineralisation filter.
Is this your only autoclave? Buy more capacity than your minimum, or consider a second machine for redundancy.
Would you rather spread the cost than pay upfront? Ask about leasing with servicing and validation included.
Want advice on the right autoclave for your practice?
Call us on 01274 265566 or get in touch here for a no-obligation conversation. We’ll talk you through the options based on your actual workflow, not a sales script.
BS EN 13060: Small steam sterilizers. British Standards Institution.
MOCOM (2025) B Futura: product specifications. Available at: https://www.mocom.it/en/products/autoclaves/b-futura (Accessed: April 2026).
Pressure Systems Safety Regulations 2000, SI 2000/128. London: The Stationery Office.
GQ Decontamination provides autoclave servicing, validation, pressure vessel inspections, and equipment supply for dental, veterinary, and podiatry practices across the UK. Based in West Yorkshire with nationwide coverage.
