Top-loading lab autoclaves and the vertical configuration of the chamber allows for efficient research-scale bioreactor and fermentor sterilizationEvery laboratory needs a way to sterilize articles safely, quickly, and reliably, making autoclave sterilizers essential tools. However, since every laboratory has different needs, there isn’t a one-size-fits-all autoclave solution. Autoclaves come in many shapes and sizes–from compact and portable to built-in wall units–and many have distinct features that allow sterilization of different articles in different capacities and speeds.

With all these different factors, narrowing down the best autoclave for your unique needs can be challenging. So, to help you in your autoclave search, we have outlined the most significant factors to help you choose the right autoclave for you.

What You’re Sterilizing

Autoclaves function primarily through gravity, vacuum-induced, or pre-vacuum sterilization methods, though some autoclaves combine both methods to sterilize.

Gravity autoclaves work for the most common types of sterilization articles, like glassware, utensils, and non-porous items. However, if you need to sterilize large and porous items such as blankets, you should use a vacuum-type sterilizer.

However, this is just a general rule; learn more about the differences between the types of autoclaves here to understand which is better for your sterilization needs.

Autoclave Capacity

One of the first things you should decide when researching autoclaves is capacity. An autoclave’s capacity is generally measured in liters and indicates the total volume inside the chamber.

TOMY Fast Lab Autoclave SX-Series Maximize Capacity

You can get a good idea of the capacity you need by determining the largest item you will need to autoclave. However, it’s important to note that the effective chamber size is usually smaller than the actual chamber size, depending on the configuration of the chamber and how the racks fit. So, while the capacity in liters can help you get a ballpark on whether the autoclave will meet your size needs, you also need to check the actual configuration of the autoclave chamber. Some items have unusual dimensions, and you will want to ensure that these items fit in the actual autoclave chamber.

Since the capacity for specific autoclave articles is not always available online, you should contact the manufacturer to confirm their autoclave capacities.

For Tomy SX-Series autoclave capacity information, please indicate the type of articles using TOMY’s contact form or email at tomy@amuzainc.com, and a representative will get back to you.

Use of Space

Picking a size for an autoclave is a balancing act. On one hand, you don’t want your autoclave’s size to limit what you can and can’t sterilize. But on the other, space is precious in a lab, and you don’t want your autoclave machine taking up more space than necessary.

While the actual dimensions of the autoclave are one component, the other is its orientation. The most common type of autoclave is front-loading, which is designed with the cylindrical chamber sitting horizontally and open to a front-opening door. While it is convenient to open the chamber door toward the user, this kind of autoclave doesn’t make the most efficient use of its space.

Autoclave chambers are cylindrical because they need equal pressure throughout the chamber, and round shapes are less prone to high-pressure breaks than rectangular containers. Front-loading autoclaves use trays that slide into the chamber. This system wastes the areas outside of the flat surfaces, such as the bottom of the autoclave, and requires tactical loading to accommodate the varying slope of the top.

Top-loading autoclaves make the best use of space as the vertical configuration of top-loading autoclaves and stackable baskets takes more advantage of the vertical cylindrical chamber.

The other difference is the shape of the trays. Front-loading autoclaves use rectangular trays, but most autoclave articles are round, including flasks, bottles, and Petri dishes.

For example, the SX-700 autoclave can accommodate up to 27 300 mL flasks in one cycle because of its top-loading design, round configuration, and stackable baskets.


Another factor to consider when picking an autoclave is how much you need to sterilize daily. An autoclave’s throughput capacity is the amount of autoclaving articles that can be sterilized per sterilization cycle (as well as the time required to prepare, load, and unload articles).

While throughput won’t be a set amount of time–since the cycle time depends on the articles’s respective sterilization requirements–each autoclave will have a warm-up and cooldown time that affects the overall cycle time. These can be dramatically different depending on the machine. Certain features like cooling fans can dramatically speed up this process, allowing for more daily cycles and higher throughput.

With the TOMY SX-Series Autoclave, the dual cooling fan system reduces the cooldown time by up to 42%, saving approximately 25 minutes on the cooldown time*, which can amount to nearly two extra loads in a standard workday.

The Number of Autoclaves

The type of autoclave that you choose can also dramatically affect efficiency. Operations that require extensive and steady throughputs may benefit from having several medium-size autoclaves instead of a single large autoclave. With multiple autoclaves, you can stagger the cycles and avoid backlog.

Depending on the size of your lab, you may already have a centralized autoclave room. It’s not always ideal to have to leave the laboratory every time you need to sterilize something. If you find your trips to the autoclave room interrupt your flow frequently, you should consider investing in smaller, portable autoclaves that you can keep on hand.

Having several smaller autoclaves can also be ideal in the event of a breakdown since you’ll have backups. If one autoclave goes down, you’ll only have to contend with lowered output instead of completely shutting your operation down.

Installation Utilities: Water and Electricity

Another thing to consider is your facility’s access to water and electricity.

Some autoclaves require plumbing, while others can function by simply adding water to the unit. Many traditional autoclaves and those with chamber vacuum functions need access to an external water main or house steam. While this allows for a steady water source, your plumbing will limit your options when choosing where to set up your autoclave.

Other autoclaves do not rely upon water or steam intakes and can function with water manually added to the chamber. While this adds a step to the process, it also makes your setup more versatile.

Autoclaves also have different voltage requirements, so your electricity source is another factor to consider. Some may require 220-240V (different from standard 120V outlets), which has the advantage of a faster heating time. A qualified electrician can change the output, but this does incur an additional setup cost.

Models from the TOMY SX-Series can be placed anywhere there is a power outlet with no plumbing or installation required. All you need to do is plug in your autoclave and add water.

Replacement Parts

Like all machines, autoclaves require routine maintenance. However, if you purchase a cheaply made autoclave, you may have the additional burden of needing to buy replacement parts frequently.

One part that’s important to assess before you purchase an autoclave is the chamber lid gasket. Because of the intense heat and pressure that gaskets are subjected to, they’re generally the part that needs to be replaced the most. A gasket’s design and material quality directly correlates with the frequency with which you must change it. Gaskets that require more frequent changes will add to the maintenance costs of your autoclave. Some autoclaves require monthly gasket changes, which can cost hundreds of dollars each time, adding up to several thousand dollars in a matter of years.

TOMY SX-Series autoclaves come with thick, sturdy, high-quality gaskets that require changing only once every three years, depending on the frequency of use.


You want an autoclave that is easy to clean since dirty water can cause significant damage. At high temperatures and pressure, impurities that get into the water from the autoclaved articles can stick and burn to the heater, preventing it from transferring heat and permanently damaging it.

For TOMY SX-Series autoclaves, you can drain water in the chamber by opening the drainage valve under the machine, which lets the water drain into a container for disposal. For biohazardous material and water disposal, especially for BSL (Bio Safety Level) 2 and above laboratories, please contact the Center for Disease Control or the relevant national authority for disposal instructions.

Technical Support

An autoclave is an investment, so you want to ensure the supplier offers quality technical support. If there is an issue with your autoclave’s operation, you should be able to get in contact quickly and easily and have access to informed help. Most autoclaves have a one-year warranty, but you should check your manufacturer’s paperwork.

If you purchase your autoclave from a large distributor, you may have access to more support, but this isn’t necessarily true. You may have to deal with long waiting lists and expensive technicians. Smaller distributors may have a smaller workforce but often provide a more personalized experience. Research customer reviews and see what support the distributor offers.

Of course, ideally, you don’t want to have to contact technical support, which is why choosing a reputable company for recognized quality and craftsmanship products is essential. TOMY has manufacturing operations in Japan, and its products provide quality and long-lasting reliability. TOMY also offers worldwide technical support and parts through distributorship.

Summary (The Bottom Line)

It can be tricky to find the ideal autoclave for your organization’s needs; you need an autoclave with the correct capacity and throughput while factoring in space requirements, installation, maintenance, quality, and overall costs over several years.

Overall, the best autoclave is the one that meets your throughput needs without taking up any more space than necessary. Make sure to assess upfront costs and the long-term costs associated with the capacity/throughput, performance, and reliability that affect any organization’s bottom line.

If you’d like more guidance in finding the right autoclave for your laboratory, we’re happy to help! Contact us to find your ideal autoclave setup.

*Save up to 25 min on autoclave cycle time with the Tomy SX-Series dual-fan cooling system, which reduces chamber cooling temperature from 121°C to 60°C from 59 minutes to 34 minutes

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