Laboratory Incubators: How to Choose, and Why "Ambient +5°C" Decides Everything
- Aug 19
- 7 min read
Key takeaways
A standard laboratory incubator can only heat. It holds temperatures above the room, typically from about ambient +5°C upwards. If you need 20°C or 25°C in a lab that sits at 21°C in summer, no amount of specification on a heating-only incubator will get you there. You need a cooled model.
Gravity convection is gentler, mechanical convection is faster and more uniform. Powders, light samples and open dishes suit gravity. Dense loads, full shelves and tight uniformity requirements suit mechanical.
Uniformity and stability are different numbers and buyers routinely confuse them. Stability is how steady one point stays over time. Uniformity is how much the temperature varies between the corners and the middle. Uniformity is the one that ruins a run.
Our range covers £555.23 to £9,309.85, and the single biggest price step is the move from heating only to cooled.
What is a laboratory incubator?
A laboratory incubator is a temperature-controlled chamber that holds samples at a set temperature for a defined period, most often to allow microorganisms or cell cultures to grow under reproducible conditions.
Beyond that shared definition, the category splits hard. A microbiology incubator holding plates at 37°C, a BOD incubator holding bottles at 20°C for five days, a CO2 incubator maintaining 5% carbon dioxide for mammalian cell culture and a shaking incubator agitating liquid cultures are four different instruments that share a name.
Choosing well means identifying which of those you are actually buying before you compare prices, because the price bands barely overlap.
Why can't a standard incubator hold 20°C or 25°C?
Because a heating-only incubator has no way to remove heat. It can warm the chamber above the room, but it cannot cool below it, and in practice it needs roughly a 5°C margin above ambient to control properly.
This is the specification line that catches people out, and it is worth stating plainly. A typical mechanical convection incubator is quoted as operating from ambient +5°C to 65°C. In a laboratory sitting at 22°C, the lowest set point that unit can genuinely hold is around 27°C.
That rules it out for a long list of common work:
Biochemical oxygen demand testing, which is run at 20°C
Fungal and yeast culture, commonly 25°C
Environmental and water microbiology at 22°C and 25°C
Plant and insect studies at controlled sub-ambient temperatures
Anything that has to survive a warm summer in a lab without air conditioning, where ambient can climb past your set point entirely
The fix is a cooled incubator, sometimes called a refrigerated incubator, chilling incubator or BOD incubator. These add active cooling, either compressor-based or Peltier, and can hold set points below room temperature. They cost considerably more, which is exactly why people try to avoid them and then find they cannot.
Decide this first. Everything else in the specification is negotiable. This one is physics.
Gravity or mechanical convection?
Gravity convection moves air by natural buoyancy. Mechanical convection uses a fan. Gravity is gentler and quieter; mechanical is faster, more uniform and recovers better after the door opens.
Gravity convection | Mechanical convection | |
Air movement | Natural, no fan | Forced by fan |
Temperature uniformity | Adequate | Better |
Heat-up and recovery | Slower | Faster |
Disturbance to samples | Minimal | Some air movement |
Best for | Powders, light or open samples, agar plates | Dense loads, full shelves, tight uniformity |
Drying effect | Lower | Higher, watch open media |
Noise | Silent | Fan noise |
For routine plate incubation at 37°C either will work. The choice starts to matter when the chamber is full, when you open the door frequently, or when the method specifies a uniformity tolerance you have to evidence.
Uniformity, stability and why they are not the same thing
Stability is variation at one point over time. Uniformity is variation between points at one moment. A unit can be beautifully stable and still be 3°C colder in the bottom corner.
Stability is easy to achieve and easy to advertise. Uniformity is harder, costs more to engineer, and is the number that determines whether a plate at the back of the bottom shelf gives you the same result as one in the middle.
Two practical consequences.
Do not load to the walls. Air has to circulate. A packed chamber destroys uniformity regardless of what the datasheet claims.
Map it, do not assume it. If your work is regulated or accredited, temperature mapping with multiple probes across the loaded chamber is what proves the incubator does what you need. The manufacturer's figure is for an empty chamber under ideal conditions, and your chamber is neither.
Which incubator do I need? A decision path
Work out your set point first, then your load, then your control requirements.
Set point at or above ambient +5°C, routine microbiology: a benchtop or mechanical convection incubator. This is most laboratories.
Set point below ambient +5°C, or a variable set point that might drop: a cooled or chilling incubator. Non-negotiable, see above.
Mammalian cell culture: a CO2 incubator. You are controlling carbon dioxide and humidity as well as temperature, and a standard incubator cannot do it.
Liquid cultures needing agitation: a shaking incubator. Combining the two saves bench space and removes the separate shaker.
Occasional use, single shelf, tight budget: a mini incubator.
The range, with UK prices
All prices below are current at the time of writing and include the discount shown on each product page.
Benchtop and small-volume
Cole-Parmer 0.1 Cubic Foot Mini Incubator, 230 V, £555.23. SKU 360815. The entry point. Suits a single small batch, a teaching bench or a satellite location where a full incubator cannot be justified.
Cole-Parmer INC-200 Stuart Analogue Incubator, acrylic, 230 V, £2,392.73. SKU 111002. Analogue control, transparent acrylic chamber so plates can be checked without opening the door.
Cole-Parmer INC-200D Stuart Digital Incubator, acrylic, 230 V, £2,564.77. SKU 111008. The digital version of the same unit. The step from analogue to digital is £172.04, which buys you a displayed set point, a displayed actual temperature and repeatable settings rather than a dial position. On a unit at this price that is a straightforward decision.
A 120 V, 60 Hz version of the digital model is available at the same price, SKU 111004, for laboratories running North American supply.
Mechanical convection, larger chambers
Cole-Parmer INC-400F-420 Mechanical Convection Incubator, 420 L, 220 V, £5,341.25. SKU 5241178.
Both run ambient +5°C to 65°C with PID control, a stainless steel inner chamber with curved internal corners for cleaning, antiskid single-handed shelves and glass doors so samples can be inspected without losing heat. Safety features include auto-restart after power loss, a temperature deviation alarm, an overtemperature set point alarm and overcurrent protection.
Note the 270 L unit's price against the benchtop acrylic models above. If bench space allows, capacity here is unusually cheap. 120 V versions of both are listed at the same prices, 270 L and 420 L.
Spare stainless steel shelves for gravity convection incubators run from £40.10 to £119.83 depending on chamber size.
Cooled and refrigerated
Cole-Parmer Chilling Incubator, 1 cu ft, 230 VAC, £3,277.74. SKU 3905025. The most affordable route to sub-ambient set points in the range.
Peltier-Cooled Incubator, £3,604.67, reduced from £4,806.22. Model IPP55. Peltier cooling uses no compressor and no refrigerant, which means less vibration, quieter running and a smaller footprint. For sensitive samples and for labs where the incubator sits near people, that matters.
Cooled Incubator, £9,309.85, reduced from £12,413.13. Model IPP410eco. The large-capacity cooled option, for laboratories running BOD testing or environmental microbiology at volume.
Specialist
Cole-Parmer H2300-HC2-E Mini CO2 Digital Incubator, 230 V, £3,873.77. SKU 360806. For mammalian cell culture, where 5% CO2 maintains the bicarbonate buffer in the medium. A standard incubator cannot substitute here.
INC 125 FCS Digital Cooling and Shaking Incubator, £6,849.50, reduced from £7,210.00. Cooling and orbital shaking in one chamber, for liquid culture work that also needs sub-ambient capability.
What else does the workflow need?
An incubator sits in the middle of a microbiology workflow, not at the end of it.
Before: media has to be prepared and sterilised. Our laboratory autoclave buyer's guide covers sizing and cycle selection, and the Astell benchtop versus front-loading comparison covers the format decision.
During plating: if you are working with anything infectious, plating belongs in a biosafety cabinet, not on an open bench. If the work is sterile but not hazardous, a laminar flow cabinet is the correct and cheaper choice.
After: plates have to be counted. Manual counting is slow and drifts between operators; our colony counters guide covers when automation pays for itself.
The WHO Laboratory Biosafety Manual, fourth edition is the reference for risk-based handling across that whole workflow.
Frequently asked questions
What temperature should a microbiology incubator be set to? 37°C for most clinical and food microbiology, matching human body temperature. 30°C for many environmental organisms, 25°C for fungi and yeasts, 22°C and 20°C for water testing and BOD. The set points below about 27°C need a cooled incubator in a typical UK lab.
What is the difference between an incubator and an oven? Temperature range and purpose. Incubators hold low temperatures precisely to grow organisms, typically up to 60-70°C. Ovens run far hotter to dry or sterilise, and dry heat sterilisation needs 160°C. See our laboratory ovens guide for the drying and sterilising side.
Can I use an incubator to sterilise? No. Dry heat sterilisation requires 160°C for two hours, which is far beyond an incubator's range. Use an oven or an autoclave.
Do I need a CO2 incubator for bacterial culture? Usually not. Most bacteriology runs in a standard incubator. CO2 incubators are for mammalian cell culture and for a small number of fastidious organisms that need elevated carbon dioxide.
How often should an incubator be calibrated? Annually as a minimum, and after any relocation or service. If your work is accredited, calibrate against a traceable reference and map the loaded chamber rather than relying on the built-in display.
Why is my incubator not reaching its set temperature in summer? Almost always the ambient +5°C limit. If the room warms, a heating-only incubator loses its margin and cannot hold a low set point. This is the single most common complaint and the only real fix is a cooled unit.
Sources and standards referenced
Manufacturer specifications for temperature range, control method and chamber construction, as published on the product pages cited.
Product prices and SKUs from the LS Scientific catalogue, verified 6 August 2026.
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