CO2 incubators can roughly be divided into two categories: water- and air-jacketed incubators. Let's have a look at the benefits and drawbacks of each.
Water-jacketed incubators rely on heated water within the incubator walls to provide a uniform temperature throughout the incubator. Due to the high heat capacity of water, they are capable of maintaining the desired temperature for a long time which is beneficial with multiple door openings or power outages.
Filling and heating the incubator takes time so the water-jacketed incubated has a long set up time. Once filled, it's heavy and hard to move. Furthermore, stagnant, warm water is an ideal place for contamination growth. This can be limited by the use of copper in the lining and HEPA filtration, but remains a risk for water-jacketed incubators.
Air-jacketed incubators are much lighter and faster to set up as the incubator walls are filled with air instead of water. They rapidly reach the desired temperature and take considerably less maintenance. They are also suitable for high heat sterilization and temperature upwards of 180°C can be reached, something not possible when using water-jacketed models.
If contaminated, air-jacketed incubators can be quickly decontaminated through, for example, high heat or hydrogen peroxide treatment. They are, however, more sensitive to changes in temperature because air has a smaller heat capacity than water. This can be problematic in case of frequent door openings or a power outage.
Temperature uniformity can also be an issue, creating cool spots. This problem has, however, largely been solved for newer models but it is recommended to inquire about the air flow and temperature uniformity before purchase. Air-jacketed incubators can also be more prone to condensation formation, although this can largely be prevented by using anti-condensation technology.