Budget-limited thermal biology: Design, construction and performance of a large, walk-in style temperature-controlled chamber

• There is widespread need for temperature-controlled chambers (TCC) in thermal biology.
• Commercially available TCCs can be cost prohibitive.
• A low-cost, walk-in sized TCC is built from readily obtainable parts.
• Accurate and precise temperature control over the range 5–37 °C is demonstrated.
• The TCC is used to measure insect metabolic rates to demonstrate its utility.

We describe a partial redesign of the conventional air-conditioning system and apply it to the construction of a relatively large (1.87 m3 air mass), walk-in style temperature-controlled chamber (TCC) using parts easily obtained in most countries. We conducted several tests to demonstrate the performance of the TCC. Across the physiologically relevant range of 5–37 °C, the TCC took 26.5–50.0 min to reach the desired set point temperature. Once at set point, temperature inside the chamber was controlled with an accuracy of ±1.0 °C. User-entry effects on deviations from and return times to set point temperature were minimal. Overall, performance of the TCC was sufficient to make precise physiological measurements of insect metabolic rate while controlling assay temperature. Major advantages of the TCC include its simplicity, flexibility, and low cost.