A well-plate format isothermal multi-channel microcalorimeter for monitoring the activity of living cells and tissues

•An isothermal calorimeter (CalScreener) with a well-plate format is described.•Detection limit is ca. 0.1μW as baseline stability is 0.2μW over 24h.•Metabolic heat production of microorganisms is accurately determined.•Metabolic heat production of mammalian cells is accurately measured.