An economical, low–pressure (276 kPa, 40 psi) sprinkling system was tested for its efficacy of cooling laying hens in a commercial high–rise layer house [14 Ü 130 m (46 Ü 426 ft)] in Iowa. The sprinklers, rated at 2.1 mL/s (2 gal/h) each, were equally spaced at 3 m (10 ft) apart and 2.4 m (8 ft) above the floor in each cage aisle of the layer house. They were controlled to operate 10 s every 10 min when the inside temperature exceeded 32 _ C (90 _ F). The system was shown to improve egg production by 2.6% overall and 5.6% for the top deck (P < 0.01). There was no sign of sprinkling damage to eggshell integrity. Autocorrelation analysis has the potential to quantify the impact of heat stress history on subsequent egg production response of the hen. Work is needed to optimize the layout of the sprinklers for uniform water distribution and water application rate as a function of environmental conditions.