Much of the published work concerning the response and power output of closely spaced arrays of heaving wave energy devices concerns behaviour in regular waves only and is based on numerical analysis. To date, limited experimental work has been published and it remains unclear how device interactions predicted in idealised models relate to the response of proposed devices in realistic irregular wave-fields. Experimental measurements of the power absorbed by a small two-dimensional array of heaving devices in both regular and irregular waves in a wide flume are reported. Under certain conditions, positive interactions (where the average power output of the array exceeds the same number of isolated devices) are measured. Initial measurements suggest that positive interactions correspond to individual float displacements much larger than the incident wave amplitude. From regular wave tests, the presence of positive interactions is largely dependent on the incident wave period and the performance of adjacent devices. Preliminary tests indicate that float responses tend to be smaller when subjected to short period irregular waves of equivalent peak frequency. The data presented provides an insight into interactions within irregular wave conditions and forms a basis for evaluating numerical models.