Epoxy alumina nanocomposites were prepared to understand the space charge variations with ultra violet (UV)- and water-aged specimens. Addition of alumina nanofiller to epoxy resin had suppressed the space charge formation. A pulsed electroacoustic technique was employed to measure the space charge accumulation in epoxy-alumina nanocomposites. A marginal increase in space charge with enhanced electric field in the bulk volume of insulation was observed with UV- and water-aged nanocomposites. It was observed that 3 wt% sample showed better performance in all ageing conditions, which was confirmed through space charge studies and by the measurement of the dielectric parameters especially dielectric constant and tan(δ). © The Institution of Engineering and Technology 2020