When should I replace the evaporative cooling pads? With Aspen or Woodwool pads, you should expect to change these, every 3 or 4 years. This can vary with water quality and local conditions.
WARNING With any filter pad, failure to replace filter pads when they are past their useful life may result in reduced efficiency/performance of the evaporative air conditioner. Water may carry over into the duct work and/or electrics, which may result in expensive damage and repairs