Maintenance cost for major home appliances can really eat up the family budget, so how would you like appliances that cost nothing but a few minutes of time to maintain? Evaporative air coolers are one of the devices that are free to maintain, unlike their air conditioning counterparts that can cost $100 – $250 for maintenance. Evaporative air coolers simply need their cooling pads cleaned on a regular basis. This process is simple and costs nothing.