1 These are kits that contain all of the supplies and items needed to install a pool in your home or building. 2  These will cost around $5,000 to $20,000 not including installation. 3  If you are wanting an average-sized indoor swimming pool you may need to set aside at least $20,000 to $40,000 to complete the job. This price would be for a home that has already been prepped for pool installation. 2  Extremely large pools, on the other hand, cost more than $50,000 to $75,000 since they are deeper and will usually need detailed attention to heating or filtration.