Dry-type transformers have less maintenance and operational costs than oil-cooled transformers, leading to a lower total cost of ownership (TCO). They can also be installed more economically, as no special building or civils infrastructure is required. These transformers are typically located indoors, where they can be much closer to the load. This reduces electrical installation costs.
Maintaining a dry-type transformer is relatively simple and much less costly than oil-cooled transformers. The latter demand regular oil inspections and sample testing, for instance. These transformers can also experience leaks. This carries the risk of environmental pollution and associated remediation costs. Leakage also undermines the quality of the internal oil and can lead to moisture ingress. The maintenance cycle to avoid this must be regular and systematic, and is invariably fairly expensive.
There are also systemic costs related to the maintenance requirements of oil-cooled transformers. When they are being serviced, for example, they need to be de-energised and often removed from service for a period of time. With their much less frequent and less intrusive maintenance regime, dry-type transformers can allow users to avoid these costs.