There are three types of Tenancy options available for Amazon EC2:
-
**Shared Other AWS accounts might also have instances on the same host
-
**Dedicated Only your AWS account will have instances on the same host
-
**Dedicated Host The host is fully dedicated to your use
When launching
**Shared** or **Dedicated** instances, the hourly cost of running the Amazon EC2 instance will include the cost of the Operating System

When launching instances on a
**Dedicated Host there is **no charge for the instance itself** (nor the Operating System) because you pay for the whole Dedicated Host

Dedicated Hosts are commonly used for
**Bring Your Own Licensing** for both Operating Systems and Software. A Dedicated Host also has visibility of Sockets and Physical Cores that can be used to manage licensing for server-bound software that is licensed **per-socket or per-core**

See: Comparing Dedicated Hosts to Dedicated Instances
However, Dedicated Hosts are very big and are typically used to run multiple instances on the Host

**Bottom line It is not worthwhile using a Dedicated Host for a single Windows license. Just launch a normal Shared-Tenancy instance.