The Philips HS1 and the Philips Heartstart Home are names for the Philips Heartstart Onsite.
In the United States and other parts of the world, the Philips Heartstart Onsite is called the HS1. "HS" stands for Heartstart, and 1 is the designation as being the the first model for the Heartstart series. The HS1 is exactly the same machine as the Onsite. All the accessories (e.g. pad cartridge, battery) for the Onsite can be used for the HS1.
The Philips Heartstart Home or the Philips Home is also the same machine as the Onsite. Costco sells the Onsite as well, but calls the machine Philips Home. The reason the machine is called Home is because in the United States, a medical prescription is usually required to own an AED. The Philips Onsite is the only AED device that Americans can buy without a prescription. This allows Philips to market the Onsite for personal use, which is why the device is marketed as Philips Heartstart Home.
In Canada, a medical prescription is not required to own an AED.