How do I tell the difference between an electric heat pump and a gas pack?
According to my landlord and the previous tenants of my house, we have electric heat and a gas water heater. My gas bill is so high, the gas company says our heat has to be gas. All I see outside is an electric heat pump. No furnace inside. Central air and heat. $400 gas bill. Landlords are sure the heat is electric. How to know for sure?

Sounds like you don’t have all the parts for a heat pump. There has to be a back-up furnace, inside someplace. Electric or gas. There are two parts to a heat pump, the outside unit and inside unit. We have one, the backup unit inside is electric. Sits in the basement, looks just like a furnace, but usually runs on the heat pump. Only kicks over to the furnace when it is very cold or when it needs to defrost.
First, ask how much the gas bill was for the previous tenant. If it has jumped up, then there is a problem that has recently developed. Then, check the reading on your last bill against your meter, it could be the gas company is billing you for someone else’s meter. Regardless of the answers to those questions, ask the gas company to send someone out to check the line, meter, and the furnace that they are insisting you have. If there is a furnace, they will find it, if there isn’t, they should be able to find out why the billing is screwed up. After all, if there is one hiding away somewhere, best you find out soon, since no one will have serviced the poor thing in years, owing to the fact no one knows about it.