When I'm asked to explain what type of "System" I have in my house, I'm
at a loss for words as to how to explain it properly. They ask: Gas
or Electric? Heat Pump? Forced Air? Oil Heater? Apollo? All these
terms are very confusing to me. I was wondering if someone more
knowlegeable in these areas could help me out.

I've checked the water heater, and I have a ruudglas pacemaker dv
p400v. I was told when I bought the house that I have an "Apollo"
System for heating and air conditioning. My air conditioning unit
outside the house says it is a Janitrol.

When someone asks me what type of water heater do you have, gas or
electric or heat pump or forced air or apollo system, etc. How
should I answer them?

Thanks