Here's the scenario: Main panel is a 100A service (GE PowerMark Gold LoadCenter) with all slots filled. A 60A breaker runs to a sub-panel that currently contains breakers for the electric stove (50A), electric dryer (30A), washer (20A), and a room with a light and a few outlets (15A). There are open slots in the sub-panel. My propane water heater needs replacing and I am looking at around a grand just for the replacement. I need to know if I can add a two-pole 30A breaker and run 10-2 wire to an electric water heater (4500 watt). The electric water heater is less than half the price even for a larger tank. As best I can tell I might be spending more on propane ($3.50+/unit) compared to what electric would cost to run (9c/kwh).
There have been no issues with tripped breakers under the current configuration. I just need to know if my setup can accommodate an electric water heater. IF I have to upgrade the electrical service on the main panel to do it I might as well stick with propane. I appreciate any knowledgeable wisdom sent my way. I think some of the labels are inaccurate as the washer is clearly running off the sub-panel at this point.