I'm fairly certain that all energy prices are likely to rise over time. Given that all fossil fuels can be used to generate electricity, I think it's unlikely that electricity will rise much faster (or much slower) than gas or oil.
That said, it's almost always more efficient to burn a fossil fuel (like gas) to heat something (house, water, etc.) directly than it is to convert that heat into electricity at a generating plant and then back to heat through resistive elements.
On that basis, I'd go with a gas water heater (even though their initial cost is higher). If gas is available, I'd also go with a gas furance over any electric heating option using resistive elements.
One electric option that may be worth considering is an electric heat pump. There are many types, but the basic principle is that the electricty is used to run a compressor that extracts heat from outside air (or something else like the ground). The heat extracted can be much greater than the energy expended to run the compressor, and so it's a much more efficient way to use electricty to warm a house. And it acts as an air conditioner in the summer too (since it works on the same principle as your refrigerator).
I know you're curious... I have a 93% efficient gas furnace that runs on cold days when my heat pump isn't enough.
Facebook
Twitter