I am a home improvement contractor and I was told be a customer that there is an electric tankless water heater with a propane back up. I have never heard of such, nor can I find one online. If you know of one would you please paste a link for me.

I am looking into pruchasing a tankless water heater but do not want to pay more to operate it than the tank i have now. I know my tank runs on 1000 btu's and most tankless heaters run at about 10 thousand. Is it worth it to switch over?