My wife and I recently bought a 2 bedroom, 1 bath ranch house. We are planning on being here for 10-15 years, until we get close to retirement or retire. The 40-gallon hot water heater that is in the house works fine, but is old (18 years). We were talking about replacing it, but didn't know if a tankless heater, for just the two of us, would save us enough money to have one installed, or if we should just go with another 40-gallon tank heater. Thanks for your input.