[haystax]

FineHomebuilding mag just did a big story on water heaters - they say a savings of about 19% is what you will see from a tankless heater compared to standard however since you never get out of the shower you probably end up using more water and more power than a conventional.

Article suggests a 190,000btu with .82 or better energy factor for your size family -

I'm a little skeptical about full life cycle costs of tankless heaters and wonder if they are really worth the investment. At less than full flow, the heater short cycles and that is never good in any type of machine. You will also be out of hot water during a power outage (assuming you have a pressure tank or utility service) and hard water will eat up a tankless way faster than an anodized tank heater. Sediment also has no where to go and utility lines w/ water hammer can send junk into your tankless that you never knew was there before with a tank model. This is my opinion as a homeowner looking to build new based on a winter's worth of online, magazine research and plumber ?'s - obviously there are people who are happy with them as well but i believe it is too early to tell on a full life-cycle ROI type analysis. A near 100% efficiency tank heater is pretty bulletproof and would probably serve you well in your specific circumstance IMO

I would suggest subscribing to the online magazine for some really good ideas and no-nonsense articles. Especially if you are looking at building or buying a new home in the near future this magazine has been a GREAT resource for me. Good luck