is out there in abundance. Thanks for thinking of me JJ. Hi Tim, 80 gallons is a big water heater, which means higher stand-by losses. Sizing a cold water heater, is a little trickier than is generally thought: What's it going to be used for, is it for a big family, or do you want it that big to be able to fill a large tub? Do you really want to heat 80 gallons of water 24 hrs/day just so it'll be there when you want it, or would you rather heat water when you need it, and save money on your electric/gas bills. There are as many ways of using tankless water heaters to get you what you want, as there are personalities & lifestyles of the folk who want it. Please re-post, Tim, and let me know what you'd like to achieve and I'll try to give you better, or more specific advice. Is it electric, gas, big/small family, # of bathrooms etc'. There are tankless water heaters out there ranging from 120volt 3.1kw, to 480volt/3ph/144kw. And gas units from 38,000btu to 235,000btu. I can run 20 tankless heaters with one controller, get as little as 1gpm at 25,000btu, or 8,400gph at 4,700,000btu's, without using a tank. I've read so many posts, saying "tankless water heaters don't produce enough hot water" that I don't respond to them anymore. I have tankless cold water heaters, that an average family cannot overpower. They'd have to run the bathtub and two showers at the same time, to make them run tepid. The average family never does that, because a tank heater would run out too quickly. That's enough rant from me, tankless has come a long way baby. I won't respond to anyone who wants to argue about this, but if anyone wants a water heater which costs more than "home centre cheapie", but less than a commercial water heater, then please contact me. Sorry for the rant, Jay J. I have Bob V's home # if anyone needs to know from the horses mouth, that tankless really works, I'll have Bob give you a call. Gotcha, just kidding. I will really, really miss this board. Thanks for all you've done for us, Jay J, Henry, Harold, John 2000, andi, Steve, Bob B, the Dodgeman, Jim, Rodney @ Warmfloors, Jack D, The Wick, Bob F, JB, PB, GdDog & AzFred. I know I missed someone, sorry. This old board has personality, friendship, easy-going one-upmanship, the other board has none of this. What will I do with my evenings, go back to the pub scene, I don't think so. I'll just sit here & wilt, while watching re-runs of "This old house", and saying to my befuddled old self, "look, the episode where Bob installed that tankless water heater, I bet it's still working". Gotta go, sniff, sniff. Take care out there. Brian.