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Tanklets > Better Plumbing Systems

Q: I am in the process of building a new home with a geothermal system and I'm trying to determine if I should go with a tank or tankless water heater. I would appreciate any feedback or experience anyone has had with tankless units.

A1: You can view Larry Weingarten's and my feelings about tankless at: https://www.waterheaterrescue.com/pages/Longevity/tankless-water-heaters.html . But I hope some other folks will add their experiences, good and bad. -- Randy

A2: Hello: Geothermal is normally used just for space heating. It sounds like you're looking to make it do water heating as well? Before you build would be a great time to research "structured plumbing" and "Gary Klein". He's written some articles on this topic that you NEED to see :cool: Done right, structured plumbing will save you water, energy and waiting time. It's good. -- Larry

Q1: I am installing a hot water loop but I didnt think about the heat loss of the typical recirculating setup. Plumbing has not been completed in the basement yet so it may not be too late to go with the on-demand 3/4 recirculating setup. If it is too late do you think it would be better to scratch the loop and just wait for the hot water to get there?

A3: It really is a matter of size and layout of the house. If you could get hot water quickly with little waste by using a manifold system, good. If things are spread out, structured plumbing makes better sense. Gary Klein's thinking is ideally to waste no more than a cup of water before hot arrives. Less ideal but still good is two cups. But waiting for minutes at a time doesn't cut it. Keeping the volume of water in the pipes as low as you can, helps. For example, 3/8" tube has half the volume as the same length of 1/2" tube. That means you wait half as long. -- Larry

Q2: I checked with my plumber on what system he was planning on installing and he said it is called "Just Right" by Nibco. It is a pumpless on demand system that work on the pricipal of heat rises. I did some research on it and it looks good although I have some concerns on how effective it will be in my house as the loop doesnt go up from the water heater. The loop is approx 25' from the heater. Have you heard of this or know anything about it?

A4: The D'mand system https://www.gothotwater.com is going to be more energy efficient and will work regardless of layout, but if your plumber will guarantee your happiness with the Nibco system... (12/27/07)