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Originally Posted by DETRoadster
I dont know much about the on-demand tankless electric, but our architect and builder are both thinking it might be an option for our master bath which is a pretty far shot from the mechanical room. We could be spending a lot of time running the water, waiting for it to heat up, in that room. And since the master is the biggest consumer of hot water, that's a concern. I can tell you they pull a shit-ton of power. I looked at a unit that can do just under 5.0 gallons per minute (about what you'd want to support filling a baththub) and that sucker needs 120 amps of service! Probably a non-starter for us as we have an electric car and I have a shop full of woodworking equipment. We'd need a 400 amp service into the house to ensure my wife could take a bath while I escape to the shop to do some woodworking, while her car is charging.
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My current small house only has a 100 amp service...and we own *two* electric cars!
Why I was wondering this last night is because of a problem that we're having in our house. When I turned the thermostat up for the first time this fall on Wednesday night, the oil boiler didn't warm the house. (It also does our hot water via an attached storage tank, but that has been fine and running all along.)
After two visits, the repair company said that the boiler was shot and needed to be replaced. They slickly offered several replacement packages like a used car dealer, with the premium one costing $23K
and the cheapest at around $14K. I may have been born at night, but I wasn't born LAST night!
I was looking at all of the options for heat and hot water last night, from a clean-slate perspective. As you noted, I don't have the power budget for even a small old-school electric tanked water heater. A replacement boiler costs $2,100 to buy, plus $$$$ for the hot water storage tank. (I would replace both, just because they are coming up on 20 years old and our well water literally eats through copper pipe.) Fortunately, we have our ducted "ductless" heat pump system, so other than cold showers we will not be cold indoors until the polar vortex dips again.
Long story short, my DW found this Navien combo-boiler and hot water unit that runs on natural gas or propane:
https://www.navieninc.com/products/ncb-190-060h
The street price is $2,500, it hangs on the wall, vents exhaust to the outside via 2" PVC pipe through the wall, has stainless steel heat exchangers to hopefully cope with our pipe-eating well water, and the hot water function is whole house, on demand. Oh, and it is Energy Star, 95% efficient, and qualifies for a federal tax rebate. If we have to replace our current boiler setup, this is my current #1 choice (and converting from oil to propane).
When my DW's family got wind of the $23K quote this morning, my legally-blind plumber-in-law showed up at our door right away. He confirmed my suspicion that there was something wrong with the water pressure in the radiator loops, and discovered that the automatic fill valve was frozen due to corrosion from the water. I'm not convinced in his prognosis that the boiler is otherwise healthy, but he thinks that it can run for a few more years if we change the $60 fill valve. Did I mention that he's legally blind and found an obvious problem that the professional repair dude either didn't discover or chose to intentionally hide from us?
Quote:
Originally Posted by dreamingat30fps
We have a large tank in FL so it’s very rare to run out, however in theory I liked the idea of the tankless never running out. It’s also MUCH smaller and ours runs on propane. Overall I think if I had a choice I would have a tankless.
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What I discovered while looking at the options last night is that modern plumbing installs use a hot water loop to the fixtures, with a circulator pump that keeps the hot water fresh near the faucets with a return pipe back to the water heater. The Navien unit above is designed for this. Since
DETRoadster is doing a clean-slate design, this is something that he may want to discuss with his planning engineers as an option instead of point-of-use water heaters.....