Saltidog, Dude, chill. I was respectfully saying you had a different opinion - not what your opinion was or that it had anything to do with the heating elements. You can disagree without being disagreeable. I do understand thermodynamics very well, thank you. There is no "trend" and no misrepresentation. Yes, the units have resistive elements as backup, for high demand situations, and when the ambient temperature gets low enough that enough heat can't be extracted using the heat pump (for geospring unit that's 45 degrees F) Saltidog, I don't know what you are getting your panties in a bunch about... yes, I understand your heater works well for you. I would expect that. It's installed in a basement that's at least 700 cubic feet of space. Because it's underground it will maintain a temperature of around 50 - 55 degrees or more if there are other heat sources in the basement. That's enough to allow the heat pump to work just fine. The water heater will work in almost all situations / applications where one would normally install a tank heater. It will even run on the heat pump in most situations. The question is when you have the water heater in a fully conditioned space (not basement) and that space is being heated. At that time, one is shifting the heating load of the water heater to the furnace - which may or may not be more cost effective. I think the water heaters are great - esp if they can work out the reliability problems (which I think are teething pains, not inherent problems). I stick by my assertion that there are three applications whereby they produce the most system efficiency / cost effectiveness.

This is the review I wrote on the building forum. Feel free to ask any questionns: My Rinnai gas tankless water heater has a built in recirculation feature. My furthest bathroom is 50' from the tankless. The shower is hot within 8secs of turning it on. My recirculation pump is on a timer and is programmed based on my family behavior. I was really concerned after reading so many of the reviews online about tankless water heaters topics like temp sandwich and not being able to use multiple showers and appliances at the same time. I have low flow shower heads in my bathrooms from Grohe and Hansgrohe. Two of my bathrooms have thermostatic valves. The third has a very old pressure balance valve that will be replaced soon. The shower heads are rated at 2.5gpm. They perform really well. The tankless also has a feature to fill a bathtub,. I have used this once and the tankless worked like a champ and filled a 50gal tub in 9 mins. I have city water and will perform my first flush of the system in May. I was also afraid of the temperature drops as it got colder. We had a week of sub zero temps and I noticed no impact on the water heater. We can take two showers concurrently, run the dishwasher, washer and a faucet at the same time. My home has a crawl space and most of my plumbing runs through the crawl. The tankless unit is hanging on the wall in the utilities room. Just wanted to post another experience in tankless. One of the main drivers for going with tankless in my case was that I needed the space. The tank heater blocked access into the utility room and a wall needed to be taken down to remove the heater. I have a Rinnai RUR98i.

Thanks, this is all really helpful. Unfortunately AC isn't really a major concern with the home, as it's in the mountains and stays quite cool in the summer. Heating is obviously my bigger cost. The one question I have about cooling and the room being unconditioned is, doesn't there have to be some heat since this is where my plumbing begins? The basement is only around 3.5 feet underground and has windows so I imagine it will get cold in the winter. I am installing a mini split system in the whole home and was going to put one head in the basement, mainly to keep an ok temp throughout the winter. Is there any risk that the heat pump water heater could make the basement too cold for the plumbing? Or too difficult for the heater to keep the basement above 50? I just bought the home and it was a foreclosure and the pressure tank and some pipes are cracked from freezing. So I'm trying to come up with a setup here to A) keep utility costs down and B) prevent the plumbing from freezing again. All your insights are so helpful!

200k btu (199k). Always. There's no compelling reason not to - and the higher btu will give you plenty of headroom when there are multiple demands at the same time - particularly filling a tub in the winter. So that you know, tankless will modulate the burner down to the appropriate level for given inlet temp and water flow. If you exceed the ability of the heater to provide hot water it will reduce the flow of water so it can maintain outlet temp. Pay attention to minimum flow rates to activate and to keep running. Rheem has always been very good on the min flow rates, but check the brand you are considering.