Unless you have a direct vent with no electronics.

Yes! The other benefit the parents experienced was much, much longer life out of the dehumidifier they had to run nonstop and empty twice a day. Now the heat pump h20 heater takes the majority of the moisture out of the basement. BUT- as mentioned, it does have a cooling effect on the area its placed in.

Interesting discussion.

I had not thought that in some homes you can “tweak” the HVAC somewhat.

Upper floors of a home tend to be warmer.
In some instances a heat pump water heater should be upstairs?
( maybe in an attic? )

When I had an all electric on demand hot water heater around year 2000 I had to let a pencil sized stream of hot water flow in the sink to take a shower without wild fluctuation in shower temperatures.

When I was in England (in the USAF), one house we were in had a system with a small (probably 10 gallon) tank-type hot water heater for the sinks and washer, and a wall mounted on-demand unit next to the tub for it and the shower. This unit was about 12"w x 18"h x 4"d. and had an on-off switch and a temperature dial. When you flipped the switch you got almost instant water at the temperature dialed in, forever. I've seen similar point-of-use heaters on Amazon, but as stated in other replies, they only advertise a temperature rise above inlet. With England's temperate climate, inlet temps didn't vary enough to really matter. With utility costs in Europe, it seemed to be an economical way to get the best of both worlds.

We have a Takagi Jr heating our shop floor at the farm for at least 12 years and never had an issue with it. Building is 60x80 and once concrete is warm it hardly runs. I am pretty sure someone bought Takagi.
I am single and got tired of the hot water heater rotting out and put in an A.O. Smith on demand with propane. That was about 5 years ago and never had any issues with it. Even had a hot water tank go bad under warranty and the installer would have had to order one and I would have had to pay shipping. That was about as high as just getting a new one.

They bought one at work. It sucks. The water gets pretty warm. But it never gets so hot you can not hold your hand in it non stop
That was set at max. It would never be good for washing dishes. A quick shower maybe. But not for dishes

I've replaced several tank style water heaters over the years just being the family handyman. Moms house, brother's house, in law's, neighbors, and a few of my own. I've had 2 houses of my own over the years about 30 miles from my relatives and my current one is 6 miles from my 1st. When Ive put them in up north for my relatives (again only 30 miles from my place) they last way beyond the warranty rather easily. .
Here I haven't had one last thru the warranty yet. I buy the 12 year ones. Once I got a 9 year ("middle of the road" quality) and it didn't make it to the end of the warranty either. At least the replacements have been free.
In both of my houses I came in to find a 30 gallon tank and upgraded to 40 gallon models. All nat gas models. And un both of my houses the units I removed were removed just because they "looked old" weren't leaking yet. I'm sure the one I p put in this house in 98 replaced the original which was from 1967. And I'm on my 3rd water heater. The last one that went lasted about 7-1/2 years.
. When that one went, I took my replacement credit (which was alot more than I'd paid for the 1st one I'd put in, that 2nd one was also a free replacement for the 1st one I bought) and put it towards an AO Smith wall mount tankless, since they were on a good sale so I didn't have to add much to make up the difference in price between the current value of a 40 gallon tank and the tankless.
My biggest reason for the tankless is that where the water heater was located it is directly in front of the furnace, with not a whole lotta room in between in order to reach the furnace when it needs maintenance. I've had to remove the tank type water heater a couple of times over the years to access the furnace, then Reinstall it. With the tankless off of the ground I have a lot more room to get at the furnace. So far I like the tankless. It's been in place about 2-1/2 years so far and has a 15 year warranty.
Hopefully now that we have "city" water that will make a difference in helping this one to last. Though we had the same source of city water at my old house too.we had well water when I moved here.

I have had one of these https://www.ecosmartus.com/ for about 8-9 years now. It is the 18,000 BTU mdl. 1200 sq ft house , 2 baths. It replaced a 40 gal electric heater. We have lime deposits in our water. I installed 2 sediment filters the the inlet side of the hot water heater and a filter on the outlet side to catch the lime scale deposits. I change the filters every 12-18 months. if you want to be able to use hot water at multiple locations at the same time. I would get the bigger unit 24,000 I think. But this works well for just the wife and myself. As stated it is nice to have unlimited hot water. The is no doubt in my mind that it paid for itself in 3-4 years. My electric bill went down considerably.