That's what I found, the heat exchanger would clog up. I used a sump pump in a bucket with CLR in it to clean it up, but I found I was doing that every two months. With the softener in line, I've never had to do it again.

At my house, you can see the deposits on every tap and shower head, so it's pretty clear what the problem was.

Your water company probably publishes what's in the water. As I recall, all of NY has good water.

My Rinnai was $800 with the $300 tax rebate, including the coax stainless duct.

What I love about the Rinnai is that it never shuts off. You can take a 4 hour hot shower if you want. The Sakura would turn off every 20 minutes, so I'd have to shut off the shower to restart it.

I find that 125 degrees is minimum for me. When it's cold out I'd crank it up to 130.