Do instantaneous water heaters and storage water heaters genuinely save money?

 AZFan77:

I don't know if I want to wait 45 mins for the tub to fill either. We used the soaking tub at the hotel we stayed at over the weekend and it filled in maybe 15-20 mins.

I am not a  professional, but have had a Noritz tankless HWH for 20 years. Minimal maintenance, all DIY. My water is soft; if yours is not, that could be the deciding factor, against.

Inner-Confidence99:

We have a Nortiz as well. I flush mine in the spring, we have hard water. So far no issues and a lot easeier to do thank flushing a tanked system

Huge factor tbh. We’re only 2 and I can’t stand my tankless. Running the water for 45+seconds at the kitchen sink just to get warm water to wash a plate feels rather wasteful, but at least I’m saving the cost of having to keep a tank warm consistently. I shower at the gym 3/4 of the time anyways so I’d imagine a tank would be less efficient, but I’m still irritated by the delay.

As far as the low volume hot water, most residential tankless do require .25 GPM or more to start heating water. It can be an issue, but a small electric under sink heater like the ones offered by Steibel Eltron can help with that, as some models have much lower volume requirements.

I have a soaking tub as well. My old big hot water heater to fill up my tub took over 2 hours. I had to cut water off every 20 minutes because hot water would be out, then wait 30 minutes before running more water. The Tankless fills my tub in 45 minutes. My husband can even get a shower right after and still have hot water no problem. Power bill didn’t jump at all. 

We ended up with a combi boiler tankless. Does domestic hot water and baseboard heat. Our boiler and hot water heater were OLD and not efficient at all. This thing is about 2*3 mounted on the wall to a single 15a 110 circuit. Electric and gas usage are way down. Cost $3200 all in 3 years ago.

I went with a tankless because I wanted hot water that actually lasts longer than 30 minutes. A huge tank wouldn't fit. Now I can take a scalding hot shower as long as I want, and my wife can do the same right after me. I don't care about efficiency, it's not going to be noticeable on your bill. I also airbnb part of my house and they won't run out of hot water either. 5 years in and no problems. It's serviced and cleaned every 2 years.