I was curious what the reason was for not wanting a tankless natural gas unit. 50 gallons is a lot of water to keep hot and ready. but then again in this day in age the prices of natural gas is up there. I don't blame you for not wanting something that would use a LOT of gas if you have several folks using water for showers and what not.
I spent most of the time it was down trying to figure out doing a tankless.
Problems:
The insanely hard water here (worst in country) means the maintenance flushes have to occur out here every 3 months as opposed to 12 months most everywhere else.
The tank units can be 40,000 or 50,000 btu burner. I use the 50,000 for faster recovery.
The tankless is 200,000 btu. I have 3/4” line there and they say that is minimum and might not be enough- it is better to have 1” line from the meter. That is major construction because meter is opposite side of the hose from the water heater. Then with all the other gas stuff we run here, I would need to pay for a larger meter install from the gas company even if the 3/4” line is enough. So that adds cost and time.
Then with the increase in btu, more air supply and different exhaust is required. Punching the exhaust directly out the wall is not an option, so going out the roof vent past the stairs, through the wall and out the roof is major construction. And according to a few of the manufacturers I read, there is an exhaust fan required to do that method. So now the construction costs and materials costs are even higher.
The tankless water heater itself is a lot more expensive.
The yearly maintenance if a person can do that- is way more involved than simple flush of a tank.
With our hard water, even servicing every 3 months- about 85% lifespan tankless vs tank. Nicest water out there and they say tankless outlast tank by 10-15% on average.
Tankless advantages:
Then the water heater itself is a lot more expensive. IF A PERSON doesn’t have these particular construction restraints- absolutely it is worth it.
Something we looked into is rebate and tax stuff. The water heater we bought was $689. The comparable tankless units was $2,019 and there were a few exactly at that price. However for the ones we were looking at that are top efficiency, there is a $225 rebate from our local gas company, and there was a 30% tax rebate. Not deduction but rebate, so 2019- 30%= 1,413.30 then the 225 off is $1188.30. Sales tax is more of course, so call it $600 more for just the tankless purchase.
For many people, an expansion tank is also required on tank water heaters now since municipalities are adding back flow preventers. So the cost of that should be factored in along with earthquake straps it not already there. So those add on about $50 each.
If a person does all the maintenance and cleaning themselves- then those added economic costs aren’t a concern. But if someone can’t diy- you can eat up more money.
So how much money does the tankless save in order to start working down that cost of investment. From everything I read, it would eliminate approximately 30-35% of the gas usage. My monthly average is $45. So I would save $15 a month, maybe $20. I’ve no idea on natural gas prices elsewhere. But to me, saving $240 per year my break even is 2.5 years not counting interest. So yes, absolutely worth it is boat loads of construction isn’t required.
I seriously thought about rerouting plumbing and giving up part of the back of the garage to allow exterior ventilation. One of those- if I had planned all this out and done the prep work ahead of time- would have done that. So my suggestion is you guys seriously should plan out swapping to tankless- get prep work done as a side project along the way if needed so when your current tank water heater pops- you can switch.
Btw if you have electric- you have to run new, much larger wire for it and the panel feeding it has to be able to withstand the added load.
