Tankless water heaters

[Tech Tonics]

Hey all. I've had a tankless water heater in the past. A rinnai, and it was pretty badass.

Our current house has a water heater that was designed for a 1-bath house. It'll handle two showers, but no more. It's location is in a little closet and we are not able to fit a larger tank in it's place. Now we have 2 bathrooms and our water heater is too small. i had to take a cold shower today wtf.

My girls are getting older, and hence, they tend to clean themselves (slightly) more often now. Some mornings there are 3-4 showers in our house.

We have natural gas. Installation should be easy.

Anyone have any advice on any whole-house tankless heaters? I'd like to not spend thousands of dollars on a water heater. ugh.

[MTT]

Hey all. I've had a tankless water heater in the past. A rinnai, and it was pretty badass.

Our current house has a water heater that was designed for a 1-bath house. It'll handle two showers, but no more. It's location is in a little closet and we are not able to fit a larger tank in it's place. Now we have 2 bathrooms and our water heater is too small. i had to take a cold shower today wtf.

My girls are getting older, and hence, they tend to clean themselves (slightly) more often now. Some mornings there are 3-4 showers in our house.

We have natural gas. Installation should be easy.

Anyone have any advice on any whole-house tankless heaters? I'd like to not spend thousands of dollars on a water heater. ugh.

Why not install a second tankless close to the second Bathroom?

I tried the Tankless solution and tore it out, I went with multiple 8.4 electrics, they just could not get it done like my 40 Gal Nat Gas Water heater

[GeezerSteve]

We have a natural gas Navien HPE unit with a recirc loop, came with the new house 1-1/2 years ago. So far, it's great, zero problems.

[MontuckyFried]

From what I've heard, skip the electric ones. The natural gas ones however, can be awesome.

[bagtagley]

Definitely look into recirculation. My old man has a gas Noritz. The unlimited hot water is great, but the wait to get it is not so great. You get used to turning the hot water on and doing something else for a minute or so.

[Nwsno]

They are all fairly pricey. But worth the cost if water volume is your issue.

Mount it on the out side of the house. If the closet is too small. If you can locate on the outside wall of the current closet the plumbing shouldn’t be a big hassle.

[fatnslow]

Do you currently have a gas water heater ? Easy is relative to you skill set and amount if shit involved in the permitting process. If you currently have a gas water heater and do it yourself you should just be able to use the exhaust, gas and water lines in the closet. If you choose to permit it might be a whole different ball game with current location of the water heater.

[iceman]

Pretty decent long thread from 3 years ago: https://www.tetongravity.com/forums/...ghlight=rinnai

[MTT]

From what I've heard, skip the electric ones. The natural gas ones however, can be awesome.

Yea, I don't want to mess up this thread, but cant do it on a budget, it's go big or go home when it comes to Tankless

when My Water heater needs to be replaces I will probably go with the biggest overbuilt Tankless Nay Gas solution out there.

I like the idea of the recirculating system and Radiant water heated floors

[MontuckyFried]

Yea, I don't want to mess up this thread, but cant do it on a budget, it's go big or go home when it comes to Tankless

I've heard that as well. The cheap-o electric unit from your local Home Depot ain't gonna cut it. And THOSE are the ones you hear people being disappointed about.

Something to consider too however, is long term costs. Sure, a good tankless will cost twice as much as a traditional tank, but evidently they last for freaking decades with very little maintenance. Apparently super reliable. A butt ton easier to swap than a tank too. Man, I've had some bad experiences with totally plugged up tanks before. I am DEFINITELY going tankless next time I have to swap one.

[mcski]

I've been thinking about moving to tankless for our Tahoe house. My main reluctance is my scientifically meritless feeling that there will be less continuous heat transfer thru the pipes and thus more likely to freeze. We've never had an issue w frozen pipes so I'm wary of rocking the boat. Talk me out of this nonsense.

[DBdude]

do the cold water pipes freeze?

[Dantheman]

Something to consider too however, is long term costs. Sure, a good tankless will cost twice as much as a traditional tank, but evidently they last for freaking decades with very little maintenance.

When I looked into it ~10 years ago, it was more like a 4-5x premium, maybe that's changed. The traditional tank I went with only costs about $10/month to operate, so it was a looong payback time, if ever. SILs family put a tankless in last year and the dealer told them a water softener was basically mandatory, so factor that into the cost, too. On a cost-of-ownership/energy efficiency basis I'm definitely not convinced they're worth the extra money. If you buy one, buy it because you don't have room for a big enough tank and/or just really want unlimited hot water.

[KJA64]

I have a Takagi tankless for over 10 years now and love it. We switched out when remodeled. You may have to increase the gas pipe in. Secondly mine is really loud , like a jet engine in the garage and I still can hear it from the bedroom. It does take a minute or 2 to get hot depending on the distance. This is also used for radiant heat so we have saved a lot over the years. You won’t run out of hot water which is good and bad my boys have taken way too long showers. I’ve been tempted to turn it off after 10 minutes

[MontuckyFried]

If you buy one, buy it because you don't have room for a big enough tank and/or just really want unlimited hot water.

THAT'S what it's all about right there. The payback could be there (not if you move within a decade), but it's way out there. It's definitely less about economics and more about getting to take the longest showers of your life...even after your teenage daughters have already plundered the bathroom. Totally worth it IMO.

[::: :::]

THAT'S what it's all about right there. The payback could be there (not if you move within a decade), but it's way out there. It's definitely less about economics and more about getting to take the longest showers of your life...even after your teenage daughters have already plundered the bathroom. Totally worth it IMO.

we have a separate tankless unit for the master bath, which is another way to enjoy no breaks in the hot water


we used to turn off the water heater on my kid because he'd get in there and just sing/play for 30mins

we have a navien unit that runs heating water & domestic & a rinnai that covers the master bath

[MontuckyFried]

we have a separate tankless unit for the master bath, which is another way to enjoy no breaks in the hot water


we used to turn off the water heater on my kid because he'd get in there and just sing/play for 30mins

we have a navien unit that runs heating water & domestic & a rinnai that covers the master bath

Hmmm. You just gave me a thought. Maybe OP should get a tiny 10 gallon water heater for the kids to share. Tankless for the master. Win/Win.

[skaredshtles]

Just talk to the kids and tell them max 5 minutes for showers. And teach them how to take a "navy shower."

Wife might balk at this if she's a long-showerer, but use the save-the-planet guilt to pull it off.

Also - ALWAYS make sure you're the 1st one in the shower in the morning. Very important...

This would be the cheap-ass route, if not obvious.

[Rico in Flag]

Something to seriously consider is if the gas piping system in your house will provide adequate volume of natural gas to that bitchen new tankless water heater with endless hot water.
Your old tank water heater was probably burning about 35,000 btu. The fancy new Navien tankless heater are gobbling up 199,000 btu. For conversion, 100 cubic feet of gas equals about 103,700 btu. That Navien tankless is consuming almost 200 cubic feet.
If you see 1/2" metal pipe coming out of the wall at your water heater, be nervous. It may have easily served your old tank heater, but for just 10 feet of pipe, 1/2" only provides 131 cubic feet (and the chart only goes down from there), and so would be insufficient for a tankless. I would hope to see 3/4" pipe at your water heater if you're considering a tankless.
It's worth doing a schematic of your gas system from the meter to all of your gas appliances, to make sure you have the piping to deliver the necessary volume. There are several online schematic helpers to do this.

[MTT]

Not to mention the water pressure and volume feeding the tankless.

[DJSapp]

Something to seriously consider is if the gas piping system in your house will provide adequate volume of natural gas to that bitchen new tankless water heater with endless hot water.
Your old tank water heater was probably burning about 35,000 btu. The fancy new Navien tankless heater are gobbling up 199,000 btu. For conversion, 100 cubic feet of gas equals about 103,700 btu. That Navien tankless is consuming almost 200 cubic feet.
If you see 1/2" metal pipe coming out of the wall at your water heater, be nervous. It may have easily served your old tank heater, but for just 10 feet of pipe, 1/2" only provides 131 cubic feet (and the chart only goes down from there), and so would be insufficient for a tankless. I would hope to see 3/4" pipe at your water heater if you're considering a tankless.
It's worth doing a schematic of your gas system from the meter to all of your gas appliances, to make sure you have the piping to deliver the necessary volume. There are several online schematic helpers to do this.

I came here just to post this. To get enough BTU's for a tankless setup, you're looking at needing a 1.5" gas service. If you already have that at the meter, great. If not, upgrading your entire gas system from the street can get VERY expensive.

edit: and MTT, if you're on a city connection, you shouldn't need an upgrade to water service. 100 psi and you're not upping the flow out of the showerhead, that's just fine.

[Danno]

Pretty decent long thread from 3 years ago: https://www.tetongravity.com/forums/...ghlight=rinnai

Heh, I started that thread over 9 years ago, holy crap!

[old goat]

We have a Navien 200K BTU tankless that does fine on 1 in gas pipe. Easily handles 3 hot water sources at a time--although that is influenced by California's restrictions on faucets and shower head flows. Our LEED certified architect friend feels that from an energy saving standpoint it doesn't make economic sense compared to a modern tank. Recirculation reduces the energy savings more. But for unlimited hot water it's great. The warmup time is not an issue close to the tank but a lot of our house is pretty far from the unit, especially the kitchen, so the wait for hot water would be bad even if we had a tank. We usually can find something to do with the cold water while we wait for the hot. One solution for distant faucets is a point of service heater. We may yet do that in the kitchen.

[skaredshtles]

Cheap route lookin' a lot better, ain't it?

[mcski]

We have a Navien 200K BTU tankless that does fine on 1 in gas pipe. Easily handles 3 hot water sources at a time--although that is influenced by California's restrictions on faucets and shower head flows. Our LEED certified architect friend feels that from an energy saving standpoint it doesn't make economic sense compared to a modern tank. Recirculation reduces the energy savings more. But for unlimited hot water it's great. The warmup time is not an issue close to the tank but a lot of our house is pretty far from the unit, especially the kitchen, so the wait for hot water would be bad even if we had a tank. We usually can find something to do with the cold water while we wait for the hot. One solution for distant faucets is a point of service heater. We may yet do that in the kitchen.

I can't recall when you retired, but what about when you were part time at the house in Donner...? Wouldn't tankless be more economical in that situation since your not heating water when you're not there? Or still not worth it once you factor in cost of tankless system?