Experience with tankless LP water heater

[Mike Cutler]

Eduard
Not trying to talk you out of it, because I think the tankless water heaters are very cool, but an 80,000 BTU, 48 gallon, LP, storage tank water heater will fit in the same space. It is a much easier install. It's also about 6 times more powerful than your current water heater.
The plumbing, water and gas, for the tankless water heaters is more difficult than a storage tank water heater. If you already have LP to the house, it is very doable to install an LP storage tank water heater. Not as cool as a tankless water heater, but capable of putting out a lot of hot water.
The smallest LP water heater is 3 times more powerful than an electric water heater. While not "unlimited", the recovery of LP water heater is much quicker than an electric heater.

[Malcolm Schweizer]

Eduard
Not trying to talk you out of it, because I think the tankless water heaters are very cool, but an 80,000 BTU, 48 gallon, LP, storage tank water heater will fit in the same space. It is a much easier install. It's also about 6 times more powerful than your current water heater.
The plumbing, water and gas, for the tankless water heaters is more difficult than a storage tank water heater. If you already have LP to the house, it is very doable to install an LP storage tank water heater. Not as cool as a tankless water heater, but capable of putting out a lot of hot water.
The smallest LP water heater is 3 times more powerful than an electric water heater. While not "unlimited", the recovery of LP water heater is much quicker than an electric heater.

I do not want to sound argumentative, but how is the plumbing harder? I installed my tankless myself. The only difference is the clean out valves, which isn’t that much of a big deal, and there is no drip pan to install, and since I got the outdoor model, no flue to install either.

[Patrick Walsh]

Oddly it has been my experience that not one single plumber had anything good to say about on demand hot water.

Maybe they know something I don’t know yet and I’ll give them that. But so far so good for me. Four years and never once flushed and I just had it serviced and was told it looked brand new.

I used to go through whatever tank joe the plumber would throw in like every ten years.

[Lee Schierer]

It depends on how hot you want the water and what flow you need. With 40 degree water coming in, a typical tankless heater with a 165,000 Btu burner can raise the water temperature to 110 degrees and deliver 3.8 gallons per minute of this heated water indefinitely. If you need more flow the temperature will be less than 110.

[Mike Cutler]

I do not want to sound argumentative, but how is the plumbing harder? I installed my tankless myself. The only difference is the clean out valves, which isn’t that much of a big deal, and there is no drip pan to install, and since I got the outdoor model, no flue to install either.

Malcolm
It's not difficult, just more involved. At least here in Connecticut.
The larger units are going to run 200,000BTU's. They will require a 3/4", or 1", LP line to them alone. If you're already running LP to the house, you may need to add a second regulator, or a branch off a higher capacity regulator.
The water side of the plumbing for the LP storage heater is exactly the same as electric. It will probably fit right into the same space.With a tankless there are a few more parts.
Don't know how it is now, but when I looked at installing a tankless system, the vent piping was double walled stainless. The vent for my LP water heater is 4" PVC. The vent piping for me, for a tankless, was going to be close to $400.00 by itself.
All told it was going to cost me $3300 if I had it installed., not including the electrical work, or modifications to the LP supply piping external to the house. About $1600.00-$2000.00 if I did it myself ,not including any changes required for the LP supply lines, and a new reguator.
I really, really, wanted to go tankless in a bad way.To me it's the future of hot water heating. In the end though, a$1000.00 for a 80,000BTU, Bradford White, TTWII delivered to the door, some PVC vent piping and I was done. At most, I lost water to the house for an hour.

[Jim Becker]

Looks like a only good experience so far. Thank you everyone for your time and information.
Another question - if I will install by myself and only gas line by professional - would I be covered with warranty or everything needs to be done by professional installer?
House, I want to install this unit, located middle of nowhere, with closest Rinnai certified installer about 200 miles away.
Ed.

You can install them yourself...I've installed a several. Be sure you get the proper valve setup so that the periodic maintenance already mentioned is easier to do. Installation is very straight forward relative to the plumbing. You do need to take care with your venting as that's the "dangerous" side of any gas appliance other than the actual gas line. You need the correct size, the correct slope and the outlets outside configured properly to insure that exhaust gasses go where they need to go and clean intake are gets to where it needs to be.

-----

Mike, current condensing on-demand (tankless) water heaters use SCH-40 PVC for venting...it's been that way for a decade or so. Unless the runs are long, most also use 3" which is easier to get where it needs to go, too.

[Eduard Nemirovsky]

Oddly it has been my experience that not one single plumber had anything good to say about on demand hot water.

Maybe they know something I don’t know yet and I’ll give them that. But so far so good for me. Four years and never once flushed and I just had it serviced and was told it looked brand new.

I used to go through whatever tank joe the plumber would throw in like every ten years.

This is a main reason of my question. Contractor, who build our house, tell me not to install tankless system - a lot of problem, difficult maintenance and so on. Conversation happened a few years back and I stop thinking about tankless heater. Now I come back to idea of installing it and start investigation again.
Here, at USA, appliances less advanced or a new coming with some delay. I don't know reason - different standard or matter of habit? Gas tankless water heaters in Russia working for 30-50 years. Same in Europe - Germany, France and other countries. Same for refrigerators, ranges, washer/dryers.
Last time in Japan, when we went to appliancy store, I was shock by advances in technology for kitchen. And I am not talking about differences in toilet , just look this video .

Ed.

[mike stenson]

We had a commercial type tankless install at our last house (for a bit over a decade). Every year I had to flush it, that was the end of maintenance and never had any trouble I will point out that it'll take longer for hot water to get from a tankless heater to the tap. Other than that, it was wonderful always having as much water as needed. That was the biggest downside. Our new house has tank heaters (2, one is a lift heater for the main), and I miss the tankless. When these go, I'll probably go with a hybrid system, that allows for some conduction heating, and reduces the hot water at the tap downside a bit I've heard.

edit: The install was more complicated. We had to run new gas line to cover the gas usage (but the original line wasn't big enough anyway, so would have had to with a replacement tank to be honest), and we mounted it on the roof, so that added some complexity, but it bought a lot of usable floor space for nothing

[Mike Henderson]

Oddly it has been my experience that not one single plumber had anything good to say about on demand hot water.

Maybe they know something I don’t know yet and I’ll give them that. But so far so good for me. Four years and never once flushed and I just had it serviced and was told it looked brand new.

I used to go through whatever tank joe the plumber would throw in like every ten years.

I think the reason plumbers don't recommend tankless is that they're more complex than tank type water heaters and the plumbers don't know what to do if they give problems. They're familiar with tank type water heaters and know how to work on them.

I had an issue with one of my tankless water heaters and called a plumber. The guy was completely lost - he didn't have a clue about how to approach the problem. Later I called Rheem and they told me what the problem was. The plumber could have done that on his cell phone while he was standing in front of the unit. But he just shrugged his shoulders and told me he couldn't help me.

Mike

[Steve Demuth]

Eduard
Not trying to talk you out of it, because I think the tankless water heaters are very cool, but an 80,000 BTU, 48 gallon, LP, storage tank water heater will fit in the same space. It is a much easier install. It's also about 6 times more powerful than your current water heater.

Why are they harder to install? You have cold water in, cold water out, gas in, combustion air in, and vent, same as for any gas appliance. If it's a condensing unit, you have a condensate drain. It took me about 3 hours to hang and install the one I recently put in our guest house, in a utility room where the water and gas were already reasonably close. Everything standard plumbing.

Of course, they are much more complex appliances than a tank type heater. There is a lot packed into a little box, including very sophisticated electronics and sensors. More like a modern, condensing LP furnace than a water heater.

[Steve Demuth]

Maybe they know something I don’t know yet and I’ll give them that. But so far so good for me. Four years and never once flushed and I just had it serviced and was told it looked brand new.

I used to go through whatever tank joe the plumber would throw in like every ten years.

I've never descaled the one I've had in our main house for the last 15 years. We soften the water ahead of the water heater, because our water is so hard that it will scale up a heat exchanger in a matter of months. I used to have to descale the exchanger on our solar heater every 6 months or so, until we started putting only softened water through that too.

[Malcolm Schweizer]

Malcolm
It's not difficult, just more involved. At least here in Connecticut.
The larger units are going to run 200,000BTU's. They will require a 3/4", or 1", LP line to them alone. If you're already running LP to the house, you may need to add a second regulator, or a branch off a higher capacity regulator.
The water side of the plumbing for the LP storage heater is exactly the same as electric. It will probably fit right into the same space.With a tankless there are a few more parts.
Don't know how it is now, but when I looked at installing a tankless system, the vent piping was double walled stainless. The vent for my LP water heater is 4" PVC. The vent piping for me, for a tankless, was going to be close to $400.00 by itself.
All told it was going to cost me $3300 if I had it installed., not including the electrical work, or modifications to the LP supply piping external to the house. About $1600.00-$2000.00 if I did it myself ,not including any changes required for the LP supply lines, and a new reguator.
I really, really, wanted to go tankless in a bad way.To me it's the future of hot water heating. In the end though, a$1000.00 for a 80,000BTU, Bradford White, TTWII delivered to the door, some PVC vent piping and I was done. At most, I lost water to the house for an hour.

I did not know you could use pvc to vent a gas water heater. It seems it would melt. I learned something new. (No sarcasm intended there.) True that indoor installation of a tankless requires a more expensive flue. I went outdoor so it was not an issue.

In regards to the comment from someone else about the outlet temperature, they are limited at 120F, but you can get a device to up that to 140. It is a safety feature. 120 is supposed to be the safe temperature for hot water to be plenty hot but not burn. I’m not sure, however, in cold climates where the inlet temp is a lot cooler if they can get to that 120F. That might be a consideration. I was planning to install a 140 thermostat, but I find it’s not nescessary.

[Steve Demuth]

I did not know you could use pvc to vent a gas water heater. It seems it would melt. I learned something new. (No sarcasm intended there.) True that indoor installation of a tankless requires a more expensive flue. I went outdoor so it was not an issue.

In regards to the comment from someone else about the outlet temperature, they are limited at 120F, but you can get a device to up that to 140. It is a safety feature. 120 is supposed to be the safe temperature for hot water to be plenty hot but not burn. I’m not sure, however, in cold climates where the inlet temp is a lot cooler if they can get to that 120F. That might be a consideration. I was planning to install a 140 thermostat, but I find it’s not nescessary.

Some newer models are fully condensing, just like a super high efficiency furnace. The exhaust gases are warm, but not anything you'd call hot. My old one exhausts through double-wall stainless. My newer one through Sch 40 PVC. Both are indoor - can't put anything with water in it outdoors in a place that sees -30F in winter, because they'd have to run constantly just to keep from freezing. One thing I like about them is that they will heat themselves to protect their heat exchangers if they get too cold - a real possibility when you have a subzero wind whistling down the exhaust stack and the water heater in a cold cellar.

Both my Takagis have remote temp controllers. You can select outlet temps from wherever you care to mount the controller, anywhere between 100F and 140F. You have to take extra "are you sure" steps to set above 120F.

[Mike Cutler]

Malcolm

It kind of surprised me that 4" PVC could be the vent pipe for my water heater, but then the blower on top is in a plastic case. The instructions clearly defined the 4" PVC. Which was good , because my direct vent water heater from the late 70's was no longer code compliant, so I has to install a new vent pipe.
Home products change so fast now. There is some really nice stuff out there.

[Jim Becker]

One other suggestion for these newer systems that have electronics (tankless heaters for sure, but other items, too, including mini-splits, etc.)...put a surge suppressor on the power outlet for the unit. A new "brain" can cost nearly 2/3 of the cost of a new water heater. Twenty bucks now is totally worth it. I did have a unit get fried, but fortunately, it was near to the expected end-of-life for the system anyway.