Tankless Water Heaters?

[murchmb]

My wife and I are in the process of doing a major addition/renovation to our house. One of the things that will be replaced is the water heater. We have a smallish electric model now and planned on installing a larger gas water heater as part of our project. Our local gas company suggested considering a tankless model that they sell that would be eligible for a significant rebate. It's made by Rinnai.

Does anyone have experience with tankless gas water heaters? They look great on paper, but I'm wondering what the real world pros and cons are. Price to operate, efficiency, maintenance issues, etc. I know that they are prone to scaling problems with hard water and could require occasional service to clean out the deposits. Past that, I'm pretty ignorant of the subject.

 

[Bertilak]

I have one of these, a Rinnai LP gas model, and it works like a champ. Natural gas might even be better.

Be sure to get a model that can handle the capacity you need. They do come in different capacities. I know someone who installed an under-capacity electric model and was not happy. In my case I can have the clothes washer, the dish washer, and the shower running at the same time. As things turn on and off the temperature in the shower does change a little but there is always enough hot water available.

There are options for fancier and extra control panels. We didn't bother with that and don't miss it/them.

They should also be on their own gas feed, splitting off just after the pressure reduction valve coming in from the main line. At least that's how the LP connection works. Not sure if natural gas is different but your gas company should know. Mine was happy to come out after the contractor installed things and inspect it.

 

[The Nid Hog]

I've had one in my home and I've also lived in an apartment complex that had an in-line heater. In both cases, I was always satisfied with the results.

 

[miket]

We have a Rennai natural gas model that supplies two bathrooms. We love it. You never have to worry about running out of hot water in the shower. We have a separate electric water heater for the kitchen and washer because we also have a geothermal cooling/heating system that helps heat the water for that tank. We had a different brand of instant water heater in a previous home and had good results with it as well. IMHO its the only way to go.

 

[Dharion]

I've got an eletric water heater but a a gas water heater is more (cost) effective and I gladly would switch if I could. I live in a rented apartment. It takes a few seconds before the heater has got the temperature right were I want it but that is not an obstacle even if straight razor shaving (rinsing under running water).

 

[sapito318]

I've heard good things about em. They are a real energy saver too. If I was renovating my house, I would certainly install one.

 

[S. Holmes]

We have a Bosch that we purchased at Lowe's. It is great, we are very happy with it. We also have a water softener. If you have hard water consider adding a softener. It will give you better lather also

 

[sapito318]

we have a bosch that we purchased at lowe's. It is great, we are very happy with it. We also have a water softener. If you have hard water consider adding a softener. It will give you better lather also

+1

 

[Mejnoon]

I've had a Rinnai for over 3 years and I'm very pleased with it. Its the only way to go IMO.

 

[SepticTank]

Had gas-fired "on demand" water heater here for the last 15 years - way better than heating a tank, and way cheaper (here at least) than electric. Can adjust the water temp from 40C to 90C (almost good enough to make tea without a kettle ) - only bummer is that if the electric goes off then the hot water does too (all the electric trickery required for the on demand part) - solved by the 4kW generator though since it requires less than 100W for the electric part

 

[rAZor]

You might want to check out this article from Consumer Reports. As a result, I recently replaced mine with another tank model. Hope this helps.

 

[burnwood]

Interesting posts. We are thinking of going this route also.

 

[Bertilak]

You might want to check out this article from Consumer Reports. As a result, I recently replaced mine with another tank model. Hope this helps.

I read through that and think most of it is unhelpful.

I agree that replacing an existing water heater just to save money is probably a waste but for new construction, or if your old heater has just gone belly up, you need to spend *something* and the extra cost over a tank heater provides benefits other than money savings. But don't forget the tax rebate.

The comment that there is cold water in the pipes is bogus as this is the same for tank heaters. The selling point of the tankless heaters is that you don't run out of hot water and the typical units installed deliver on that. The "instant" part is that the heater will *always* provide you with hot water *whenever* you want it. You will never need to wait for it to re-heat a depleted tank after someone's long shower. The supply is continuous and not limited by anything except perhaps running out of gas!

About taking time to heat the water -- the temperature ratings are for a continuous flow so the time to heat the water is not a meaningful concept. There is some start-up involved for the unit to recognize that water has started to flow and that the output is not up to temperature but that is a matter of a few seconds (one or two? I never tried to measure it, a pointless task.) and is easily dwarfed by the amount of time it takes to flush the unheated water already in the lines. It does take some time for the pipes themselves to heat up and therefore stop cooling the water, but again, this is also true of tank heaters.

On scale build-up. Well, it happens to tank heaters as well and may even be their biggest cause of failure. You really want a water softener no matter which way you go.

One other big fault of the review -- Rinnai is by far the most popular model, at least in the USA, and they (a USA organization!) didn't even test it. Kind of like reviewing popular cars and leaving out Toyota.

BEGIN CONSUMER REPORTS RANT

A long time ago I lost faith in Consumer Reports when I saw that they ranked lawn mowers based on their pet hot button at the time -- automatic shut-off handles. They completely rejected many mowers that didn't have them so their resulting review was worthless for anyone who wanted to learn about actual performance, reliability, ease of starting, etc.

Another example of poor reviewing by Consumer Reports was their review (again, a long time ago) of hi-fidelity stereo equipment. In their judgment they all sounded about the same so their rankings were based on other things that I now forget.

 

[nikkuchan]

Gas water heaters are widely used here in Japan. I enjoy it because I can never run out of hot water (and no matter how much I use my gas bill barely changes). Also, a gas heating system takes up A LOT less space than a tank.

 

[SRock]

Gas water heaters are widely used here in Japan. I enjoy it because I can never run out of hot water (and no matter how much I use my gas bill barely changes). Also, a gas heating system takes up A LOT less space than a tank.

+1 both homes I've lived in here in Japan had tankless heaters. Ours is adjustable for temp via a control panel. For example we may use slightly less hot water for showering or hotter water for laundry dishes etc. It gives us a ton of flexibility, it is instant, and it does not run out.

 

[Bertilak]

Also, a gas heating system takes up A LOT less space than a tank.

An absolutely excellent point I forgot to mention (and never mentioned by Consumer Reports). This is a huge advantage as it takes up notfloor space, no attic space, no garage space -- no space at all. Mine is installed within the thickness of the outside wall of my house.

 

[Phog Allen]

We are seriously considering one of these as well. Our tank heater is getting long in the tooth and since about 2000, gas fired tank heaters in the States have gone up a BUNCH. This is mainly due to safey equipment mandates by the gub'ment. They have a blast shield and firetrap type of plate on the bottom and a way to limit oxygen feed in case of fire or gas leak. I am not one hundred percent sure of the exact devices on them but the testing procedures added major costs. So a tank heater that was say, $289 ten years ago may be closer to $489 now. This makes the tankless models much more attractive. I am also intrigued by the tax break thing. Can someone elaborate?

Regards, Todd

 

[Bertilak]

I am also intrigued by the tax break thing. Can someone elaborate?

Ask the gas company -- they took care of the whole thing for me -- filled out and submitted the paperwork. I forget how much it was, but on the order of several hundred bucks.

 

[murchmb]

Thanks for the comments. I think we are going to go for the Rinnai. I too take the CR article with a grain of salt.

We have a closet going in on our addition dedicated for a water heater and going tankless will free up some more space for vacuums, cleaning supplies, etc. After reading through the users manual, it seems a pretty straightforward process to flush the unit out with vinegar yearly. I just have to make sure the plumber configures the valves and bypass properly and that the gas guy uses the proper sized pipe so the unit gets enough gas pressure.

 

[Bertilak]

Thanks for the comments. I think we are going to go for the Rinnai. I too take the CR article with a grain of salt.

We have a closet going in on our addition dedicated for a water heater and going tankless will free up some more space for vacuums, cleaning supplies, etc. After reading through the users manual, it seems a pretty straightforward process to flush the unit out with vinegar yearly. I just have to make sure the plumber configures the valves and bypass properly and that the gas guy uses the proper sized pipe so the unit gets enough gas pressure.

How many square feet of space does the closet have? Typical new construction now-a-days is $200 per square foot or more. So if your closet is 3 feet by 4 feet that's 12 square feet or at least $2400. Hope that helps you feel better about spending the big bucks!

(And get the gas company to inspect it to be sure the points in your last sentence are addressed!)