We're looking at replacing our existing 40 gallon water heater to a slightly bigger one. Our current heater works just fine but since we've remodeled our master bathroom and added a Jacuzzi Whirlpool tub, it takes all of the hot water so we're looking at maybe a 75 gallon water heater.

I've heard a lot of good things about the tankless water heaters and I was wondering if anyone here has one and would like to hear your opinions on them. Can I install it myself or does it require a pro to install it? Or should I just go with a bigger tank model?

We are stuck with using heating oil which costs an arm and a leg out here so we have gone to the TOYO tankless model and it not only works great it saves us a ton of money over a boiler or traditional holding tank system that you are looking at replacing. There are some gas models that are worth looking at as well, I am guessing you have gas down there and that would be cheaper than the TOYO oil system.

Down side: Toyo systems are spendy up front bet the saving adds up fast and they are simple.

Walt

IMHO, having had tank-type, electric tankless, and now gas tankless, I can wholeheartedly endorse gas tankless as the ONLY way to go.

We cut our electric bill by over 40% just switching over, they are very efficient, and we have endless hot water.

They are not difficult to install, but get a good one! We have both Rinnai and Rheem units on our home and rental properties. The others, including the Bosch units are not rated as well as the Rinnai and Rheem units.

Ed

Our house has two propane tankless heaters, Rinnai R85's, and we are pleased with them. No issues and quick hot water when needed. Note that our house was built with them as original installations. I believe that the gas flow rate for the tankless geaters is higher than that of a similarly "sized" conventional one so I suggest you confirm your exising gas line is adequate for the required flow. Ours each have key pads that allow temp setting and diagnostics. I have no clue as to how difficult they are to install.

Yeah, the Jacuzzi requires an 80 gal. tank.. We had to install that when we remodeled and added our Jacuzzi..

IMVHO, tankless is great for bathroom basins, kitchen sinks etc., but it will not work for filling a bathtub - and certainly not a Jacuzzi..

Maybe the newest ones and/or additional offerings re: sizes can actually do it.. Oh, and if you do it, GAS is the way to go. The electrics just can't keep up (from those around here who have 'em)..

I've had one Rinaii in rent house a couple years ago. I was real unimpressed with it, as in the master bath, you turn on the hot water and then wait a few minutes before you eventually get hot water.

My new house came with a Rinaii, to my surprise (and objection). I think because it's new it may work a little better. It maxes out at 120 degrees, which is something else I don't like.

An upside is, if you have several people in the house, or a lot of hot water usage, then you don't run out of hot water.

They do require occasional cleaning/maintenance, otherwise the heat exchanger can get plugged, which reduces its efficiency.

I've sold and installed Rinnai units and recommend them, but I suggest you take a hard look at he Eternal brand tankless. They have a lot of great features including an all stainless heat exchanger/tank.

I know a guy that installed a gas tankless heater from a car wash supply house. It's an industrial/commercially rated unit designed to operate 365/24/7 that supplies his needs and cost half as much as the popular residential units.

Denny.

Good info so far guys, appreciate it!

Our current setup uses natural gas and we are sticking with that and i'd like to install it myself if it's not that diffcult. It would be in our crawl space where our current tank heater is installed.

Redneck, why won't the tankless work for filling the Jacuzzi tub?

a big 'ol +1, as he hit it right on the head...

Redneck,

The newer models have no problem filling a large tank with hot water, much less a bathtub. We have done this on several occasions.

Tex_n_cal, we have the types mounted on an outside wall and plumbed into the house instead of having the unit indoors.

They DO require a 3/4" gas line instead of a smaller line, and the temperature CAN be raised beyond 120F. There is a sequence of operation to allow this, but the water heater MUST NOT be operating to do it, and you can go to at least 140F with them. They are set with a default 120F to prevent scalding.

The smaller units come with thermocouples preset to certain temps and you just install the one that you want, the larger units can be changed via the keypad.

Ed

How far from the bathroom was the heater? If not right in the bathroom, it takes time for the hot water to get through the pipes.

We just replaced our 1975 boiler and 1995 water heater (both gas) with a new high-efficiency boiler and side-arm water heater. The water heater is only a 40-gal unit, but it gives us more hot water at the tap than the old 50-gal stand alone unit did.

The tank temperature on the new water heater is held at 160 degrees and the outgoing water goes through a mixing valve that drops it to our desired setting. This makes the tank of hot water go a lot further than its 40-gallon capacity suggests. We can also add a programable thermostat to the water heater, to further reduce our gas consumption by letting the water tank cool down during periods of low demand. We haven't done that yet, though.

We're really happy with the new setup, and we've noticed that we no longer have to adjust the water temp while taking a shower. The shower temp stays pretty constant now, and we don't run out of hot water while the showers and washing machine (or dishwasher) are running at the same time.

We debated about putting in an on-demand water heater, but we got too many mixed reviews from people that had them. Of the folks we talked to, some loved them and others hated them. Everyone that had a side-arm water heater/boiler setup raved about it, though, so we went that route.

Water is expensive to heat. Usually it's the most expensive energy use in the house. Why would you heat it hotter than you need just so you can cool it down to use it? I think you'd save money by not heating it any hotter than your max use, like 120 to 130.

This is just a guess but it sounds to me like they do this to make more hot water.

Another vote for the Eternal hybrid gas unit. It has a small (two-gallon) tank that it keeps hot; that eliminates any "lag" when you turn on the tap. By the time that's gone, the unit can keep up. We have ours set at 130� and for a hot shower, the mix valve in the shower is right in the middle. We bought the unit sized for a family of four, with a thought to eventual sale of the house. We can run two showers and the dishwasher at the same time with no loss of hot water.

Cost to run? Our natural gas bill since we installed it in February has been $12 a month. The estimated cost sticker on the side of the unit says it will run for $192 a year and so far, we're a good bit under that. It has a 20-year full warranty.

I'll never consider having anything else.

Very good to know.. Thanks for the update..

I had a plumber give me an estimate on a Rinai 2 years ago when our Heater went south. The only reason I did not buy it was the very expensive insulated tubing that would have to be ducted thru our roof from the garage otherwise it was a done deal.

January last year, I had a Rinnai RV53 installed. I am very happy with it. Yeah, it takes a few moments to get the hot water to the tap, but after that, it just runs and runs.

I don't know about the other mfg's, but Takagi was highly recommended to me by the folks I bought my Pex and circulators from, and I'm using one of their largest tankless propane-fired units to heat the concrete floor in a 2800 square foot shop. I raised the default temp to its max via dipswitches on the PC board.
I see no reason why these couldn't handle all the needs of a residence; they're pretty awesome units.

As a plumber and plumbing estimator, I deal with a lot of the points that have been raised on this thread. Some of the issues to keep in mind when changing from a tank style water heater to a tankless water heater are-

-Sizing. To be satisfied with the system, it's gotta be sized properly. As a general guideline, the average size residential tankless water heater will provide between 5 and 9 gpm at a 70 degree temp rise. In my area the average ground water temp is 48-50 degrees (colder groundwater temps mean less gpm of available hot water). Starting with that knowledge I can calculate that I can get 5-9gpm of 120 (the code maximum allowable residential temp in my State). The EPA mandates (wink, wink)that shower heads are limited to 2.5 gpm. The average person showers with mix of 1 part cold to 3 parts hot, manually adjusted by the user at the shower valve. So, a 5 gpm tankless WH will provide enough volume for approx 3 standard showers at one time with practically nothing left over. Depending on the occupancy of the house and the amount of hot water needed a house might require a large tankless WH or 2 smaller units. The lower available gpm from tankless style water heaters is probably what Redneck was thinking of when he mentioned that they may not work for filling a whirlpool since most whirlpool have high flow valves that run somewhere between 10 and 20 gpm, depending on individual model. A tankless will do it, but either may not fill the tub as fast or may not provide hot enough water at the higher flow rate-different tankless WH manufacturers have different ways of controlling the outgoing temp or flow rate.

-Venting. Keep in mind that some units use stainless piping (usually just for the exhaust side) and some, like the Rinnai, use a proprietary direct vent with a pipe within a pipe. Many of the newer designs are able to be vented with solid core schedule 40 PVC pipe.

-Gas piping. The typical household tank style water heater usually has a 1/2" gas, connection whereas even the smaller tankless WHs typically require a minimum of a 3/4" gas connection and some require as large as a 1" gas supply. Make sure that your gas piping in the house and the line to the heater itself is sized for this additional demand. We often have to retrofit the gas supply when switching a customer over from a tank to a tankless style WH.

-Hard water. Hard water can create a clogging problem for many tankless WH heat exchanger designs. In order to heat the water quickly as it passes through the heat exchanger of the tankless WH, there has to be a lot of surface area exposed to the hot fuel gases. This is typically done with dozens of very small water passages in the heat exchanger and these small passages can become clogged as the quickly heated water releases molecules of minerals like calcium and lime. The Eternal tankless WH is supposed to be capable of using water up to 12 grains of hardness. I'm unsure if there are any other tankless makes with the same capability.

We strongly recommend that folks with hard water use a softener in conjunction with a tankless water heater and also get the tankless heat exchanger flushed annually.

-Avoid waiting for hot water at distant fixtures with a recirculating line. Some of the tankless models out there have a small built in tank that allows the use of a recirculating line to keep the hot water main up to temp, which means no or very little waiting for hot water. Eternal and Navien are 2 that I'm familiar with that have this feature. I haven't installed a Rinnai in the last couple years, but at that time a small separate electric water heater and pump were required to have a recirculating line.


I'm seriously considering going tankless when our electric tank water heater kicks the can. Probably the only things that might stop me would be the initial cost and the fact that I try to avoid adding to our propane use.

That's about all I can think of for now.

Thanks Ed - mine is on the outside wall, in the garage, obviously vented to the outside. It's probably ~40-50 feet from the master bath, just guessing.

I'm painting the garage floor this weekend; I'll try to snap some photos of it.

Sounds like tankless is the way to go and the Eternals are the best make. How about installation of these units, can a guy install these with basic hand tools or does he need specialized equipment?

Thanks, Scott. I forgot to mention that we had a really good water softener installed at the same time we did the Eternal tankless heater. Both units togather take up less room than the old 40-gal tank they replace, btw.

All the hot water I want, with water that really and truly lathers. All for $12 of natural gas and $3 worth of salt a month. Ahhhhhhhhhhhhhhhh!

Edit to add: I had a plumber install them both at the same time. Took about two hours total, and installation was included in the price.

We too have a softener as our well is pretty hard. One of ours is mounted in a closet in the garage, the other in a closet with an outside access door on the opposite side of the house. Both have keypads. When my water heater dies in Idaho it will be replaced with a tankless as well. Only way to go IMO.