Plumbers: DIY tankless water heater installation.

After reading reviews (and one thread on GRM) we're considering a gas tankless water heater to replace our gas tank unit that's currently leaking on our basement floor.

Installation from the folks at the hardware store is going to cost nearly $3200 (includes Navian 240s heater, labor, and materials). That's a bit more than I care to spend.

Is there anything magic about the installation of a tankless unit vs a tank unit? The reviews on Amazon say "ZOMG, you NEED a real plumber to install this or it's the end of the world" but I'm not thinking Amazonians are really GRM type of people...

The gas line and water line are already pretty close to where the tank unit will be located. The best I can figure is I'll have to mount it to a couple studs, put in a couple service valves for later cleaning, read the instructions, and run a new exhaust (exhaust is about 20ft. it will exit above basement concrete wall, and below the first floor through a wood barrier to the exterior).

With this unit apparently PVC is ok for the vent line (as the exhaust is cool enough).

What say you?

almost forgot:

For our purposes we're wanting a tankless unit for "endless hot water". Eventually we'll have three kids and two adults in the house and we have only one bathroom.

Thanks

You probably need a larger diameter gas line, IIRC we we put ours in they ran a dedicated 1" line to it.

Damn!

Ran it from the meter to the water heater I assume?

I would check the local codes, the PVC vent sounds sketchy to me?

EASY! I have done a number of boilers, that run radiant heating also, its simple.

What size is the gas line, most Navion units are 199k BTU IIRC

I'll check when I get home and let you know (at work, on cough cough lunch break at the moment)

You're spot on with the BTU rating.

The distructions say a 1/2" to 3/4" gas line is preferred. The unit has a 3/4" fitting. It also says it wants the water heater to be the first appliance on the gas line to ensure sufficient supply. In our house it'll probably be the third appliance in line, as we have a gas furnace and a gas fireplace (that we never use) plumbed inline before hand. Not sure how hard it'll be to change the order of things there...

Never installed one but these were standard issue in Japan, man they would do the trick on hot water. Nice choice.

TRoglodyte wrote: I would check the local codes, the PVC vent sounds sketchy to me?

That's the standard furnace exhaust up here. Is there a reason it would be different for a water heater?

In reply to keethrax:

Nope PVC is getting to be the norm now. Many of the on demand ones need sch80 for the first foot or so connected to it. Usually will come with it if needed.

watching with interest to see your final tally

PM'ed you Bill

I've yet to hear that the tankless water heater concept actually works. Manufacturers are good at selling the idea to consumers, but fall short on delivering a product that can live up to expectations. Love to hear your assessment of the installed system.

Plumbing this in is easy. I just relocated my water heater this weekend, so my skills are fresh!

Let me know if you want some help on this one. Totally a DIY project for someone of your/our skill set.

In reply to 1988RedT2:

I had one in my 3 person shared apartment in Germany. I liked it and it worked well. I didn't have to pay for gas or electricity so I don't know about any sort of savings however

Mezzanine and Java: GRM party at my place? I'll supply the projects and the beer/gin/190-proof

T2: There's a thread on here that had some pretty positive reviews of peoples experience with tankless heaters. I know elsewhere they tend to be back and forth, but I trust GRM folk.

I think to get the warranty, it has to be installed by a real live plumber.

In reply to Hungary Bill:

We may just have to do that!

I'm in! Plus, this puts me in for more favors as I get closer to my kitchen remodel that I'm digging into as we speak.

If helping you remodel your kitchen means getting to eat more of that delicious stuff that comes out of it, count the whole family in!

We use them in commercial applications in small retail space bathrooms all of the time. I have also used them for hand wash stations. As long as your use provides enough flow to trigger the system they are really good.

The most bad ass installation of them I have ever come across in a house involved a small one on the feed into each of the bathrooms and at the kitchen (i believe 4 in total). This was then backed up by a 100 gallon water heater in the garage. The insta hots where only there to provide hot water until the water came from the garage (large house).

Off topic, but epic-ally cool. You never had to wait for hot water anywhere. The reasoning had to due with wasting water in the middle of the desert (it was Desert Palms, CA), but I just thing it was another feature to a sweet house.

On topic, I have come across quite a few in snow bird homes around phoenix. They don't demand any energy while they are away for months and seem to have less issues sitting and being turned back on.

I narrowed it down to two: The Bosch C 950 ES and the Navien NPE240s. I went with the Navien based off price, flow rate, and Java's brand recommendation via the PM conversation.

I bought it from Amazon for $1355 which is about $150 more than the installer wanted for their unit, and about $150 less than the Bosch NG example (the LPG one, oddly enough, was only about $1200. ah well)

So, the goal becomes the usual GRM jive: "can I do this in 10x the time for 9/10ths the cost and be happy with the result?

Water heater ETA is 1-week, the price to beat is $3300.

Wish me luck.

PS

Java: I measured the o.d. of the pipes. From the meter into the house it's 1-1/4" o.d and going into the water heater it's 7/8" o.d. I estimate that to be about 1" coming into the house, and 1/2in going to the heater. Based on the spec sheet of the heater I bought, there is a 1/2" connection on it so all should be good

Make sure you get a high flow flex connector for the gas, and due use one with a "safety valve" . And you didn't let me check my pricing!

D'Oh!

When you said the guy you talked to stocked Takagi, I thought that meant it was the only option...

High flow flex with a safety valve. Got it.

Hungary Bill wrote: Damn! Ran it from the meter to the water heater I assume?

Yes. We mounted it on an outside wall about 10 feet from the gas meter, so it was easy. We were replumbing the house at the time (it had 1960s-vintage galvanized pipes that were mostly full of rust), so running new hot water lines to it wasn't a large additional expense. We also live in California where it doesn't freeze much, so mounting it outdoors is fine (it will turn the burner on if necessary to cope with an occasional mid/high-20s night, but it's not designed to tolerate extended periods in single digits). This meant that the new gas line was relatively cheap. It might have been 3/4" instead of 1" (don't recall), but it was a dedicated line coming straight from the meter, and no way was the line originally intended for the tank heater big enough.

Overall, I was pretty pleased with the tankless unit. It needs annual descaling, which isn't a big deal as long as the service valves were installed properly. Basically you shut off the gas, turn the valves to isolate the water heater, then pump distilled vinegar through it for an hour. The plusses of it are that it gives you infinite hot water (so your teenage daughter can't use it all up taking a 45 minute shower leaving you with nothing but cold water), and it takes up way less space than a tank unit. Another plus is that the thermostat temperature is usually set to around 115/120 rather than 150/160, which means less risk of someone scalding himself with max-temperature water. You need the high temps with the tank unit to increase the available volume of desired-temp water, but that's not a concern with the tankless due to the 100% duty cycle capability.

The downsides are cost and complexity. Some people will say that the limited max volume of water is a downside, but all that means is that you need to size it properly, which just means it costs more. The problem with complexity is that they have a lot of parts, and nobody has those parts in stock. This means that if it fails (which it does more often than the tank units do), you need to first diagnose what's wrong, then order the part, wait for it show up, then install it. This means more downtime than a tank unit, especially if the initial diagnosis was wrong.

Ignore the energy efficiency aspects, you'll never pay back the cost of buying it to begin with through lower energy bills.

We bought a new house last year, it had an old tank unit that needed replacement. I thought about another tankless but decided to go with a tank unit. This was really just an economic decision -- the new house had already been repiped with copper, so outdoor wasn't an option and using the existing location would have required both a new gas line and new vent piping,

We had a Noritz.

Oh, one other minor downside, it requires electricity to run. This means that if you want to work during a power outage you need to put it on a UPS.