Getting a Tankless Water Heater Installed

[triguy128]

Rather than relining the chimney, I'm biting the bullet and just going with a HE tankless. The existing Water heater appear to be 14 years old anyway and it only a 40 gallon unit in 3 bedroom a home with 2-1/2 baths. It hasn't been an issue, but our daughter is only 3 years old. I know we've run out once when we had company over.

The real upgrade will be the recircualtion loop I'm adding with it. IT will also include replacing some remaining galvanized pipe. Some if it we might push off until later depending on where we're at on costs.

I selected a Navien NR-240a which is a 200k BTU, 97% efficient unit with a 1/2 gallon buffer tank and integrated circulation pump. IT vents using regular PVC, not soem fancy overpriced spcilized vent kit that I think Rannai and Takagi require. Not cheap at $1700, ut that includes the service valves, PRV and again, the buffer tank and circulation pump. Looking online my plumber is getting me a godo deal. I don't think he's marking this up much if at all since it's one of his first installs of this particualr model. But I've done my research and I'm comfortable wth his vele of expereince and knowledge with these units.

FO rhte systme ot operate best, you actualyl set the water temp much lower tha nyou would a tank. Basically, somewhere aroudn 108-115F rather than 120-125F. The major thing that I'll have to get used to is that in msot all cases, when you want hot water, you won't need to temper it much if at all. But your goal is to maintain maximum water flow rate through the unit when possible.

The one dissapointment was discovering that my chimeny has 3 sections and that there's a jog 1/2 way up so it won't be feasible to vent up the chimney to the roof without using an expensive SS flexible liner and not direct venting. So We'll have to rearrange the existing PVC vents for the furnace that go out a basement hopper window. Not the greatest set-up since you can hear it a little downstairs and get the water vapor comming out. It's also near the condensers.

[shazapple]

I haven't heard many good things about tankless. Expensive, low return, complicated design, and higher maintenance.
http://www.greenbuildingadvisor.com/blo ... aste-money

[Daniel Meyer]

We LOVE LOVE LOVE ours....

[Daniel Meyer]

I should also mention our installed cost was about $1100.

Just replacing the tank-type would have been much more, as it would have needed to come up to current code...it needed new stack, a large closet built around it and external air intake.

The tankless got stuck in a wall cabinet.'

http://theoldvictorian.com/2009/10/14/science-project/

[triguy128]

That was my problem, Just relining the existing chimeny, if it was feasible, since it has a jog in the middle, would have cost at least $500 or more. I could have saved $200 and not gotten the circulation, and could have gone with one size smaller for $100 less.

Simple payback over a standard tank is about 5-7 years after the utility rebate. Service life is 20 years for the tankless, HE warranty is 15 years. But I think we waste quite a bit of water waitign for it to get warm, and now we can actually wash our hands with warm water all the time.


Most problems come from improper gas perssure or gas line sizes, inproper venting, or improper water piping. Many users try to still use 120 or 125F water temps and then mix at hte faucets so their flow rate is low. The whole point is to set it lower and temepra it as little as possible. You also have ot have descent water quality and do regular PM's. But even a tank type should be flushed once a year. The overall function is no more complicted than a newer HE furnace and those are known to run reliably for years. The first generation Naviens had some issues, but thsi model has been out for 2 years and has a pretty large market share now.

As many bad reports as I have I also hear how much people love them... as above.

Just met with the plumber at lunch. Looks like I can save seom installation costs and mount it at an existing abandoned cold water drop, that right next to where the gas service comes in and under a hopper window that already has an abandoned clothes dryer outlet, so I can use the smalelr 2" PVC and it will be <5 in length.

Again, with my install I get instant hot water, endless hot water for 2 showers + 1 faucet simulateously at even 40F incomming water temps and there's no cold water "sandwhich". We're also repalcing a few sections of older galvanized piping while I'm at it.

I'm also going to keep the old tank unit as an emergency, short term back-up. Just drain it and shut off the gas. I'll cap the chimney, but leave a vent over that section.


I'll report bakc how start-up and installation goes.

[gmf001]

I've had a tankless heater in my cottage for 15 years. It is an early Bosch unit - doesn't have all the bells and whistles that the newer units have, but it's worked flawlessly for the entire time, despite extremely hard well water. It has the traditional problem of the cold water sandwich, but the unit you've selected is supposed to solve that problem. I have been looking at the same unit that you are going to install for my main house (a 1884 Victorian). I'd be really interested in your experience with your install and how it works out for you.

[triguy128]

Good to hear that there are plenty of happy users. I realize that there are electronics and more components to fail than a simple tank heater. But if there were widespread problems, companies would have pulled them off the market and they'd get a bad reputation.

One challenge is that the installation of these is more similar to that of a furnace than a toilet, sink or faucet, so many plumbers that aren't true mechanical contractors get over their head,

I'm also good with controls, so if it throws and error code, I can troubleshoot it and replace a simple switch or transmitter.

Again a real key is to not run the water temps too high so you have good flow, a good delta T and reduce mineral deposits. Deposits form faster at higher temperatures.

[KathyJB]

We have an electric tankless water heater and we love it. We got it at Lowes. I didn't want to put in a new line for propane or a new vent. Unfortunately the electrical board went out and since it was Winter we opted to buy a new one and order the board and maybe use it at the future camp house at our pasture.

[Abuela]

We've only had ours a few months but we love it. I'm not going to be able to realistically assess how much it's saved since the old tank was electric and this is natural gas, and our water usage hasn't been the same since it was installed (first a lot of family here while I was recovering from surgery, and now step-d and babydaddy living here, plus a lot of baths and long dual-shower-head showers that we didn't take before). But I love that I can soak in my new insanely deep bathtub or take a ridiculously long shower without worrying about running out of water, and that I don't have to worry about timing the hot laundry loads to avoid when various people might want to shower, and that it takes up far less space in our small laundry room than the tank.

[angolito]

the waste of water isn't actually solved unless you also install pex lines, which i believe daniel did. you still have to push water through the traditional pvc lines before the heated water is coming from the faucet. also, you should put in a good hard water treatment in order to minimize issues with the more sensitive and compact nature of the unit.

to solve issues with our upstair bath (if we ever get it started) i will install an inline hot water booster for the tub.

i have two 50 gallon tanks ( high efficiency electric ) which serve a two adult household and the additional load of floor heat in a 5x12 bath. during the summer we turn off one tank alternating each year. we have a softener and reverse osmosis system.

kinda had to laugh at the "if there were widespread problems companies would have pulled them off the market" comment. since when does it matter to marketing and corporations if their products are ..... crap? speaking generally, of coure, but with few exceptions in my own experience.