Tankless Waterheater recomendations Needed! (please) - DIY Chatroom

fremault · 01-21-2008, 11:17 PM

Good Afternoon and welcome.
Today I am in search of the needed info for which type or brand of home use tankless waterheater. I plan on doing the in stall my self by I also know that if the nat gas (which I have) pipe is NOT the right size then there is issues. Help me out folks and shoot some ideas across the board thanks.

ranman469 · 01-22-2008, 08:26 AM

tank less is not for everyone.
in cold locations of the country. they have degree of rise. if the water coming in is cold it slows the flow to heat the water. therefore lowering the gpm.

also depends on the demands. faucet gpm and how many are used at the same time.
example in Michigan a tagagi tank less 380.000 BTU for thousand$$ installed for a 3 bath home it has a master bath with a huge high flow tub and a high flow shower with 4 body sprays.
the problem was it would run the tub or the shower with no problem but it you try ed to run 2 things at one time the heater would slow the flow to heat the water.
we ended up just piping the master bath with the tank less and installed another tank for the rest of the house.

do your home work. they have allot to the install. bigger gas pipe and some you must use their vent kit. and whether it has enough GPM to the faucets you have.
tank less are mainly for low flow faucets and shower heads

as for my home it had 3 baths 1 with hi flow faucets and on 3 different floors. i could have got 1 for free to install and i did not us it. it did not work for me i installed 2 high eff 50 gallon tanks in series and a circulation system for the hot water. never ran out of hot watter and we could take 3 showers at the same time, with no flow issues.

moneymgmt · 01-22-2008, 03:06 PM

here we go again.... do a search for threads in this forum on tankless water heaters. There are at least a few and some very strong opinions regarding them. Ranman is right, they're not for everyone. BUT, I live in Michigan and swear by my electric tankless. One correction though, tankless heaters are like standard tank heaters in that they do not have a flow "pump". If you draw more water than its rated to heat, the water will come out full pressure but less than hot.... just like if you run out of water in a tank system. My unit is only turned to about 2/3 heating power because it heats faster and hotter than we need it.

Gas vs Electric is a huge decision and there are enormous differences. The vent system on a gas tankless was very expensive in my situation (the vent pipe costs a fortune per foot) and electricity here is cheap. I did a crazy amount of research and wound up with the best set up for my house. Granted an electric unit is easier to install (no venting) but it was a breeze. Regarding your gas line, if your current pipe is 1/2" and the unit requires 3/4" you've got big big issues. If it requires 1/2" and you've go 3/4" than all you need is a reducer.

When I was researching I found out that the people who had all bad things to say were the ones who never experienced a tankless unit first hand. Do some looking around on the internet, prices are another huge variance from company to company.

jpplumber · 01-22-2008, 08:18 PM

Hey Moneymgmt....How cheap is your electricity in Michigan?
Our company doesn't even install electric tank less. Natural gas is so much cheaper in Texas and I wish I had a tank less in my house. I replaced our 30 gal unit when it went out (it's in a kitchen closet and didn't have the cash for the tank less)) with a 40 gal and it is not enough.
We install Noritz 7.51 GPM nat. gas units (7.51 will usually cover a 3 bath home depending on water temp) and our customers love them, there are venting, gas sizing, water usage and incoming water temp. to consider and if there is a knock on them it is that you have to limit the number of fixtures running at one time or the temperature will drop...not the pressure as far as I know.

moneymgmt · 01-23-2008, 11:26 AM

I don't know the exact cost, I'd have to look at a bill. I will say that I had a 54amp unit when our house had one bath and my electrical bill increased about $10-15/month. In the winter time it is more like a $20 increase because the water is so much cooler coming in (and my wife needs extended showers in the winter of course). I was shocked because people told me to expect 5 times that increase. I'm glad I didn't listen because I realized that most "advice" and "knowledge" found in the forums is sometimes better heard as opinions of people who don't really know.

With a second bathroom I had to decide between a bigger unit or running a second unit parallel. I opted for the second unit, which took a little plumbing work but I think does better than one larger unit. Which brings me to a question I wondered about when I was doing the plumbing.... I'll post a new thread.

When you get into having more than 2 bathrooms I think the gas units are more likely the way to go. I've seen electric units that are rated at 200amps but by that point I have to imagine gas would be effective. I wouldn't know how to prove it, but my head says that electric are more effective in 1-2 bath houses but then gas steps in above that. The other consideration with electric is panel power. Most houses around me are 50-60 years old and only have 100amps. An increase in service can cost $1200-1600 around here which puts you right up with the cost of the gas units.

fremault · 01-24-2008, 07:27 AM

thanks for the heads up.

Marlin · 01-24-2008, 07:30 AM

Don't get a Bosch, I can tell you that much for sure. I also highly recommend a gas unit even if you have to bring a larger gas line to it. the black pipe is probably less expensive then the heavy gauge copper wire you will have to bring to an electric anyway. Don't forget the venting requirements for these units either.

Michael Thomas · 01-27-2008, 04:00 PM

I have a 5 Takagi tankless WHs installed at my house, office and at rental properties, and I've seen a number installed a home inspections here in Chicago. Eventually we got them all working well, and I'm quite satisfied with them, but we encountered a number of issues when installing them.

I ended up writing about this so much that I eventually put up a web page which discusses some of the "gotcha's" we have encountered and how to avoid them. It also has some information on calculating the payback of tankless heaters:

http://paragoninspects.com/home-insp...blems-faq.html