Tankless Water Heater

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ferco

Recycles dryer sheets
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Don't know if this topic has been discussed recently. I was at Lowe's recently and the salesman mentioned a possible way around the rising gas bills, particularly for empty nesters who don't use continous hot water might be to get rid of the tank water heater and go with a tankless system.
He mentioned a base cost around $430 + installation.

Anyone have any experience with this conversion in their homes? How much do they cost, system and labor. Do they tear up your house to put them in. Do they give you hot water on demand , as the salesman said ? Do they save on the gas bill significantly? What are the down sides? Is any model better than the other? Would you have Lowe's install yours?
 
I don't have one. Be careful to run the numbers and figure out how many years it would take before it pays for itself, though.

I know that in my case, my gas bill covers a lot (such as heating the house and running my gas dryer) so I have doubts as to whether or not I would save enough to benefit from that type of system.

Maybe if I had six teenaged daughters taking continual showers... :)
 
Want2retire said:
Maybe if I had six teenaged daughters taking continual showers... :)
Click to expand...

A DOMs dream come true... >:D

My gas bill in summer, when water heating is the only natgas usage, is $17 or so. Could be, though, that with water shortages looming in many locales, that POU water heaters will be required in new construction.
 
We got a tankless this past spring. We didn't get it to reduce the gas bill, but to replace a traditional tank that was in the attic. I did not like having that much water sitting above my son's room! For us, the total cost of the tankless was about the same as getting a new tank relocated to the basement. ($2500 - I know it's a lot, and several quotes were higher for both options!)

From my research, I don't know if $430 gets you a whole house unit for several bathrooms. They do make smaller units, and some people get one for the upstairs, one for the laundry/kitchen, etc.

Regarding the gas bill, I don't expect it to make a noticeable difference for our family of four. When we were gone for 10 days on vacation last month, our gas bill went from $20 to $15, but other than that there hasn't been much difference in the monthly bill.
 
Do a search on tankless. There are a few threads you might want to look at.
 
Paloma tankless unit

Installed a Paloma unit one year ago in a 1 bathroom house. Found it new on ebay for $230. Unit has saved approx. 30% of gas used for hot water. I installed it myself in basement in place of an old conventional water tank.
Biggest problem: Be aware that 0.9 gallons per minute water flow is needed to trigger boiler in unit to ignite at a water temp difference of 40 degrees between input and output. This is not so much a problem in the winter when the incoming water temp is lower. In the summer when the incoming water temp is 70 degrees sometimes you can't get the 0.9 gallon flow with one spigot open. You can't trickle the water at the hot faucet and expect the unit to stay on. Takes some getting used to. Home Depot at one time was selling the Bosch units. They have discontinued that line due to numerous customer problems.
 
I seriously looked into this a few years ago. The cost would have been $3000-$3500. The unit itself was maybe $800-$1000 for a unit that could handle 2 full baths and a kitchen in a home with 4 people. The rest of the costs included changing the plumbing from the meter to the tankless water heater, the current water heater is in the same location but they wanted to upgrade the pipe diameter. But the largest cost was the special venting that a tankless system uses. Our regular water heater has a simple vent up the chimney, next to the furnace vent. A tankless needs a special vent that goes directly outside close to the tankless unit. It's a double wall insulated venting because the exhaust gases are very hot. They told me the vent pipe is like $100 a foot. Also they wanted to upgrade our gas line to a larger size, otherwise when the tankless fire lights, it reduces the pressure to the furnace. Obviously, the labor for the installation and all these changes is what makes this so expensive.

We live in an area that has very hard water. It's common that you replace a water heater every 10-12 years. We bought a fast recovery 50 gallon regular water heater for about $900.

I really wanted to get the tankless, I liked the idea of only heating water when we used it instead of storing it 24 hours a day. But the cost was out of line. I had 2 companies come to the house and do estimates and others gave me a ballpark figure over the phone.

It's a great idea. If I was building a new house it's definately the route I'd take. But a retrofit didn't seem to make much sense.

I tried to get an estimate from Lowes. It seems that the plumber who does these for them really doesn't like to install them. He never called and I had to keep calling about it. Finally I just went in and got my money back. It was one of those estimates that you had to pay for, maybe $15 or something close to that.
 
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Got one 2 years ago, no problems, love the endless hot water when there are house guests. No risk of tank failure obviously.

Ours runs off propane and is cheap to use.
 
hogtied said:
Installed a Paloma unit one year ago in a 1 bathroom house. Found it new on ebay for $230. Unit has saved approx. 30% of gas used for hot water. I installed it myself in basement in place of an old conventional water tank.
Biggest problem: Be aware that 0.9 gallons per minute water flow is needed to trigger boiler in unit to ignite at a water temp difference of 40 degrees between input and output. This is not so much a problem in the winter when the incoming water temp is lower. In the summer when the incoming water temp is 70 degrees sometimes you can't get the 0.9 gallon flow with one spigot open. You can't trickle the water at the hot faucet and expect the unit to stay on. Takes some getting used to. Home Depot at one time was selling the Bosch units. They have discontinued that line due to numerous customer problems.
Click to expand...


Yes... the .9 GPM is a killer for some... I had to get rid of the low flow shower head as I could not keep the water flow enough to get it running unless it was cooking me... but, I took it out and it works just fine for me..

I do have the Bosch and no problems after 4 or 5 years...
 
I'm getting one installed next week. Hope it saves me some money in the long run. It is very efficient, and has a small tax credit associated with it to bring its cost to about $1000.

Also replacing my grossly oversized oil boiler with a much smaller unit. Hope to save money in the long run with the set up.

Mine is .5 GPM low side, so we will see if I have issues. I like the idea of only buring fuel when water is used.
 
Bimmerbill said:
I'm getting one installed next week. Hope it saves me some money in the long run. It is very efficient, and has a small tax credit associated with it to bring its cost to about $1000.
Click to expand...

A co-worker put one in a couple of years ago. He figured it would take about 8 years to pay back. Then the price of gas went up. Now pay back is less than 5 years.
 
I believe that is the Energy Policy Act of 2005 Tax Credit eligible items must be purchased between 1/1/2006 and 12/31/2007.
Try GAMA: an Association of Appliance Manufacturers to reseach eligible items if it doesn't work let me know and I will find the exact location for you.
 
I'm having a really hard time figuring out these pay back numbers. Gas appliances I have in the summer are:

1. Hot water heater
2. Stove.

Gas bill in the summer is: $15.29 That leads me to believe that even if I had a "uses no gas" system, I could at most save $15.29. Realisticly, I would guess it would save me $2-$5 a month. It still has to heat the hot water I do use. The base cost difference is pretty big between the two different systems. I put a new hot water heater (normal) in for ~$320 . As far as I can tell, going tankless would cost me ~$1000-1500 since I would need to change things I couldn't do myself. (gas line changes/vent changes) So saving gas to pay back this seems unlikely. $680/$5=11 years payback even at what I think is the "perfect world". Given the more realistic world we are talking 49 years payback...

And then you start adding all the "problems". Doesn't seem worth it to me. The instant on hot water isn't as "real" as it seems either. First it takes a moment for it to detect water flow, come on and start heating the water, second unless it is very close to the output, you still have to pump that cold water out of the pipe. (So whole house units are not going to give you instant hot water)

So if you want Instant hot water, seems like a reciruclating pump is a better idea...

So I've pretty much ruled it out as good idea, on my normal house, and my "dream" house. I think they are a solution looking for a problem that doesn't really exist. Hot water sitting in a tank is actually pretty efficient if the tank is insulated correctly. The only place I could see using it is to get rid of somewhere you don't want a bunch of water sitting (like in an attic).

-d.
 
We live somewhat in the country and use propane for gas. Short of reading the pressure gauge it is hard to tell how much we are using each month. However, this being said, at the end of Feb. the gauge read 60%. The guy came to check it around the end of Aug. it still read 60%, and the gauge works! So for the warmer months, we don't use much gas. We use gas for water (2 water heaters), dryer, cook, and heat. Heating is what really chews up the gas. If I change anything out it will be a heat pump, however, the house is only 3 years old, so it won't be soon.
 
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Rustic23 said:
at the end of Feb. the gauge read 60%. The guy came to check it around the end of Aug. it still read 60%, and the gauge works! So for the warmer months, we don't use much gas.
Click to expand...

Rustic, you can't go by pressure to tell how much you used. The pressure stays nearly constant until it is near empty. The liquid propane converts to gas to maintain a near-constant pressure as you draw from it.

As it approaches being very near empty, the pressure will drop very fast, as there is no more liquid available to convert to gas. At that point you are just tapping off the gas pressure.

-ERD50
 
Yea, I knew it was a not that good, but it is the only thing available. When it is full it reads 90%, and goes down slowly. I always assumed it was a preasure gauge. Anyway, thay put in 100 gal. which brought it back to 80%. As it is a 500 Gal tank, it seems close. I have checked the web to see how these things work, but, have not come up with an answer yet.

Found it. Seems it is a float guage. Live and Learn
 
I'm glad you figured out it wasn't a pressure gauge. When I read ERD50's response I thought, I hear what you are saying, but it doesn't make sense with the way my propane tank worked. Maybe that is how it works on the very small tanks, but I had a 500 gallon tank, and it seemed to very accurately track my usage. I used to watch it ever week or so during the winter to see, and it gradually went down like I would have expected. It did not stay high until the last moment and then sink.

A float gauge makes a lot more sense with what I saw.

Laters,
-d.
 
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DW must have been a early adopter. Ours is about 20 years old. We actually purchased the replacement a couple years back, saw one at a Big Box store on sale for a few hundred dollars, essentially the same unit updated, figuring the plumbing would like match up nice. The old one so far refuses to die, it's a we really should get around to it project but likely we'll procrastinate a bit longer or that final failure will make us do it. Thought I'd chime in just to show the longevity is real and true. Unlimited hot water when you want it, and little or no cost when you don't. A good thing.
 
We have electric WH the builder put in. Its 80 gal and its gottta go. Any gas WH will be pricey due to add'l plumbing for the vent.

I have an idea to use a tankless unit with a very small (10-20gal) storage tank installed downstream to avoid the low flow problem? The tankless unit could very efficiently heat large volumes while the storage tank only maintains the temp for small draws and until the tankless kicks in. tis scheme might also require a tempering valve.
 
Ours was $1700, installed in 2005. It will have paid for itself soon, since by reducing propane usage, we can buy propane only in the summer, when it's cheaper (currently $2.42/gal).

Main disadvantage: Hot water doesn't diffuse into the pipes, as it does with tank. So it takes longer for the hot to get to the faucet -- up to two minutes.
 
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