# instant hot water heater



## ship1of2 (Jun 27, 2003)

I was looking into changing the hot water over to one of the instant type. Then someone told me about the need for the exhaust pipe and how it cost about half as much as the heater. Is this extra expense worth what you save with the instant hot water? Sure does seem like $300 is a lot for the vent pipe.
Anyone out there with experience on this subject?


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## SolarGary (Sep 8, 2005)

ship1of2 said:


> I was looking into changing the hot water over to one of the instant type. Then someone told me about the need for the exhaust pipe and how it cost about half as much as the heater. Is this extra expense worth what you save with the instant hot water? Sure does seem like $300 is a lot for the vent pipe.
> Anyone out there with experience on this subject?


Hi,

You are talking about a tankless gas water heater?

My understanding was that they can be vented out the sidewall. I did not think the vents were that expensive -- maybe this is something that varies with brand? Here is a listing for the Bosch Aquastar 125FX that lists a vent kit for $174.
http://www.tanklesswater.com/produc...ource=NexTag&utm_medium=PPC&utm_term=125FX-LP

I think the tankless water heaters are a good idea -- I plan to change over to one when my tank needs replacing. The energy factors (roughly the efficiency) of the tankless gas heater is around 0.86 where a new tank type gas heater runs about 0.6 energy factor. That would imply about a 30% reduction in fuel use -- one of the sites I looked at claimed 33%. 
They basically eliminate all standby losses, which are large for regular gas water heaters because of the flue running right up the middle of the tank.
They also last a long time, and have long warantees. 
Some of the places seem to be listing a $300 tax credit -- see this link:
http://www.gamanet.org/gama/inforesources.nsf/vContentEntries/Product+Directories?OpenDocument

Here is an Energy Star doc that gives some estimate of saving:
http://www.energystar.gov/ia/new_homes/features/WaterHtrs_062906.pdf

If you are thinking about eventually doing solar water heating, then be careful to get one that works with a solar water collector -- basically it needs to have a gas burner that can be throtled down to only add as much heat as is needed after the solar has preheated.

Gary


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## Ed_Stanton (Dec 28, 2004)

My Bosch heater was over $1000. The insulated B vent with a fan, might have cost me $300 including installation. (I'd have to find the invoice). It's not hard to do yourself once you've seen it installed, the vent that is, but I opted to have the propane installer do it. 

If you don't need an insulated B vent type then your costs should be quite a bit lower for the materials. So the cost might depend on the type of venting pipe that fellow was talking about & perhaps the length required? Just see what all the options are and perhaps get two different quotes by suppliers or installers? I "apparently" needed the more expensive B vent pipe & a rubber foam insulating blanket to help prevent condensation in the pipe in winter.

Yes the heaters are very efficient BUT if they are placed too far from where you use most of the hot water, then you'll waste a lot of water by letting the cold water in the pipe run until the hot water gets there. So, for my kitchen, which is on the opposite side of the house to the heater, I waste a fair bit of water. Also, you need good water pressure to get the thing to automatically fire up, so you may need to open the tap FULL open until the piezo igniter catches & fires the propane. Mine doesn't always catch & I've tried every adjustment that I can find & so now & then I have to try several times. Once in a blue moon, even though the water pressure is good, it won't fire up & I have to go to the basement laundry tub & try several times from there. Not convenient when I need a shower, which is on the top floor. Also, I seem to sometimes get discolored water out of mine for the first part of the flow. It shouldn't be rust being copper tubing & plastic water pipes & I don't have iron in my water, but overall, with lots of use, you may not have that problem. My unit at times, will sit idle for a few days. My unit is 3 years old now & with my being off grid I love it, as I'm not using fuel or energy when it's not producing hot water. Also being off grid, I need to have a light on to start the heater's fan. The unit will not fire up if the propane heat exhaust fan is not running. The fan's current, activated by the piezo & water pressure isn't enough to get my inverter to kick in on it's own, even on the inverter's lowest Search setting.

Anyway, regarding the venting, find out what type you need for your particular installation & house & shop around if you can & then decide if the highest cost makes the unti worthwhile? If you use a lot of hot water as part of a few people, then yes I'd think it would be worth it any way. If you use very little hot water, then the higher cost might not be worth it unless you plan to live there for a long time, or you are able to get the cost back when you sell the house?


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## vallyfarm (Oct 24, 2006)

Ed- I do not know anything about them, other than I think I will get one when it is time, but shouldn't they be BETTER if you use only little hot water? That tank heater would cycle on all day for just a few minutes of use. But if several people were using MORE hot water, then the tank heater would be cycling during fewer non-use periods. I'm asking, because that is what I've been told about them, not to be snotty. Mike


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## painterswife (Jun 7, 2004)

We heat our home and all our hot water with a small Takagi propane heater.
It is a small house(1200sq ft) and only two of us. I bought it online and it costless than 600.00 at the time.

I the female of the family, installed and plumbed and vented it. Our vent was less that $100.00 and htrough the wall.

I can have endless hot showers. I also have a remote thermostat on the heater. With it I can adjust the temp on the outgoing water when ever I want. It also tell me the incoming water temp and flow rate..

It does only heat water as you use it. This means no hot water sitting in the lines and a longer wait time at the tap.

You do need a water softner if you have hard water. It reduces the scale.

I will not go back to a standard water heater.


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## Ed_Stanton (Dec 28, 2004)

Valleyfarm: Yes as you suggest, I do think that these units are MUCH better than a normal tank heater for those of us that use only a little hot water, and they're better for folks that use a lot, because as Painterswife suggests, the supply of hot water never drops unlike a tank. 

But for some units, at least here in Canada, the initial cost is considerably higher for a tankless heaters from what I've found. The prices are dropping but some supposedly premium brands like Bosch, are still quite high. Painterswife has had good success with hers, mine seems to be a bit fiddly to fire up at times. 

I needed a fan exhaust & B vent pipe for the propane burner, which is due to my having the unit in the same room as my woodstove. So, if I don't have any power to run the exhaust fan, then I can't use the heater. With a tanked heater, I've had some stored hot water when the power went out for short periods.

Each type has their pros and cons I guess but the tankless use less energy overall.


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## okiemom (May 12, 2002)

my BIL just installed one. He can take a two hr. shower if he wants, but he can't take a shower, run the dishwasher and clothes washer all at the same time. Two showers can't be running at the same time. 

the way I understand it is for best results teh tankless heater needs to be designated to almost single use areas. One tank for the bathroom, another for the kitchen and again another for a guest/kids bathroom. 

that would save water traveling long distancees, but add additional tank costs. 

We are think of using them in our new house. there would have to be more than one


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## Ed_Stanton (Dec 28, 2004)

Hi again okiemom, and not meaning to debate another thread with you, but I've not got that experience with my system. Several uses from my tankless heater can be going at the same time no problem. Perhaps Bil's system isn't plumbed properly or has low water pressure? Otherwise, running hot water to several appliances or more than one shower shoudn't be a problem. All my water comes from a central spot in the basement and the pipes all connect there, just as they would with a hot water tank.


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## tim_the_biggen (Sep 19, 2005)

we have a tankless water heater there's 5 teens and the wife and i and we( NEVER ) run out of hot water ours is a (VENTLESS) just like our ventless gas heater. we have had no trouble @ all


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## WisJim (Jan 14, 2004)

You need to size your tankless water heat to the use expected. A small unit isn't going to supply hot water to everything in the house at the same time, if you have showers, dishwashers, etc., going at once. But units with larger capacity are readily available, and are able to supply lots of water to numerous users at the same time. Be sure to buy one as large as you need.


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## okiemom (May 12, 2002)

Good point on getting the right size. I think the unit my BIL bought was one carried at HD or Lowe's. I have no idea what size that is. I think they only have one size there. It is *fairly* new appliance around here. 

Glad to know that is not how they all work. I will make sure the specs. match our demand.  

Ed, I don't mind debate, as long as it is not rude or bashing when it is done it  .Your good. I can always "agree to dissagree".


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## okiemom (May 12, 2002)

Hi,

Got an update on my BIL take that is not worth shooting. He kept getting an error reading of not enough gas flow. He updated the lines put in a new regulator and did everything he could to match the specs for the tank. He still is getting the not sufficient gas flow error. 

He is thinking there is something bad w/ the internal board. Anyone know what this could be?


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## TxGypsy (Nov 23, 2006)

I just helped to build a new house that has a tankless hot water heater for a good friend of mine. He had a lot of trouble with it at first. Something about the gas pressure not being high enough in the mornings and it wouldn't work. Since he likes to take his shower in the morning he wasn't real happy about this. He had to have the special vent you're talking about. I really wouldn't trust the 'ventless' model(just my 2 cents). 

I probably used the water in the kitchen and the laundry room more than he did since we worked out a nice barter. He pays for the groceries and I cook....he lets me do my laundry at his place and I do his too(don't you just love barter!). From my observations I'd say that it uses WAY too much water. There is a delay in firing of 30 seconds. As Tom put it, the system wants to make sure than you really want hot water rather than that you put the faucet lever in the wrong postion when you turned it on. You have to have the faucet open all the way so you waste all that water and then you waste all the water that you would normally waste while waiting for the hot water to get through the pipes to you. He put his kitchen sink as the last thing on the water line so he wastes a LOT of water. There is a bit of 'heat up' time too. In other words the water gets a lot hotter after a little bit. I guess I am a bit prejudiced since I have lived without plumbing and it just seems like a shocking waste of water. 

However if your goal is to have unlimited hot water then this is the system for you. If you are looking to save money as your main goal then I would recommend putting an electric hot water heater on a timer(ie it wouldn't be heating water while you are asleep). You might even consider putting a small(small water heaters 'catch up' quickly) water heater underneath your sink. We use hot water throughout the day mostly at the kitchen sink. If you were to put your main hot water heater on a timer you could either set it for mornings only or eveningings only depending on when your family takes their baths and you would just do laundry at that time too. That way you would have your hot water heater maintaining hot water when you don't need it. You would be saving the money to heat the water and saving a lot of water too


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## TxGypsy (Nov 23, 2006)

okiemom said:


> Hi,
> 
> Got an update on my BIL take that is not worth shooting. He kept getting an error reading of not enough gas flow. He updated the lines put in a new regulator and did everything he could to match the specs for the tank. He still is getting the not sufficient gas flow error.
> 
> He is thinking there is something bad w/ the internal board. Anyone know what this could be?


I missed seeing your posting before I wrote my response. My friend had this same problem. It seems to be fairly common. Tell your BIL to bite the bullet and get a plumber out there. They will have to do pressure tests and all that good stuff. I think they ended up running a larger line from the gas tank to the water heater on his. His house is so new that he hasn't had to have more gas delivered yet. I know he was bracing himself for his gas bill.


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