Tankless water heater

ken werner

Member
Messages
3,377
Location
Central NY State
Thinking about replacing our older unit with one like this:

http://www.amazon.com/BOSCH-HEATERS...15-2384662?ie=UTF8&s=hi&qid=1188212693&sr=1-3

[bosch tankless or similar LP unit]

We have hard water, but it has a 10 yr warranty.

Anybody with experience with this type?
Does it make noise?
Our current unit is a gas fired water tank, but has a power vent with a fan that makes alot of noise as it turns on and off at night.

TIA
Ken
 
Doug, I'm going to disagree with you on this one, the elecrtic units that are big enough to do the job right, use a LOT of electricity, gas ones are cheaper to run, even here in Tokyo.

Just my experience.

Cheers!
 
Mixed responses from those folks I know who use them. Some love 'em, some hate 'em. My son built a lake house and has them, takes 10-15 minutes before warm water begins coming through. He hasn't investigated why so it could be a plumbing situation not heater fault. But rapidity of response is something to ask about.
 
Rate of flow

Ken
I wanted to convert to a tankless water heater back in 1995. :rolleyes:
Had the foresight to take a 5 gal bucket up to the shower and time the flow of the "BIG" "falls like rain" shower head. Guess what - the tankless would not keep up with the flow - ah! shucks. :huh:
Hence no tankless here.
So I said to myself - how about two in series or parallel? :thumb: BUT at $1100 a piece - am I crazy? :rofl:
Alas, no new technology.
Daniel :dunno:
 
Our gas ones provide hot water in about 10 seconds, and it will run the shower at full tilt, the dishwasher, the washing machine and the kitchen sink, I know, we tried it :D

At the touch of a button ours can also change temps, from a low of about 30C (86F) to a scalding high of 60C (140F).

I guess we fall into the "Love em" category. :D
 
Well, like the ads say, size counts.;)
If it takes more than the time to run the water through the pipe to get hot water, your heater is too small.

I have an electric 36 KW unit that can keep up with everything except filling the bath tub in the middle of winter with the hot valve wide open. The solution is to run the water at a slower rate. The water temp out of the heater is 125 degrees. The unit only serves our two baths in the bedroom area. I think that I would go with a 26 or 30 KW unit if I were to do it again. Our house is totally electric, and we are paying 12 cents per KWH.

For the kitchen and laundry, we have a 50 gal Rudd Marathon electric heater. IF you are replacing an electric hot water heater, it is the way to go. R17 insulation all around and a lifetime fiberglass tank. This heater also gets supplemental heating from our geo-thermal system.
 
Thanks for your many replies. We have LP fairly reasonably available, and 'lectric is $.16 per KH, so I'm definitely going with gas, BUT - do these things make noise when they run?

I've seen at least one with some kind of venting fan - which is what we have now on our gas-fired tank, and it is loud.

Ken
 
Ken, I've got a Rinnai unit that we installed in our house when we built it last year. It's a natural gas unit and I'm sold on them. It powers our laundry, 2 baths with showers and a large Jacuzzi type tub. We have used both showers at the same time and never run out of hot water. Nor do we run out of hot water filling the Jacuzzi tub. We have hot water in the time it takes the hot water to get from the unit to the faucet. As the unit is pretty close to both baths, I don't think we're seeing much more than a gallon of water go down the drain before the water is hot.

As for noise, you can barely hear ours run if your standing right next to it. Noise was my concern also, as ours has a output of 185,000 BTU. It's much quieter than a regular gas water heater with a tank.

I will be getting another one for the kitchen when the 40 gallon tank unit we have for that area needs to be replaced.

I like ours and I do believe we are saving money by having it.

Karl

Ken, I just read about the unit you mentioned. It is not big enough to replace a tank type HWH. You would need something with a flow of at least 6 GPM. Also, you should check the incoming water for temperature. I'm on a well and my water comes into the house at between 50 and 52 degrees. From what I'm told most city water comes in closer to 60 degress. That will make a difference. I have my tankless unit set for 120 degrees. That is plenty hot for showers and normal washing of hands etc. The dishwasher and washing machine have heating elements that heat the water they use, so a hotter setting on the tankless unit is not necessary.

Karl
 
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I am in the midst of an addition build so I got some good advice on this subject as I have debated the same thing.

In my case anyway a tankless hotwater heater is the most inefficient way to go. In order to heat water sufficiently for my needs, (domestic hot water and radiant floor heat) I would need a 150,000 BTU propane unit.

Now if I purchase a hot water storage tank, I can get by with a 30,000 BTU unit that will have enough recovery to keep my radiant floor warm, and my hot water needs from ever running out of hot water.

For me its a no brainer, and the way my plumber/ heating tech describes it, the tankless units are just not worth it. As they age the delay between water start and when warm water starts flowing, will steadily increase.

As for electricity, there is no need to even debate that issue. The Maine Public Utilities Commission is currently suing the local power company because they want to increase our rates by another 12% in order to pay for powerplants that need to be built in Connecticut. Our rates are already twice that of Utah. Electric costs are just insane here.
 
Karl - Thanks very much. That's the info I was seeking. Is there a model # you can recommend? Is 285K BTUs medium or large for this kind of unit?

Thanks again.

Ken
 
First let me say I mis-spoke about the output BTU on the unit I have. I went to the basement this morning and checked it. I have a Rinnai model R-85 which has a maximum BTU of 185,000. I'm not sure how I put in that 285,000 BTU in my original post, but I've changed the original post to reflect the lower BTU.

At a flow rate of 6.5 GPM it will raise the water temp 50 degrees. Bear in mind that at a lower flow rate [I.E. one outlet open the flow rate is lower so the water temp will be higher, up to the temp set on the unit] you will be able to achieve max temp per your settings on the unit. Most units are preset at 120 degrees, but can be changed. My unit is set to 120 degrees. The other thing you have to keep in mind is when using hot water, do you really use just hot water? Most of the time you will be mixing cold with the hot, so the water flow through the unit will not be the water flow coming out the faucet or shower head. Even when filling the Jacuzzi tub we don't use straight hot water.

http://www.takagi.com/index.asp
http://www.rinnai.us/icms/rinnai/content/

Above are a couple of links to the units I looked at before I purchased. I got most of my information from the Takagi web site and was ready to purchase one of these, but I could not find a Takagi dealer within 100 miles of my home, so I went with Rinnai. These sites can answer most of your questions about tankless units.

Just as a side, when I looked at my unit it has the yellow sticker showing average cost per year. My unit costs, on average, $167.00/year to operate. In comparison my 40 gallon natural gas tank heater costs, on average, $257/year to operate. So there is a savings, but what I like most is that we can use both showers at the same time and not run out of hot water.

Karl
 
Our unit is badged as "Tokyo Gas" but it is a Rinnai, we had a minor problem (after 5 years of use) with a flow control valve, they replaced it under warranty. The tech who came out was a Rinnai guy.

We use our unit a LOT, I take one or two showers a day, as my work is physical, and I stink after a 12 hour day, and I have two daughters........nuff said :D
 
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