Are dual purpose water heaters any good?


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Old 01-27-13, 05:38 PM
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Are dual purpose water heaters any good?

I just had a gas well drilled on my property and now get free gas!! Only problem is now i need to change all my appliances (had no gas available before). I've been looking at tankless dual purpose water heaters (my local supply house deals with Quietside) for my heat and domestic hot water. I have been hearing drastically different reviews from local HVAC guys. They look pretty cool but almost seem to good to be true. I have in floor radiant heat (in slab in basement and in joist bays upstairs). I would love to hear some reviews
 
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Old 01-27-13, 05:45 PM
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Free gas.....awesome

In my opinion....stay with a standard gas fired domestic hot water heater and a separate gas boiler.
 
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Old 01-27-13, 08:02 PM
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Are dual purpose water heaters any good?

I just had a gas well drilled on my property and now get free gas!!! The only problem is that i need all new appliances (no gas available before.) I've been looking at dual purpose water heaters (my local supply house deals with Quietside) for my heat and domestic hot water. They look pretty cool but almost seem to good to be true. I have heard conflicting reports from local HVAC guys. From what I've seen here so far, nobody really likes tankless water heaters but since I would be using a 120,000 BTU or larger due to heat as well, does this change anybodys opinion? I have in floor radiant heat (in slab downstairs and in joist bays upstairs.) My existing boiler is 87,000 BTU
 
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Old 01-27-13, 08:52 PM
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I just had a gas well drilled on my property and now get free gas!!!
Yeah??? Who did that???

What are you running now oil?

Id get a regular water heater if it where myself and not paying for gas. If tankless for hot water 199k btu is the smallest I would install.

Boiler I would put in a mod con since you have radiant

 
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Old 01-27-13, 09:08 PM
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There are many really good, real combi systems.
Quietside has been around a long while, but service is a nightmare.

Depending on the heatloss of your home there are many great options.
 
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Old 01-28-13, 05:28 AM
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1) a small local company who is drilling a lot of shallow wells in the area (apparently the geology is good around hear)

2) yes im running oil now (and getting tired of buying it when i dont need to)

3) what is mod con?

ps. sorry but i dont know how to attach quotes from your answer that i am replying to
 
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Old 01-28-13, 05:34 AM
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Modulating condensing boiler. Like a tankless heater but for your homes heat.
 
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Old 01-28-13, 07:09 AM
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the (Quietside) im looking at has 2 seperate heat exchangers. 1for heat and 1 for DHW. It modulates down to 50%. I saw a dual purpose heater on the net (Navien) that modulates down to 12.5%. If i went to 199,000, i would probably need to get the latter so my heat doesn't short cycle?

One of the reasons I origionally liked the dual purpose was to combine (2) power vents that i need to bring out the front of my house
 
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Old 01-28-13, 07:38 AM
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I havent done a heat loss since i installed the pex (10 yrs) but i have a 1000 sf ranch with 1000 ft walk out basement (good insulation but need windows and doors). On the DHW side I have 2 full baths, laundry, dishwasher

The other one i've seen is a Navien. I like somethings about each.

Quietside 1) buy local and hopefully it would be easier to get help if and when it breaks

Navien 1) it modulates down to 12.5% vs 50% 2) when i jump to 199,000 the price doesn't go as high as the other (someone said i will need 199,000 for my DHW). 3) if I go with 120,000, it has 3/4" DHW hookups vs 1/2" I dont like the Naviens controller. maybe im just not understanding the directions that would come with it but it seems there is a problem with setting on/off temperatures (can only set one or the other)
 
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Old 01-28-13, 07:45 AM
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Good Lord, no, you don't need 199,000 BTU for hot water!
 
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Old 01-28-13, 03:09 PM
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I have a similar thread going in plumbing/ water heaters. Thats what the moderater suggested
 
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Old 01-28-13, 03:37 PM
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Now I gonna go look... sounds a bit on the excessive side to me...
 
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Old 01-28-13, 04:01 PM
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I have a similar thread in HVAC/ Boiler. I wonder if these 2 threads could run together?
 
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Old 01-28-13, 04:05 PM
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I have a similar thread in HVAC/ Boiler. I wonder if these 2 threads could run together?

Done .

I did not suggest 199K btu.....


Get a heat loss calc done.....

 

Last edited by lawrosa; 01-28-13 at 04:09 PM. Reason: Left a redirect but not sure what it does..????
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Old 01-28-13, 04:15 PM
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I did not suggest 199K btu.....
Not in post number 4 ?

If tankless for hot water 199k btu is the smallest I would install.
Mike must have merged these while I was typing my other reply... looks like it got lost in the crossfire!

Mike, you are talking about the 'instant tankless' units, correct?

Does this also apply to a 'combi' or no?
 

Last edited by NJT; 01-28-13 at 04:35 PM.
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Old 01-28-13, 05:13 PM
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Mike, you are talking about the 'instant tankless' units, correct?

Does this also apply to a 'combi' or no?





Im talking just hot water from my experience with the GPM issue.

But now that you brought it up I need to go back and look at the specs for that Bosch combi I installed.... It was only 100K with 3 zones and HW.... I never did look at the HW gpm specs...
 
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Old 01-28-13, 05:49 PM
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Mr Trooper,

I think we lost our thread in HVAC. I thought it was interesting to hear from differing view pts. Can this thread appear in both simultaneously?

Ps. Are you still topic moderator over here in plumbing?? Just kidding buddy
 
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Old 01-28-13, 06:45 PM
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I merged the two threads together per your request chip. Your post #13.... Both threads are here....
 
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Old 01-28-13, 07:47 PM
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I know.

thanx for your help, i do really appreciate it. sorry I think we lost our way.

Are dual purpose water heaters any good?
 
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Old 01-30-13, 04:19 PM
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Im thinking of buying a dual purpose water heater

Im looking at buying a dual purposer water heater for my heat and DHW. Somebody told me i should get 199,000 btu just for my wife to take a shower. It seems i should almost be able to steam clean my truck with that btu. I would love to hear some input on these dual purpose water heaters
 
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Old 01-30-13, 04:36 PM
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Give us a link to the heater that you are considering. Remember that it takes one BTU to raise the temperature of a pound of water one degree Fahrenheit. There are about 7.5 pounds of water to a gallon.
 
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Old 01-30-13, 04:48 PM
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Old 01-30-13, 04:58 PM
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Just a note chip has a thread going here regarding this.

http://www.doityourself.com/forum/wa...-any-good.html

Chip I also see you started another thread with this question in water heaters again... I deleted that thread.


Why not just post back to your original that I merged for you per your request? Almost seems like your advertising or something....
 
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Old 01-30-13, 04:59 PM
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?? ?
 
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Old 01-30-13, 05:05 PM
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lord no im not advertising.. Im just sick of buying oil when i can could be hooked up to my free gas. I just want to know what peeps think of dual purpose water heaters for heat and DHW
 
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Old 01-30-13, 05:25 PM
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In that case, I would recommend that since you are asking the same thing again, to go back to the original thread you started and continue from there.

It's too confusing to have multiple threads on the same subject in different forums. Pick one and stick with it.

I think this new thread should also be merged into that one also...
 
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Old 01-30-13, 05:32 PM
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Last night I had two threads going. you responded to me that 199,000 btu for DHW was way a lot. I referred you to the other thread in plumbing that suggested it. Those two threads were merged last night and somehow I lost everybodys interest (that thread is still there in water heaters.) Sorry I was just trying to keep it at the forefront but I shall cease
 
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Old 01-30-13, 06:01 PM
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OK lets put it this way. You need to do a heat loss of the home that will dictate the size boiler you need.

Now with the combi boiler. If you went with your brand and a 99k unit here, it would be probably too big for your home heat wise, but it does modulate. Only down to 48 k. On the flip side the HWH capacity may be insufficient.

See here that at 50f water a 120f shower only produces 2.6 gpm. Thats one shower. Cant run nothing else that requres hot water. The unit will shut off. Do you take a 120f shower? I dont.....



http://www.quietside.com/images/Quie...al 12-2009.pdf

Now lets get to what will satisfy your HW needs..... Oh the 199k!!!! Looky there....4.4 gpm @ 120f water with 50f incoming... But holy cow 199 k on the boiler end? Yes but it modulates down to 26k. So may be the better choice.

http://www.quietside.com/images/Quie...al 12-2009.pdf

Again do a heat loss. And remember these type boilers you still have to wait for hot water, and you get the hot and cold sandwich effect with them unlike traditional HWH's. These are big bucks too.

Free gas? I would through a traditional dual 40 gallon HWH's in. Couple that with a traditional regular eff boiler per your heat loss....


I dont like the combi units myself because of the fact I described above. I would install two seperate units if you insist on the mod cons types. Install a boiler per your heat loss and a tankless by your GPM needs.
 
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Old 01-30-13, 06:36 PM
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I dont have a preference for mod con. Im just looking for input
 
 

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