Help me pick a water heater.


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Old 03-21-13, 07:47 PM
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Help me pick a water heater.

Ok we're building a new house and I've been doing a lot of reading on different things and am trying to make everything the best way the first time.

Our house is in Iowa and it will be a 2200 sq. ft ranch. 2 and 1/2 bath

I've really been looking at going with a tankless system. I know everyone says they're not as efficient as the claims are. My main reason is for the never ending supply of hot water. There are 5 of us in the house and I like the idea of never running out of hot water or even being able to take 2 showers or run dishwasher etc.. at the same time.

Our master bath will also have a large jetted tub and I'm afraid a conventional water heater won't have the capacity to even fill it.

We are looking for a natural gas system. Sky is pretty much the limit right now. The house will start being built in the next couple weeks if the weather would straighten out.

Thanks,
Matt
 
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Old 03-21-13, 09:15 PM
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Most tankless you will need the benefit of a buffer tank. That is an added expense..

IMO look for a heater that combines the features,,,


NEXT Hybrid® Gas - Water Heaters Residential by A. O. Smith

Or go with the 90 % vertex.


NEXT Hybrid® Gas - Water Heaters Residential by A. O. Smith

Just my two cents.....
 
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Old 03-22-13, 04:58 AM
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So those units are a tankless with a built in tank then?
 
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Old 03-23-13, 05:22 AM
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Ok, I've now had a chance to do a little more reading up on NEXT model and it looks like it would be a pretty good unit.

Have you ever used or seen one in use? Can it keep up with a normal tankless model? Would I be able to run 2 showers or like a shower/dishwasher at the same time without running out of hot water?

Thanks,
Matt
 
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Old 03-23-13, 05:39 AM
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Our master bath will also have a large jetted tub
That's the question I ask my clients when they go to remodel and include a jetted or whirlpool type tub in the mix. They hold 40 gallons of water, you have a 30 gallon water heater. What will you do for the remaining 10 gallons of cold water introduced? Internal heaters can do just so much.

Mike seems to have a good idea for your large demand, and you are doing right to research it thoroughly.
 
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Old 03-23-13, 06:25 AM
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The problem with large jetted tubs and tankless heaters is the GPM. Often the faucets used for these tubs are upwards of 9 gpm or more.

Is it a room issue not to go with tank type units?

Have you ever used or seen one in use? Can it keep up with a normal tankless model? Would I be able to run 2 showers or like a shower/dishwasher at the same time without running out of hot water?

I have never seen one or used one. But what AO smith is doing with that heater is what plumbers typically do on normal tankless heaters. It is a tankless heater with a buffer tank.

Navian does it too but AO smith has a larger tank.

The next says 120 g recovery @ 90f rise... Thats huge and at 140f water. Lower it to 120f and goes even higher.

Have you thought of going green with solar?


Other options would be dual tanks. Two 50g or two 40g. The thing with the dual conventioal tanks is its needed for the big tub. Often people dont use these tubs and shut down one of the heaters after the inspections are over.

I will research the next more. I think it can handle what you ask, but tell me how big the tub is? Often they are 80 gallons or so.
 
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Old 03-23-13, 07:30 AM
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after further review the next may not be for you if you need high draw.... The next eqates to about 2 gmp after the 25 gallon tank empties.


Another question is how are you heating the home? If going with a boiler then plan on an indirect. Having a home built are you taking advantage of installing a radiant heating system?

Hydronic heat is far superior IMO then hot air....
 
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Old 03-24-13, 07:20 AM
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I've never really considered solar just because I figured the recovery time would be way to long for what we would want.

We will have a full basement under the house. Size of the units aren't really an issue I can pretty much make the mechanical room as big as needed.

For the heating and cooling we are going with a normal Nat. Gas forced air furnace and are going with an air-air heat pump for cooling/heating as well. I'm running all the tubing in the concrete in the basement and garage for a radiant floor system to be hooked up in the future.

I'm not real sure on how many gallons the tub will hold. I'd have to talk to the builder to find out.

A little more info on the house. The walls will be an r22 on the main level, basement will be insulated under the slab with 2" of foam and so will the walls. The attic will be blown in with an r60 rating.
 
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Old 03-24-13, 10:38 AM
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Hmm...I don't understand why you would want a forced air system or heat pump in IA.

Building a new home I would certainly do all radiant with a high eff modulating boiler. Too many people just go with what the builder wants to install. Its cheaper for them IMO.

IDK maybe others will chime in...

Basically I would just install two 50 gallon standard power vents. You will need two tank less heaters with a btu rating of 199k btu each probably if you have a big soaking tub. And that may not be enough for the 9 gpm +++ tub faucets that are out there.
 
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Old 03-24-13, 01:11 PM
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I am the builder for my house. I would say that 90% of houses in this area use a forced air system. And a lot of them are upgrading to air-air heat pumps for the added utility savings over a plain furnace application.

Please fill me in on the radiant systems. I know how to do it with the tubing in the concrete in the basement. How do you go about doing it on the main level? I know you can put the tubing up in the floor joists but I would think that would be pretty inefficient with having to transfer the heat through the wood in the floor. I do not like having the baseboards along the walls or the free standing radiators. It's still definitely an option at this time.
 
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Old 03-25-13, 08:06 AM
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Well I will try to address all issues if I can. Hopefully others will chime in.

First off a hydronic heating system offers better temp control over hot air. Modulating boilers fire rates varies with heat loss which saves fuel. Additionally you have better zone control with heating different parts of the home. Hot air systems are often on or off with one fire rate.

Here are temperature examples.




Read here. Uponor is an example of radiant heating products and best way to install IMO. You dont want the staple up method. ( I am not affiliated with this company and is for reference only.)

Uponor - Radiant Floor Heating

Here is another system heatply. There are many out there but this is an example. If your building a home radiant is best installed before the floors are put in.

I am just trying to show you that there are better ways to heat the home then hot air.



http://www.youtube.com/watch?v=GV8dJgfyOnc&playnext=1&list=PL907A5ED857CFD38F&feature=results_main
Aside from infloor heat and if you do not like the look of baseboard you can use attractive panels. This is for example only. There are many manufacturers.

http://www.runtalnorthamerica.com/re...08Hydronic.pdf


I know how to do it with the tubing in the concrete in the basement.
Maybe its better to use a system and keep above the cement....????
 
 

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