Tankless Hot Water Heaters

[JohnGuc]

I think this is a good place to ask this since geo has the desuperheater options which suppliments or replaces hot water so Im hoping that some of you have experience with tankless water heaters

Im looking at replacing my furnace possibly with geo

If I do this I would like to use a desuperheater to replace the electric water heater it is 80 gallons and a pig using about 25kw electric per day

Or if I use a Air source heat pump would still like to possibly eliminate my electric water heater

The question is I probably wont be able to supply hot water 24/7 with the geo desuperheater
and if I use the air source heat pump no hot water supply at all

Is a tankless really efficient enough to warrant the replacement costs in the real world?
Ive read where it may not be effective enough in northern climates that have cold ground water
Im in Ohio 50* ground water I believe
Thanks
John

[SkyHeating]

If you want dedicated water just add a second geo unit! We add the WaterFurnace NSW018 or NSW025 with an 80-110 gallon storage tank and after tax credit it usually costs less than a tankless to install and is more efficient

[waterpirate]

When I gutted the boiler at my house and went geo, I lost my domestic hot water loop. So I was in a quandry. In my case it made sense to install a tankless propane dhw over geo because I have a 350 gallon whirl pool tub in the master bath. I need large volumes of hot water, intermitantly. Made more sense than to do it with geo.

Tankless is a lot like variable speed water pumps in that they have applications where they really shine, but in alot of cases it is more cost effective to get it done with traditional equipment. For dhw it is about the volume needed and storage.
hope this helps
Eric
p.s.
I installed a Navien, purely for the ease and less expense of the intake and exaust piping being conventional pvc pipe. My install would have prompted the purchase of many dual wall pipe joints had I went with other brand.

[JohnGuc]

Sky
I understand the concept that another geo might be more reliable
But dont see how it could possibly end up actually be cheaper in the long run
The difference in costs of the equipment is huge 10's of thousands different isnt it?

Waterpirate
I would most definitly want the pvc vents heard the vent pipe costs almost as much as the heater
Do you find it really could be worth replacing a perfectly usable tank even with the cold ground water for the tankless?
I believe Delaware is about same climate as here in Ohio

[SkyHeating]

JohnGuc, I think geothermal water heating(if you are already doing a geo system and loop) will cost the same if not less than a tankless after install and tax credit, not to mention be about double a tankless efficiency(up to four times if it's LP gas)

I can tell you more about pricing etc offline my name is Travis and you can find my email on my website

[waterpirate]

Everything in the world revolves around economics, and usage. In my application the high intermittant usage took geo hotwater off the table as well as storing that amount of hot water for intermittant high usage. Tankless for me at that point was a no brainer. If I had not been location challenged by my old farm house I may have looked at feeding the tankless via a buffer tank hooked up to the geo, but the tankless is in a outbuilding some 70 feet from the nearest compressor section of geo.

The unit I bought has a setting for well water to address this issue. Sans the whirlpool tub that we do not use all the time we could have had a lot of other more cost effective options. I wound up installling a unit that produces 3.5gpm of finished water at 135 deggrees.
Eric

[JohnGuc]

The system Im looking at is the ClimateMaster 27 or 30 with desuperheater
There doesnt seem to be any competent WaterFurnace dealers near me I already had what appeared to be the best one try to talk me out of geo altogether

Got some estimates from the Climatemaster guy today
It was between a Geo and a air source heat pump with a solar array to supplement electric
The Solar ends up being to expensive for only about 9kW per day supply

So looks like probably geo he's going to also quote an air source high efficiency just to make sure the cost to operate numbers of the geo are as good as we think

He really seems to believe from what he has seen the the tankless are oversold that they really arent as great as the manufactures say I tend to believe him
He even thinks that a high efficiency propane tank heater probably is way better then my electric tank

Looked up the WaterFurnace NSW018 number I see that this is a water to water dedicated geo
unit I didnt realize that it was stand alone Im going to see if Climatmaster has something like that
Can that be done without adding to the loops?
Also saw something about it making basement cold?

Thanks
John

[waterpirate]

Again the question comes back to how much hot water does your house consume, in the 2 peak periods? Before work and after dinner. If you do not have high, intermittant, or consistant hot water usage a tankless may not be the best option for you.
Eric

[JohnGuc]

Well I think its fairly consistent day to day
I use about 25kW worth of electric per day
It cycles about 4 times on a 80 gallon tank I figured about160 gallons a day
Im aiming to get the electric down Im averaging 80kw per day which is very high bills

[waterpirate]

Given the amount of hot water usage just figure out what it costs to produce and maintain 160 gallons of hot water useing electric vs. the cost of fuel for the tankless being fed with buffered water from the geo + total cost will give you a rough ROI. If you are going geo anyway, start by feeding your existing unit with buffered water and see what you get.
Eric

[JohnGuc]

Well its costing me about 1200 a year for water
The contractor is going to look into the geo for water generation and see what we come up with

What about the cold basement concerns is that real?
If we generate hot water we get cold air right?
where would it go?

[SkyHeating]

What about the cold basement concerns is that real?
If we generate hot water we get cold air right?
where would it go?

John, for your and other references a geothermal water heating system does make the basement or wherever the water heater is cold. The reason you may think this is an air source heat pump water heater does take heat out of the air in the basement and makes it cold. Since a ground source heat pump uses water in a loop that is the only area that cold will be expelled.

[JohnGuc]

After researching all 3 sources for the hot water
Geo
Heat pump
Tankless
They all seem to have their pros and con's
Biggest con for all is initial cost
And possibly not really good return on the pro side that their technology promises
I think Im going to wait a little and see if there are improvements and lower initial costs later
I have til 2016 to do the geo and get the tax credit
That would be my preference

Thanks
for the help
John