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-   -   Are tankless water heaters a good choice for the midwest (http://www.diychatroom.com/f7/tankless-water-heaters-good-choice-midwest-29713/)

darkman32 10-10-2008 05:56 PM

Are tankless water heaters a good choice for the midwest
 
I live in Chicago, IL and have heard that tankless water heaters aren't a good choice in this region. How true is this? I know heat pumps dont do so well in this area but is that also true for tankless water heaters?

Marvin Gardens 10-10-2008 06:05 PM

Quote:

Originally Posted by darkman32 (Post 170637)
I live in Chicago, IL and have heard that tankless water heaters aren't a good choice in this region. How true is this? I know heat pumps dont do so well in this area but is that also true for tankless water heaters?

Is this going to be gas or electric?

When people tell you they are not good for your area do you ask why?

I would be interested to find out why they say that.

jerryh3 10-10-2008 06:21 PM

Quote:

Originally Posted by Marvin Gardens (Post 170642)
Is this going to be gas or electric?

When people tell you they are not good for your area do you ask why?

I would be interested to find out why they say that.

It's probably because of the incoming water temperature. I think some tanklesses have a hard time making up the difference with a low incoming temp.

Marvin Gardens 10-10-2008 06:40 PM

Quote:

Originally Posted by jerryh3 (Post 170652)
It's probably because of the incoming water temperature. I think some tanklesses have a hard time making up the difference with a low incoming temp.

Ground temperatures are less in Oregon and the tankless units are the big rage here.

http://www.greencastonline.com/SoilTempMaps.aspx

ScottR 10-10-2008 11:03 PM

jerry probably hit the nail on the head about groundwater.. I'm assuming that beacuse you're asking you're considering a tankless HW heater? And b/c I'm bored, I wrote all this.

The tank vs. tankless is an old debate.. There's _tons_ of discussion and information on the web already, so I'm loathe to jump into it here. If you Google "tankless vs. tank water heater" you'll probably get a lot to read and wind up more confused than before. (I've done it).

The fact is that there are a few main things to consider:

- Your water usage.

- The efficiency/age of your current HW heater.

- The cost of installing the tankless system vs. how much you'll save.

For example, if you had a vacation home, or you just didn't use much hot water, then tankless would probably work well for you. Heavy hot water users will generally not get that much more efficiency from a tankless.

If your current HW heater is aging and probably not too efficient, you'd see a big difference going tankless. Then again, you might see a big difference just getting a new tank. :)

Finally, cost-wise, a tankless system is more expensive (both for the unit and for the installation -- it's not a "drop in" replacement for a tank unit), so if you are a heavy hot water user, it may take more years for the tankless unit to pay for itself than it will last. Though if you need a new HW heater anyway, you'd be spending some of that money no matter what.

Sooooo, I guess my point is that for Chicago or anywhere else, it really depends on a bunch of factors how well it will work for you. If you definately want to go tankless, modern units deal better with cold groundwater temps than older ones -- depending on the model, they can monitor incoming and outgoing water temp and "throttle" the burner (or electric element) accordingly.

BTW, regarding that tankless isn't a "drop in" replacement for a tank: You'd probably need better venting, maybe a bigger gas line to the unit than to your current HW heater, almost certainly the gas line would have to be moved a few feet (if gas), maybe a higher current circuit (if electric), and water pipes would have to be moved.

I'm not saying that to dissuade you, but if you're not planning on doing that stuff yourself, it can really add to the cost. More so for gas than electric, though it depends on what you have in place now.

Termite 10-10-2008 11:29 PM

Quote:

Originally Posted by ScottR (Post 170753)
jerry probably hit the nail on the head about groundwater.. I'm assuming that beacuse you're asking you're considering a tankless HW heater? And b/c I'm bored, I wrote all this.

The tank vs. tankless is an old debate.. There's _tons_ of discussion and information on the web already, so I'm loathe to jump into it here. If you Google "tankless vs. tank water heater" you'll probably get a lot to read and wind up more confused than before. (I've done it).

The fact is that there are a few main things to consider:

- Your water usage.

- The efficiency/age of your current HW heater.

- The cost of installing the tankless system vs. how much you'll save.

For example, if you had a vacation home, or you just didn't use much hot water, then tankless would probably work well for you. Heavy hot water users will generally not get that much more efficiency from a tankless.

If your current HW heater is aging and probably not too efficient, you'd see a big difference going tankless. Then again, you might see a big difference just getting a new tank. :)

Finally, cost-wise, a tankless system is more expensive (both for the unit and for the installation -- it's not a "drop in" replacement for a tank unit), so if you are a heavy hot water user, it may take more years for the tankless unit to pay for itself than it will last. Though if you need a new HW heater anyway, you'd be spending some of that money no matter what.

Sooooo, I guess my point is that for Chicago or anywhere else, it really depends on a bunch of factors how well it will work for you. If you definately want to go tankless, modern units deal better with cold groundwater temps than older ones -- depending on the model, they can monitor incoming and outgoing water temp and "throttle" the burner (or electric element) accordingly.

BTW, regarding that tankless isn't a "drop in" replacement for a tank: You'd probably need better venting, maybe a bigger gas line to the unit than to your current HW heater, almost certainly the gas line would have to be moved a few feet (if gas), maybe a higher current circuit (if electric), and water pipes would have to be moved.

I'm not saying that to dissuade you, but if you're not planning on doing that stuff yourself, it can really add to the cost. More so for gas than electric, though it depends on what you have in place now.

What he said. :thumbsup: Tankless installations are not for the average DIYer, whereas conventional water heaters are more DIY friendly.

jogr 10-13-2008 02:59 PM

Quote:

Originally Posted by Marvin Gardens (Post 170659)
Ground temperatures are less in Oregon and the tankless units are the big rage here.

http://www.greencastonline.com/SoilTempMaps.aspx

Interesting map but those are today's temps. Check Chicago's soil temps in January and see how they compare to Portland.

Marvin Gardens 10-13-2008 03:07 PM

Quote:

Originally Posted by jogr (Post 171816)
Interesting map but those are today's temps. Check Chicago's soil temps in January and see how they compare to Portland.

Yea, I saw that after I posted.

The water is below the frost line in Chicago and is in the range of 50-55 degrees and so the water will come out at that temperature.

My vacation home is in the desert and we have similar temperatures to Chicago only we get up to 120 in the summer. No matter what the temperature is it comes out of the tap at about 55, give or take a few degrees, year round.

My point is that the water temperature is consistent and is not a reason to not install a tankless water heater.

There has to be a more compelling reason to not want to install them.

ScottR 10-13-2008 03:17 PM

Quote:

My point is that the water temperature is consistent and is not a reason to not install a tankless water heater.
Where I am in NY cold water temp varies quite a bit. Water from the tap is ice cold in winter, and coolish in summer.. I know that's not the most scientific assessment, but it's enough of a difference to be noticeable.

But agreed, it's not a reason to eschew a tankless because modern units can keep up...

jogr 10-13-2008 03:37 PM

Quote:

Originally Posted by Marvin Gardens (Post 171820)
The water is below the frost line in Chicago and is in the range of 50-55 degrees and so the water will come out at that temperature.

My point is that the water temperature is consistent and is not a reason to not install a tankless water heater.

There has to be a more compelling reason to not want to install them.

The constant water temp story is a myth. Like Scott, our water temp varies considerably by season and 40s water temps in mid winter are common. If you check the charts it takes quite a monster unit to bring 43F water up to 120F at a decent flow rate. With the good insulation found in tank water heaters these days it all boils down (pun intended) to your water useage and existing gas/electric infrastructure as to whether a tankless heater is economical.

Marvin Gardens 10-13-2008 03:44 PM

It would be interesting to see what the water temperature is coming out the tap water year round.

I know I can cool my vacation home with ground water at 55 degrees after months of 90+ weather and no rain. It is only buried about 6 feet down.

jogr 10-13-2008 03:52 PM

Quote:

Originally Posted by Marvin Gardens (Post 171841)
It would be interesting to see what the water temperature is coming out the tap water year round.

I know I can cool my vacation home with ground water at 55 degrees after months of 90+ weather and no rain. It is only buried about 6 feet down.

I'll have to try to remember to check in January. 6 feet is nice and deep. I bet most around here aren't that deep.

ScottR 10-13-2008 03:54 PM

Quote:

Originally Posted by Me
Where I am in NY cold water temp varies quite a bit. Water from the tap is ice cold in winter, and coolish in summer.. I know that's not the most scientific assessment, but it's enough of a difference to be noticeable.

Woops.. What I said is valid, but it's not a good counter-argument to the ground-temperature issue. Just remembered that all of our water comes from wells and then up into water towers. Then it goes underground.. So it's probable that the air temp has a lot to do with our water temp. Those water towers must be insulated, but 20deg in the winter and 100deg must make a hell of a difference.

NYC's water goes through open resivoirs between source and delivery. Must be decent temp changes there too.

I guess the lesson to be learned is that water delivery factors in as well as ground temp. So back to the OPs question, that could be why tankless WHs don't work as efficiently in Chicago. Not sure how you guys get your water though.

Quote:

Originally Posted by Marvin Gardens
I know I can cool my vacation home with ground water at 55 degrees after months of 90+ weather and no rain. It is only buried about 6 feet down.

I'd love to use geothermal.. Off topic question, but how difficult was it to install the loops? How many sq. ft. of your yard did you dig up? (Edit: I'm assuming you're using horizontal ground loops here.. Let me know if that's not the case.)

Marvin Gardens 10-13-2008 04:20 PM

Quote:

Originally Posted by ScottR (Post 171846)
Woops.. What I said is valid, but it's not a good counter-argument to the ground-temperature issue. Just remembered that all of our water comes from wells and then up into water towers. Then it goes underground.. So it's probable that the air temp has a lot to do with our water temp. Those water towers must be insulated, but 20deg in the winter and 100deg must make a hell of a difference.

NYC's water goes through open resivoirs between source and delivery. Must be decent temp changes there too.

I guess the lesson to be learned is that water delivery factors in as well as ground temp. So back to the OPs question, that could be why tankless WHs don't work as efficiently in Chicago. Not sure how you guys get your water though.



I'd love to use geothermal.. Off topic question, but how difficult was it to install the loops? How many sq. ft. of your yard did you dig up? (Edit: I'm assuming you're using horizontal ground loops here.. Let me know if that's not the case.)

The thing about water is that it all goes underground at some point. My guess is that it spends enough time there to assume that temperature whatever that might be.

As for my ground loop I have 2 setups that I have put in. One at my rental near my vacation home and another at my vacation home.

For one I used 300 feet of 1/2" pex in 2 trenches at 6 feet. Each trench went out about 60 feet and I put an outgoing and incoming in each trench. So it was 60 feet out and 60 feet back and then over to the second trench which about 10 feet away and out 60 and back and then into my system.

The rental used 3/8" pex and I put in 1000 ft. It was in a smaller yard and I put it in 20 foot trenches, 4 I think it was, and went back and forth till I started to run out of pipe.

The advantage of 3/8 is there is more surface area per volume of water to cool it faster. If I had it to do over again I would use 3/8" at my vacation home also.

The disadvantage is that 3/8" will kink easier and needs to me handled carefully.

Does it work. Oh yea and it is real cheap once it is installed. I just put in a thermostat and a Taco pump and when it gets too hot the pump goes on as does the fan blowing the air through the A coil I pulled out of a furnace we were replacing.

ScottR 10-13-2008 06:10 PM

Quote:

The thing about water is that it all goes underground at some point. My guess is that it spends enough time there to assume that temperature whatever that might be.
True, but if the ground is a steady 55, then it must be changing temp somewhere else, no?

Quote:

Does it work. Oh yea and it is real cheap once it is installed. I just put in a thermostat and a Taco pump and when it gets too hot the pump goes on as does the fan blowing the air through the A coil I pulled out of a furnace we were replacing.
No compressor? Is the coil relatively cold enough to pull humidity out of the air?

Good to know.. And yeah, I can imagine how cheap that is if it's just a pump and blower.

Sadly I can't just go digging up my yard.. I'd need a permit, and therefore the work would all have to be done by someone licensed which makes the cost absurd.. etc. I'd do it anyway, but someone's bound to notice. :) You do all the digging yourself? Bobcat? (Can't do that by hand..)


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