Tankless water heater

Greebo said:
But those rules of faster heating vs. slower heating efficiency are NOT RELEVANT to the issue of tank based standby losses. Your tank type water heater HAS to keep the water hot all day. It doesn't just heat the water then shut off til you use more water, it heats the water, and if you don't use it, it will still kick on again in a while to maintain temp. THATS the energy loss you don't have with tankless.

http://en.wikipedia.org/wiki/Water_heater#Tankless_heaters
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That's what I tried to say. If you use a slow recovery tank type (very efficient heating) but will loose some to maintaining. Compared to fast heating tankless (Less efficient) but does not loose to maintaining. You would break even. My boiler has the highest eff rating because it is variable heating (Only uses as much energy as needed to heat the water). So the slower you heat the water the better eff you get. The rep was right. Heating it faster lets more energy out the pipe without heating the water. You cannot just say one is better than the other without knowing how it is used. Washing your hands once a day with a 50 gallon hot water tank is not going to be as good as a .7 gph tankless. But heating a space with a slow recovery (sized right) tank heater is going to more eff than a 10 gph tankless.

Dan
 
Replacing my single handle valve with dual valves sounds like a fairly cheap solution. I've got to fix/replace a shower valve soon anyway so I'll give it a try.

Bruce
 
Diana said:
Somebody suggested that we replace the hot water heater in the hangar with a tankless, on-demand water heater that just hangs on the wall. We'd never heard of those before. Does anybody have experience with those? I heard that you can get some kind of tax credit if you have one.
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I've used several brands that have pretty much all worked equally well. The gas fired ones are about as an efficient way to get domestic hot water as there is. The thing I really like about them is there is no running out of hot water.
 
Do you need to replace the water heater or just looking for an alternative way of heating the water? If your tank is still good and looking for a cheaper way to heat the water, go solar. You have a perfect location for that with the hangar being open to the south sky. If you just want to replace the water heater in the apartment, you might want to just go with a small 10 gallon. No more than it gets used, why heat 40 or 50 gallons. You could leave it turned off when not in use and turn it on a few hours before your guest arrive and it will be hot. It would be just the right size for one - three people.
 
Dean said:
Do you need to replace the water heater or just looking for an alternative way of heating the water?
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We found out that there was a crack inside the heater. After doing some research, we decided to just go ahead with replacing it and keeping it in the same location. Otherwise we would have needed to do a lot more work to go tankless.

Thanks again everybody for your input. :)
 
one useful addition when putting the new water heater in might be a catch pan under the tank, plumbed to the nearest drain ...
 
gkainz said:
one useful addition when putting the new water heater in might be a catch pan under the tank, plumbed to the nearest drain ...
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I was under the impression that this was required by code, now.
 
cameronbm said:
I've been using a Bosch Aquastar Tankless for the last 20 years. The only maintenance has been to replace the thermocouple. Basically, the beast sits on the wall and waits until you turn on the water then it ignites and makes sounds like a blow torch on steroids. Hot water hits the tap about a minute later.

You need to size the heater for the number of major hot water appliances you want to run simultaneously. The rule of thumb is that you need a 45 deg temperature rise at 6 gallons per minute to run 2 showers (or a shower and a dish washer, etc) simultaneously.

The biggest plus of a tankless is that you never run out of hot water. The biggest downside is that the temperature rise is dependent on the flow through the heater (the slower the flow, the hotter the water) -- this leads to the "scald-o-matic" phenomenon -- just after getting into the shower temperature just right, some clod will turn on a cold water faucet full-bore thus dropping the flow through the heater -- your shower goes from comfortable to you-can-cook-lobster-in-this in 3.2 seconds.

If you are in an area with hard water, you may want to put a water softener ahead of the tankless water heater. Hard water scale will kill a tankless heater much faster than its tanked cousin -- hey, the thing is basically a radiator sitting over a heat source; plug up one of those little tubes and the thing is tango uniform.

I've been happy with mine and would buy another.

Bruce
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I've been using the Bosch AquaStar for about five years. My experiences are the same as Bruce's. I would never go back to a regular tank water heater.
 
Greebo said:
I was under the impression that this was required by code, now.
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Chuck, when you live in the boonies, "Code" means... well, very little.

No permits, no building inspectors... stuff happens.
 
SCCutler said:
Chuck, when you live in the boonies, "Code" means... well, very little.

No permits, no building inspectors... stuff happens.
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Heck, happens in the city too.

I didn't get a permit when I added a new circuit for my computer room renovation. ;)
 
gkainz said:
one useful addition when putting the new water heater in might be a catch pan under the tank, plumbed to the nearest drain ...
Click to expand...

Greebo said:
I was under the impression that this was required by code, now.
Click to expand...

I intend to install the electronic system with a water sensor and solenoid valve that will kill the water supply. Rich Trethewy on "Ask This Old House" retrofitted one with the valve on the supply side of the water heater. I'd put it on the water main right after the meter and main shut off.

With multiple sensors you pick up water near the dishwasher, washing machine, fridge, etc. and have an instant shut down of the water so you don't come home to find your house is a indoor water park

Home Depot has it. Found it. The WaterCop http://www.homedepot.com/webapp/wcs...catalogId=10053&marketID=401&locStoreNum=8125
 
I install water heaters as a part of the HVAC business (I hate doing them but that's another topic for another day). In 10 years I have only seen one ruptured tank (seam). Most water heaters fail due to rust in the tank and start out as a slow drip. These are almost always over ten years old, and many times over fifteen years old. If your water heater is in a critical location, somewhere where a water leak could cause property damage then I would replace it every ten years. Otherwise monitor it regularly and replace it at twelve or so years. I have never seen anyone go to the trouble of installing sensors and solenoids to shut off the water. While I'm sure it's possible I'm not sure how practical it really is. A water alarm does make sense though.

BTW I see far more property damage from neglected air conditioning condensate.
 
I just replaced the kids' water heater and the cold water inlet on the tank has a slow leak - wells up into the recess after 3-4 hours ... any ideas? I've already removed and replaced the nipple (new, with verified clean threads) and used teflon tape on the fitting. Ideas?
 
I have had trouble with small leaks in the fittings in the tank before. They can be irritating. How many rounds of teflon tape did you use. You'll probably need 7-8 rounds. You really have to tighten them good. The threads are steel so there's little chance that you could over tighten.
 
gkainz said:
I just replaced the kids' water heater and the cold water inlet on the tank has a slow leak - wells up into the recess after 3-4 hours ... any ideas? I've already removed and replaced the nipple (new, with verified clean threads) and used teflon tape on the fitting. Ideas?
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Rich on Ask This Old House sometimes adds "wicking," which is string you wrap around the threads. He used it when he installed a new thermal valve on an old radiator
 
thanks, guys. I'm only using a couple of rounds of tape. I'll pile a few more on and give it a try. Also thought about the goopy pipe dope if more tape doesn't seal it up.
 
Just had to install a new water heater last week. I considered the tankless type, but the reviews I saw said the average savings on a tankless would take over 20 years to recoup the increased upfront cost.
 
Well, we just got home from a funeral in Milwaukee and found the new tank we bought this time last year leaking all over the place again. Now we're seriously looking at tankless again.
 
Diana said:
Well, we just got home from a funeral in Milwaukee and found the new tank we bought this time last year leaking all over the place again. Now we're seriously looking at tankless again.
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Is your current one gas or electric? Do you know where/how the new one failed? Most water heaters will have at least a 5 year warranty on the tank, so you may get warranty relief. I always think it's a good idea to use dielectric unions to help protect the tank from corrosion, might want to check into that, and make sure you don't have some stray current flowing in the piping that's accelerating corrosion.


Trapper John
 
Diana said:
Somebody suggested that we replace the hot water heater in the hangar with a tankless, on-demand water heater that just hangs on the wall. We'd never heard of those before. Does anybody have experience with those? I heard that you can get some kind of tax credit if you have one.
Click to expand...


I've used several, they are great, and for the hangar apt shower, they serve extra well $$$ wise since you don't keep water hot for all the ime you aren't using it. You never run out of hot water unless you run out of propane. In the apartment I was living in in London, we had an electric one that worked just fine, but I'm pretty sure you need 220 electric to work them.
 
Diana said:
Well, we just got home from a funeral in Milwaukee and found the new tank we bought this time last year leaking all over the place again. Now we're seriously looking at tankless again.
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Doesn't it have a warranty? It should be no sweat for it to last 5-10 years.

You must have some acidy weater.
 
Diana,

Should be covered under warranty if it's a year old.

As for tankless, I seriously looked at it a few weeks ago as I was having some issues with the current heater & the area where it's located is tight.

I found out that not only would the cost for the unit be pretty substantial (higher than the cost of a replacement gas unit + the work on the wall to get it in and out), but also that the gas line would need to be upgauged ALL THE WAY FROM THE METER. That alone would add $750-$1000 to the project. I've got a new electric panel and upgraded service, but if I went the electric route, it would be pricy, too.

I resolved the heat-trap issue and I'll keep the water heater running as-is for a bit longer.... I plan to do some remodeling in that room (and some overall plumbing work) in the near future - will schedule to do it then.

Every professional I talk to says that the tankless are *much* more expensive to install because they reguire much heavier gauge wiring and larger gas piping.
 
wsuffa said:
Every professional I talk to says that the tankless are *much* more expensive to install because they reguire much heavier gauge wiring and larger gas piping.
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We found the same thing. To get a tankless with the flow and delta T we needed has a monstrously big burner (something like 150 MBH). Also, going though the calcs, we would need more outside (combustion) air, which meant adding an air-to-air heat exchanger - the cost just spiraled out of control and ended up with a really negative rate of return. Too bad, they are a neat idea...


Trapper John
 
I put 4 to 6 electric tankless cold water heaters in per year for my client. Not by choice, this is what they specify.

In areas of hard water they are almost always replaced in the first year.
 
Our home water heater died a few months ago, and I looked at a tankless heater. It cost around $2400 installed (with a tax credit) versus around $800 for a tank. Main reason was that with a three floor house, it takes longer for the water to flow before you get hot water out of the tap. My friend has one in his hangar, and it works great- unlimited hot water!
 
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