Tankless water heaters. Any opinion?

[rumdrinx]

Long story short: am looking into water heaters for a house at the shore. people keep talking about tankless water heaters but there is actually a plumber down there who claims that since it needs to draw more air to operate, the more salt air it will naturally absorb and is less durable than a " regular" water heater. Does anyone have any comments about this? Thanks so much for your help and opinions (and link to resources if you have them - this is the sort of thing on which i need to provide back up)

[Red Rooster]

I jsut bought a new 50 gallon tank. I was looking at tankless, but the venting would not work for my home. You can't vent it through the existing chimney like my current HWH. It needs to be vented Horizontally through a wall or Vertically through the roof.

I'm not sure about the salt air factor. I hope this helps.

[StanfordGable]

I jsut bought a new 50 gallon tank. I was looking at tankless, but the venting would not work for my home. You can't vent it through the existing chimney like my current HWH. It needs to be vented Horizontally through a wall or Vertically through the roof.

I'm not sure about the salt air factor. I hope this helps.

Is your chimney diagonal? I doubt that's up to code. Please explain because you have me laughing pretty hard. I'm gonna read it again.

[elfreth]

High efficiency gas heaters can't vent via a regular (brick) chimney since the exhust is so cool it will condensate on the brick inside the chimney. You vent with PVC pipe usually.

I would ask a manufacturer regarding the 'salt air' factor.

[StanfordGable]

High efficiency gas heaters can't vent via a regular (brick) chimney since the exhust is so cool it will condensate on the brick inside the chimney. You vent with PVC pipe usually.

Gotcha....that makes sense. What about a lined chimney?

[elfreth]

Gotcha....that makes sense. What about a lined chimney?

no idea. I just knew about the high eff because I got a high eff gas heater in my last house and I was told about the PVC venting. Mine was done horizontal. Ultimately you can't have water coming back the vent, so I would think that a high chimney and possibly a wide vent\chimney may not work either since it provides more cooling area (both length and diameter).

[johnnie]

I just saw them install a tankless water heater on This Old House. The exhaust from the tankless is much less volume/speed so it cant make it all the way up a typical chimney. The moisture condenses and will comeback down or rot out your chimney.

They installed a horizontal flue with an inner tube for the exhaust with an outer tube to bring in fresh air. They also had a condensate tube from the base of the flue running to a sink/sump pump to get rid of any condensate running back to the tankless heater.

Dont know about the salt in the air ruining the equipment. Most are stainless steel so I dont think it would be a problem, but check with a manufacturer.

[bluecuracao]

Have you looked into electric tankless, rather than gas? That might be better for you.

[GMonkey]

I've only heard awesome things about them. Everytime the tankless water heater commercial comes on tv, my husband gets a woody about it. I'd talk to the manufacturer, as well as a plumber who is hip to modern technology. I can imagine an old-school plumber trying to talk you out of it because it may be out of his realm of expertise.

[ShoshTrvls]

I considered tankless a few years ago, but the big stumbling block for me was that it would have required a pretty expensive upgrade to my electrical system, since they run on a higher voltage than most households are equipped for. Or at least that's my understanding.

[Scoats]

We just installed a gas tankless water heater in my house. Luckily we were able to vent it outside. I have mine set hotter than my old tank heater since there's no waste in heating and reheating water that's not being used. I'm enjoying the hotter showers.

The biggest surprise for me is the wait factor. You have to run the water for a good 60 to 90 seconds to get hot water. I have yet to figure how what the minimum flow of water to get the heater started up is. Also, I could be wrong, I think the water pressure in my shower has lessened with the installation of the tankless heater.

[HogIslandGrip]

Hate mine! Hate mine! Hate mine! Hate mine! Hate mine! Hate mine! Hate mine!

Where to begin.

I think placement is everything. The farther away from your points of use, the worse the performance. Mine is about 40' away from the shower head, thanks to the stringent venting requirements.

Electric whole-house models require at least three breaker spaces, usually 60 amps each, and heavy gauge cable as well. It's possible I may switch to one of these, as I have the breaker space for it, but...

Another consideration is flow rate. Most articles I've read talk about the maximum flow rate. None of them discuss the MINIMUM flow rate required to activate the heater. Mine is a Bosch Aquastar 2400, and it's minimum flow rate is .8 gal per minute. That's kind of high. When I get the temperature of the shower comfortably adjusted, the hot water flow goes below the minimum and the tankless unit shuts off. About a minute later there is nothing but icy water, so I'll readjust the valve, wait another minute, and now the water is scalding, so I adjust it again, and the whole cycle repeats. I've started taking showers with the bathroom faucet running in order to keep the hot water flow rate up. And wasting water.

With simple hand washing, I turn the water on, wait then get impatient. I finally wash my hands, and just after my final rinse, I might get some hot water out of it. I've just paid to heat water I didn't use. Kind of like a tank.

And forget about a nice trickle of warm water. It's not happening, thanks to a high minimum flow rate.

I also haven't noticed a significant change in my gas usage from before the installation of the tankless. So much for savings there.

Now, I still think it's a neat concept. I will probably install a small point-of-use unit in my shop bathroom, right next to the sink. If I were to do the house all over, I would probably go with two or three smaller tankless heaters placed as closely as possible to each point-of-use.

I do know other folks with tankless heaters, and they are having varying experiences. Cpnmarko, for instance, has a Paloma Legacy series, which has a lower minimum flow rate, but also requires a pilot light. He has not had the same issues that I have had. Another friend has the Aquastar 1500, which also has a lower minimum flow rate, but their shower is also equipped with multiple wall jets, thus increasing flow rate.

As it stands now, I'm probably going to sell the unit on craigslist to someone who has more appropriate conditions for it, and I'll get a high-efficiency tank model to replace it.

[HogIslandGrip]

Oh yeah, my water usage has indeed gone up since before installation.

[Red Rooster]

I'm installing my new 50 gallon tank this weekend. I will be installing Solar PV and water heating this spring, so the gas usage isn't an issue.

Also, don't take the advice of the amateurs at your local home centers, or Plumbers looking for a quick buck. I was looking at the Paloma at HD and the "expert" there said that there was no difference in venting. I called Paloma's customer service hotline and was told the truth about the venting.

[rumdrinx]

this is a nice chunk of information! thanks so much. keep it up.

basically, we need to pick a hot water heater for a family house remodel at the shore. one family member is shouting Tankless from the mountain tops, and will not take a local jersey plumber's word for it. So, as the family member with more netsurfing time ( yet with admitedly less knowledge about water heaters than any of them to begin with!) my homework was assigned to come up with pros and cons of these tankless gizmos, and/or pros and cons of "regular" hot water heaters.


I am not sure how the family is leaning vis à vis gas or electric - I know that we have access to gas so at least we have an option of either one of them.

HIG your post is very very informative!

[johnnie]

this is a nice chunk of information! thanks so much. keep it up.

basically, we need to pick a hot water heater for a family house remodel at the shore. one family member is shouting Tankless from the mountain tops, and will not take a local jersey plumber's word for it. So, as the family member with more netsurfing time ( yet with admitedly less knowledge about water heaters than any of them to begin with!) my homework was assigned to come up with pros and cons of these tankless gizmos, and/or pros and cons of "regular" hot water heaters.


I am not sure how the family is leaning vis à vis gas or electric - I know that we have access to gas so at least we have an option of either one of them.

HIG your post is very very informative!

Is this just a summer house? I mean is it only going to be used sparingly? If so, having a tankless would be the way to go. Even turning down the hot water heater to away while your not using it, would waste a lot of energy.

Just my 2 cents.

[CapnMarko]

tankless hot water heaters? - PhillyBlog - Philadelphia

We installed a Tankless Hot Water Heater last year and all is well. The plumber tried over and over again to talk us out of it because it would never provide enough hot water for what we will need. Fortunately he was completely wrong. He heard it from another plumber who heard it from another plumber and so on ... Also the way they rate the tankless models is different than the tanks it's not 30,40,50 gallons or whatever it's gallons per minute.

The big problem we had was that we didn't have a way to vent to the outside of the house our basement doesn't extend in the back under our kitchen, and you have to vent at least 7' up if it goes out toward a sidewalk. Or they require Category 5 or 3 or something really expensive venting for all the power vent/newer models.

So I found a legacy tech that vents through regular household venting (you just need 7 inch off the heater and then adapted down to what goes up your chimney.)

There is a pretty extensive discussion here ....

http://www.phillyblog.com/philly/ask...er-heater.html

And if you get a low flow shower head that takes 1.5 gallons per minute if your tankless is rated for 4 gallons per minute in the dead of winter you can be running 2 showers (we only have one so no worries there) and still have a gallon per minute for washing machine and/or dishwasher.

The only drawback is that it takes maybe 30-50 seconds for the water temperature to heat up, but it used to take almost as long for the hot water to work it's way through the pipes up the bathroom anyway.

As to energy savings probably not so much as when you can take a 5 hour hot shower you tend to ... were as in the past you'd jump out when the water started getting cold. But the thing should last a good 20-30 years (fingers crossed.)

My plumber was very vehement about it not putting out enough hot water but when in all my googling I kept finding these things being sold by car wash supply places and comments from car wash owners in Minnesota and such ... I was pretty sure it could keep up with a shower, washing machine and dishwasher all at the same time.

Easy way to be sure is just check your appliance manuals for how many gallons per minute they require at peak use, if you don't know what your shower uses put a bucket of a known # of gallons and time how long it takes to fill.

http://www.palomatankless.com/produc...gacy_ph24.html

[CapnMarko]

If your just going to use the home during the summer mostly you might want to look into a solar hot water setup. Solar hot water is super-efficent and can even be used rather successfully in the NE. But if you do winter trips or rent the place and want to insure hot water for even the cloudiest weeks you should have an in-line electric tankless as a backup.

EERE Consumer's Guide: Solar Water Heaters

There will be a much larger expense on this set up than just throwing a tank in there but the solar units have little wear on the parts so should hold up for years to come ...

[Red Rooster]

this is a nice chunk of information! thanks so much. keep it up.

basically, we need to pick a hot water heater for a family house remodel at the shore. one family member is shouting Tankless from the mountain tops, and will not take a local jersey plumber's word for it. So, as the family member with more netsurfing time ( yet with admitedly less knowledge about water heaters than any of them to begin with!) my homework was assigned to come up with pros and cons of these tankless gizmos, and/or pros and cons of "regular" hot water heaters.


I am not sure how the family is leaning vis à vis gas or electric - I know that we have access to gas so at least we have an option of either one of them.

HIG your post is very very informative!

Electric costs about 30% more to operate. I would stick with Gas. I think they all have a Vacation mode, which keeps it at a VERY low temperature while you are not at the house. Since it is probably a seasonal property, I wouldn't waste extra money on super efficient. You'll never make up the difference in investment.

[johnnie]

Electric costs about 30% more to operate. I would stick with Gas. I think they all have a Vacation mode, which keeps it at a VERY low temperature while you are not at the house. Since it is probably a seasonal property, I wouldn't waste extra money on super efficient. You'll never make up the difference in investment.

Good point but some advantages of a tankless are it won't bust after +/- 10 years and flood your property, unless installed with a pan and drain, and it's lifespan is 2-3 times as long as a tank HWH. Also, you have to rely on people using your property to turn the thermostat back down when leaving.

If youre gonna hold the property for 20 years or so Id go with the tankless. I think you would make the investment back in the long run.