Age old question - tank vs tankless

Koan

Hi all - asking for more wisdom please

Replacing a 40 gal gas HWH that is slightly undersized for family of 4. Has 3 full baths, laundry, Tubs are used for baths and showers. Options are 50 gal tank HWH - thinking Rheem, Kenmore, whirlpool. OR
tankless. Rannai, Noritz, Takagai.

Will be in basement, Baltimore city, Maryland (for weather and delta t), hot baths and long showers are normal.

I like the space saving of tankless and the idea of efficiency. I understand the venting cannot go up the chimney
Gas main is substantial. I know only way to make more instant is to use recirculating pump. I understand the occasional cold water sandwich

Last review of tankless brands was 2014. Looking for best option in type and brand and size.
I researched but no seems to be both objective and knowledable

please help - cold showers are a downer!

cutter

AOSmith would be my choice. Stay with the 40 gallon you have and change your bathing habits. You are being wasteful and teaching waste to your children. This might be a little over conservative. Years ago aboard ship we would get wet, turn water off, soap up, rinse off, and you are done.

Leon82

Buffer tank will fix the cold sandwich. Some have them onboard.

bob eck

Look at installin a Bradford White 50 gallon with 65,000 BTU input 110 gallons first hour and recovery of 70 GPH at a 90 Deg temp rise. Take your shower heads and change them to 1.5 GPM shower head. There are many good shower heads that work great. You can put a tempering valve looks a cash Acme tank booster mixing valve on the water heater. Turn the water temp up as high as it goes to 150 deg or higer and mix cold water with the hot water and you will get more hot water out of your tank type water heater. If you have room you could go to a 75 gallon tank that recovers 82 GPH not much difference. You could go to a tankless gas water heater 199,000 BTU input that will give you about 5.5 GPM at 70 deg temp rise. You should never run out of hot water. Need to upgrade your gas line and must vent sidewall with PVC pipe. Some tankless gas water heaters can be vented up the chimney with a plastic chimney liner kit from innoflue. If doing it this way this is the only unit that can be vented into the chimney. You are using the chimney like a chase.
Do you have a gas or oil boiler? Put in a indirect water heater and then you do not have to worry about venting the indirect water heater. Find a professional Heating or Plumbing contractor and they can go over the different options to make hot water.

njtommy

tankless is great, but if you need a ton of hot water you may need two of them.

Or the HTP crossover or HTP Phoenix light duty would work.

http://htproducts.com/crossover.html

http://www.htproducts.com/phoenixldwaterheater.html

Aaron_in_Maine

I have a Rinnai in my house and love it. I can run kitchen sink, dishwasher, shower and bathroom sink all at the same time with no problem. I have the cold coming off the water main first and feed the Rinnai with a 3/4" line.
Make sure the heater is sized correctly. But if your house is plumbed in 1/2 copper you can only flow so much water anyway. You can put in a monster water heater but if you don't have the plumbing you spent money for bells and whistles you didn't need.

ChrisJ

I'm a bit confused here.

So far, no one has mentioned service that tankless heaters require that tank type do not and no one asked about their water quality.

What gives?

Koan

@cutter - not my children LOL - i have taken plenty of cold showers as well. but the way I see it, if using a tankless, the shorter the showers the more direct the lower energy use?

Koan

@Aaron_in_Maine : main lines in the house are 1", very little 1/2" copper. Thanks!

@Leon82 : what size/ make buffer tank if external?

@bob eck main in house is 1" I'll measure the gas line coming in but it is pretty big, probably 1.25". I am assuming full flow to a 3/4" gas line for a tankless with a 3/4 plumbing feed to the tankless is sufficient?

Have heard a few complaints lately about bradford white - but maybe their lower level stuff.

We do have a gas boiler - big old sucker - like 300,000 BTU from the late 60's, doubt we want to run that all year. Heating pro said not to get involved with using boiler to make hot water

Use of chimney is interesting. Gas flue is lined with stainless, does that mater?? gas boiler use has an 8" flue and existing defunct State Select 40 gal tank heater has a 3" flue both going into that stainless lined chimney flue. Thanks!

@njtommy never seen HTP - thanks!

@ChrisJ please comment away!!! what service do they require?? what about water quality (ours is pretty good - fairly soft. is that what you mean?) thanks!

Thank you all for your help!

ChrisJ

@Koan

I'm not a professional on the forum so I don't know too much on the subject, but from what I recall tankless heaters over time get a build up of minerals and junk in the heat exchanger that needs to be flushed out from time to time (every few years?). The amount of time depends on your water.

I installed a 50 gallon Bradford White power vent tank model because I didn't want to deal with a tankless.

Leon82

I have a 4 gallon mini tank,which also heats the recirculation loop.

Ariston brand but any would do

For maintenance I descale with vinagar twice a year. I bought a flow aid kit but you just need a pump, bucket and 2 washing machine hoses

Koan

@njtommy - getting information on HTP, looking at either the Hydra smart RTC-199 or crossover RGH-199 but their website is horrible - have you worked with HTP stuff - looks like a gret product with lousy marketing.

njtommy

No I haven't, but @Rich I'm sure has. He knows the HTP products like the back of his hands.

4Johnpipe

Rich and I both have...what would you like to know?

njtommy

Thanks @4Johnpipe

Steamhead

http://forum.heatinghelp.com/discussion/156675/ng-supply-for-tankless-hwh

This is why we recommended a 50-gallon tank-type heater when we looked at the job.

Robert_25

"Take your shower heads and change them to 1.5 GPM shower head. There are many good shower heads that work great. You can put a tempering valve looks a cash Acme tank booster mixing valve on the water heater. Turn the water temp up as high as it goes to 150 deg or higer and mix cold water with the hot water and you will get more hot water out of your tank type water heater. "

Good advice. The existing water heater may be adequate if the other changes are made.

ChrisJ

Perhaps.

Except that I used to run such when I had a tankless coil and as soon as that was gone so was the shower head.

I now run a twin 2.5 GPM head (one is switched) because I honestly don't have time for slower in the morning.


Sounds like @Steamhead already looked at this and quoted a tank?

rick in Alaska

4Johnpipe:
In your Torphy picture, how did you manage to come out of the floor with back pipe, go uphill to the left, and then have it go straight up? Is that some of the Chinese fittings we were talking about? Or is it just a severe optical illusion?
Also, what is the reason for a mixing valve on that unit? Does it not modulate to control the output temperature?
Thanks, Rick

Steamhead

ChrisJ said:

Perhaps.

Except that I used to run such when I had a tankless coil and as soon as that was gone so was the shower head.

I now run a twin 2.5 GPM head (one is switched) because I honestly don't have time for slower in the morning.


Sounds like @Steamhead already looked at this and quoted a tank?

Correct- we recommended staying with a tank-type, but hadn't got to the quoting stage yet.

4Johnpipe

@rick in Alaska The room was at one time an outside porch. It is an optical illusion. The floor slopes down, the roof slopes down and the grout lines on the tile are square to a wall that's out of camera shot. My guys noticed that too...our piping is level.

4Johnpipe

@rick in Alaska The unit makes 140 degree water when set for heating option with supply and return to the heating coil. Then we use the TMV to mix down for domestic hot water.

http://htproducts.com/crossover.html

rick in Alaska

Thanks for the clarification. Figured it was an illusion! And, I thought it was a domestic water heater only. Makes sense now.
Rick

Koan

@ChrisJ and @Steamhead
Interested in other's point's of view as well. To be fair I did ask @Steamhead 's opinion and he did suggest staying with a tank, but others have suggested changing. Figured it might be smart to learn more to make a better decision.

SWEI

I'll expand a bit on my comment from the other thread:

Out here in hard water country, we see plenty of real issues with tankless heaters. Still, they do have their uses. We happily specify and install them when they do make sense. Our primary job is to make sure the customer makes an informed decision.

Tankless water heaters are not the be-all and end-all that many purport them to be. They really are the best solution for some applications. Knowing when and how they should (and should not) be specified requires an in-depth understanding of local water conditions, customer use patterns, fuel supply, and venting. If Frank says it won't work, I'd be inclined to listen to him.

Koan

@Rich and @4Johnpipe thanks for offering to help. HTP's website is the pits.

From an engineering standpoint looks like a great product, but they don't seem to have good Marketing or product representation. Trying to understand the Phoenix Light Duty vs the Crossover Vs the Hydra Smart Tankless . Seems like if you started at a conventional tank, the next step would be Phoenix Light duty, then the Crossover, then the Hydra smart Tankless as a progression to not storing any hot water. Big questions are customer service if there is an issue, customer satisfaction, product reliability, and longevity. Can you shed any light on these and on relative costs within this set. Please don't comment on specific pricing as that is against the rules.
I really need to learn more about this, and HTP is not a very well-known brand.

@Steamhead suggests a 50 gal Bradford White, but I looked online and there have been a lot of complaints about tank longevity. That could still be an option, just don't yet know.

ChrisJ

Sadly, reviews are often useless.

If you read reviews of hard drives they apparently all fail and yet I've had close to no failures since 1993. People tend to review things more often when it's negative rather than positive.

Bradford White is still considered by most professionals to be the best when it comes to a tank heater.

Koan

@ChrisJ Thank you - that us helpful.

JAdams

No matter what you decide to install, there's still going to be maintenance in order to maximize the life of the product. Sized properly, a condensing instantaneous water heater is the way to go. They are much more efficient than any tank heater out there and they are capable of delivering as much hot water as you need/want. If you decide to go instantaneous, I suggest you find one with a stainless steel heat exchanger, stay away from the copper ones.

aircooled81

You can get a very high efficiency tank style water heater, and have a great recovery rate.
I loved that cartoon about the tankless water heaters posted way back!!! Im still laughing.
Tankless is great, if you can afford the upfornt costs and size it correctly. Also if you like maintenance projects around the house.
Tankless for eye wash/shower stations, single spa type soaker tubs, small break rooms in offices, all too common. For the house, i dont know that consumers have really got the download yet on the pros and cons.
Consumer reports did a report many years back finding tankless water heaters take upwards of 20years to make back the initial cost of installation, vs gas savings. So if your trying to save money, might not be the best route...
But, if you love the idea of never ending water, you better size that puppy right. That little 1/2" gas line is useless anymore if you want 'endless hot water'.
Here in san jose, we had an inspector (great guy btw) that would not let you keep the tankless unless you could turn every faucet and fixture on in the house at the same time and still have hot water coming out of all taps. Well the gpm for the tankless was never designed for full load like that, and it took many years before new houses and remodels were able to squeak by that standard.

Koan

@JAdams I have no problem with maintaining the house. I am one of the few who replaced the anode rods every few few years and flushed the hot water tank at least once a year.

Doing an annual vinegar **** of a heat exchanger in a tankless unit would not be an issue either.

Koan

@aircooled81 I have no problem with maintaining the house. I am one of the few who replaced the anode rods every few few years and flushed the hot water tank at least once a year.

Doing an annual vinegar **** of a heat exchanger in a tankless unit would not be an issue either.

Koan

@aircooled81 The main gas feed looks like 1.5 inches, with better than 1" coming through the meter - but running a 300k BTU gas furnace, a cook top and whatever HWH system we employ.

ChrisJ

I have no problem with maintaining a house either, or installing a steam boiler or even restoring antique refrigerators that use flammable toxic refrigerants.

But I want no part of a tankless heater.

Koan

@ChrisJ LOL! thanks for your candor!

njtommy

@ChrisJ it's ok if you don't won't to walk on the wild side of DHW.

Robert O'Connor_12

@JAdams , I think I've installed just about every kind of tankless available in my area. I have no use for any of them. You must be real lucky.

Robert O'Connor/NJ

ChrisJ

Maybe it's just me, but our water heater costs us around $25 a month to run.

It's never been something that's really been enough of a deal for me to worry about increasing it's efficiency. Same goes for my refrigerators costing $3-5 a month to run. It's just way too small to care about and higher efficiency water heaters both cost a fortune to install and simply don't seem to last long enough to ever matter.

If someone knows how to "increase the efficiency" of my Comcast or Verizon bills each costing hundreds a month I'm open to suggestions though.

KC_Jones

ChrisJ said:

If someone knows how to "increase the efficiency" of my Comcast or Verizon bills each costing hundreds a month I'm open to suggestions though.

Have Comcast install a high efficiency water heater at their offices?

ChrisJ

KC_Jones said:

ChrisJ said:

If someone knows how to "increase the efficiency" of my Comcast or Verizon bills each costing hundreds a month I'm open to suggestions though.

Have Comcast install a high efficiency water heater at their offices?

That'll make my bills go up because it'll only save them $4 a month for 10 years and will end up costing them thousands in the end.