Water Heater Choices

Users who are viewing this thread

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
Years ago I went through water heater choices and I simply decided to do nothing. Now, I am tried of not having ebnough hot water.

I live in North carolina so weather is not extreme but we do get a decent amount of cold in the winter. We currently have a 50 gallon (inexpensive) gas water heater in the garage. Nothing special and most likely not the highest BTU. The house is 25 years old, water heater I am guessing is nearing end of life (around 12 years old.. no rust showing in water though). Water heater is located in garage and is atmospherically vented via a 3 inch duct (first restriction).

When we re-did bathrooms a few years back we considered changing to a 4 inch vent but the $1250 estimate, mess and associated delays convinced us to do nothing.

Everytime I start thinking tankless (I know many who love theirs) I read and realize it isn't the best choice for us. Here is the bottom line problem:

We have a decent sized tub (75 gallons to the overflow) that I use to help ease the pain in my back and legs. My wife takes a shower every night and sometimes a bath. water temp wise she never requires a really hot shower or bath whereas I prefer very hot/warm water.

In summer months our existing water heater often does ok even though we will need to have a little time between her shower and my bath. In winter months it is just irritating. If I take a bath first (assuming I get enough hot water) it is a LONG wait before she can shower. I usually let her shower first, wait an hour and then fill the tub. Sometimes it is warm enough. Other times it may turn into a drain and refill, or a half fill, wait 40 minutes and fill up rest of way.

I do not see a tankless as the best option for the tub fills (long fills) and I am not sure I want the maintenance.

I do not know the set up for our gas lines under the house. If BTU's on new water heater climb I assume we will need to have lines evaluated. I would prefer NOT to have to also update the meter, if it can be avoided.

Obviously we can go to a larger sized tank water heater and vent via power vent out side of garage. That is one option that comes to mind. Then we can balance out the BTUs, recovery rate. I also am guessing the first hour rating for a water heater will not help much in filling the tub with nice hot water.

I also read about other water heaters including the Phoenix Light, Vertex, and Polaris. The Vertex has a 76K BTU version but I'm not sure it really offers enough to justify the price at that BTU level. Going larger no doubt means gas line changes.

Any advice on which direction will work the best? I am ok with having new gas lines installed if that is a solution. We aren't taking dual showers while running dishwashers and so on. But the current lack of hot water for the tub is irritating, especially when you fill it and it is lukewarm at best! Thx John
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
You might be able to turn it up a bit. What is it set at now?

It's Maxed out on temp. Recovery is definitely slower than desired but the volume in winter seems to be the biggest issue. I usually run the tub a couple inches shallower than desired to get the temp up but that sort of defeats the purpose of the soaker tub!

A larger sized rheem (75+ gallon ) power vent w/h may be the simplest option if doing so avoids any gas line upsizing. Recovery time may not be tons better though.

This was why the tankless always seems appealing. At 5 gpm fill time would be ok. To get there though I would need 199K BTU and without question more gas and possibly larger gas meter. Then the other issues tankless may present.

Polaris though is quite pricey and most likely would need increased gas. Phoenix Light Duty while pricey in its own right may require less customization (gas, meter upgrade). Ack! :)
 

JRC3

Member
Messages
250
Reaction score
21
Points
18
Location
S.W. Ohio
This was why the tankless always seems appealing. At 5 gpm fill time would be ok. To get there though I would need 199K BTU and without question more gas and possibly larger gas meter. Then the other issues tankless may present.
Fill time for bathing would be a mix of both hot and cold water so you would get more gpm at the spout than what the heater is producing.

Besides the flue and a little maintenance, what other issues might a tankless present?
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
Fill time for bathing would be a mix of both hot and cold water so you would get more gpm at the spout than what the heater is producing.

Besides the flue and a little maintenance, what other issues might a tankless present?

Thanks for the reply. Tankless will without question require new gas line and new gas meter to be installed. There is no way I can provide 199K BTU's with our other gas loads we have. The maintenance part doesn't thrill me as it become yet one more thing I have to manage on top of all the other one more things. But, that said, if it is what we should do I'll go that direction. I realize there is no free lunch no matter what we decide.

But I also hate to think about the expense due to my tub frustration. Which right now I am waiting for the water heater to recover so I can finish filling! Other than that we do not have tons of water heater demands.

But other than the Phoenix Lite, the other water heater options (tank) would most likely cost more than tankless should I desire really fast recovery. A 75 gallon Rheem with power vent would be the cheapest overall but recovery time wouldn't be anything to brag about.

Lastly, we plan to be in this home 5 to 8 more years. Another consideration.
 

JRC3

Member
Messages
250
Reaction score
21
Points
18
Location
S.W. Ohio
What are your other gas loads? I have a standard 250 cuft gas meter. The inspector from the gas company told me they are good for about 1/3 more than the rating . I also have an 90k btu furnace and a typical 30" gas range (48k or so) and I have no issues getting enough gas from that meter.

I have an inexpensive Richmond/Rheem 150k btu tankless (RMTG-64DVLN) and I just checked and at 140 degrees it puts out 3.8 gpm. Right now the well water from my crawlspace PT is 58 degrees, probably a little colder when it runs a bit. The tap produces a mixed temp of 110 degrees at 5.3 gpm. I figure 110 is about what you run a bath at because it will cool down a bit before you get in.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
High recovery gas WH can do what you want. They tend to be a bit noisier than a 'normal' one, but being the garage, that probably isn't an issue. Depending on the distance you water needs to run, the higher you may want your storage or setpoint for a tankless to overcome losses in transit. Does your hot water run underneath the slab? That can be a big heat drain on the system all by itself. The first hour rating takes into account what starts out as hot in the tank, then adding cold to it while cranking the burner up full to help offset the incoming cold...so, first hour is a useful number. But, that also assumes you had an even flow for that hour so the effect of the burner can be felt (might be true with a shower, but not a tub fill).

Depending on where your water comes from, how deep it is in the ground, and how cold it is outside, the supply can be quite cold (I've measured mine at 33-degrees!). That makes a tankless really tough to get decent volume. A shower doesn't need all that much, but filling a big tub can be a pain. FWIW, it just didn't work out for me, but I'm much further north than you are.

For a shower, if you're not on a slab, and a ranch (sounds like you might be), a hot water recovery system could help immensely for the shower use (but not the tub, since it isn't draining while you're using it!). You do need your drain line available with some drop for that to work, so a multi-story or a garage under might work, but a typical ranch wouldn't be a candidate for one of those.

5gpm is about 41#*60minutes*70-degrees=172.2K BTU at 100% efficiency (it's not). That's assuming 50-degree incoming water, warmed to 120-degrees. So, that would be about maxing out a 199K BTU unit by the time you took efficiency into account...and, that's if you keep the heat exchanger clean of minerals.
 

Dj2

In the Trades
Messages
2,611
Reaction score
258
Points
83
Location
California
I second jadnashua's answer above...a 50 gal high recovery, higher BTU rating can do the job.
Get one with double insulation.
As for the vent, read the mfg'd requirements in relation to the BTU.
3" vent might prove to be enough.
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
What are your other gas loads? I have a standard 250 cuft gas meter. The inspector from the gas company told me they are good for about 1/3 more than the rating . I also have an 90k btu furnace and a typical 30" gas range (48k or so) and I have no issues getting enough gas from that meter.

I have an inexpensive Richmond/Rheem 150k btu tankless (RMTG-64DVLN) and I just checked and at 140 degrees it puts out 3.8 gpm. Right now the well water from my crawlspace PT is 58 degrees, probably a little colder when it runs a bit. The tap produces a mixed temp of 110 degrees at 5.3 gpm. I figure 110 is about what you run a bath at because it will cool down a bit before you get in.

Thanks for the reply! Our total load (realizing not everything would be in full usage) includes about 96K for the upstairs gas heat system, 36k BTU for gas logs (wife uses often in winter), and 144K BTU open burner range top (6 - 24K BTU burners). Without question we would never burn all 6 burners full open simultaneously. I fear a 199k BTU tankless would necessitate some gas line/meter upgrades. One way to find out though!
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
High recovery gas WH can do what you want. They tend to be a bit noisier than a 'normal' one, but being the garage, that probably isn't an issue. Depending on the distance you water needs to run, the higher you may want your storage or setpoint for a tankless to overcome losses in transit. Does your hot water run underneath the slab? That can be a big heat drain on the system all by itself. The first hour rating takes into account what starts out as hot in the tank, then adding cold to it while cranking the burner up full to help offset the incoming cold...so, first hour is a useful number. But, that also assumes you had an even flow for that hour so the effect of the burner can be felt (might be true with a shower, but not a tub fill).

Depending on where your water comes from, how deep it is in the ground, and how cold it is outside, the supply can be quite cold (I've measured mine at 33-degrees!). That makes a tankless really tough to get decent volume. A shower doesn't need all that much, but filling a big tub can be a pain. FWIW, it just didn't work out for me, but I'm much further north than you are.

For a shower, if you're not on a slab, and a ranch (sounds like you might be), a hot water recovery system could help immensely for the shower use (but not the tub, since it isn't draining while you're using it!). You do need your drain line available with some drop for that to work, so a multi-story or a garage under might work, but a typical ranch wouldn't be a candidate for one of those.

5gpm is about 41#*60minutes*70-degrees=172.2K BTU at 100% efficiency (it's not). That's assuming 50-degree incoming water, warmed to 120-degrees. So, that would be about maxing out a 199K BTU unit by the time you took efficiency into account...and, that's if you keep the heat exchanger clean of minerals.

Thanks for the reply!

House is 2 story and sits on a crawl space. Gas meter is on opposite side of house as is water heater. So if anew gas line needed to be run my guess is we are talking 40 feet in a direct line.

The way the house is laid out, the water heater does not have a long run to any of the bathrooms ( 2 1/2) or the kitchen.

Water supply is city water. I have not measured the temperature in winter during cold spells but my guess is 45 to 50 degrees give or take. Maybe less if really cold out. During summer months I can usually get tub filled with warm enough water so the 50 gallon low BTU tank we currently have is marginally capable at times. Even then I typically run off some hot water and wait 30 minutes to fill the tub. I will measure the water temp next time it gets cold. It could easily be cooler than I am imagining.

Tankless always sounds good until I dig into details a bit more, and then I talk myself out of it. Showers aren't currently a problem mostly because my wife does not like very hot water and she uses shower more than I do. I know odd I am :) I do like keeping things simple and that is one reason I have been hesitant to go tankless. Just seems our issue is mostly will filling the tub and seems we should be able to find a decent semi cost effective solution other than tankless! Maybe tankless in our retirement house we plan to build but that is another story!
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
I second jadnashua's answer above...a 50 gal high recovery, higher BTU rating can do the job.
Get one with double insulation.
As for the vent, read the mfg'd requirements in relation to the BTU.
3" vent might prove to be enough.

Good idea on the BTU requirements. I was taking the vent size specified in the PDF files as a requirement. If there is a safe legal way to vent via our 3 inch vent THAT would be the most cost effective solution! Some of the larger tanks do not have high BTUs but do specify a 4 inch vent size.
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
Bumping up to a ~76,000 BTU/hr burner still works with 3/4" gas line just fine even at 80 "equivalent feet" (the equivalent lengths of all the fittings and valves added in), so you probably make it if it's a home-run from the water heater back to near the regulator, not teed off a 1" line feeding the 96K furnace. But anything bigger is a problem.

If the existing water heater keeps up with tub-fills in summer, but not in winter it could be a matter of raising the storage temp to 160F or something and tempering it down to 120F (or less) at the output. A typical shower is 105F, a tub fill might need 110F, but not much more.

Filling a 75 gallon tub with a tankless (even a big 'un) is an exercise in tedium. You never run out of hot water, but the fill rate is slow.

BTW: A 96,000 BTU/hr furnace is on the order of 3x - 4x oversized for the average heat load of a 25 year old house in NC. With hot air furnaces that isn't an efficiency issue, but one more appropriately sized for the load is quieter and more comfortable. ASHRAE recommends no more than 1.4x oversizing, AFUE testing is done at 1.7x oversizing for the heat load at the 99% (not the 99.6%) outside design temperature. When it's old enough to be considering replacement, run this analysis, and down-size to lower up front cost and higher comfort. If it's the original furnace, it's nearing that time, so having the heat load and proper oversizing factor already teed up puts you WAY ahead of the game. Most HVAC contractors would just swap like for like rather than doing any real analysis, and put in something equally oversized (or even bigger.) Air conditioners and heat pumps are also typically oversized by huge factors like that, but they never need to be, especially when you can analyze the loads by the behavior or fuel use of the existing equipment. (With AC you may need to buy something to log the duty cycle on hot days to figure out the oversizing factor, and what the most appropriate replacement would be. It's not hard, but it takes more time than a fuel-use base heat load calc.)
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
Bumping up to a ~76,000 BTU/hr burner still works with 3/4" gas line just fine even at 80 "equivalent feet" (the equivalent lengths of all the fittings and valves added in), so you probably make it if it's a home-run from the water heater back to near the regulator, not teed off a 1" line feeding the 96K furnace. But anything bigger is a problem.

If the existing water heater keeps up with tub-fills in summer, but not in winter it could be a matter of raising the storage temp to 160F or something and tempering it down to 120F (or less) at the output. A typical shower is 105F, a tub fill might need 110F, but not much more.

Filling a 75 gallon tub with a tankless (even a big 'un) is an exercise in tedium. You never run out of hot water, but the fill rate is slow.

BTW: A 96,000 BTU/hr furnace is on the order of 3x - 4x oversized for the average heat load of a 25 year old house in NC. With hot air furnaces that isn't an efficiency issue, but one more appropriately sized for the load is quieter and more comfortable. ASHRAE recommends no more than 1.4x oversizing, AFUE testing is done at 1.7x oversizing for the heat load at the 99% (not the 99.6%) outside design temperature. When it's old enough to be considering replacement, run this analysis, and down-size to lower up front cost and higher comfort. If it's the original furnace, it's nearing that time, so having the heat load and proper oversizing factor already teed up puts you WAY ahead of the game. Most HVAC contractors would just swap like for like rather than doing any real analysis, and put in something equally oversized (or even bigger.) Air conditioners and heat pumps are also typically oversized by huge factors like that, but they never need to be, especially when you can analyze the loads by the behavior or fuel use of the existing equipment. (With AC you may need to buy something to log the duty cycle on hot days to figure out the oversizing factor, and what the most appropriate replacement would be. It's not hard, but it takes more time than a fuel-use base heat load calc.)

Thx for reply and good catch. I went back anbd checked the specs for the system we actually had installed in 2008. I did have a quote for a 96K system but did not go with that supplier. The system we installed is a 70K BTU Bryant 2 stage gas furnace for the upstairs system. So a little less BTU to factor in.

I will double check later to make sure I am not lying but I believe I have the existing water heater output maxxed out on temperature. It is quite hot when it starts. I just don't get enough heat in winter to fill the tub. At one time Bradford White made a 60 gallon lower BTU water heater but it was very expensive and I did not feel secure enough to go with it. I don't think they make it any longer.

The most cost effective solution sounds like a power vent AO Smith or equivalent 75 gallon water heater and more than likely an upsize to the gas line if needed. The Phoenix Lite water heater would offer a faster recovery albeit with a water heater brand that potentially could be harder to find service if needed. The polaris and Vertex models start becoming pricey.

I agree that a tankless would be an exercise in tedious for the tub. Can imagine slow would be the operative word and getting to 199K BTUs would not be cheap. I need to check my existing gas line but it may be able to supply the 76K BTU wise. No free lunch. Had builder installed a 4 inch vent I could look at atmospheric vented models.
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
That thing must be a monster. You must have quite the kitchen.
It is pretty nice (Capital Culinarian). Long story how we got there but when we decided to remodel our kitchen, we ended up making osme concessions due to cost and also mess/time. But my wife loves to cook and she also works very hard so I urged her to invest in a nicer than average rangetop. It actually was not any more pricewise than a Wolf and its performance is incredible. plus it was built cleanly and has easy access for tear down/clean up (that part is for me!). Mostly though I wanted her to have something nice. But there are times when the house temp is low enough I'll use 2 burners to warm me up a bit :)
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
if you have the room
why dont you just install 2 50 gallon common gas hot water heaters
in series with each other one a 50 power vent and the other tied into your original flu
No room in garage for a second water heater to fit easily. But if I am going to have a hole cut in side of garage for a power vent I'll most likely upsize the water heater while I am at it. Our current WH is getting a bit long in the tooth so replacing it isn't necessarily a bad idea.

I remain curious about the Phoenix Light Duty heater though it ends up significantly more $$ than a standard 75 gallon wh. Faster recovery and more efficient though But it also runs off 76K BTU which is similar to the 75 gallon tanks. A 50 gallon vertex would also most likely work but with its added BTUs I am guessing anew gas line would be mandatory. Not sure I can see an advantage there.

Based upon the help and information everyone has provided (thanks) it seems like the most logical choices are the 75 gallon power vent option or the Phoenix Light Duty. There may be some other 50 gallon high recovery tanks I have omitted. The 50 gallon Phoenix is rated for 133 gallons first hour delivery and the 60 gallon size at 140. Each size is rated for 98 gallons per hour rise at 90 degrees, The 75 gallon AO Smith powervent is rated at being able to supply water for 139 gallon tub (without saying at what temp) and its 1 hr recovery is listed as 80 gallons. This option is quite a bit less expensive.
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
I just noted the 50 gallon Vertex 76K BTU heater is rated at 127 gallons first hour delivery and 92 gph recovery. This heater would be priced between the 75 gallon normal type power vent heater and the Phoenix Light Duty. For now I am assuming it will run off the existing gas line though this would need to be verified.
 

Jdavis37

Member
Messages
59
Reaction score
0
Points
6
Location
NC
If you were wise you would go with either a Smith power vent or a Rheem 75 gallon power vent.

the Rheem 75 power vent would be my choice..

with either of them will never give you the troubles you could have with the Vertex units...
Thanks Mark,

After reading specs and then various comments on here, the Vertex is not currently at top of my list. It costs more than either the Rheem or the Smith 75 gallon units, and seems to have a reputation here at least of being problematic. My current water heater is a fairly low end 50 gallon 40K BTU heater branded by GE made by Rheem. And while it is not up to the job I can say it has been trouble free for 12+ years. I like simplicity and like things that work well. reliability is always important. I knew it would be a throw away tank when I bought it and all it has done reliably for years is heat water.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks