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  1. #1
    Join Date
    Jul 2007
    Posts
    12

    Opinions need for a new water heater

    The house currently has an A.O. Smith 40gal water heater. From what I can tell from the label, it's rated 72FHR, 40k BTU, R value 7. Lately, it's leaking a small amount of water from the base so I know it needs replacement. Afterall, it look like the unit is installed back in 1997.

    I have 6 adults in the house with 2 bathroom. Half like to take baths while the other half like to take showers. I have the temperature dial between B and C and that seem to be just enough hot water. From research, I should get a unit with R16, magnesium anode, and a high FHR.

    I seem to narrow it down to the A.O. Smith Conservationist XGV-40 but that unit seem very pricey compare to others, especially for a 40gal unit. It does have a high FHR of 81. The other is the Rheem Professional Guardian System 22V50PROF. I am a bit confused between the Rheem 22V50PROF and the 42V50-40PROF. They are both 50gal but the 22V50PROF is rated with FHR 90 with only 38k BTU while the 42V50-40PROF is rated with 83 FHR with 40k BTU. So is the 22V50PROF more efficient?

  2. #2
    Join Date
    Jan 2007
    Location
    Minneapolis, MN
    Posts
    415
    Neither of these water heaters are efficient. Their energy factors are .59 and .58 meaning they are only 58-59% efficient (this style heater is old technology). If you want efficiency look for a water heater that is energy star rated. My personal preference is an on demand water heater... no stand by losses and unlimited hot water for the entire family when sized properly.

  3. #3
    Join Date
    Jul 2007
    Posts
    12
    Are you referring to a tankless configuration? If you are, it's not something I want. From research, I hear the upfront cost is high, maintenance cost is high and it's not durable. Beside, I'm in the northeast, wouldn't the water temperature be too cold in the winter for the unit to get real hot, even if I get a unit with a high GPH rating?

  4. #4
    Join Date
    Sep 2003
    Posts
    1,677
    Quote Originally Posted by zuffy View Post
    Are you referring to a tankless configuration? If you are, it's not something I want. From research, I hear the upfront cost is high, maintenance cost is high and it's not durable. Beside, I'm in the northeast, wouldn't the water temperature be too cold in the winter for the unit to get real hot, even if I get a unit with a high GPH rating?

    6 adults and you only have a 40 gallon hot water heater

    WoW

    You must stagger your showers

    You need a 50 gallon tank with a highter rate of recovery

    I like the New AO Smith direct vent water heater a bit pricey and it might be a bit extreme for your needs but man does it deliver the water

    http://www.hotwater.com/lit/spec/res...RG-SS01306.pdf

  5. #5
    Join Date
    Jan 2007
    Location
    Minneapolis, MN
    Posts
    415
    Look into this site http://www.rinnai.us/Products/water_heaters.aspx

    I'm not promoting this company but its a popular brand. I installed two Bosch units for an ice arena hockey locker room and they have been trouble free for two years. It runs five showers and five sinks. I am not sure were you got your information about durability and maintenance but these type of heaters are very popular in Europe and Japan and have a proven record. With energy prices continuing to rise I wouldn't recommend a water heater that is only 60% efficient. Also when it comes to cost you should consider the total cost for the life of the unit, not just the up front costs. Good luck with your search.

  6. #6
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,516
    i would twin two 40 or 50 gal heater together and you should never run out
    as long as they are twinned properly

    the least you should be looking for a with a famialy that size is a high output 50 gallon

  7. #7
    Join Date
    Oct 2005
    Location
    MN
    Posts
    133
    I have a 75 Gal Rheem and wouldn't want anything less.

  8. #8
    Join Date
    Jul 2007
    Posts
    12
    small change, that unit is too pricey. I am trying to keep this replacement under $1k. Another factor is the limited space. The current WH is 18" in diameter and I think the largest I can put there is 20 - 20.5" and approx. 68" height. That is why I was looking at the A.O. Smith Conservationist 40 gallon. It has a higher FHR and recovery rate than my current one. Since everyone's schedule is off by 30-60 minutes, the current WH seem to handle the hot water situation fine.

    Sorry mbarson, still no tankless in my future.

    So, any other WH that might be better than the A.O. Smith Conservationist within my budget and within my space limitation?

  9. #9
    Join Date
    Nov 2007
    Location
    Chicago
    Posts
    76
    What are the schedules? You should size the residential water heater for the worst two hour load and use the FHR + recovery as the basis for it. E.g. if all 6 people take their showers in a two hour period, you would need 20 gal X 6 = 120 gallons of hot water. You would want the first hour rating + recovery to be equal or greater than 120.

    Bradford White makes nice water heaters and so does Lochinvar. I personally use and spec A.O. Smith's myself.

  10. #10
    Hi zuffy
    "seriously"
    You should consider a aquastar water heater,I installed one 10 years ago and the only problem I've had was was to replace the relief valve twice.It's been a fantastic heater. We never run out of water.They require a large flue if you don't get one with a direct vent.

  11. #11
    Join Date
    Jul 2007
    Posts
    12
    My parents and grandmom does not shower or bath in the morning. Just need some hot water for wash up. Wife uses the bathroom @ 7am and I use it around 8am. Sister uses it around 9-10am. So I think the morning is covered. As for night, The most is back to back shower/bath, never more. So I think the night is covered too. Also, we don't use the dishwasher and laundry is done on sunday afternoon.

    So hvacconsultant, base on your calculation, the Conservationist 40 gallon is rated 81 FHR + 41 recovery so that equals 122. Is that enough?

  12. #12
    Join Date
    Jul 2007
    Posts
    12
    chillidog, I have search on tankless in several forums and I see a clear split. I just don't think I am ready for it yet. As I pointed out earlier, I live in the northeast, no way the water temperature is going to be 60-65 in the winter where they use as baseline. Also, the boiler and WH are venting to the chimney, not sure if the tankless can vent to it without modification.

  13. #13
    Join Date
    Nov 2007
    Location
    Chicago
    Posts
    76
    The problem with tankless is that you would probably need to increase the size of the gas piping since they have a much greater input. In that same vein, you will probably need to add combustion air or provide a two pipe PVC combustion air / exhaust vent. They make sense in new construction, but not so much in a retrofit simply because of the gas piping.

    As far as the size, with the demand spread out like that, and you said that the current WH is performing adequately, I think any standard 40 gal tank with 40,000 input is adequate. You may want to go with a higher recovery just in case you have an extra load thrown in like another shower, washing machine or dishwasher. In that case, I would go with a a 40 or possibly 50 gal tank and 50,000 input. I am all for energy efficiency, but you could simply install heat traps on the inlet and outlet piping, insulate the tank and first 8 feet of piping and cover a lot of your standby losses.

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