Desperately seeking gas water heater smaller than 30 gallons?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by babbo, Oct 8, 2019.

  1. babbo

    babbo New Member

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    My house is set up with a gas water heater that serves only the kitchen sink and washer. (There's another that supplies the showers and lavatories.) The current 30 gal tank needs replacing and I was thinking that we could get by with a smaller unit but I don't see any gas water heaters smaller than 30 gals on line. Does anybody make such? Is going smaller than 30 a bad idea? Many thanks.
     
  2. dj2

    dj2 In the Trades

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    You can find small tank less natural gas water heaters online.
     
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  4. Reach4

    Reach4 Well-Known Member

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  5. babbo

    babbo New Member

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    Thanks but I don't have the gas volume for a tankless.
     
  6. babbo

    babbo New Member

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  7. babbo

    babbo New Member

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    Any recommendations for brands of 30 gal?
     
  8. Terry

    Terry Administrator Staff Member

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    Last edited: Oct 11, 2019 at 10:05 AM
  9. wwhitney

    wwhitney Member

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    There are small gas tankless heaters with a low BTU input rate that should be able to work on a gas line sized for a conventional tank water heater. They obviously can't provide a very high flow rate, but I would think it would be adequate for a kitchen sink and washer (be it dishwasher or clothes washer). For example, here's one with only an 80,000 BTU/hr input rate, not a recommendation, just an example:

    https://www.homedepot.com/p/MAREY-3-1-GPM-Natural-Gas-Tankless-Water-Heater-GA10NG/204357298

    You can also get a compact 20 gallon tank unit, but it's a stainless steel tank, so it is pricey:

    https://www.homedepot.com/p/Westing...urable-Stainless-Steel-WGRGH20NG75F/302289769

    Cheers, Wayne
     
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  10. Reach4

    Reach4 Well-Known Member

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    If you have natural gas, but you are pipe-limited, consider asking your gas company if they can give you 2 psi gas instead of the current ~0.25 psi. If you do that, each appliance gets its own regulator, but the existing pipes can carry a lot more BTU. Some utilities do that willingly for a residence, and some won't do it.
     
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  11. hj

    hj Moderator & Master Plumber Staff Member

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    There are MANY 20 gallon gas water heaters. Just do an internet search.
     
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  12. wwhitney

    wwhitney Member

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    There are? The only one my internet searching turned up is the Westinghouse line I linked to earlier. If you're aware of others, please give us an example.

    Thanks,
    Wayne
     
  13. ImOld

    ImOld Octogenerian

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  14. WorthFlorida

    WorthFlorida Black Belly Whistling Ducks

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    If your purpose is to to cut down on energy consumption going to an electric unit with 10 & 20 gallon units are readily available. If you have the space in your electric panel you might want to look into it. You can add a timer or cutoff switch and only power it on when needed.
    I just was away from home for 14 days and I turned off my 50 gal electric water heater. May have saved me about $20-$30 on the electric bill.
     
  15. wwhitney

    wwhitney Member

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  16. wwhitney

    wwhitney Member

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    I think it is more like $1, depending on your electric rates and age of your electric water heater:

    I took a look at the cheapest new 50 gallon electric water heater at homedepot.com. It has a UEF of 0.93 and the Energy Guide shows an estimated annual kWh usage of 3493 kWh. Assuming those are based on the same test conditions, then 7% of that annual kWh usage is losses, or 245 kWh/year. That works out to a loss rate of 0.67 kWhr/day, or 95 BTU/hr, which we can assume worst case are all standby losses. I'm also going to assume that the operational delta T of the tank is 70F and that the actual tank volume is 45 gallons.

    If I did my exponential decay math correctly, after 14 days the tank would have cooled off to only 21F above ambient. So to reheat it to 70F above ambient took (49 F)*(45 gal)*(8.33 lbs/gal) = 18400 BTUs, or 5.4 kWhrs. But you avoided 14*0.67 = 9.4 kWhrs of standby losses, so you saved a net 4 kWhrs. Depending on your electric rates, that's $0.40 to $1.

    Cheers, Wayne
     
  17. babbo

    babbo New Member

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    Nope.
     
  18. babbo

    babbo New Member

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    Yep.
     
  19. babbo

    babbo New Member

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    Thank you Wayne, I really appreciate your thoughtful answers. It looks like the unit you mention allows for B-vent, but would Z-vent be better? What do you recommend? What else would installation require?
     
    Last edited: Oct 13, 2019 at 10:15 AM
  20. babbo

    babbo New Member

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