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  1. #1
    Join Date
    Feb 2013
    Posts
    1

    Default Choosing the right Water heater

    I am writing on behalf of seven families that need to pick the right water heater for our 7 unit condominium complex located in Santa Monica CA. The current water heater is a 13 year old american standard 100gal 199BTUs and has minor spots of rust appearing around the tank. Water heater manufactures have calculaters on their sites but their recommendations are so inconsistant that it is difficult to validate the right solution. The complex has five 2 baths and two 1.5 baths, 3 internal stacked and one common area washing machine, and there is no water softener. One suppler I called said that the rule of thumb is 10000 BTUs per unit plus 20% and recommended a 100gal 100BTU but said the trade off in price is that it will only last half as long as the 199BTU tank. I saw the episode on anode rods and looked into changing the anode but as noted, some tanks like mine hide the anodes under a layer of insulation and a metal cap. Due to age and the cost of dismantleing the water heater, changing the anode was not recommended. Hot water supply has never been a problem with the BTUs of our current tank. Our concern is being penny wise and hot water foolish. We need a commercial tank with the right combination of gallons and BTUs, and with an accessabe anode rod to extend its life and mazimize the cost benifit. Can you help us stay in hot water?

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    5,436

    Default Re: Choosing the right Water heater

    If you've had good luck with the existing heater, then replace it with same kind. Today, they run about $5000 plus labor and supplies.

    If you are on a budget, consider 2 - 50 gallon high recovery gas water heaters instead. Labor will be higher, but total cost will be less. They run about $600 each plus supplies and labor.

    I think that 100 gals for 12 baths, 6 kitchens and a washing machine is not enough. Rule of thumb: a 50 gal tank will service 4-5 people comfortably.

  3. #3
    Join Date
    Aug 2008
    Posts
    69

    Default Re: Choosing the right Water heater

    Determining the hot tap water, or domestic hot water (DHW) for 7 families in a condo requires the services of a heating contractor who is familiar with small commercial DHW units in the stated 200k stated range, either run separately, or even better, run as part of the indirect zone of the condo's heating system (hopefully, a forced hot water boiler is in place now); based on the calculated PEAK HOUR DHW USAGE of each of the units, and totaled up for a daily usage, based on that peak hour of hot water usage; large size indirect hot water heaters are run off the forced hot water heating system (if this is the heating system now in place), as the most economical way to obtain the DHW; if some other form of space heating is present, a stand-alone DHW heater will have to be used.

    There are calcs (below) that get a close estimate of how much DHW is needed & used during PEAK, by each family member per unit, and for the total of the 7 units, which is usually during the morning rush hour(s), when most occupants are showering, washing, cleaning, etc. in the process of getting ready for work, school, etc; each of the 7 families has to be interviewed as to the DHW usage for each family member, especially during the PEAK HOUR of usage.

    Consult the Yellow Pages under Heating Contractors and have several pros come over to evaluate the situation, to offer written bids that can be decided upon by the occupants/condo management.


    http://www.ag.uiuc.edu/~disaster/replace/waterhtr.html
    http://www.aceee.org/consumer/water-heating
    Last edited by von_steuben; 02-24-2013 at 03:33 PM.

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