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Indirect hot water heater

Advantages galore, Saul. More hot water, better operating efficiency by demand starting the boiler (it runs only on a call for heat or hot water) and longer life are just the highlights.......we've seen an average of 25-30% fuel savings by switching from tankless coil to an indirect. All systems are different and your's is no exception. Depending on the type of system you have and the way you make hot water, you can see a payback in 3-5 years. so it's definitely worth looking into.


  • saul deutschsaul deutsch Member Posts: 15

    What are the advantages or disadvantages with installing an indirect hot water heater versus a typical hot water system? Any gas savings etc?
  • Big EdBig Ed Member Posts: 1,117

    A boiler could have a higher eff over a direct fired hot water heater.Depending on equitment.

    Single burner could be within range of chimney compacity.

    You could put a indirect anywhere away from chimney.

    One less burner to maintain.

    Could be within range of fuel supply.

    The cons.

    High mineral water areas foul up heat exchanger.

    Sometimes the need to over size boiler for hot water load.
  • saul deutschsaul deutsch Member Posts: 15

    How is there a fuel savings with the Indirect system if the Boiler is working basically all year rather than just a 7-8 months? I currently have a Slant-Fin gas boiler with about 90,000 BTU in a one family residential home. Do I currently have enough BTU to handle this? And doesn't this wear out your boiler sooner-so what savings is there really?
    Can you recommend any particular models and companies to look into? How much more should I expect to pay upfront for this versus a typical 75 gallon water heater?

    Lastly, Is there a website that I can access for more info on water heaters including "direct" and independent ratings.
  • ConstantinConstantin Member Posts: 3,782
    It all depends.

    For a indirect to have the highest possible savings, it should be connected to a modulating, condensing boiler. Currently, such boilers are only available on the gas side.

    Your Slant-Fin is probably an 80% AFUE boiler, i.e. not the most efficient source of heat. On the other hand, hooking it up to a indirect will save you a lot of gas/oil over a hot water coil inserted into the boiler. That is because more of the boiler output will be absorbed by its overal heat exchanger than via a coil. Plus, coils plug up with scale very easily.

    Indirects are also more efficient than gas-fired water heaters because they don't feature a unlined chimney in their center, nor does their HX waste 30%+ of the fuel (in most models). Plus, indirects do not require a chimney connection and usually are made more durably than their direct cousins. For example, SuperStors from HTP carry a lifetime warranty in residential applications, if memory is serving me correctly.

    The main benefit of any storage-style water heater over a coil though is its ability to handle a large "dump load" like a jacuzzi, etc. By the time most tankless systems get the jacuzzi full, the water inside is cold. A large storage system allows you to dump lots of hot water quickly so that the inhabitants can not only enjoy a hot bath, but do so quickly (don't foget to have adequate pipes!).

    The 90kBTU input/output rating is more than adequate for most indirect water heaters. After all, most gas-fired units max out at 50kBTU input... With a good indirect WH, I would expect a 2x faster recovery than with a regular gas-fired water heater.
  • DanDan Member Posts: 388

    This link will give you PDF files of 2005 ratings for gas and oil fired boilers and water heaters. These are not consumer "ratings", but rather, a comparison of efficiencies and key data points.
  • GuyGuy Member Posts: 159

    Anoher advantage- LIFETIME WARRANTY!
  • DanDan Member Posts: 388

    Beware, that most "lifetime" warranties have disqualifying limitations. They are usually limited to the original owner, and cannot be transferred to any subsequent purchaser of your home. Some manufacturers offer supplemental warranties for an additional fee, which are transferrable to the next homeowner.
  • Big EdBig Ed Member Posts: 1,117

    It takes one btu to heat one pound of water one degree.When we are talking efficiency...... Where this btu comes from matters little .We will more concerned about the feasability of fuel to produce it ,the efficiency of the machine to convert and tranport it as well as means to prevent loss of it.

    A boiler will wear out quicker from lack of use .

    I would recommend to invest into efficiency until it hurts. I told you to vote for Kerry.........
  • saul deutschsaul deutsch Member Posts: 15
    Indirect Fire Water Heater

    How about an "Indirect Fire Water Heater"? What are the advantages of this versus a standard HW? How does this differ from a Indirect Hot Water Heater?
    Can my Boiler work for this?
    Annual savings/Efficiency?

    Is it cost effective in a one family residential home?
  • Big EdBig Ed Member Posts: 1,117

    90K is a little lite for 75gallon indirect.More suited for a 50 gallon.It would heat it but it would take too long when you also trying to heat the home.
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