Sizing Domestic Hot Water Heater Systems


Sizing a domestic hot water heater system constitutes an talent more than theory. For anything aside from somewhat residential system, you cannot visit a table or chart and select. Codes provide only generalizations for instance “Cold and hot water will most likely get offers for to everybody sinks, lavatories, showers, etc.” They do not indicate the quantity warm water is required. Codes do, however, give more knowledge about pipe materials and minimum and maximum flow rates to fixtures (combined cold and warm water), and in addition they address safety concerns for instance maximum temperatures and needed safety devices.

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Numerous factors is extremely suggested when sizing a technique, and experience plays an enormous part. Best wishes differs, therefore the path resulting in final selection may also be different. Two structures might be physically the identical (i.e., have similar quantity of fixtures), but the quantity of water needed may be different once the structures will likely be occupied by different groups of people. For instance, a condominium for seniors may have another use profile compared to a single that mainly houses families.

Information Gathering

How should we size and select a domestic warm water system? The initial step ought to be to collect the information needed to define the system parameters and narrow the options. A couple of within the information will likely easily be available, however, many may require somewhat digging. This really is frequently a relatively extended list of questions, while not every them affect every situation.

  • Where’s the dwelling located?
  • What code or codes should be adopted?
  • Cause local amendments apply?
  • Will the building’s owner or operator have unusual needs?
  • Exist more warm water systems inside the building?
  • What is the area useful for?
  • The amount of plumbing fixtures maybe there’s?
  • What sort of fixtures maybe there’s?
  • Who unquestionably are together?
  • What are high-usage fixtures, for instance spas or laundry machines?
  • Exist purports to expand the power afterwards?
  • Maybe there’s a laundry or health club area?
  • If that is the issue, the amount of areas will likely be applied concurrently?
  • The quantity space may be acquired for that system?
  • What forces are available? (Gas?Lp? Steam?Warm water?Fuel oil? Heat reclamation?)
  • Which power source is most economical for that location?
  • Whereby the dwelling will the various tools go?
  • Will flues or combustion air be described as a problem, due to the location?
  • What is the cold water source?
  • What is the water hardness?
  • Will the system be inactive for extended occasions?


When using the information you’ve collected, you are able to calculate the job (i.e., recovery rate and storage volume) required for your facility. Once again, this is not easy. There are many approach to calculating the job within the building. One of the ways is not always a lot better than another, even if you considerably better suitable for that specific application.