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ww Member Posts: 263
The hot water is provided by the coil in the oil boiler in a two family house. I would like to install a unit that will produce hot water other than put the boiler on in non heating months or when heat is not needed.
The boiler exhaust goes into a chimney.

I have a natural gas connection available and electrical outlets for 110 and can hook up 220 if needed.

I am looking for a setup that would work best. The two kitchens and two bathrooms are in line with each other and a couple of basement sinks and washer and dryer are there.

Most of the time very minimal hot water is used and only for a shower and dish washing.

I can put bypass valves between the boiler and water heater to switch what i'll be using.

i don't want to add alot of high amp breakers...put vent pipes in chimney..etc.


  • STEVEusaPA
    STEVEusaPA Member Posts: 5,195
    An indirect storage tank would be best.
    Being 2 family, who’s paying for the hot water?
  • Jamie Hall
    Jamie Hall Member Posts: 16,637
    There are any number of very good natural gas fired on-demand water heaters (usually tankless water heaters). They are direct vented through the sidewall of the house, and are -- relatively speaking -- very small (usually wall mounted). The main trick with them is matching the unit to the demand.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ww
    ww Member Posts: 263
    to use the indirect tank doesn't the boiler have to be on to transfer the hot water to the tank?...i pay for the heating of the house.
  • mattmia2
    mattmia2 Member Posts: 3,714
    Keep in mind a tankless water heater requires a huge gas supply, you need to be able to supply that if that is the route you go.
  • ww
    ww Member Posts: 263
    ok...i don't know which way i'll go with this yet...that's why i need ideas...but that is some good info. i want to go with a simple solution here....wonder how much electric would be used in a 110 electric hot water heater....or what about these oil hot water heaters...trying to get ideas here on that. thanks
  • Zman
    Zman Member Posts: 6,807
    Assuming your existing boiler is a hot water and based on the fact that you do not want to run new venting. My first thought is an indirect water heater. The boiler would not be hot or heat the house all the time, it would just fire up to heat the indirect tank as needed. The other way to do this is to use an electric tank in conjunction with your existing tankless coil. In the summer you would run electric, in the winter the tank would serve as extra storage for the coil. There is a simple recirc setup that makes this happen.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ww
    ww Member Posts: 263
    this sounds good to run an electric tank with the tankless coil...what are some models of these you are referring to...any specific types and brands so i can search some out. thanks
  • Redwalsh87
    Redwalsh87 Member Posts: 1
    I was recently contemplating doing something similar. Currently I have a domestic coil supplying all the hot water. I am going to install a heat pump hot water heater to do this instead but I wanted to leave the domestic coil since I can use this for hot water when the power goes out (my generator is not strong enough to run an electric hot water heater). My thinking was to tee the electric unit off with valves and completely bypass the coil unless I need it in which case I would switch the valves back and have the coil during an outage. The teeing off and valving would be similar to how you bypass a water filter for servicing and such. I don't see anything wrong with this but I'm no expert...