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replacing gas fired water heater

Hello guys, I was wondering if someone might tell me if I can replace my gas fired 40 gallon water heater with a tankless(on demand type) heater? My question is centered around the fact that my gas fired,( 6 year old ), boiler serves my steam radiators..(.house was built in 1927.) I don't really understand the relationship between my (present) gas water tank and the steam that is produced in my boiler which eventually goes into all my steam radiators. I hope this makes is pretty new to me
thanks in advance....hope you guys aren't laughing too hard at the question


  • FredFred Posts: 8,282Member
    No one is laughing!That question pops up all the time. Is there anything wrong with the current water heater? If not, I'd continue to use it until there is a problem (which more often than not will be a small leak when it fails and needs to be replaced. There really is no relationship between your current water heater and your steam boiler, other than they are both gas fired.
    Some boilers are designed to have a tankless coil installed in them, as an option, some are not. They work well but they are probably not as efficient as a standalone water heater in that they require the boiler to run all year long (even during the summer) to heat the water for your on-demand requirements. While the boiler will not heat unless there is a call for heat, it still will run, at a lower temperature to provide hot water.
    The other option is a standalone tankless, on-demand water heater but they have there limitations, as it relates to the amount of hot water they can supply if you have a high demand for showers, kitchen use, laundry, etc, all at the same time. I think most here would say stay with a standalone water heater, but I'm sure others will comment and offer their opinions.
  • laura_3laura_3 Posts: 7Member
    Thank You for your water tank was put in 2006, now 10 years later i think I should be thinking about what the replacement options are. I heard that there are different code requirements on the new water tanks like they are wider and more complicated venting...all for energy efficiency
    So i am exploring all options ...
  • Hap_HazzardHap_Hazzard Posts: 2,081Member
    No relationship, if I understand you correctly. Your steam boiler runs all winter and sleeps all summer, but the water heater works year round. Your steam boiler comes on when your house gets cold, but the water heater when you run your washing machine, dishwasher, or take a shower.

    As for whether you can or should replace your water heater with a tankless, on-demand unit, that really depends on how long all your runs are from one central point where venting is also feasible, assuming you're sticking with gas, but that's just my opinion. I'd post that question to the Domestic Hot Water forum if you want to get the attention of some real experts.
    Just another DIYer | King of Prussia, PA

    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
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