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Energy Kinetics: Indirect Water Heater or Not?

hughbucks Member Posts: 9
Looking to replace my 30+ year old oil-fired boiler with summer/winter hookup with an Energy Kinetics system.

All the other contractors I've talked to want me to get an indirect water heater off the boiler saying it will save me money for domestic water.

My Energy Kinetics contractor is saying I'd be fine with the Ascent with no indirect water heater; only need it if I'm gonna have some humungous tub or jacuzzi. Is this true? I thought one of the benefits of the EK is the idea of the thermal purge. If you don't have a place to purge too -- like in the summer -- aren't you wasting all that heat at the boiler? You call for hot water, boiler fires on, and then as soon as you turn off the tap, the boiler has all that residual heat and no where to put it, right? With the indirect water heater, it would be able to pump into that for later consumption.


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,127
    I would use a small indirect, but you don't have to. One of the EK's people will probably pop on and respond.
    Keep in mind even with a super insulated indirect, and insulated pipes you will lose heat from the indirect. So purging into and indirect, and not using hot water for a few hours is probably the same.
    Many people have come on this site (including Dan) and raved about the EK's.
    I'm sure it will save you money over your present summer/winter set up.
  • Roger
    Roger Member Posts: 280
    edited January 2019
    Thank you for your question, @hughbucks , you framed that question nicely.

    The Ascent Combi does a much better job at producing hot water than tankless coil boilers, and it’s annual efficiency is much higher as well (due to low mass, much more effective insulation and design, and better load responsive controls). Going several steps further, our other models with the plate heat exchanger and storage tank can substantially exceed the Ascent hot water supply (storage is the main difference), and do it at much higher hot water and annual efficiency due to the Energy Manager control with thermal purge.

    Thermal purge combined with our well insulated low mass designs can save up to 40%, where the Ascent Combi can save up to 20% as it does not have thermal purge. So you just about “double” the savings with the Energy Manager control models. Just adding an indirect tank to an Ascent model will not have a substantial impact on energy savings as it does not have thermal purge. Cold start helps only helps a little bit as typical household hot water demands require the tank to be heated 3 to 5 times a day, keeping the boiler warm. Cold finish (thermal purge) is where the energy is recovered and savings really add up.

    Our rule of thumb is that if you currently have a tank (or have 2 or more heating zones), put in a heating system with the Energy Manager and thermal purge for the best in comfort and efficiency.

    Energy Kinetics, Inc.
    Erin Holohan HaskellGBart