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Community and Q&A

Gas direct vent water heater

toymaker | Posted in Mechanicals on

My water heater guy tells me that NG direct vent water heaters only exhaust outside and draw combustion air from inside the home’s envelope. I am trying to avoid any such pressure causing devices and leave air exchange to the HRV. Does anyone know of a 40-50 gallon water heater that draws combustion air from the outside and exhausts outside too? If they don’t exist is this the best reason to go tankless?

thanks, john

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  1. J Chesnut | | #1

    If you have a high efficiency modulating boiler I would recommend an indirect hot water tank. An indirect is heated by the boiler and not having a combustion unit itself it can be insulated to a much higher degree.

  2. GBA Editor
  3. toymaker | | #3

    Thanks guys. Looks like I need a new water heater guy.

  4. J Chesnut | | #4

    HVAC contractors are usually tied to certain brands of appliances. Sometimes it takes researching finding what appliance specifications you want and finding a contractor that uses these products.

  5. steve bumpus | | #5

    I just got done investigating them myself, and you got two choices: powered direct vent that require 110v. and about $500 more over the basic direct vent. the direct vent uses combustion air from outside via double vent pipe. ( better for tighter homes, but the power direct vent will require combustion air from inside air already heated, so in my case, just a direct vent water heater is more appealing and economical in a couple ways!!

  6. Tony Olaivar | | #6

    Most high efficiency WH units are capable of using outside sources of combustion air. This is a step that gets skipped for the convenience of the technician. Not a good sign that he/she has your best interests at heart. Find another dealer. Tony Olaivar - HERS Rater, BPI Professional - Lanz Heating and Cooling

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