GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

I need to know if I could use the blower from my gas furnace to circulate the heat from my wood furnace

hmiles00 | Posted in General Questions on

My wood furnace is hooked up to my gas furnace so the heat would come out the floor vents. It works great except the fan on the wood furnace does not blow out as much as the gas furnace. Can I use the blower from the gas furnace instead of the one on the wood furnace?

The gas furnace works good but we do not use it at all (we do not even have gas hooked up to the gas furnace).

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    You haven't provided enough information. Does your wood furnace have separate ductwork from your gas furnace, or do they share the same duct system?

    If the two furnaces share the same duct system, how are the plenums connected?

    Is your wood furnace a true furnace, designed to be connected to a forced-air distribution system, or is it simply a wood stove with a blower?

    Have you read the installation instructions that came with your wood furnace?

  2. hmiles00 | | #2

    The wood furnace has the one pipe going to the chimney and the other goes from the wood stove to the back of the gas furnace. It shares the same duct work. It looks like they cut a hole in back of the gas furnace and installed the pipe from the wood furnace and sealed it up. It is a Englander Add On Wood Furnace 25-3500.

  3. GBA Editor
    Martin Holladay | | #3

    Here is a link to the manual:

    Was everything hooked up properly?

    The manual advises, "The hot air supply outlet of this supplementary furnace should not be connected to the cold-air return inlet of the central furnace, since a possibility exists that components of the central furnace could overheat in this situation and cause the central furnace to operate other than as intended. Before making the hot air hook-up, you should have your unit positioned as close to the flue connector as possible and have your flue pipe installed. If this has not been done, please do so before continuing. Located on the top, near the front of the unit is an eight-inch opening for the mounting of the flue collar. When mounting this part, be absolutely sure it is fastened securely to the opening, as this will be the hot air exit.

    "Thirty gauge or thicker pipe should be used from here to the hot air trunk line of your existing hot air system. Using the least possible amount of pipe will help the heat transfer to your duct system. Cut an eight-inch diameter hole in the main trunk line of the furnace duct, which is usually located on the top of the central furnace. Place the 8” (8 inch) pipe from the wood furnace into the hole (see Figure 3) and seal the connection with duct tape. Thirty gauge or thicker black pipe should be used for the first two feet and then thirty gauge or thicker galvanized pipe can be used to connect to the existing furnace duct. Sheet metal screws should be used to secure each joint of pipe, and an aluminum heat resistant tape can be wrapped around each joint to give an airtight seal. See Figure 3 for more information, including the use of a Backflow Damper. Follow the manufacturer’s instructions when installing a Backflow Damper."

    Consult the manual for instructions on wiring the blower motor.

    The instructions aren't very detailed concerning the interaction between the two furnace's blower motors; when in doubt, you can always call the manufacturer for technical advice. The phone number for technical support is 800-245-6489.


  4. hmiles00 | | #4

    Martin, everything is hooked up right except the damper is on the pipe that's going out to the chimney. Do I need to move it to the other pipe or use two dampers?

  5. GBA Editor
    Martin Holladay | | #5

    Clearly, if the instructions call for the installation of a backflow damper, and you haven't installed one yet, you should.

    If you have further questions about the furnace blower motors, you should call the manufacturer's technical help hot line at 800-245-6489.

  6. hmiles00 | | #6

    Martin, Thank You for your help and the manual. I will get that other damper put in also. Thank You again

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |