Originally Posted by how
My first worry for your present situation would be from the CO from the HWT.
Your option of an electric tank may not be as expensive as you think, compared to the other options. Try turning off the gas to the HWT and temporarily plugging its flue. Now test the wood burner to see how it operates without the open HWT flue.
Let us know what happens.
I tried the stove with the basement intake (hot water heater flue) plugged. There wasn't much of a difference that I could notice. I had to keep the door of the stove slightly open for it to get enough air. I wonder if adding a 6" SS liner for this stove will solve it and encourage a better draft that will overcome the weak intake.
My plan now for the water heater is to replace with an electric and seal off the basement illegal flue.