I assume that you're not using the fireplace since you made a hole in the chimney. But just out of curiosity, do you have CO detectors in the house? I have oil heat and I have them peppered all over the place since you never know when a vent joint might come loose, some mortar will develop a crack, etc, etc. Those things are absolute indispensable. I especially like the ones that now give you a peak level. This is the best model I've found so far. It doesn't reset the peak reading automatically like some models do -
https://smile.amazon.com/gp/product/B004Y6V5CI
No I don't use it, it's one of those old style ones, they suck more heat out of the house than what they actually produce. The fireplace has an electric insert which is basically just a decoration and I want to just make it a bare wall so I can put the couch there. And I'll want to remove the chimney which is in the garage and it will buy a bit more room in there. My living room setup is terrible right now as there is no way to set it up so that the couch is actually in front of the TV. When I have friends over I just move it in front of the fireplace.
I do want to look at getting a high efficiency wood stove at some point though as a source of extra cheap heat. Great for the -40 months too. The logical thing would be to get an insert and put it in there, but it does not solve the living room arrangement issue. I'll probably put it in the garage and have glycol lines running into the house in a heat exchanger and then have hot water radiant heat throughout. Or I might put the stove in the basement and the heat will eventually circulate throughout the house. When I shop for a wood stove I'll try to see if I can find ones that are already designed for heating water. You can buy actual boilers but they're way more expensive and bigger than I need.
I do have two CO detectors actually, they're mandatory here now. Not a bad idea to have anyway.
As a side note I measured my roof for solar panels today. I have nowhere near the money right now for that project but I seriously want to start saving and planing for it.