5 cord of wood is a lot of heat. Most of that heat is leaving through the stove pipe probably. Extract as much of it as you can from the system before it leaves the house.
The brick adds thermal mass which does store heat. It also protects the iron from the extremes of the fire as an insulator. If the purpose of a stove is to cook, then you want to have little thermal mass so the stove gets to cooking temp as soon as possible. But if you want to heat an air space over time, it is usually better to make as much of a heat sink as possible while still allowing the exhaust gasses to be hot enough to make a draw. Cool them too much and you start clogging things up and condensing water vapor etc… But it has to get pretty cool before that happens. I don’t know how that works with your extreme cold environment. Don’t have much experience with that…
The bricks help make the heat sink. Also you could heat a large volume of water or sand to help with this. Then, the heat would radiate from the heated medium throughout the night.
Or, add a heat exchanger inline in the exhaust pipe above the stove. I just finished a pizza oven/heat exchanger for green house heat. I’m using a rocket chimmeny for a heat source (for fuel efficiency) but you could use your stove. I split a drum in half and bolted it over another drum so the hot gasses flow between the barrels. There is a manifold on bottom and top and a stove pipe coming in the bottom and then out the top. It makes an incredible heat exchanger. You could use heavier steel for longevity. And put a fan in one end. You’d get cooked out probably. This would allow you to extract more of the heat that you are already producing which is ending up outside through the stove pipe.
… says the southern boy to the yankee…Yeah, I know, what do I know about wood stoves…lol.
But in all seriousness, this is actually what I do.
I will try to post some picks if you are interested…