So I can contribute to this thread as this is what I do this year.
I began last year mining in june not because of the boom but after selling my house...
We took a rented house heated with oil : I drive an electric car, try to have my company as green as possible (i am working selling second hand equipment) and the new house was heated by oil... no way !
That's where came the idea of heating with cards and making money
We are in the middle of the winter and I must say... The winter is not cold enough
(I am living in France)
We have in total 34 cards working. I put them in different places in the house and it works, we have to keep windows opened.... (3 floors, 140 m2)
Now, there is the downsides :
-Choosing cards making the less noise as possible. For this, I have NVIDIA Cards at some place, and I found out that 3 fans or NITRO+ cards where the best for the AMD models. The worst ones I have are the RedDevil Powercolor RX580 which have good hashrate but make lot of noise...)
-Accept living with "noise" : yes ! even choosing the best cards will make noise !
-Invest in fans : fans is the solution : as the fasn will push hot air, the cards will be less hot... but it will also spread the air everywhere.
-And accept changing currency when friends are coming (actually my guest algos is Cryptonight on AMD cards and equihash on NVIDIA cards as they are the one making less noise)
Now, I must say that I am really happy to spend a full winter earning money with my heater (after having the investment bask as this was a big one
but I am also really excited to get the new house built where the cards will be in a dedicated place and I won't hear them anymore
I am now thinking how I will mush this hot air in the rest of the house., but that's another storry !