Bitcoin Forum

If I'm running 2x 6950's then I'm probably paying more in electricity than money I am generating... correct?

Second question. The difilculty within a year changes how much? Will 2x 6950's generate a good amount of bitcoin for another year or do you guys have to upgrade GPU's for bitcoins every year?

Even if you got your electricity for free, I still don't think anyone would recommend mining Bitcoin with 2 GPUs these days.  GPU mining is pretty much strictly altcoin territory now.  If it's not an ASIC, it won't even touch the sides, as the proverbial phrase goes.  And if it's not a fairly recent ASIC, even then, it's still probably ideally suited as a space heater rather than a miner.  If you haven't got the latest tech, it's probably going to cost you more in the long term than you'll ever make back.

There's no set amount for how much the difficulty will change.  It adapts (https://en.bitcoin.it/wiki/Difficulty#What_network_hash_rate_results_in_a_given_difficulty.3F) based on the total amount of hashpower out there.

So how about I set up a miner setup in my basement to offset costs to heat my house and then get bitcoin, in essence, by heating my house?

better choose "nicehash" if you want to get Bitcoins

People have had some success heating greenhouses (https://cointelegraph.com/news/cryptomatoes-grows-5-acres-of-fruit-from-bitcoin-mining-heat) with their miners.  I'm not sure how well it translates to heating an actual house that someone would want to live in, though.  It's not like you can just adjust the thermostat on them, so depending on where you live and what time of year it is, there will probably be occasions when you get too much heat and you have to switch them off.  Might be okay if you live in Siberia (https://www.curbed.com/2017/11/9/16619032/bitcoin-mining-heat-homes-siberia-russia), apparently. 

You're likely to be making a heavy loss by running those GPUs to mine, unless you happen to start mining a new altcoin that suddenly moons.  You will need to replace your GPU once they being unprofitable to run, which in your case is right away. If you have free electricity, then you might as well start mining. There are pools that automatically switch mining power to the most profitable coin, those would be a good start for you.

To be more specific, he wouldn't be mining Bitcoin directly but altcoins and then paid equivalent in BTC. Also, I would be more careful with Nicehash, did they pay people for their work after they got hacked? As other people mentioned here, mining Bitcoin with GPUs is no longer profitable. He should consider buying ASIC miner but honestly, I wouldn't buy it anytime soon since Bitmain could release a new model and then the old would become unprofitable (or it wouldn't pay off quickly).