I'm currently working on something like this heater for me.
standalone with RPi or TPLink router inside.
Might have a few pics within 1 week or so.
I would love to see what you've done.
I really think that future of decentralized home mining depends on also using the heat.
Here's a simple back-of-the-napkin calculation - I would be curious to hear if people think this is wildly unreasonable or not.
Let's say the whole thing costs you $1500 to build a 1000W system and you spend about $1700 in electricity for the season (Nov - Feb @ 24h x 30 days x 4 months x 6 cents per kwh) to run it. As long as your mining efficiency is better than break even for the power you'll make $1700+ in bitcoins. Assuming you were going to have to burn that electricity anyway for heat, your net cost is $1500 instead of $1700 for the season.
Next season you only swap the mining boards so your cost is $1000 for 1000W, but you can reuse the $500 radiator unit. Assume you again break even, now your net cost for the season is $1000. Or, if instead you keep your old boards which are now mining at a 50% loss, then you spend $1700 in electricity for 1000W of heat and make $850 of bitcoins. Either way, you cut your power bill down from $1700 to $850 or $1000.
If the bitcoin price goes up, your mining efficiency is > break even on power or you can use the heat all year (eg. to augment a water heater) then the economics look even better. If the bitcoin price crashes or mining difficulty increases faster than expected, you'll lose - but nothing ventured nothing gained.
This isn't a get rich quick scheme, this is a get rich slow scheme. And hopefully fun; people spend much more to overclock their home PCs with no financial gain.
The three financial caveats you need to accept are:
1) you were going to spend the electricity for heating anyway (24x7 during the coldest months)
2) your mining revenue is greater than, or equal to your electricity costs to run the mining boards (during the season)
3) the up-front cost of the mining boards is less than the cost of a season of electric heating
Notice that the only real unknown is the mining revenue. However, it is safe to say that the expected return for any mining boards should be greater than the cost of the electricity or else no one would even consider buying it. From a strict business perspective, the mining operation still runs at a loss of the invested capital ($1000) even if you break even on electricity.
A clever accountant might also recommend you treat the whole thing as a home business. Then you can deduct the cost of the mining equipment and electricity against the bitcoin revenue and deduct the loss on your taxes for a few years.
Please let me know where my math is wrong; I know I am taking a big risk by proposing a profitable scenario in this forum. :-)