Power costs money

Power, the biggest expense of mining, is tax deductible. The issue, though, is how do you prove how much power you actually used for mining versus day-to-day living?

Well, the answer is a separate power meter.

Your CPA would know best for your situation, but mine had said that, distinctly, a separate meter will keep you out of trouble. Otherwise, you will be limited to deducting based on the square footage of your house versus your mining area.

I think we all know that this would not correctly represent the amount of power you are using.

Turbo-tax wrote a great article that explains this in better detail.

This is what the instructions for the 8829 state.

Direct expenses benefit only the business part of your home.
They include painting or repairs made to the specific area or
rooms used for business. Enter 100% of your direct expenses on
the appropriate line in column (a).

Indirect expenses are for keeping up and running your entire
home. They benefit both the business and personal parts of your
home. Generally, enter 100% of your indirect expenses on the
appropriate line in column (b).

Exception. If the business percentage of an indirect expense
is different from the percentage on line 7, enter only the business
part of the expense on the appropriate line in column (a), and
leave that line in column (b) blank. For example, your electric bill
is $800 for lighting, cooking, laundry, and television. If you
reasonably estimate $300 of your electric bill is for lighting and
you use 10% of your home for business, enter $30 on line 20 in
column (a). Do not make an entry on line 20 in column (b) for any
part of your electric bill.

You can see by this last part that it would be in your best interest to have a separate meter or even a shed that was set aside solely for mining. Hopefully the IRS will modify this for those mining.

(Pro Tip: Call your Congressional Rep)