You can file a Sch C without profit. Just be sure you do show one soon. The IRS expects a business to make money 3 out of 5 years, otherwise it is a hobby.
- An office in home can only be deducted against income.
- If the home solar system is part of your business, then you would add the Sch C, all the information and add the system as an asset to depreciate - except it is on your home and personal use.
A home solar system and a business schedule don't normally go together. Perhaps you should reply with more information to make sure what you are doing is correct.
A home solar system should qualify for an home energy efficiency credit on the federal and maybe state returns. Energystar is a government agency with details.
See IRS Small Business