It is pretty simple. Is the dwelling designed to be a place where people live – residential. If designed for commercial purposes – commercial. I feel you are going to try to claim that the house was unoccupied and therefore not residential, it’s a thought but will not work. Get an attorney.
Mr. Driessen is a former Deputy DA in Orange County with over 8 years of criminal law experience. Nothing stated on this site shall in anyway be construed as legal advice, or as creating any attorney client relationship. If you would like to hire Mr. Driessen, feel free to contact him at www.theocduiguy.com.
The distinction between 1st degree burglary, residential, and the less serious 2nd degree burglary, turns upon whether the structure entered is inhabited or not . Second-degree burglary, also known as commercial burglary, is generally charged when one is accused of entering a business establishment to commit a crime inside the business; typically theft.
Further, CalCrim No. 1701 on burglary degrees, a residence is considered inhabited "if someone uses it as a dwelling, whether or not someone is inside at the time of the alleged entry."
I hope that helps.