Recommend that you don't do it..
I worked full-time from home for 3 years. Spoke to our tax guy on possible write offs. He told me the amount wasn't worth the hassle as it was the first thing the IRS looked for to do audits. Have to prove the room you use as an office is used 100% for work, or that when you wrote it off, you only took the percentage actually used.
Maybe your company will offer a monthly payout for "incidentals".
Our company is giving us $40 a month for cell service, internet, etc.