I work from my condo as a salaried employee required to maintain a home office. My heating is paid within my condo fees; how do I separate out the portion that is heat?

Separate your heating fees from your condo fees, then take that amount and % it out based on the amount of space you are using for home office. 

Example : Condo is $3000 a month, your heating is $1000 of that $3000. You are using 25% of your home as an office, so that means you are also using 25% of heating, therefore your heating cost will be claimed at $250 for your home office.  

Remember to always keep your receipts in case the CRA wants to verify later.