Have a Tax Question? Ask a Tax Expert
The home can be your primary residence regardless of how long you live there during a tax year. IRS Publication 523 states that your primary residence is your "Main Home".
If you own or live in more than one home, the test for determining which one is your main home is a “facts and circumstances” test.
The most important factor is where you spend the most time. However, other factors can enter the picture as well. The more of these that are true of a home, the more likely it is your main home:
The address listed on your:
U.S. Postal Service address,
Voter Registration Card,
Federal and state tax returns, and
Driver's license or car registration.
The home is near:
Where you work,
Where you bank,
The residence of one or more family members, and
Recreational clubs or religious organizations of which you are a member.
So the home can be your primary residence regardless of long you actually reside in the home due to your working travel requirements.
You will need to keep good records of your rental days and income/expenses and report them annually via Schedule E of your Form 1040.
Here is a good resource for your review - http://www.irs.gov/taxtopics/tc415.html
Note that if and when you sell the home, and if at a gain, part of the gain main not qualify for exclusion. See link here for more information - http://www.irs.gov/publications/p523/ar02.html#en_US_2014_publink1000200611
I hope that provides the information you were looking for. Please let me know if something is not clear and I will get back to you as soon as I am able.