I have a consulting/writing business and have a home office in my main residence and in my summer home. How can I deduct expenses for both home offices?

Yes, you can. Here are some hints:

All of the qualifying questions for claiming a home office will be covered first, then there is a question about whether you lived in the same home all 12 months of the year.  If you answer No, then you will be given the option of qualifying a second home office.  You will be asked all of the same questions again to be sure that the second home office qualifies. 

Then, there will be a question to allocate your business activity between the two offices (for example, 50/50 if you lived in each home for 6 months).  Finally, you will enter a description for each home office, such as your home address.

Then, when you are working through the expenses for your business and you go to the Home Office Expense, there will be two home offices listed to work on one at a time.  This is where you will designate the period of time that each office was used as well as the size of the office and all of the other associated expenses that go along with a home office. 

If you have other questions about this, ask in the comment section below.