You can file as head of household even though you do not claim your unmarried dependent child as an exemption if you meet all of the following requirements:

1. You are unmarried or considered unmarried on the last day of the year.
2. You paid more than half the cost of keeping up a home for the year.
3. A qualifying person must live with you in the home for more than half the year (except for temporary absences such as school).

Refer to Publication 501, Exemptions, Standard Deduction, and Filing Information, for more information.

References:

• Publication 501, Exemptions, Standard Deduction, and Filing Information
• Tax Topic 353, What is your Filing Status?

Source: www.irs.gov