To make a second home your primary residence, you must legally live in it for the majority of the year, update official documentation to that address, and treat it as your main home for tax purposes. Key steps include moving in full-time, updating your driver’s license, voter registration, and mail, and, if necessary, refinancing the mortgage to a primary residence loan.
In some cases, you may be able to reduce your overall tax bill by making your second home your main residence, for example if you intend to downsize.
Your primary residence is different from your second home, vacation home, and any rental properties you own. The Internal Revenue Service (IRS) only allows filers to have one primary residence – and most mortgage lenders follow suit.
The IRS defines a primary residence (or principal residence) as the home where you live for most of the year, the one you spend the most time in, and typically the one listed on your tax returns, voter registration, and driver's license. While it's the home where you live most often, you can only have one principal residence at a time, and factors like proximity to your job and where you file your taxes help establish its status.
The IRS uses a few factors to verify your primary residence. For example, the IRS will check the address on your tax return, your voter registration, and where your home is compared to your employer. If the IRS can't verify that a home is your primary residence, it may ask for supporting documents or other proof.
You might consider buying a second home as a primary residence if you plan to make it your main dwelling after a certain period, or if you're temporarily living elsewhere but intend to return to this specific property as your permanent home.
If you use your former home to produce income (for example, you rent it out or make it available for rent), you can choose to treat it as your main residence for up to 6 years after you stop living in it. This is sometimes called the '6-year rule'. You can choose when to stop the period covered by your choice.
The IRS is very clear that taxpayers, including married couples, have only one primary residence—which the agency refers to as the “main home.” Your main home is always the residence where you ordinarily live most of the time.
The biggest tax mistakes people make include filing late, math errors, incorrect personal info (like Social Security numbers), forgetting deductions/credits (like EITC), misreporting income, not signing forms, and making errors with bank details for direct deposit, all leading to delays, penalties, or missed savings, with using tax software or professionals helping avoid these common pitfalls.
Tax laws dictate a five-year holding period for 1031 exchanges that become primary residences. Specifically, you must own the property for a total of five years or more to receive a Section 121 exclusion. For example, say you purchase a property and rent it out for two years.
To prove the IRS's 2-out-of-5-year rule, you must show you owned and lived in your home as your primary residence for at least 24 months (two years) (not necessarily consecutive) within the five years before the sale, using documentation like utility bills, driver's license, voter registration, tax returns, bank statements, and mail all showing the home address. This proves you meet both the ownership and use tests for excluding capital gains on the sale, requiring documentation to back up your claim of residency during that period.
It allowed sellers to claim CGT exemption for the final 36 months of ownership, even if they had moved out. However, this was reduced to 18 months in 2014 and further to 9 months in 2020, which remains the rule today. This general law is in place as it prevents short-term transaction benefits concerning taxation.
The IRS prohibits married couples from claiming two primary residences for tax purposes. The designation of a primary residence, or “main home,” holds significant importance for homeowners due to the array of tax benefits tied to this status.
If you own another home, you'll need to cover the costs of running it. Depending on how often you stay in your second home, you may want to pay someone to keep on top of things, such as a gardener. You'll also need to pay utility bills like gas and electricity.
Rules about primary residences
For conventional loans and government loans, you must occupy your primary residence by a certain date after closing (often within 60 days) and intend to live there for at least one year after closing.
The six-year rule provides a CGT main residence exemption, which allows you to treat your main residence as your primary home for CGT purposes even while you're using it as a rental property, for up to six years, as long as you don't nominate another property as your main residence during that time.
The IRS second home rules define a home as a "residence" if you use it personally for more than 14 days or 10% of rental days (whichever is longer); if rented under 14 days, income is tax-free, and deductions apply like a primary home; if rented more, expenses must be split between personal/rental use, with specific rules for mortgage interest ($750k acquisition debt limit post-2017) and property tax deductions.
On a $100,000 capital gain, you'll likely pay 15% for long-term gains, resulting in about $15,000 in federal tax (plus potential state tax), but it could be 0% or 20% depending on your total taxable income and filing status, while short-term gains are taxed as ordinary income (potentially 22-24%).
To qualify for 0% capital gains tax, you must have long-term capital gains (assets held over a year) and your taxable income (after deductions) must fall below specific IRS thresholds, which change annually but are roughly <$48,350 for single filers and <$96,700 for married filing jointly for the 2025 tax year, allowing for higher total income when combined with deductions like the standard deduction. The key is keeping your adjusted gross income (AGI) low enough so that after subtracting deductions, your taxable income remains within these limits.