The 'Main Home' Exclusion in 2026: Avoiding the Tax Traps of Mixed-Use Properties
- Joshua Flack
- Jul 1
- 3 min read
TL;DR
The main home exclusion keeps your family home outside the bright-line test. Simple in theory. The traps appear when the home isn't purely a home: a room rented out, a home office claimed, short-stay accommodation, or a period where the property was rented before you moved in. In those cases the exclusion can be partial or lost entirely. This post explains how the exclusion works and where mixed-use blurs the line in ways that cost people at sale.
Most people assume the family home is automatically tax-free at sale.
It usually is. But "usually" is doing a lot of work in that sentence.
The main home exclusion from the bright-line test has conditions, and modern living, working from home, renting a room, the occasional Airbnb, quietly breaches them more often than people realise.
How the Exclusion Works
The bright-line test taxes gains on residential property sold within the bright-line period. The main home exclusion takes your primary residence out of that test.
To qualify, the property has to have been used predominantly as your main home for the relevant period. "Predominantly" is the key word. It's about both area and time.
If more than 50% of the property was used as your main home, for more than 50% of the time you owned it, the exclusion generally applies in full.
Where Mixed Use Breaks It
Renting out a room.
Flatmates are generally fine. But a self-contained, separately let portion of the property starts to erode the "predominantly main home" position if it's a large enough share.
Home office.
A genuine home office claimed for tax can introduce a business-use element. Modest home office use usually doesn't break the exclusion, but it needs to be proportionate.
Short-stay accommodation.
This is the big one. Listing the property, or part of it, on short-stay platforms creates periods of income-producing use. Extensive short-stay use can reduce or eliminate the exclusion for those periods.
Renting before moving in.
If you rented the property out before living in it, that period counts against the "main home" time test.
The Apportionment Trap
Where use is mixed, the exclusion can apply partially. The taxable gain is apportioned based on the non-main-home use.
Worked example, simplified. You own a property for three years inside the bright-line period. For one of those years it was fully rented before you moved in. Roughly one-third of the gain could fall outside the exclusion and into the bright-line test.
The numbers get more complex with part-property use, but the principle holds: mixed use means partial exclusion.
What to Do
Keep records of how and when the property was used
Be honest about short-stay periods, the platforms report income
Get advice before selling if the property has ever been rented, partly let, or used for short-stay
Don't assume "it's my home" settles the question if the use has been mixed
Where This Leaves You
The main home exclusion is generous but it's not unconditional. The more your home has done double duty as an income earner, the more carefully you need to check the position before selling.
If your property has been purely your home the whole time you've owned it, you're fine. If it's been anything else, get it checked.
Mixed-use properties raise lending questions too, particularly where short-stay income is involved, because banks treat it differently to standard rental income.
At CRISP, we help investors structure mixed-use and short-stay properties so the lending and the tax position both work. The two interact more than people expect.
Get both right, or neither works.
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About the Author:
Joshua Flack is a mortgage and lending adviser and the founder of Crisp Financial. Before finance, he spent two decades running businesses across construction, facilities services, and franchising, which is why his advice starts with how the numbers actually work rather than how the brochure says they should. He works with home buyers, investors, and self-employed borrowers across New Zealand, with particular depth in complex and non-standard lending. Crisp Financial Limited (FSP1012114) operates under the Link Financial Group FAP licence. The information in this article is general in nature and is not regulated financial advice.
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