At least a year.
The GST Rebate on New Homes. The GST rebate is available upon the purchase of new homes valued at less than $450,000. This rebate will amount to a 36% kickback of the 5% GST portion of the HST. For instance, in a new home that is valued at $100,000 the GST portion of the HST would be $5,000. Multiply this amount by 36% and an individual will be eligible for a rebate of $1,800 on the purchase of this new home. This will be true for any purchase of a new home of which its value does not exceed $350,000. In a nutshell, in order to qualify for new home (or condo) HST rebate, the new home or condo has to be either your primary residence or you must prove that you have rented it out for at least a year.  In order to qualify for the HST rebate, the house or condominium must be acquired for use as the primary place of residence of the titled purchaser or his or her relative. (See box below) If you moved into the unit as your principal residence, the builder credits you their HST rebate upon closing.  You may be eligible for an HST rebate of up to $24,000 if you have done any of the following in Ontario: 1  Purchased a newly constructed home. 2  Purchased a new condo. 3  Built a house. 4  Contracted someone to build a house. 5  Substantially renovated a house or condominium. The new house HST rebate in Ontario essentially kicks back 75% of the Ontario portion of the HST, up to a new home purchase amount of $400,000. This results in a maximum rebate of $24,000 ($400,000 x 0.08 x 0.75). In other provinces, the new home rebate is clawed-back for any house purchase over $450,000 The Ontario new residential rental property rebate would be available in respect of the provincial part of the HST so that qualifying newly constructed or substantially renovated properties of any price would qualify for a maximum rebate amount of up to $24,000 per rental unit. For instance, in a new home that is valued at $100,000 the GST portion of the HST would be $5,000. Multiply this amount by 36% and an individual will be eligible for a rebate of $1,800 on the purchase of this new home. This will be true for any purchase of a new home of which its value does not exceed $350,000. The Ontario new home HST rebate or NRRP rebate must be filed within two years of a new home or condo closing. If you are applying for an HST renovation rebate, you have up to 2 years to apply following the completion of construction. The new house HST rebate in Ontario essentially kicks back 75% of the Ontario portion of the HST, up to a new home purchase amount of $400,000. This results in a maximum rebate of $24,000 ($400,000 x 0.08 x 0.75). In other provinces, the new home rebate is clawed-back for any house purchase over $450,000 Yes. In order to have a primary residence an individual or special trust must have “an interest” in a residence. The term “an interest” includes, among other things, a real right and a right of use or occupation. A long-term lease may comprise a real right (for example, a registered lease of at least 10 years). 1 The exclusion will not apply to any capital gain or loss in respect of a period on or after the valuation date (1 October 2001) when the person was not ordinarily resident in the primary residence (paragraph 47 of the Eighth Schedule). 1 The residence must not be let for more than five years. 2  You, your spouse or a beneficiary of a special trust must have resided in the residence for a continuous period of at least one year before and one year after the period of absence. 3  You treated no other residence as a primary residence during your absence. 1 The exclusion will not apply to any capital gain or loss in respect of a period on or after the valuation date (1 October 2001) when the person was not ordinarily resident in the primary residence (paragraph 47 of the Eighth Schedule). The amount of the HST due typically amounts to be between $19,000 and $31,000. The income property HST rebate program is available for new build properties to allow investors to recover up to $27,000 of the HST paid for the final closing. 
http://fmtlaw.ca/real-estate-corporate-estates-law-hst-rebates-homes-renovations-rental-properties/ https://www.linkedin.com/pulse/20140516042244-92542783-investment-properties-and-the-hst http://askross.ca/2014/03/condo-investors-losing-thousands-in-hst/ http://www.hstrebatenewhomes.ca/ http://fmtlaw.ca/real-estate-corporate-estates-law-hst-rebates-homes-renovations-rental-properties/ http://www.hstrebatenewhomes.ca/ http://www.sars.gov.za/TaxTypes/CGT/Transact-Connected-Persons/Pages/Primary-Residence.aspx http://www.sars.gov.za/TaxTypes/CGT/Transact-Connected-Persons/Pages/Primary-Residence.aspx http://incomepropertyhstrebate.com/
how long do i have to stay as primary residence to qualify for hst rebate