Haw. Rev. Stat. § 521-66
When a tenant exercises a right to terminate the rental agreement pursuant to section 521-62, 521-63, or 521-65 the landlord shall return to the tenant, not later than fourteen days after the termination, the amount of any advance rent paid apportionable to the remaining days of the term and the amount of any security deposit that the landlord is not authorized to retain pursuant to section 521-44. A return of advance rent or of a security deposit complies with the requirements of this section if it is mailed to the tenant, at an address supplied to the landlord by the tenant, by certified mail, return receipt requested, and postmarked before midnight of the fourteenth day after the date of the termination of the rental agreement.
HRS § 521-66