Even if you rent I assume a "second home" is still a second home because you don't live there for x amount of time?
Are you talking "second home" for tax purpose?
IRS Defn:A second home can include any other residence you own, and treat as a second home. You do not have to use the home during the year. However, if you rent it to others, you must also use it as a home during the year for more than the greater of 14 days or 10 percent of the number of days you rent it, for the interest to qualify as home mortgage interest.