home equity line to purchase investment property?

[Gordon Wong]

I have a home equity line of credit for up to $100,000. The deadline to take out any money is Dec 2012. All the fees have been paid for already. A little info on the line of credit. APR is .25% less than the wall street journal prime rate, which is 3.25% right now. It is adjustable every month. The max change within a year is 4%. The loan term will be 20 years.

My question is:
Should I use this line of credit to purchase a investment property? A house or condo to rent out that would be less than $100,000. Pay for the whole property with the line of credit or pay some with cash, like 20%? The part that bothers me is that I would not know what my interest rate would be in a year or two or whenever down the line. I know I can get a fixed rate mortgage and I wouldn't have to worry about that but I already have this available and want to know if I make use of it.

So should I use the line of credit or just let it expire? Any suggestions to how I can use it to invest in a rental property? Thanks