我的前提是你有下一个投资的目标，Refi的利率是可以定期的。

If you have an another house to buy as your next investment property, I would use refinance to borrow the money out of your current home or current rental property to pay for this new property by using a fixed rate mortgage.  This way, your mortgage expense is fixed and one less thing to worry about since you will have a lot of unexpected things in your rental property investment.

After you have bought the new property and you have equity in this new property, you can open a HELOC account on this new property to get ready for the next investment opportunity.

But if you don't have a next investment in sight, I would get a HELOC on your current property to wait for an opportunity.