Getting a HELOC for REI Entry

[Jared W Smith]

As part of my investment plan, I formulated the following: Use a portion of equity in my current single family home for down payment to purchase an investment property. Home was purchased as an estate sale in original 1960s condition, there's ample equity given that I made several updates, some as pure sweat equity. (As most say, your own SFH is not an investment but a liability. Well I am trying to change this, partially.)

My question, which option to go with (Current mortgage- 30yr fixed conventional at 4.125%):

1. Refinance (rates are 3.9-4.7 based on credit & loan amount)- This is my last option as there are more fees associated and I am immediately hit with the higher payment for total amount even if I do not use/need.  

2. HELOC (with outside lender)- Looking at credit unions for this. Flexibility to only be charged on the money I use.

3. HELOC (with current mortgage holder)- This would be from the large bank/lender. Flexibility to only be charged on the money I use.

Thoughts? Comments/Advice from those that may have gone down this route? Thank you!  

[Loan Officer, Lender, Mortgage, Bank, Financing]