I could be wrong, but I think the $ you borrow will be taxed twice. You’re paying back with after tax $. When you withdraw later, it’ll be taxed again. So, unless I’m wrong or you’re in the 0% tax bracket, it doesn’t make sense to borrow from your 401k to refi. Also, if you quit or get fired, you need to pay that money back immediately. The $ in your 401k is protected from bankruptcy. They can’t go after that $. However, they can go after your house if you filed for bankruptcy.