是这样的。

HELOC rate is determined by a short term rate called Prime Rate which is US Fed Fund Rate + 3.  Mortgage rates are determined by 10-year US Treasury Bond.  General speaking, interest on HELOC is higher than mortgage rates. 

For the past 10 years, you can see HELOC rates are the same or even lower than the mortgage rates, that is because Federal Reserver Bank has been keeping the Fed Fund rate at very low level.  Because competition, some banks are offering the first year HELOC rate 1% lower than actual HELOC rate.

With current Federal Reserve Bank rate normalization process, we have been seeing the Fed Fund Rate going up for the past 1.5 years.  We should expect HELOC rate and mortgage rates normalized as well.