Heat pump, fan on or auto?

Over the years, I've had 2 different HVAC repair men come to my house, and I've been told contradictory information. Who do I trust???
I mentioned my ridiculously high electric bill to the first repair man (roughly $400/month for an 1800sq.ft house). He suggested that I should leave the heat pump fan on ON all the time. His logic was that it would keep the air ducts dry and cool, so that when the pump comes on it doesn't have to work as hard to cool the house.
I've done this for several years, and while I didn't notice a change in my electric bill, I assumed that the heat pump was running more efficiently and would last longer, anyway.
Recently, the reversing valve went out on my heat pump, and I had to have a different repair man come out to fix it (the guy that came out years ago has since retired). He asked why I had my fan on, and I told him the explanation that the other repair guy gave. He said that that was entirely incorrect; the fan being on all the time could raise my electric bill by as much as 25%!
So, who's right? Should I leave the fan on, or put it on auto?
TIA,
Jason
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This is pretty basic. Running the fan takes energy doesn't it? And how does leaving it on keep the ducts cool and dry? They should be dry no matter what. If they run through some space where they can take on heat, then running air through them constantly is going to just pick up that heat and move it into your house.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Auto, the first guy was an idiot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The 2nd one was correct.
Ken
Opportunities are never lost. The other fellow takes those you miss.
| Torrey Hills Technologies, LLC | | www.threerollmill.com | | www.torreyhillstech.com |
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.