Replacing evap coil costs?

DONT, its going to be the same price or most likely even cheaper to replace your 20 yr old outside unit (because if its r-22 its definitely 20 yrs old or older) and inside coil to switch to the new cheaper freon and it will be more efficient to boot. that said you are not going to gain a lot with still having the old heating system.

if you are smart you will just upgrade the whole complete system to a new high efficiency one

Well I just upgraded mine.

Weighed the cost of a replacement outside vs new efficient train. It's knocked off at least 30$ a month in terms of electricity and that's with my above ground intex pool running 4 hours a day.

That's plus cost of outside unit and r22 made is a no brainier.

Lots of places do 0%financing.

I put down about $2500 and just financed the rest for 36 mo. Probably pay it off by next year anyway. One unit turnaround and it's paid.

I replaced two of mine last month. Both had coils leaking and I replace the whole thing.

My unit was put in my house by me and a friend back in 92 and it is still working---well, the inside portion anyway since I had to replace the outside unit after Katrina.

I know I should replace it and am waiting until the fall to do so since I'll have to run new supply duct work off the unit and tie in all my lines in the attic. I'm not fond of being in my attic in the summer months with it being in the 120 degree range most of the day.

I know a more efficient unit will pay for itself in a few years time compared to what I'm currently paying for utilities every month this time of year.