Coils Rusting on Air Handler - Replace vs Repair
We are looking to replace the fiberglass duct board in our downstairs zone due to health reasons. While the HVAC tech was here, we told him that we were told a few years ago that the coils on the upstairs air handler were rusted, so we had him look at it for us. Downstairs unit is also a little rusted, but not as bad.
He was trying to sell us the entire BS story about how R22 will not be available after January (which is true to a point) and we need to switch both air handlers and get new A/C units now. I wasn't falling for it until we checked it out here on the handy-dandy HVAC forum which I found a post which says this is not so.
However, these are our questions.....
1) the coils are definitely rusted on the upstairs unit. The unit is roughly 15 years old.
Do we try to have the coils replaced or do we install a new air handler? I did read on another post that in the HVAC world, you can add an adapter to a 410 air handler to go with a R22 A/C unit (??).
Current air handler is an Inter-City Products air handler. Yes, we have a mish-mosh of equipment. I guess it was whatever the cheesy builder could get his hands on for the "cheapest" price.
Is the cost of replacing the coils vs replacing the entire air handler significant? If we are dismantling the duct board in the basement maybe we should get a new air handler anyway. We will also have a new 4" HE filter unit installed. However, what about the unit in the upstairs zone which we were not planning on doing anything with?
He ALSO told us that we would need ALL new duct work upstairs to adapt to the new 410 air handler. We currently have flex duct throughout the house.
2) he also looked at one of the A/C units.. (AG high efficiency - model AG036G1) and said the motor inside looked like it was running hot b/c of how brown/rusted it looked. Our second unit is a Lennox (prior owners had replaced that one which I would guess would have been an AG HE as well). He told us the AG unit will probably need to be replaced too. Both units are clean inside, no debris, but no we have not had them serviced.
Thus why he told us we would need two new air handlers and two new A/C units for $15k-$20k, but the gov't is offering some great energy star rebates....LOL!!
One last question, we are wondering if the anti-freeze that is in the pipe lines could have possibly contributed to the corrosive nature of the coils or does this generally occur of so many years regardless. We hired a new HVAC tech last year and he told us the anti-freeze begins to attack metal after so many years and you need to have it drained and replaced. We are actually going to have it drained and leave it at that.
If you have any questions to help you understand this please let me know.
As always, thank you for your help.