First off, I apologize for not reading all posts up till now. I am not an HVAC expert, but I did work in the industry a lifetime ago...
Herro ATOT.
Recently bought ourselves a new house. New Lesson in life: Regardless of inspections, hire an HVAC to inspect everything AC related on their own. NO QUESTION.
Turns out, the ACs on our new property seem to be filled with mold - and also the copper coils are (unsurprisingly) rusting and leaking.
This makes me question (everything, lol) the affiliation of the inspector with a repair company.
Dust gets through the system even with a filter, builds up, and that can in itself cause mold, or just be very similar looking to mold. You would need it tested to be sure, and of course there may be "some" mold, inherent in any system that condenses water, or at least fungus if the drain became partially plugged.
Coils leaking, is highly suspect if it still gets cold. If it gets low on refrigerant it will tend to ice up. Will there be some corrosion over time? Of course, but did the technician identify a leak? Without a sensor to do so, it is premature at least to diagnose a leak without other evidence like it not getting cold.
I understand that copper coils are something that ACs are no longer made with, because it is now widely understood that they leak as of today. I'm not surprised by this. I also understand that ACs are something that have a general lifespan of 10-15 years - and if you don't maintain it (like the previous owners) it will lean more towards the 10 year mark.
?? Not necessarily. Coils were made of copper that didn't leak for 20 years. It's just a more expensive metal while it still made sense to use aluminum fins.
Lifespan, it's a moving target. Climate, sizing for the building, initial build quality of the unit, of the fabbed installation, etc. You can expect a new midrange priced unit to have shorter lifespan due to the higher pressures used with newer refrigerant if nothing else and that elusive "higher efficiency" which means pushing everything harder for it.
Regardless, we called an HVAC to our new home today to look things over. They are basically under the impression that we should replace everything. Given the coils falling apart, mold in the ducts, etc... I'm inclined to... at least... mostly agree with them. These are AC units that are builders grade that are right at 10 years old. It's pretty apparent that the previous owners didn't take very good care of them.
Most homes do start out with builder's grade units. That's including units that last 15-20 years instead of only 10, BUT if you have to start paying someone to service them, then you have to estimate the cost for it. Some pay yearly for service, $100 or more each unit, which adds up. The greater question to me is whether there is mold contamination which you can measure elsewhere in the dwelling rather than a guess about a tiny bit in the HVAC stack.
So since we recently bought the home, we have a home warranty service. The A/C Repair company we are working with has basically said they will utilize the home warranty service, as well as manufacturer discounts (Trane) to equal a total of about $22,000 out of pocket to us. This is to replace 3 A/C units, the ducts, coils, etc... all throughout the home. Also comes with parts and labor warranty for 10 years.
This seems like an elaborate scheme to screw people. Trane is overpriced and their service leaves something to be desired. It's the last brand I'd ever go with, so any pretend savings, is probably a lie. You're probably paying at least $5K more than you would with an equal quality different brand with better parts availability and costs.
If you want to pay that premium towards a 10 year warranty, it's up to you but look into what it covers, as some things have a warranty of a few years anyway and what are the terms? Must you pay someone to do XYZ service to retain that warranty at some annual period?
Any HVAC experts or experienced folks here want to comment on how screwed I'm getting? Or how decent the deal is?
There is no easy answer to how decent the deal is except I'm pretty sure it's a few thousand overpriced. Replacing one unit with another, costs change as the plumbing (gas and air not just water) routes change, as the stack size changes, how much of the ductwork they are going to open up for mold remediation versus just spraying some chemical in.
Long story short, I would get a 2nd and 3rd estimate. You might be able to get the cost lower than quoted even without any home warranty involved, and have it cheaper to repair later.
Trane... no. Out of principle I would not give them business.