How does high static ductwork ( Mobile home) affect AC Seer rating?
The statement is not accurate.
The seasonal energy efficiency ratio is how efficient the system is at converting electricity into cooling.
The biggest gain is with variable speed compressors that run at a low level with very few starts.
The worst efficient systems 13 seer are the ones that the compressor starts pumps to a high level and shuts down then restarts in 5 minutes.
1 inbetween is a 2 stage compressor that can pump at a lower level and change to a high level without stopping.
The inside unit the air handler may have a higher static pressure but if the duct work can handle the pressure the flow can be increased without affecting the heat transfer at all.
One thing to look at is the payback in some cases the additional cost of a 24 seer unit VS a 16 seer may not be worth the cost!
What is the warranty length?
Higher seer units have more active components and fail more frequently (they usually won’t tell you that) but they are getting better.
When comparing a less expensive 16 seer to a 24 seer unit the cost can be 30% more will it save that additional 30% cost in power consumption in my experience no but it’s better for the planet.
So just making a statement because you have a type of home you would need your duct work replaced I would challenge that.
Ask to see the flow curves and the size of the evaporator housing. If it is the same size as your existing system there will be no difference.