Deciding Between Ducted AC Unit 13,500 BTU Or 15,000 BTU Coleman Mach In 2019 Keystone Cougar

Published 04/27/2026

Products Featured in This Question

Coleman-Mach Signature Mach 3 RV Air Conditioner System - 13,500 Btu - Ducted - Polished White - R32

(6)

$1329.82

Coleman-Mach Signature Mach 15 RV Air Conditioner System - 15K Btu - Ducted - Polished White - R32

(11)

$1429.67

Question:

I’ve got a 2019 Keystone Cougar with a rooftop AC that finally quit, and I’m trying to decide between the Coleman-Mach Signature Mach 3 # CM83RR and the Signature Mach 15 # CM52RR. My trailer has ceiling vents throughout, so I’m pretty sure it’s ducted, but I’d like to make sure before I order the wrong thing. How do I check that, and do you think the 13.5K is enough or should I move up to the 15K?

asked by: Aaron

Expert Reply:

Hey Aaron, if you’ve got ceiling vents spaced through the trailer that carry the air away from the AC opening, that’s the big clue you have a ducted setup, and these Coleman-Mach systems are for ducted RV units only. A quick way to double-check is to look at your current ceiling assembly. If the main AC ties into a network of ceiling ducts and vents instead of only dumping air right at the unit, you’re in the right category for the ducted units like Signature Mach 3 # CM83RR or Signature Mach 15 # CM52RR.

Between those two, I’d lean toward the Signature Mach 15 # CM52RR for a Cougar that sees real summer camping. The Mach 3 # CM83RR is still a solid complete ducted system, but if you’re already replacing everything and you camp in hot, humid weather, the extra cooling capacity of the 15K gives you a little more cushion when the trailer is heat-soaked. Both are complete systems with the rooftop AC, ducted air distribution box, and wall thermostat, and both run on standard 115/120V AC power.

So the short version is: yes, these are the right style only if your RV is ducted, and if your old unit ever struggled in peak summer heat, I think you’d be happier stepping up to the Signature Mach 15 # CM52RR. Aaron, if you want, tell me your trailer length and what AC you’re replacing now, and I’ll help you make sure you’re landing on the better fit.