Window Air Conditioner vs Rooftop vs Portable
TLDR - Window air conditioners are far superior to rooftop and portable air conditioners. I knew they would be better, but how much better was shocking.
I thought about doing a YouTube video on this with quantifiable data but I just haven't had the time. But I thought I would still share my experiences in the Texas heat over the last 2.5 summers using various types of air conditioning.
I am living full time in my travel trailer in north Texas on my own land. I am much more tolerant of discomfort than most and never have my thermostat below 76, even when I owned my own home. But air conditioning is still critical in 105 degree Texas heat and I've been struggling to find an efficient way to stay under 80 without running the rooftop AC all day. I am on 100% off-grid solar power.
The first summer I used a dual hose 10,000BTU portable air conditioner. I made a very nice window mount for the hoses that was well sealed and reasonably insulated. My trailer was partially in shade from trees and I rigged up tarps to shade the roof so it was not in direct sun. However, the sun did hit the sides of the trailer for part of the day. The portable AC ran constantly (with the compressor on) all day and by the end of the afternoon the temperature indoors would be 85+. Since the AC ran all day, I did not have enough solar power to keep up with it (1000W+ from about 9am to 9pm or approximately 12kWh) so I had to run my generator a LOT to supplement.
The second summer the only thing that changed was I installed a metal carport overtop of the trailer so it does not get direct sun on it at all. Same result. 85F or so by the end of the afternoon.
This summer I ditched the portable air conditioner in favor of a 6,000BTU window air conditioner. The main reason I didn't do this from the beginning was it is rated at 6,000BTU vs 10,000BTU and the only window that it could be installed in is not very conducive to a window unit. But I build a wooden stand that sits outside the window and supports the weight of the air conditioner and used a metal rod on the inside of the window to hold the air conditioner in the correct position. I then used 1" foam board and cut out a very precise piece to fit in the window and then sealed it all with HVAC tape.
The difference has been huge. The much smaller window unit uses half the power of the portable AC (500W vs 1000W) and actually keeps temps below 80F as the sole air conditioner in my 32' trailer. I'm actually in shock. It still runs nonstop from 9am to 9pm but the shocking part is that it actually performs better than a 10k dual hose portable unit. I knew portable units were crap but the dual hose units were supposed to be much better than single hose variants. But the flaws most people point out (heat radiating into the room from the exhaust hose, drawing in warm air into the intake hose from the exhaust hose) are not really the issue. The issue is they just are poorly rated and ultra inefficient.
Not only does the window unit outperform the cooling for half the energy but it actually removes humidity better, too. I used to wake up in the middle of the night and feel cool but sticky with the portable AC on. The window unit keeps cool and much dryer.
One note on the rooftop AC. It obviously cools down the trailer in a hurry. But it uses an insane amount of power. So much so that I literally can't use anything else in the trailer except for lights and smaller loads when it is running or it will trip breakers. And no, it doesn't need a soft start added on. It does not just happen when the compressor kicks on. It uses 1300+W continuously, is extremely loud (I am on zoom calls and on the phone half the day working from home), and I can't run my desktop computer or refrigerator or other devices without a tripped breaker. So it just isn't viable. Very effective cooling, but inefficient and overpowered for the trailer wiring.
Hope this anecdotal summary helps some folks. Stay cool this summer!