I base out of KLBX south of Houston and use mine for Angel Flights and when I'm with my wife from mid-June through around mid-September. Without it it's pretty uncomfortable sitting in the plane while getting a clearance, loading a flight plan, etc. I've had it take 15 minutes from cranking the engine until take-off out of KHOU in Houston and that's a long time when the outside air temp and humidity is in the mid-90's. The ice AC system helps a lot.
The outside air temps dont get below 70 until you're over 5000' and the Houston controllers tend to keep you down around 3000 until you're north of IAH when crossing south to north across Houston. The wings on the Cardinal RG sit far enough back that you have great visibility but it also results in a real green-house effect. Without the system running you're going to be sweating for 30- to 45-minutes flying out of KLBX from the time you crank the engine until you get up to the cooler air during the summer. It was 87 at 9 PM last night and in the mid-80's when I woke up today so leaving early or late doesn't help a lot.
My system needs a 1 1/2- to 2-gallons of water to pump reliably without cavitation. I keep water jugs in the fridge in the hanger so we start with cool water when flying from home. With 30 lbs. of cubes it will stay cool as long as we need it on take off but the ice has generally melted by the time we get to the other end of the trip. We usually fly to someplace cooler so that's OK.
I've started using gallon tubs to make blocks of ice in the refrigerator's freezer in the hanger. With room temperature water from the store, 20 lbs. of cubes, and 4 of those blocks, I still had blocks of ice 8 hours after take off when we flew to Naples, FL a couple of weeks ago. I can't always find blocks in stores when I travel but the goal now is to get one bag of cubes to cool things quickly and then one or more blocks to keep things cold for the entire trip. Worst case many if the FBO's in the south have ice-machines and will refill your system when you stop for fuel if you ask.
We start the cool air going as soon as we get everything loaded into the baggage compartment and find it will drop the cabin temp by 10- to 15-degrees in the time it takes to finish prepping the plane. In general the air out of the systems duct runs around 20 degrees cooler than the ambient air in the cabin with the pump running and ice in the water. I'm told that you can extend the time the ice will last by just running the fan but the fan alone doesn't help a lot here. We keep the water pump and fan going until we get up to 5000' and then shut everything off until we get to about the same point when we're landing.
It really helps a lot and as a result we do more summertime trips than we did before we got the system. It's 60- to 70-lbs. of added weight and takes time to set up and break down again so I frequently don't use it when I fly by myself. However, I will fly with less fuel if needed to be able to use the system and carry multiple passengers when I take someone with me. It's makes for a much nicer trip and comfort is key whenever I have passengers.
Gary