Pineridge, I used mine all summer, and didn't notice it being too bad as far as the greenhouse effect goes. The windows open up. Plus, you also have a circulation fan, and the duct blowers that you can run to keep a fresh breeze on you. I honestly think with the dark tinted glass and canopy you are actually cooler than not having a cab at all on some days. But yes, you could easily remove some of the windows if you wanted too. I talked to Jodale about getting A/C when I bought the cab last year. And they said they were coming out with a better unit later in the year. So I was going to just hold off and get the A/C later. But after using it last summer, I really didn't see a reason to get it. Believe me, I don't like the summer heat either, but it honestly it wasn't that bad using the tractor with just the windows open and the circulation fan running (which is right near your right window) so that keeps a fresh breeze on you at all times. I have no complaints about heat at all. And the right window can open up all the way, and you could latch it completly open if you wanted to. For the little heat you may have in the summer without AC is a small pay off for the warmth you have in the winter. It really isn't an issue with the heat in the summer time. The only time it is hot is if the machine has been sitting in the sun with all the windows closed, and that is only for a few minutes until you open the windows and circulate the air inside. I'll put up with that any day before freezing my butt off in the winter time. The one great thing about this cab is that all my winter work gets done perfectly because I'm not rushing to get back into the warmth of my house. Basically I quit when the job is done, before I used to quit when my body was frozen to the bone and I was covered in snow from blowing. I just listen to the tunes, in the nice warm heat and let the time pass having fun on my machine. Who could want more than that out of life? You will always have people tell you how bad a cab is in the summer w/o AC. But you should only take the advice of the people who have the same exact setup you are asking about. It really isn't that bad, I should know, because I have it, and I use it, almost everyday of the year.