I have an old open loop system that has been great but lately has given me some trouble with a slow R22 leak. I'm considering replacing the unit with a new one. The quotes I have gotten were all pretty high and the installers didn't instill the biggest level of confidence (I felt more informed of the products they sell than they were after just a couple of days of research coupled with my pre-existing technical understanding). I can get the same unit for thousands less if I install it myself. I'm the kind of person who prefers to DIY whenever possible and quite honestly I don't see the big deal in swapping in a new unit. Everything is there and functional and the current capacity fits the house very well so that's the size I would go with again. There are no permit or licensing requirements where I'm at either. The one thing I'm not sure about is warranty coverage. Looking at the climate master warranty certificate in the installation manual I didn't see a disclaimer against DIY installlations but I'm wondering if anyone has experiences with the topic?