George,
Is the gain worth the effort on any project? How do you measure each and compare? Everyone would measure differently, and have a different opinion. Just like "beauty is in the eye of the beholder".
I once worked witn a man who would not even try do do most repair or beautification tasks at home that he could pay someone else to do because "it wasn't woth his effort." How did he decide? He based that on his salary rate while working. In other words, he made about $25 an hour at work at that time, so, if he could hire someone to perform a task for less than $25 an hour, that justified having it done, and not doing it himself. He said he was saving money. I thought that way of thinking flawed. My attitude was a dollar saved was a dollar earned and I did all tasks at home myself that I could do so as not to spend money. I didn't consider my time at home being at $25 an hour. See, it is all in the opinion of the "doer" if the gain is worth the effort.
I find it interesting that since EIEIO1 posted the initial message asking if the door mounted AC unit was practical, there are 3 pages of replies, none of which are from EIEIO1 (or are any the same person under a different name). Well, EIEIO1, based on all of the opinions of your idea, what do you think of the idea now? Will you persue it or not?
