By now, I hope you have called the local home improvement center and have workers installing the unit of your choice. Did you wait to have your husband buy your sewing machine? Consider your comfort part of your quilting and creativity. As far as the basement being unpleasant and having creepy crawlies, I would stock up on Kilz, stark white paint and a few brushes and rollers and start moving stuff around to paint walls and ceiling white. Unless water is pouring into the basement, you could turn it into your studio.
Anyone who swelters and suffers because of the cost of electricity should compare the cost of medical care with what a change in temp would do for their well-being.