Thanks for the article. Had a close call last night myself. It has been hot during the day but waited til late evening (10-15 degrees cooler around 70) to run some blinds. It wasn't until on her way back from the last one that the symptoms showed up. Seems like there is a fine line you need to pay attention to there. It's the first time that ever happened to me and panic sets in rather quickly. Caught it before it got bad so that was a good thing.