Alert: If you are in the DFW area keep an eye out for improperly converted furnace closets. I had a call a couple of weeks ago where the homeowners were exposed to CO gases all night. When I arrived 4 hours after the furnace had been turned off, my CO detector read 98 ppm within 4 minutes. The homeowners had allowed Oncor to send out contractors (homeowner couldn't remember what company) to convert the furnace closet. IE seal the closet. Well they sealed it alright but forgot to cut in combustion air vents into the attic. The homeowners said it looked like a couple of kids that came out and did the job. They were lucky to have awakened that morning. It took 40 minutes with all of the doors open to clear the house down to 0 ppm. I wonder how many more are out there like that. BTW Oncor hung up on the homeowner twice and told her that that program has ended and they didn't keep any records of who did the job, which has to be BS. I refered them to the Dept of Licensing and Regulation and the city.