I've been renting this house for three months. I've been using the gas heater for the past two weeks with the weather being cold here in seattle, wa. Everything has been working fine up until last night when I felt a constant cold breeze. I check the heater vents and there blowing cold air. I checked the thermostat which was set to "heat on" and was previously set to 70 degress but now reads 62 degrees. I went out to the garage to check to see if the furance was running and it sounded like it but right off the bat I noticed a horrible gas/propane smell. It was serviced June 2011 and filter was replaced then. I took the filter out to look at it and it did'nt look clogged or dirty. I believe it's a fairly new furance because the owner converted from electric to gas. It says on the furance that it's self igniting. So any thoughts? I'm a women :confused: and don't know much about this guy stuff, lol. Thanks for listening to my blabbing I just wanted to be as detailed as possible. Furance is a Trane TM XE 78

(( but right off the bat I noticed a horrible gas/propane smell)). You answered your own question. CALL for service right away and in the mean time open the door or windows in the garage. This could prove to be an explosive situation. You might take the extra step to call the local fire department to shut off the propane gas.