I have a sound coming from the same spot in the attic. It is coming from a bedroom in the house that is above the furnace and water heater. It sounds like the furnace burner is kicking on, then there is a sound like a low thunder rumble. This only happens when it is calm outside. It will keep doing this for an hour or so, especially in the late afternoon. The rumble will last about 5-10 seconds, then will intermittently repeat the process. Also, this only happens in the winter time, have never heard it any other time of the year. I have gone to the basement numerous times to find the furnace and water heater still on the pilot mode and not running. So, the sound is not from coming from those appliances.
- I have detectors for propane and carbon monoxide gas on all levels of the house.
- Ranch style home, with a full basement
- House is about 12 years old
- Just started noticing this recently.
- We had a mild day today, so the furnace did not go on much at all. It still hasn't kicked on tonight (11 PM) - but I heard the noise today, with nothing running. Thanks for any advice! Ken