Question: Every time my heat comes on while watching TV, the TV gets snowy and sometimes loses the signal. As soon as the heat turns off, the TV returns to normal.
Answer: We can’t really diagnose this remotely but here are some things that come to mind:
Make sure your antenna (over the air/cable/satellite) connections are good and solid. Inspect them for breaks in the wire or corrosion in the connections.
Next make sure that the furnace is still properly grounded. Loose grounds can cause static or interference in a TV. Another likely suspect is a motor that that runs while the furnace is on (forced air heating). After years of service, components (such as brushes in a motor) wear down and cause interference in electronics.
We’ve done some internet searches and the best sources found were these two from the UK. Here is a source of help if you want to take the time and effort to read the following link: http://vwlowen.co.uk/radio/radtech.htm#Qrn. It has a good explanation of the different types or interference and some possible problem sources and how to fix them. Although, some of the fixes are way above my head, you may find it helpful.