I have an electronic home furnace with 93% high efficiency, its been 5 years since I bought it. Tommy suggested to me to have a furnace check, so I called for a home furnace cleaning service since I'm so busy with my work, I was surprised when they found out there's a small hole in the backside of the furnace. they recommended a carbon monoxide test to make sure if there's any mark of carbon monoxide leakage inside our home. I even bought a carbon monoxide detector afraid to cause severe home hazards. I thanked Tommy for his good suggestion to check my furnace regularly. I posted it to call the attention of the other members to check out their furnace and air conditioning to prevent home hazards. Hope this experience of mine may help you.