The answer to 'heat exchanger high energy bills' is that a cracked or damaged heat exchanger can cause high energy bills. A faulty heat exchanger allows hot combustion gases to leak into the home's air supply, forcing the HVAC system to work harder to heat the home. This results in higher energy usage and costs.
Some common symptoms of a bad heat exchanger include strange smells, soot buildup, and higher-than-normal energy bills. If you suspect an issue with your heat exchanger, it's best to call a professional HVAC technician to inspect and diagnose the problem. Attempting to repair or replace a heat exchanger yourself can be dangerous due to the risk of carbon monoxide exposure.