Last fall, when the weather changed, I raised the thermostat setting & started up the gas furnace. The whole cabin filled with the odor of dead rodent; Even though it was only 45 degrees outside, I opened all the windows. I number one bundling up in jackets & our Winter time coat to inhaling that odor, unluckyly, as soon as I ran the furnace again, the odor came back. I lit scented candles, bought room deodorizers, cleaned with disinfectant & hoped it would work itself out. After several afternoons, I couldn’t stand it anymoreâ€¦ My whole family was complaining always. It was honestly horrible & unbearable. I contacted a professional Heating & Air Conditioning contractor & stressed service for the furnace. The professional took the unit apart & found a minimal buildup of dust inside, he told myself and others that the rodent was most likely inside the ducts. He wanted to know when was the last time we’d had the HVAC ducts professionally clean. I’d never had them ran tests on. The HVAC duct is concealed inside the walls, ceilings & crawlspace, so I never gave it a thought. He said that dust & debris accumulates inside the network of pipe & not only restricts airflow however absorbs odors. The odors, along with all sorts of contaminants, then get spread throughout the house! Plus, problems with the HVAC duct places added strain on the furnace & leads to malfunction & higher running costs. The professional gave a duct cleaning service. He brought in what looked a lot love a important vacuum cleaner. The equipment had a long hose & a wand with a brush affixment on the end. This works to discottage contaminants & suck them up. The duct cleaning eliminated the odor of dead rodent & improved the performance of the furnace.