Forced air heating plus cooling devices require a lot more work than I originally expected. When I first bought this household, I thought the current Heating, Ventilation & A/C device would be awesome. At last, a place that has central A/C plus central heating. No more obnoxious window A/C devices or those big aged wall A/C units from the 70s which burn through so many kilowatts they’ll run your utility bill through the ceiling. I followed the instruction from the manufacturer plus the information from the homeowner’s insurances corporation, which clearly states the two of us must change the air filter at least once a month plus have the whole Heating, Ventilation & A/C device checked twice a year plus by the heating plus A/C device corporation that the insurance corporation uses. Well, I did those things, plus I was still having a great deal of trouble with the Heating, Ventilation & A/C device. The parts were running fabulously, however I noticed the whole thing was actually cycling for much longer than it did when the two of us first bought the household several years ago. At first, I started changing out the A/C filters every several weeks. Since I have a few dogs, I thought that might be the complication. When that didn’t work, I called the Heating, Ventilation & A/C corporation. Instead of inspecting the Heating, Ventilation & A/C device, she looked at the HVAC duct plus immediately suggested a cleaning! Even with familiar air filter changes, the HVAC duct she said still needs to be cleaned at least once a year, every single year. Without regular HVAC duct cleaning, the system can get really nasty, which prohibits airflow plus makes the whole system overexert itself.