We've got warm air heating in our house, in a property built in the 1970s. Today, for the first time since we've lived here (5 years) I decided to pull off the single big intake grill and two outlet grills downstairs just to see what was behind them and discovered huge piles of dust and crud. Yuk! Having now vacuumed them out, I am wondering what state the rest of the system ducts are in, and wondering how I can clean them out. The upstairs bedrooms (3) and bathroom have grills in the ceiling which is fed by the ducts fanning out from the central heating unit located in the centre of the house. I've looked in the loft and other than dismanting the whole lot, which includes unwrapping all the wadding and hesian, I can't think how I can do it.
I've not turned the system on yet this year, but I do remember last year when we turned it on, we had to leave the house for a hour as we got a smell of burning dust. Even by the time we turned the system off again in the Spring, we still getting burning dust smell when we turned it on, albeit a lot less. We also noticed that we had to hoover and dust a lot more during the winter.
I'm not sure these systems are any good if you've got asthma or any other lung disorder. Thankfully, none of us have.