I have installed an Aprilaire 800 steam humidifier in our 2-story house. I have a downflow furnace with one duct going upstairs and another feeding the downstairs. Currently, I have the dispersion tube installed on the supply duct that goes upstairs. Unfortunately, the upstairs windows begin to condense before there is much change in downstairs humidity. If I shut off the humidifier, the upstairs and downstairs humidity will gradually equal out over a few days.
I would like to put a 2nd dispersion tube on the downstairs supply duct, but the supply duct is too low to the garage floor to have room for a drip tee and trap.
So my next thought was too install a single dispersion tube on the return duct? Is this a bad idea? I know that warm air absorbs more moisture than cold air, but with my current set up, the humidifier runs with just the fan most of the time anyways.