I have just purchased a Whole House console Humidifier - that humidifies 2700 sq. ft - which is much larger than my home. This is the only way to provide the orchids with adequate humidity levels.
DNJ - nice purchase with the whole-house humidifier.
You mentioned that you're trying to get humidity within particular levels and ranges. Does this also mean that your phals are having issues with growing - eg. noticeable issues with leaves etc in the low-humidity growing area?