We had 2 duel fuel two stage hvacs put in early last month. The upstairs unit was put in one day and the downstairs the next. They replaced gas furnaces. The morning after the downstairs unit was put in we came down and the smell was kind of like when you plug a ceramic heater in the first time, but it also left a taste in ur mouth like gasoline it was so strong. That smell went away but there is some kind of odorless vapor blowing out with the unit because all of us in the family are suffering from burning, itching bloodshot eyes (including the dog), red skin on faces, burning nose and throats and itching bodies. Humidity in the air makes it worse. I can stand over hot water running in sink and my face starts to burn because its activating whatever vapor is on my face. It is long lasting because because I have tried going days without running them and we still suffer. I crack the windows every day to dilute but it doesn't help much. The only new duct work was steel pipe painted with mastic and tape and wrapped in insulation from the unit to trunk line. Mastic painted in returns. I've had an industrial hygienist come and run tests but not coming up with anything. Anybody run across this situation ever or have any ideas? At wits end and sick over all money spent and now we are miserably sick.