Expert: Norval Trimborn - 7/10/2009

Question
I had a 4ton straight cool which was replaced with a 3 ton heat pump - per load calculation.  It ran great up to 90 degrees outside, then I could not get the indoor temperature below 80 and it ran continuously.  I had a bad humidity problem before and now it's gone.  Company is saying the load calculation was wrong and they are replacing the unit with a 4ton & variable handler.  My question, will I have a humidity problem again.  I keep my thermostat 79-80 and live in Florida. 2100 sq feet. face north south,poor insulation.
Thank-you

Answer
With a continuously variable speed motor you should have the option to decrease the air volume from the normal 400cfm per ton to 350cfm per ton for better humidity control. You will get slightly less capacity(but not 25% less as with a 3 ton unit) but better humidity control.