I live in the Peidmont of NC and just purchased a house built in the Late 50's, a Cinder Block house. still has old windows so it gets cold in hte winter. I am replacing hte HVAC Package unit with a new Package heat pump. the house is 1400 square feet. My question is from my calculations the correct size for HVAC would be 2.5 ton ...BUT I think that I neeed to up it to 3 ton. Please advise
Have your HVAC contractor do a load calculation. Not sure how you came up with 3 Ton, but the correct way is to use Manual J (for cooling) and the corresponding manual for heating. It is a fairly involved process. In the Eastern part of the US, you round down (for cooling) rather than up because of the need to remove moisture from the air.
If you don't stand behind our troops, please feel free to stand in front of them.
I second that suggestion for sure... You can really shoot yourself in the foot when installing a larger unit to an older home as well, as you need more return air for the larger system. Its not just.. "Install a 3-ton"... its Install a 3-ton, add a second return air run to increase the volume going back to the unit so it doesn't turn into a block of ice, and sound like a vacuum cleaner! :-)
Have your contractor run a load is a great way to get it right!