I recently moved into a new build house in Northern Virginia from a production builder that is two stories plus basement. They installed a 100k btu 92% efficient furnace for the basement and first floor along with a 3 ton ac unit. The area for the two floors is 2,648 sf. For the top floor they installed a 3 ton 13 SEER heat pump for an area of 1,676 sf.
The gas furnace seems to be running for short periods of time which concerns me. I asked for the Manual J report for the house and it calls for a 37,000 btu gas furnace and a 2.5 ton AC for the basement and first floor. The second floor calls for a 1.5 ton heat pump. Do these numbers sound right for northern virginia and the square footages? The heating design temp is 18 degrees and the cooling design temp is 91 degrees.
Why are my systems so much larger than the manual J report? Should I be concerned? I have attached the manual j for reference.
Thank you for any help.