How big of a heat pump do you need for a 2000 square foot house?

How big of a heat pump you need for a 2000 square foot house depends on climate, insulation, and Manual J load calculation, but typical size is 3 to 4 tons or 36,000 to 48,000 BTU, with 3.5-ton being most common for average home. One ton equals 12,000 BTU per hour, so 3-ton equals 36,000 BTU and 4-ton equals 48,000 BTU. For well-insulated new home built after 2010 with R-49 attic, R-20 walls, and double pane low-E windows, you need about 18 to 22 BTU per sq ft for cooling, so 2000 sq ft times 20 BTU equals 40,000 BTU or about 3.5-ton. For moderately insulated home built 1980 to 2000, need 22 to 28 BTU per sq ft, so 44,000 to 56,000 BTU or 4-ton. For poorly insulated old home built before 1970, need 28 to 35 BTU per sq ft, so up to 5-ton. Climate also affects: in hot climate like Texas requiring more cooling, 4-ton may be needed for 2000 sq ft, in mild climate like Seattle, 3-ton may suffice. Oversizing causes short cycling and poor humidity control at 60 to 70 percent humidity. Undersizing causes not reaching set temperature on hottest days. Proper sizing requires Manual J calculation by contractor that considers insulation, windows, air leakage, and occupancy, not just sq ft. For 2000 sq ft average home, 3.5-ton variable speed heat pump is ideal because it can ramp from 30 to 100 percent.