Why it matters to you
By those normals Houston needs roughly 2.6 times as much cooling as heating (3,288 ÷ 1,266), which is why a heat pump suits the climate and why cooling efficiency, measured by SEER2, usually matters more here than heating ratings. Equipment here also logs far more cooling hours than the same unit would in a northern city.
Practical guidance
When comparing systems, weigh SEER2 cooling efficiency first, then HSPF2 or AFUE for the shorter heating season. Use degree days to compare climates and seasons, not to predict your own bill; a contractor's load calculation is what sizes the system for your house.