Runtime hours, not years in Johns Creek
958 cooling degree days and about 23 days a year above 90F, so running hours are middling and equipment life lands near the national average.
958 cooling degree days and about 23 days a year above 90F, so running hours are middling and equipment life lands near the national average
Johns Creek runs about 958 cooling degree days a year, which is a direct proxy for how many hours the compressor will actually turn - and compressors wear out by running hours, not by calendar years.
Why this changes what you should buy
In a dry climate the machine is doing almost pure sensible cooling, so the limiting factors move outdoors: how hot the condenser gets, how much dust is packed into its fins, and how many hours a year it runs. Those are maintenance and placement questions more than equipment questions.
Johns Creek gets roughly 23 days a year above 32 Celsius, and those are the days a system that is even slightly undersized will never catch up.
What to ask for, in order
- A Manual J load calculation, not a square-footage rule of thumb
- Shade or at least afternoon relief for the outdoor unit, without blocking airflow
- A maintenance interval that includes washing the condenser coil, which fills fast here
- Duct inspection before sizing, because attic ducts in this climate leak into very hot air
The median home in Johns Creek dates from 1995, which is a good guide to what the ductwork looks like behind the walls.
Prices in nearby cities
Albany · Athens · Augusta · Columbus · Gainesville · Macon · Roswell · Sandy Springs · Savannah · South Fulton · Chattanooga · Greenville