Enter your AC's BTU rating, efficiency (SEER/EER), hours run per day, and your rate to see real running costs.
SEER ratings assume average seasonal conditions; running cost rises on the hottest days when the unit works hardest relative to outdoor temperature.
A window or central AC's power draw comes from dividing its cooling capacity (BTU/hr) by its efficiency rating — a higher SEER number means fewer watts for the same cooling output. This is the same underlying math as our general electricity cost calculator, tuned specifically for AC nameplate ratings.
SEER is a seasonal average efficiency rating used for central AC systems, while EER measures efficiency at one specific outdoor temperature (95°F) and is more common on window units — both work the same way in this formula.
Yes, proportionally — moving from SEER 10 to SEER 16 cuts running wattage by about 37% for the same cooling output, which compounds significantly over a full summer.