Less than almost anything else that heats or cools a room - but the honest answer is a calculation, not a number, because your climate, electric rate, and the specific unit's efficiency swing the bill by several times. Here's how to get YOUR number in two minutes, and the concepts that make it make sense.
Get your actual number
The operating-cost calculator takes your system's capacity and efficiency (SEER2/HSPF2 - on every model page in our database), your state's average electricity rate (we load current EIA figures), and your usage pattern, and returns monthly and annual estimates. That's the whole answer; the rest of this page explains what drives it.
What actually drives the bill
- Runtime, not size. An inverter mini split sips power most of the day at partial speed. The rated wattage on the spec sheet is a ceiling, not the draw - which is why "how many watts" is the wrong question and seasonal efficiency (SEER2 for cooling, HSPF2 for heating) is the right one.
- Heating is the bigger line item in cold climates - not because the unit is inefficient, but because winter asks for more hours and harder work. Efficiency falls as temperature falls; the calculator's climate-zone adjustment covers that.
- Your rate matters as much as your unit. The spread between low-rate and high-rate states means identical systems produce very different bills - a big part of why payback math is so local (payback calculator).
- Sizing and habits. Oversized units cycle inefficiently (why); dirty filters tax every hour of runtime; setpoint set-and-forget beats aggressive swings with inverters.
Compared to what you're replacing
Against electric resistance heat (baseboards, space heaters), a heat pump delivers the same warmth for a fraction of the electricity - that ratio is what the COP/HSPF2 figures on our model pages express. Against window ACs, modern mini splits carry substantially higher seasonal ratings. Against gas heat, the comparison is rates versus therms - genuinely local math; run the payback calculator rather than trusting any national claim, including ours.
Reading the ratings on our pages
- SEER2 - seasonal cooling efficiency; higher = less electricity per cooling season.
- HSPF2 - the heating equivalent (we show Region IV, the national test standard; Region V, where published, reflects colder climates).
- Verified badges - every rating on our model pages traces to a manufacturer document or AHRI certificate, because efficiency claims are exactly where marketing rounds up.
Sources
No model-specific systems are linked from this guide yet.