What Does a Mini Split Cost to Run in Texas?

How to calculate it yourself

The arithmetic is simple enough that you should not have to take anyone’s word for it.

A mini split’s power draw in watts is roughly its BTU capacity divided by its efficiency rating. Multiply by hours of operation, divide by 1,000 for kilowatt-hours, multiply by your rate.

For a 12,000 BTU unit at 21 SEER2:

• Average running draw: roughly 500 watts at partial load
• Texas summer runtime: roughly 8 hours per day equivalent at full output
• Daily: 500 W × 8 h ÷ 1,000 = 4 kWh
• At $0.14 per kWh: $0.56 per day, about $17 per month

Real-world figures run higher because that calculation assumes ideal conditions. A poorly insulated garage, a west-facing room, or an aggressive setpoint pushes runtime up substantially. The ranges below reflect what homeowners actually see.

Monthly summer cost by unit size

Unit size	Typical space	Well insulated	Poorly insulated
9,000 BTU	Bedroom, office	$18–$32	$30–$50
12,000 BTU	Large bedroom, small living area	$25–$50	$45–$75
18,000 BTU	Living area, 2-car garage	$40–$75	$70–$120
24,000 BTU	Large living area, 3-car garage	$55–$100	$95–$160
36,000 BTU	Open plan, large shop	$80–$145	$140–$230

These assume peak summer months — roughly June through September in most of Texas. Shoulder months typically run 40 to 60 percent of these figures, and winter heating usually costs less than summer cooling because the temperature difference the system fights is smaller.

Cost by metro

Electricity rates and cooling season length both vary across Texas. Approximate annual cost for a single 12,000 BTU unit running as a room’s primary conditioning:

Metro	Cooling season	Estimated annual
Houston	Long, very humid	$220–$400
Dallas–Fort Worth	Long, moderate humidity	$200–$360
San Antonio	Long, drier	$190–$340
Austin	Long, drier	$190–$350
El Paso	Long, very dry	$160–$300

El Paso comes in lowest despite intense heat because the dry air carries almost no latent load — the system spends its capacity lowering temperature rather than condensing water. Houston runs highest for the opposite reason.

In deregulated markets — Dallas, Houston, and most of Texas — your rate depends on your retail plan, and the spread between a good and bad plan is often larger than the difference between equipment tiers. Shopping your electricity plan may save more than upgrading your unit.

What actually drives your bill

Ranked by how much they move the number.

1. Insulation and air sealing. By a wide margin the largest factor. The same 18,000 BTU unit in an insulated garage versus an uninsulated one can differ by $50 a month. Insulating a garage ceiling and adding a door insulation kit costs $600 to $1,500 and pays back within a couple of summers while also letting you install a smaller unit.

2. Correct sizing. An oversized unit short-cycles — reaching setpoint, shutting off, restarting. Each start is less efficient than steady running, and in humid areas the short cycles fail to dehumidify, which makes the space feel warmer and drives you to a lower setpoint. An undersized unit runs at full output constantly and never quite gets there. Correct sizing is the cheapest efficiency measure available because it costs nothing extra.

3. Setpoint. Each degree lower costs roughly 6 to 8 percent more. Moving from 74°F to 78°F cuts a $60 bill to roughly $45.

4. Solar gain. A west-facing room with significant glass can take two to three times the cooling load of a north-facing room the same size. Window film or exterior shades cut peak load 20 to 30 percent.

5. Setback behavior. More nuanced than people expect — see below.

6. Equipment efficiency. Real, but smaller than most of the above. The difference between an 18 and a 22 SEER2 unit is roughly 15 to 20 percent on the cooling portion of your bill. Meaningful over fifteen years, not decisive month to month.

Do not set back an inverter system aggressively

This is the most common operating mistake, and it is the opposite of the advice that applies to old ducted systems.

With a conventional single-speed system, turning it off or well back while away saves money, because the system only has one output level and running less means using less.

Inverter mini splits work differently. They are most efficient running continuously at low output, modulating to match the load. Letting a room drift 10 degrees and then demanding it be pulled back down forces the compressor to full output — its least efficient mode — for an extended period.

For a space you use daily, a modest setback of 2 to 4 degrees generally beats a large one. For a space genuinely unoccupied for days — a guest room, a vacation property — turning it off entirely still makes sense.

Heating costs are usually lower than cooling

Texas homeowners are often surprised by this.

A heat pump moves heat rather than generating it, delivering roughly three units of heat energy per unit of electricity. Electric resistance heating — baseboards, wall heaters, space heaters — delivers exactly one.

The temperature difference also matters. In August a Texas system fights a 25 to 30 degree gap between outdoor and indoor. In January it typically fights 20 to 30 degrees, and for far fewer hours of the year.

For a homeowner replacing electric resistance heat, this is frequently where the savings actually appear — a room previously heated by a 1,500 watt space heater drawing continuously will cost dramatically less on a heat pump.

Cutting the bill

Clean the filters monthly in summer. Ten minutes with warm water. A clogged filter forces the unit to work harder for less output and is the most common cause of gradually rising bills.

Keep the outdoor coil clear. Debris, leaves, or a shrub grown in front of the condenser cuts capacity directly. On wooded lots — The Woodlands, Hill Country property — check seasonally.

Use dry mode on humid days. On a muggy 78°F shoulder-season day, dry mode removes moisture without over-cooling, and it uses less power than running full cooling to achieve the same comfort.

Run ceiling fans. A fan lets you sit comfortably 3 to 4 degrees warmer, which is a 20 to 30 percent reduction on that room’s cooling cost for the ~30 watts the fan draws.

Shop your electricity plan. In deregulated Texas the spread between plans frequently exceeds what any efficiency upgrade would save.

Insulate before you upgrade equipment. Always the better first dollar.

Next steps

For installed pricing see the 2026 cost guide. For keeping efficiency up over time see the maintenance guide. For garage-specific sizing — where insulation matters most — see garage mini splits.

Cost figures are estimates based on typical Texas usage and rates. Your actual cost depends on your electricity plan, home construction, and habits.