# Mini split operating cost in San Diego: what does it cost to run?

> What a mini split costs to run in San Diego: SDG&E TOU-DR1 and TOU-ELEC rates, estimating kWh from capacity and hours, SEER2, HSPF2, COP and gas heat.

URL: https://mesaminisplitsandiego.com/guide/mini-split-operating-cost-san-diego/

Learn

How to turn a room's cooling or heating load, the hours a head runs and its efficiency rating into kilowatt-hours, then into dollars on SDG&E's published time-of-use rates, and why heating against gas is a closer call than cooling.

A mini split’s operating cost is the electricity it uses multiplied by the price of each kilowatt-hour at the hour it runs. In San Diego that price comes from SDG&E’s time-of-use schedules, roughly 34 cents per kWh at super off-peak on TOU-ELEC up to about 73 cents in the summer on-peak window, so when a system runs matters almost as much as how efficient it is.

[Mesa Mini Split San Diego](https://mesaminisplitsandiego.com/) installs single-zone and [multi-zone mini splits](https://mesaminisplitsandiego.com/multi-zone-mini-split-installation/) across San Diego County, with the work done by licensed and insured contractors holding the California C-20 (HVAC) license. This guide shows the arithmetic behind a running cost so you can test any estimate yourself. It does not predict a bill, because a bill depends on your house, your habits and rates that change from season to season.

Key takeaways

- Running cost = energy the room needs, divided by the unit's efficiency, multiplied by the SDG&E rate for that hour
- SDG&E's on-peak window is 4 to 9 p.m. every day; summer on-peak power costs about twice the super off-peak price
- A heat pump household qualifies for SDG&E's TOU-ELEC plan, which has cheaper off-peak prices but no baseline credit
- SEER2 rates seasonal cooling, HSPF2 seasonal heating and COP heat delivered per unit of electricity
- Against an 80% gas furnace, a heat pump needs a COP near 3.3 to break even at TOU-ELEC winter off-peak prices, an estimate from published rates

## What sets a mini split’s running cost

Four numbers set the cost, and only one of them is on the equipment’s spec sheet. The first is the load: how much heat has to leave the room in summer or enter it in winter. That depends on the room’s glass, insulation, orientation and occupants, and on where the house sits. The CEC’s design data puts the 1% cooling design temperature at 82°F at San Diego Lindbergh and 90°F at El Cajon, so the same bedroom asks for more cooling inland. The second is hours: an upstairs bedroom used every night in August runs far longer than a guest room. The third is efficiency, captured by the ratings explained below. The fourth is the price per kWh at the time the system is running.

Capacity is not on that list for a reason. A correctly [sized](https://mesaminisplitsandiego.com/guide/mini-split-sizing/) inverter unit rarely runs at its rated capacity; it slows its compressor to match the load. Two units of different sizes serving the same room use similar energy if both modulate well. An oversized unit can use more, because it cycles on and off when the load falls below its minimum output, which wastes energy at each restart and leaves the air clammy.

## SDG&E rates a mini split runs on

Most San Diego homes take electricity on one of two SDG&E time-of-use schedules. The figures below are SDG&E’s published total bundled rates, which change several times a year; use them for arithmetic, and check the current table before you rely on a result.

| Period | TOU-DR1 (standard) | TOU-ELEC (heat pump, EV or battery households) |
| --- | --- | --- |
| Summer on-peak, 4 to 9 p.m. | about 69.1 | about 72.6 |
| Summer off-peak | about 46.4 | about 38.9 |
| Summer super off-peak | about 37.4 | about 34.5 |
| Winter on-peak, 4 to 9 p.m. | about 61.5 | about 50.6 |
| Winter off-peak | about 53.1 | about 37.7 |
| Winter super off-peak | about 43.7 | about 33.6 |
| Baseline credit | up to about 10.7 cents off, on usage up to 130% of baseline | none |
| Base services charge | about 79 cents a day | about 79 cents a day |

On weekdays, SDG&E’s super off-peak hours run from midnight to 6 a.m. and from 10 a.m. to 2 p.m.; on weekends and holidays, from midnight to 2 p.m. The on-peak window is 4 to 9 p.m. every day. San Diego Community Power lists its summer season as June 1 through October 31.

### Which plan suits a heat pump household

SDG&E’s TOU-ELEC schedule is open to households with an electric heat pump for climate control, and a mini split heat pump qualifies. Its off-peak and super off-peak prices sit well below TOU-DR1’s, especially in winter, but it has no baseline credit, and its summer on-peak price is slightly higher. A household that uses little power overall, or cools mostly between 4 and 9 p.m., may come out ahead staying on TOU-DR1. A household that runs heads overnight and in the middle of the day, or also charges an EV, often does better on TOU-ELEC. SDG&E’s own rate comparison, run on your meter history, settles it.

### Community power providers

In the City of San Diego, Chula Vista, Encinitas, Imperial Beach, La Mesa, National City and unincorporated areas, generation comes from San Diego Community Power by default; in Carlsbad, Del Mar, Escondido, Oceanside, San Marcos, Solana Beach and Vista, from Clean Energy Alliance. SDG&E delivers the power everywhere. The joint rate comparisons published by SDG&E and each provider show average totals within a few cents per kWh of SDG&E’s bundled price, so the arithmetic here holds within that margin. The [Escondido](https://mesaminisplitsandiego.com/service-areas/escondido/) and [Oceanside](https://mesaminisplitsandiego.com/service-areas/oceanside/) pages note which provider serves each area.

## Estimating kWh from capacity and runtime

A rough estimate follows one formula: energy used (watt-hours) equals heat moved (Btu) divided by efficiency (Btu per watt-hour). Seasonal ratings give an average efficiency, so the result is an average too.

**Illustrative:** a coastal bedroom head averages 6,000 Btu per hour of cooling for eight hours on a warm night, which is 48,000 Btu. At an illustrative seasonal efficiency of 20 Btu per watt-hour, that is 2,400 watt-hours, or 2.4 kWh. Spread across off-peak and super off-peak hours on TOU-ELEC’s summer prices, 2.4 kWh costs roughly 83 to 93 cents. The same energy used inside the 4 to 9 p.m. window would cost about $1.74. Thirty such nights add up to about $25 to $28 at the cheaper prices. These are illustrations of the method, not a forecast for any house.

Multiplying the rated capacity or the nameplate wattage by the hours of use overstates an inverter unit’s consumption, because the compressor spends most of its time well below full speed. The honest inputs are a load figure from a [Manual J calculation](https://mesaminisplitsandiego.com/guide/mini-split-sizing/) and the hours you actually expect to run.

## SEER2, HSPF2 and COP explained

**SEER2** (seasonal energy efficiency ratio) is cooling delivered in Btu divided by electricity used in watt-hours over a standard test season. A higher SEER2 means fewer kWh for the same cooling. The “2” marks the current federal test procedure, which tests at more realistic airflow conditions and produces lower numbers than the older SEER for the same equipment, so compare SEER2 with SEER2. **EER2** is the same ratio at a single hot test condition, closer to what an inland unit sees on a 90°F afternoon.

**HSPF2** (heating seasonal performance factor) does the same for heating: Btu of heat delivered per watt-hour across a heating season. Dividing HSPF2 by 3.412 converts it to an approximate seasonal **COP**, the coefficient of performance, which is heat out divided by electricity in, in the same units. A COP of 3 means three units of heat for each unit of electricity. Electric resistance heat, such as a wall heater or baseboard, has a COP of 1. COP falls as the outdoor air gets colder, so a heat pump is most efficient on mild nights, which describes most San Diego winter nights; the published low-temperature figures for the specific model matter more in [inland zones](https://mesaminisplitsandiego.com/guide/mini-split-coastal-vs-inland-san-diego/).

## Heating with a mini split vs a gas furnace

Cooling has no cheaper alternative on the bill, but heating does. An estimate from SDG&E’s published rates, using an average residential gas price of about $2.65 a therm in a recent month, puts the cost of delivered gas heat at about $3.31 per therm-equivalent with an 80% furnace. A heat pump at COP 3 costs about $3.68 for the same heat at TOU-ELEC winter off-peak prices and about $3.29 at super off-peak. The break-even COP against that furnace is roughly 3.3 at TOU-ELEC winter off-peak, about 3.0 at super off-peak and about 4.7 at TOU-DR1 winter off-peak.

In plain terms, a heat pump replacing gas heat may cost about the same or more to run, depending on the rate plan and the model’s real-world COP. The amounts are also small: the CEC’s residential appliance survey found SDG&E gas-heated homes used about 100 therms a year for space heating, roughly $265 a year at that gas price, by estimate. Replacing electric resistance heat is different. At COP 1, resistance heat costs about three times as much per unit of heat as a COP 3 heat pump, which is where heating savings are realistic. No savings are guaranteed either way. Most San Diego households choose a mini split for cooling and comfort, and the [rebates guide](https://mesaminisplitsandiego.com/guide/mini-split-rebates-san-diego/) covers what support remains.

## Practical ways to keep the running cost down

- Cool before 4 p.m. on hot days and raise the setpoint a few degrees during the on-peak window, rather than letting the house heat up and fighting it at 6 p.m.
- Close doors to rooms a head does not serve, so it conditions the space it was sized for; one head rarely conditions a whole floor evenly.
- Clean the indoor filters as the manual directs; a clogged filter and dirty coil lower airflow and efficiency. [Maintenance](https://mesaminisplitsandiego.com/mini-split-maintenance/) covers coil and blower cleaning.
- On a [multi-zone system](https://mesaminisplitsandiego.com/multi-zone-mini-split-installation/), avoid oversizing the outdoor unit for the rooms most often used alone; the [single-zone vs multi-zone guide](https://mesaminisplitsandiego.com/guide/single-zone-vs-multi-zone/) explains why.
- Compare running costs with the [mini split vs window unit](https://mesaminisplitsandiego.com/guide/mini-split-vs-window-unit/) and [mini split vs central air](https://mesaminisplitsandiego.com/guide/mini-split-vs-central-air/) guides if you are weighing systems.

## Putting a running cost next to the installed price

A running cost estimate is most useful beside an installed price, because the two trade against each other: a higher-efficiency model costs more up front and saves kWh every hour it runs. The [installation cost guide](https://mesaminisplitsandiego.com/guide/mini-split-installation-cost-san-diego/) and the [cost estimator](https://mesaminisplitsandiego.com/tools/mini-split-cost-estimator/) cover the purchase side. For a figure tied to your rooms, a site visit with a load calculation gives the load and capacity numbers this arithmetic needs; call or request an estimate to book one.

Plan a mini split around your SDG&E bill

A load calculation and a written scope give you the numbers to estimate running costs before you choose equipment.

## Questions about this guide

### Does a mini split draw power when it is switched off at the remote?

A little. With the remote off, the system is still energized at the breaker so its control boards can listen for the remote and, on some models, keep the compressor's oil warm in cold weather. That standby draw is small next to running consumption, but it is not zero. Turning the disconnect or breaker off for months of non-use is an option only if the manufacturer's instructions allow it, because some models need a warm-up period after power returns.

### Is it cheaper to leave a mini split running all day than to switch it on and off?

Often it is close to a wash, and the rate schedule decides more than the habit. An inverter unit that holds a room near its setpoint runs at low output and modest draw, while a unit switched on into a hot room runs hard for a while to pull the heat back out. On SDG&E's time-of-use plans, the cheapest pattern is usually to cool before 4 p.m. and coast through the on-peak window with a slightly higher setpoint.

### Does installing a mini split make a household eligible for SDG&E's TOU-ELEC plan?

Yes. SDG&E's published TOU-ELEC eligibility includes households with an electric heat pump for climate control, and a heat pump mini split is one. Whether the switch lowers the bill is a separate question: TOU-ELEC has lower off-peak prices but no baseline credit, so a small-usage household can pay more on it. SDG&E's rate comparison tools use your own meter data, which is the honest way to decide.

Want this answered for your house?

Call with the rooms you want cooled and your ZIP code.

## Related service

Multi-zone and whole-home

One outdoor unit serving several indoor heads, with each room sized on its own load and every drain, line and control planned together.

## More guides

- Cost Guide [How much does mini split installation cost in San Diego?](https://mesaminisplitsandiego.com/guide/mini-split-installation-cost-san-diego/)Typical San Diego-area ranges by number of indoor heads, the published permit fees, the parts of a price that only a site visit can settle, and an honest look at rebates and running costs.
- Learn [What size mini split do I need?](https://mesaminisplitsandiego.com/guide/mini-split-sizing/)Mini split size is a load question, not a floor-area question. This guide explains BTUs and tons, what a Manual J calculation measures, why inverter turndown matters as much as maximum output, and how the same room can need different equipment at the coast and inland.
- Decision Guide [Mini split vs window unit: which should you choose for one room?](https://mesaminisplitsandiego.com/guide/mini-split-vs-window-unit/)A window unit is cheap, quick and needs no permit. A mini split costs more and needs one, but it is quieter, leaves the window alone, heats as well as cools and adjusts its output to the room. Which is right depends on how long you will be there and how the room is used.
- Decision Guide [Mini split vs central air: which is better for your home?](https://mesaminisplitsandiego.com/guide/mini-split-vs-central-air/)The deciding question is usually the ductwork: whether the house has ducts, and what shape they are in. This guide works through ducts, comfort, efficiency ratings and cost, and says plainly when a ducted system is the better choice.
- Cost Guide [Is there an SDG&E rebate for a mini split?](https://mesaminisplitsandiego.com/guide/mini-split-rebates-san-diego/)The full San Diego incentive picture for ductless heat pumps: the federal credit that ended, the state and City programs that closed, the income-qualified programs still open, and the SDG&E rate any heat pump household can choose.