The fastest way to lower your cooling bill in Los Angeles under LADWP or SCE time-of-use (TOU) rates is to move your AC runtime out of the expensive peak hours. Pre-cool the house before peak, let it drift a few degrees warmer during peak, and let a smart or programmable thermostat do it automatically. Then reduce how much heat gets into the house in the first place with shading, attic ventilation and sealed ducts, and keep the system maintained so every hour of runtime does more work.
None of this requires sweating through August. It is about running the same air conditioner smarter. Below is a practical playbook for LA and San Fernando Valley homes, from free changes to the upgrades that make sense later.
How time-of-use rates change the rules for cooling in LA
Most Los Angeles homes get electricity from either LADWP (City of LA neighborhoods such as Sherman Oaks, Studio City, Encino, Van Nuys, North Hollywood and Hollywood) or Southern California Edison (West Hollywood, Beverly Hills and many other cities). Burbank, Glendale and Pasadena have their own municipal utilities. LADWP and SCE both offer time-of-use options, and many SCE customers are on TOU plans by default.
On a TOU plan, electricity costs more during peak periods and less at other times. Your exact peak hours depend on your plan, so check your bill or the LADWP or SCE website. The key insight is that in summer, the hottest part of the day and the peak price window tend to overlap or sit close together. That is exactly when an AC wants to run hardest.
The goal, then, is simple: do as much of the cooling as you can before the peak, and as little as you can during it.
Pre-cooling: the core strategy for lowering your cooling bill
Pre-cooling uses your house as a battery. Walls, floors, furniture and the air itself all store "coolness." If you cool them down during cheaper hours, the house stays comfortable longer once the peak starts and the AC can run less.
How to pre-cool, step by step
- Find your plan's peak window on your bill or the utility's website.
- Start cooling a few hours before the peak, setting the thermostat a couple of degrees cooler than you normally would.
- When peak starts, raise the setpoint a few degrees and let the temperature drift slowly upward.
- Close blinds and keep doors shut on the sunny side so the stored coolness lasts.
- Use ceiling fans during the peak so the warmer setpoint still feels comfortable.
Pre-cooling works best in homes that hold temperature reasonably well. In a leaky older home with an uninsulated attic, the stored cooling can disappear quickly. That does not mean it is useless there, but it does mean the envelope fixes further down this page matter more.
A word on heat waves
Valley heat waves often hit in August, September and October, and triple-digit days are common. On those days, pre-cooling is even more valuable, and it also reduces strain on the grid during the hours when demand is highest.
Smart thermostat schedules and setpoints
A programmable or smart thermostat is what makes pre-cooling painless. Set it once and it shifts runtime every day without you thinking about it.
| Time of day | What the thermostat should do | Why |
|---|---|---|
| Overnight and morning | Comfortable sleeping temperature; let the house cool naturally if it is cool outside | Mild outdoor air and lower prices |
| Midday, nobody home | Set higher, but not off on extreme days | Avoids cooling an empty house, prevents heat soak |
| Hours before the peak | Pre-cool a few degrees below your normal setting | Stores cooling while electricity is cheaper |
| Peak window | Raise the setpoint and let it drift; fans on | Minimizes runtime at the highest price |
| After peak | Return to your normal comfort setting | Prices drop again |
A common recommendation is to keep the house around 78°F when you are home in summer and higher when you are away. Every degree you raise the setpoint means less runtime, and you will feel it on your bill over a season.
Two mistakes to avoid: turning the AC completely off on a 105-degree day and then blasting it at 6 p.m. (the house soaks up heat all day and the system runs flat out during peak), and setting the thermostat to 65 hoping it cools faster. A central AC cools at the same rate no matter how low you set it; it just runs longer.
Also check that the thermostat is not mounted in direct afternoon sun, next to a lamp or above a kitchen. A thermostat that reads warm makes the system run more than it needs to.
Ceiling fans: cheap comfort
Ceiling fans do not lower the room temperature. They move air across your skin, which makes you feel cooler, so you can raise the thermostat without losing comfort. Set them to spin counterclockwise in summer (you should feel a breeze standing under them), and turn them off when nobody is in the room, since a fan in an empty room only adds a little heat from its motor.
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Keep the heat out: shading, window film and the attic
The cheapest air conditioning is the cooling you do not need. Many LA homes, especially 1920s through 1960s Spanish Revival, Craftsman and mid-century ranch houses, let a lot of heat in through windows, roofs and attics.
Shade the windows that face the sun
- West- and south-facing windows are the worst offenders in the afternoon. Exterior shading such as awnings, shade sails, solar screens or trees stops heat before it reaches the glass, which is more effective than interior blinds.
- Interior blinds and curtains still help. Close them on the sunny side during the hottest hours.
- Window film designed to reject solar heat can make a real difference on large or hard-to-shade windows. Check that it suits your glass type.
Ventilate and insulate the attic
On a summer afternoon in the Valley, an attic can get far hotter than the outdoor air. That heat radiates down through the ceiling. Adequate attic ventilation, good insulation on the attic floor and, in some homes, a radiant barrier all reduce how much heat reaches your living space. A light-colored or cool roof helps as well when it is time to reroof.
Seal the ducts
In many LA homes, ductwork runs through that same hot attic or crawlspace. Leaky or disconnected ducts dump cooled air into the attic and pull hot, dusty attic air into the return side. You pay to cool air that never reaches your rooms. Signs include rooms that never cool, dusty registers and big temperature differences between rooms. Sealing duct leaks, repairing crushed or disconnected runs and insulating ducts can be one of the most effective upgrades in older homes. Learn more on our duct cleaning and duct services page and in our guide to ducts and wildfire smoke.
Maintenance: the hidden factor in your cooling bill
An AC that is low on refrigerant, has a dirty coil or is choked by a clogged filter still runs, it just runs longer to deliver the same cooling. You rarely notice a gradual efficiency loss until the bill arrives.
- Check the air filter monthly in summer and during smoke or Santa Ana wind events.
- Keep the outdoor unit clear of plants and debris, and gently rinse the coil with the power off.
- Book a professional tune-up every spring, before the first heat wave.
- Have refrigerant leaks repaired instead of topped off.
- Keep supply registers open and returns unblocked.
Our AC maintenance guide for the San Fernando Valley lays out the full DIY and professional checklist, or you can book AC maintenance directly.
Zoning with mini splits: cool only the rooms you use
A central system cools the whole house whether you are in one room or five. Ductless mini splits let you cool by zone: the bedroom at night, the home office during the day, the living room in the evening. Their inverter-driven compressors also ramp up and down to match the load instead of cycling on and off at full power.
Mini splits are especially useful for:
- Older homes without ductwork, or with ducts that are not worth saving.
- Rooms the central system never cools well, such as a converted garage or a sunny upstairs bedroom.
- ADUs and additions, where extending existing ducts is impractical.
Our mini split vs central air comparison goes deeper into when each makes sense.
When an upgrade actually pays off
Replacing a working AC purely to save energy rarely makes sense on its own. An upgrade tends to pay off when several of these line up:
- The system is old, inefficient and needs a major repair.
- It uses R-410A and has a large refrigerant leak (see our R-410A phase-out guide).
- It was badly sized, so it short-cycles or runs constantly without keeping up.
- You also need better heating, and a heat pump can replace both the AC and an aging furnace.
- Utility or statewide rebates are available at the time you buy.
Since January 2023, efficiency is rated in SEER2 and HSPF2, and California falls in the DOE Southwest region, which has higher minimum efficiency for central AC. A properly sized, well-installed system with sealed ducts often matters as much as the rating on the box. For a full framework, read our repair-or-replace guide.
Check rebates before you buy. LADWP, SCE, Burbank Water and Power, Glendale Water & Power and Pasadena Water and Power have offered rebates on high-efficiency equipment, smart thermostats and heat pumps, and programs change regularly. Look up current offers on your utility's website before signing a contract, since some rebates require pre-approval or specific paperwork.
How Back2Cool helps you lower your cooling costs
Back2Cool HVAC is based in Sherman Oaks and has worked on LA homes for 12 years, from Studio City and Burbank to West Hollywood. When cooling costs are the concern, we start by finding the real reason: a dirty coil, a weak part, a refrigerant leak, leaky ducts or a system that simply does not fit the house.
- We explain findings and options in plain language and recommend only the work that is necessary. No upselling.
- We install and repair thermostats, mini splits, central AC and heat pumps.
- On replacements, we size the system with a load calculation, pull the permit, handle Title 24 testing and file utility rebate paperwork.
- Every quote is written, with exact model numbers, before work starts.
"My mini split stopped working, so I called for service. The technician showed up right on time and was very friendly and professional. He quickly figured out what was wrong, fixed the problem, and made sure everything was working properly before he left. The whole experience was easy and stress-free. Really appreciate the great service and would definitely recommend them to anyone who needs HVAC repair!"
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Book a $55 service call with code LA55, which includes a system inspection, diagnosis and clear recommendations, with the $55 applied toward the repair if you go ahead. Call (626) 635-4095, 7 days a week from 8:00 AM to 10:00 PM.