Quick answer: The average California home runs on about 690 watts of continuous power, or 16.5 kWh a day, far below the U.S. average of about 1,180 watts. Watts measure power at one moment; kWh measure energy over time, and your bill charges for kWh. At peak, with AC, a dryer and an EV charger running together, a California house can briefly pull 20,000 to 28,000 watts.
California is not a normal market for this question. Most California homes heat with gas, the coast barely needs AC, and electricity costs about twice the national rate. So a California house uses fewer watts than a home in most other states, and every one of those watts costs more. Below is the California version of the answer: by utility, by climate, by room, and at peak.
What is the difference between watts and kWh?
A watt is a rate of power; a kWh is 1,000 watts used for one hour. A 1,000 W microwave running 60 minutes uses 1 kWh. Your utility bills you in kWh. A battery or generator is limited by watts (how much it can run at once) and by kWh (for how long). Surge watts are the short spike a motor needs to start: a fridge runs at about 150 W but needs about 1,200 W for a second at startup.
How many watts does a California house use on average?
The average California home uses about 690 watts around the clock, or 16.5 kWh a day, based on EIA’s 2024 data: 503 kWh a month against 863 kWh nationally.
The main reason is fuel. According to EIA’s 2020 Residential Energy Consumption Survey, 64% of California homes heat with natural gas and only 20% heat with electricity. Space heating is about 4% of a California home’s electricity use. Take gas heat, gas water heating and a mild coast out of the equation, and the electric load that remains is small.
| Benchmark (EIA 2024) | kWh per month | kWh per day | Average continuous watts |
|---|---|---|---|
| California household | 503 | 16.5 | about 690 W |
| U.S. household | 863 | 28.4 | about 1,180 W |
Source: EIA Table 5A, 2024 data. Average watts = kWh per day ÷ 24 hours x 1,000.
How many watts does a house use by California utility?
It ranges from about 500 watts for an SDG&E customer to about 960 watts in SMUD territory around Sacramento. Hotter inland service areas run more AC; mild coastal ones run less.
| Utility | kWh per customer per day (2024) | Average continuous watts |
|---|---|---|
| SMUD | 23.0 | about 960 W |
| SCE | 16.6 | about 690 W |
| PG&E | 16.4 | about 680 W |
| LADWP | 15.9 | about 660 W |
| SDG&E | 12.0 | about 500 W |
Source: EIA Form 861, 2024 residential sales and customers. PG&E, SCE and SDG&E figures cover customers who buy power from the utility; community choice aggregator customers are excluded, which affects SDG&E most.
How does climate change the watts a California home needs?
Climate can triple a home’s summer load. PG&E sets its summer baseline allowance, the amount of power it considers essential, at 5.9 kWh a day in its mildest territory and 19.2 kWh a day in its hottest. That is the difference between a home averaging about 250 watts and one averaging about 800 watts before anything discretionary is switched on.
| PG&E baseline allowance (kWh per day) | Summer | Winter |
|---|---|---|
| Mildest summer territory (Z), basic service | 5.9 | 7.8 |
| Hottest summer territory (W), basic service | 19.2 | 9.8 |
| Highest all-electric allowance in each season | 22.4 | 26.7 |
Source: PG&E E-TOU-C tariff, baseline quantities table. Summer is June 1 to September 30.
Notice the all-electric row: a home with a heat pump and electric water heater gets up to 26.7 kWh a day in winter. When California homes electrify, winter watts, not summer AC, become the new peak.
How many watts does each room use?
A typical gas-heated California home draws about 15 kWh a day across its rooms and always-on devices, which lines up with the 16.5 kWh state average. The kitchen and laundry set the peaks; central AC and an EV charger, where present, dwarf everything else.
| Room | Peak running watts | kWh per day | Cost per month, PG&E E-TOU-C | Cost per month, SCE TOU-D-4-9PM |
|---|---|---|---|---|
| Central AC, 3-ton, summer day | 3,100 | 18.6 | $226 | $215 |
| Garage: EV charging, 35 miles a day | 7,200 | 10.0 | $122 | $116 |
| Kitchen add-on: induction cooktop and electric oven | 6,000 | 3.9 | $47 | $45 |
| Kitchen (gas range): fridge, microwave, dishwasher, coffee maker, lights | 3,510 | 3.5 | $42 | $40 |
| Laundry: washer and electric dryer | 5,900 | 3.0 | $36 | $34 |
| Home office: laptop and monitor, router, lights | 135 | 1.3 | $16 | $15 |
| Living room: TV, streaming box, lights | 260 | 1.2 | $15 | $14 |
| Garage: second fridge or freezer | 100 | 1.0 | $12 | $12 |
| Bedroom (each): lights, ceiling fan, chargers | 110 | 0.5 | $6 | $6 |
| Bathroom: hair dryer, fan, lights | 1,550 | 0.3 | $4 | $3 |
NRG estimates from typical appliance wattages and daily hours. Costs use a blended 40 cents per kWh on PG&E E-TOU-C and 38 cents on SCE TOU-D-4-9PM (roughly the annual off-peak rate plus a share of 4-9 pm use, above baseline), 30.4 days a month, before the fixed Base Services Charge. Wattages follow the DOE appliance energy guide and manufacturer specs; your nameplates will differ.
Add it up for a three-bedroom, gas-heated home with no AC or EV: kitchen 3.5, laundry 3.0, living room 1.2, office 1.3, three bedrooms 1.5 and bathroom 0.3, for about 10.8 kWh. Then add the load most people forget. An NRDC study of 70,000 Northern California homes found an average of 164 watts always on, from standby electronics, chargers and appliances that never truly switch off. That is another 3.9 kWh a day, bringing the total to about 14.7 kWh. Standby alone is roughly a quarter of the bill in a mild-climate home.
Turn on central AC for a summer afternoon or add an EV, and the picture flips. Either one uses more power than every room in the house combined. See what appliances use the most electricity for the full ranking and our refrigerator wattage guide for fridge running and surge detail.
How many watts does it take to run a house at peak?
With every major load running at once, an all-electric California home can draw about 25,000 watts, and close to 28,000 for a moment when a motor starts. Essentials alone need about 1,800 running watts.
| Load | Essential or full home | Running watts | Starting (surge) watts |
|---|---|---|---|
| ENERGY STAR refrigerator | Essential | 132-192 | 1,200 |
| Furnace fan (1/4 hp) | Essential | 600 | 1,000 |
| Lights | Essential | 600 | 600 |
| Laptop, router, phone charging | Essential | 200-250 | 200-250 |
| LED TV | Essential | 120 | 120 |
| Microwave (1,000 W model) | Essential, short use | 1,500 | 1,500 |
| Central AC, 3-ton (SEER2 14.3) | Full home | about 3,100 | about 6,200 |
| Electric clothes dryer (240 V) | Full home | 5,400 | 6,750 |
| Electric water heater (240 V) | Full home | 4,500 | 4,500 |
| Level 2 EV charger | Full home | 7,200 | 7,200 |
| Clothes washer | Full home | 1,200 | 1,200 |
| Dishwasher | Full home | 216 | 540 |
Sources: Honda generator wattage guide (most rows), Generac worksheet (lights, TV), DOE 2023 AC standards FAQ (AC at EER2 11.7), DOE AFDC (7.2 kW Level 2).
Totals, using the top of each range and adding the largest single surge:
- Essentials, no microwave: 1,762 running, about 2,800 W at startup.
- Essentials with microwave: 3,262 running, about 4,300 W at startup.
- Essentials plus central AC: 6,362 running, about 9,500 W at startup.
- Everything at once: 24,878 running, about 28,000 W at startup.
Can your electrical panel handle it?
A 100-amp panel, still common in older California homes, supplies 24,000 watts at most and about 19,200 watts of continuous load under the 80% rule. A 200-amp panel supplies 48,000 watts, or 38,400 continuous. The “everything at once” home above, at nearly 25,000 running watts, does not fit on a 100-amp service.
That is why electrification in California so often starts with the panel. Adding a heat pump, induction range and EV charger to a 100-amp house usually means either a main panel upgrade or smart load management. California’s 2025 building code, in effect since January 1, 2026, already requires new homes with service over 125 amps to be battery-ready.
What does it cost to run a house during California’s 4-9 pm peak?
Running essentials plus central AC (about 6.4 kW) from 4 to 9 pm uses about 32 kWh. On SCE TOU-D-4-9PM, that costs about $18.45 on a summer weekday at the 58-cent on-peak rate, against about $10.80 for the same hours at the 34-cent off-peak rate. On PG&E E-TOU-C, it is about $16.60 at the 52-cent summer peak rate.
Rates from SCE’s time-of-use plans page and PG&E’s E-TOU-C tariff, summer 2026.
In California, when you use your watts matters almost as much as how many you use. Pre-cooling the house before 4 pm, running the dryer and dishwasher in the morning, and charging the EV after midnight moves the same kWh into cheaper hours. A battery does the same thing automatically, which is a big reason 57% of California home solar systems installed in 2024 included one, according to Lawrence Berkeley National Laboratory.
What size generator or battery backup do you need to run a house?
Essentials need about 2,800 to 4,300 W of starting capacity; essentials plus central AC need about 9,500 W at startup and over 6 kW continuous. Here are two batteries we install:
| Spec | Tesla Powerwall 3 | Enphase IQ Battery 5P |
|---|---|---|
| Usable energy | 13.5 kWh | 5.0 kWh |
| Continuous output | up to 11.5 kW | 3.84 kVA |
| Motor starting / peak | 185 A locked-rotor (LRA) | 7.68 kVA for 3 seconds |
| Runs essentials (1,762 W, 2,800 W start)? | Yes, about 7.7 hours at full draw | Yes, about 2.8 hours at full draw |
| Runs essentials plus 3-ton AC? | Yes, if AC LRA is within spec | No, 4,862 W exceeds one unit |
Sources: Tesla Powerwall 3 datasheet, Enphase IQ Battery 5P. Hours assume nonstop draw; real runtime is longer because the fridge and fan cycle.
One Powerwall 3 holds about 82% of an average California home’s daily use (13.5 of 16.5 kWh); two cover about 1.6 days. For an SDG&E home averaging 12 kWh a day, one unit covers a full day. For a SMUD home at 23 kWh, it covers a little over half. Enphase stacks in 5 kWh steps, so essentials-only homes can start small. See our solar battery backup options.
Backup is not only about storms here. PG&E called four Public Safety Power Shutoff events in 2025, cutting power to lines in high fire-risk areas during wind events, according to its 2025 PSPS post-season report. If you live in a fire-risk zone, size backup for at least a day of essentials.
The same math sizes a generator: total running watts plus the largest single surge. Undersize the AC start and the generator trips.
How do you calculate your own home’s wattage?
Multiply each appliance’s nameplate watts by the hours you use it each day, divide by 1,000, and add the results: a 1,500 W space heater running 4 hours uses 6 kWh. Then check your total against your utility’s online usage data, which shows hourly kWh for PG&E, SCE and SDG&E customers. For ovens, see how many watts an electric oven uses, and compare your total with how many kWh per day is normal and the average electric bill in California.
How much solar does it take to run a house in California?
An average California home using 16.5 kWh a day needs roughly 3.5 to 4 kW of solar, at an estimated 4.2 to 4.7 kWh per kW per day. A SMUD-area home at 23 kWh a day needs closer to 5 to 5.5 kW, and adding an EV adds about 2 to 2.5 kW more. See how much energy a solar panel produces by city.
Frequently asked questions
How many watts does a house use per hour?
A California home averages about 690 watts, or 0.69 kWh each hour. The U.S. average is about 1,180 watts, based on EIA’s 2024 data.
How many watts does a 2,000 sq ft house use in California?
Square footage matters less than climate and appliances. A 2,000 sq ft gas-heated home on the coast may sit near the 690-watt state average, while the same house inland with central AC can double that on summer days. Add up the rooms in the table above for your own estimate.
Can a 100-amp panel run a house?
Yes, for a gas-heated home. A 100-amp service supplies about 19,200 watts of continuous load, which covers essentials, AC and laundry. It usually cannot also carry a Level 2 EV charger, electric water heater and induction range at the same time.
Can a 5,000 W generator run a house?
It can run essentials, which total about 4,300 W at startup with a microwave. It cannot add a 3-ton central AC, which pushes startup to about 9,500 W.
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