The seasonal shape here is simple: the light outdoors runs out, so people buy light indoors. The Amazon completions for full-spectrum grow lights are about form factor and timers, and the Google Trends rising queries for the same seed are up between 70% and 250% over the twelve months to October 12, 2026. What almost nobody prices before buying is the part that repeats every month.
This is a price trail on that input rather than on the fixtures. The series is EIA’s Electric Power Monthly, the forecast is EIA’s October 2026 Short-Term Energy Outlook, and the one horticultural assumption, how many hours a day the light is on, comes from a University of Maine Extension bulletin. We have tested no fixtures and we price none of them here.
Trend Signal
61/100 Steady momentum
- Emerging
- Rising
- Mainstream
- Peaking
- Cooling
Indoor growing demand is climbing into the most expensive electricity in years
The US average residential electricity price was 18.31 cents per kilowatthour in July 2026 against 17.45 cents in July 2025, and the January to July 2026 average was 18.19 cents against 17.01 cents a year earlier, per EIA Electric Power Monthly.
Our editorial reading of the cited data, not a forecast. How it is scored
By the numbers
- 18.31 centsUS average residential electricity price per kilowatthour, July 2026EIA Electric Power Monthly
- 48.00 centsHawaii residential price per kilowatthour in July 2026, the highest state averageEIA Electric Power Monthly
- 18.21 centsEIA forecast for the 2026 US annual average residential price per kilowatthourEIA Short-Term Energy Outlook
- 16 hoursDaily hours UMaine Extension recommends for seed starting with fluorescent bulbsUMaine Extension
The multiplier: what a kilowatthour costs in October 2026
EIA’s Electric Power Monthly, released September 24, 2026, puts the US average residential price at 18.31 cents per kilowatthour for July 2026 against 17.45 cents for July 2025. The trail behind that is steady and upward: annual averages of 13.66 cents in 2021, 15.04 cents in 2022, 16.00 cents in 2023, 16.48 cents in 2024 and 17.30 cents in 2025. Values for 2025 and 2026 are preliminary estimates based on a cutoff model sample; 2024 and earlier are final.
Within 2026 the monthly series runs 17.45 cents in January, 18.56 in March, 18.83 in April, 18.34 in June and 18.31 in July. The January to July average is 18.19 cents, against 17.01 cents for the same months of 2025 and 16.32 cents in 2024. So the per-unit cost of running a fixture is roughly 7% higher than a year ago and about a third higher than in 2021, both our arithmetic on those EIA values, which is what makes a timer worth more than an extra fixture.
| Period | US residential price, cents per kWh |
|---|---|
| 2021 annual average | 13.66 |
| 2023 annual average | 16.00 |
| 2025 annual average | 17.30 |
| January to July 2026 average | 18.19 |
| July 2026 | 18.31 |
Running cost per hour is up about a third since 2021 by our arithmetic, so hours matter more than wattage.
Your state moves the number more than the fixture does
EIA publishes the same price by state. For July 2026 the residential spread runs from 12.72 cents in Louisiana and 12.77 cents in Nevada up to 33.61 cents in California and 48.00 cents in Hawaii. New England averaged 28.00 cents and the West South Central division averaged 15.21 cents. A 30-watt clip fixture on 16 hours a day — a wattage we assume rather than measure — costs about $1.83 a month to run in Louisiana and about $6.91 in Hawaii, by our arithmetic on those EIA prices.
The year-over-year moves are uneven too. Maine went from 27.98 cents in July 2025 to 32.41 cents in July 2026, while Connecticut fell from 27.60 to 24.16 cents and Louisiana fell from 13.12 to 12.72 cents. If you are choosing between one large panel and several small clip lights, the state column matters more to the five-year cost than the fixture does.
| State or total | July 2026 | July 2025 |
|---|---|---|
| Hawaii | 48.00 | 39.36 |
| California | 33.61 | 32.66 |
| Massachusetts | 30.49 | 30.07 |
| US total | 18.31 | 17.45 |
| Texas | 15.88 | 15.36 |
| Louisiana | 12.72 | 13.12 |
What the October outlook adds for the heating season
EIA completed the modeling for its October 2026 Short-Term Energy Outlook on October 1, 2026. It forecasts a US annual average residential price of 18.21 cents per kilowatthour for 2026, up from 17.30 cents in 2025, with a fourth-quarter 2026 average of 18.16 cents against 17.63 cents in the fourth quarter of 2025. Wholesale prices across the eleven hubs EIA tracks are expected to average $52 per megawatthour in 2026, 11% higher than in 2025, with PJM up 41%.
The same report carries the 2026–27 Winter Fuels Outlook. EIA expects homes using natural gas and propane as their main heating source, collectively around half of US households, to spend less on those fuels than last winter, and homes heating mainly with electricity to spend slightly more. It assumes 3,150 heating degree days across the winter, 3% fewer than the previous ten-winter average, while forecasting a cooler-than-average October at 236 heating degree days, 7% above the ten-year average for the month.
Hours times watts: where the bill actually comes from
A grow light bill is hours multiplied by watts multiplied by the price above, and the hours figure is not a matter of taste. University of Maine Extension’s seed-starting bulletin, updated January 2021, says that for seed starting with basic fluorescent bulbs it is generally recommended to run the lights 16 hours a day, with the lights 2 to 4 inches above the tops of the seedlings. That is the number to budget against, and it is why the with timer completion is the most useful one in the demand list.
One worked figure has both of its inputs published. The same bulletin specifies a shop lamp with two 40-watt fluorescent bulbs, so 80 watts for 16 hours a day is 1.28 kilowatthours daily, about 38.4 kilowatthours over 30 days, or roughly $7.03 a month at the July 2026 US average of 18.31 cents, by our arithmetic.
The LED figures that follow use wattages we assume rather than measure, because no maker page we opened publishes one. An assumed 30-watt clip fixture on 16 hours a day draws 0.48 kilowatthours a day, about 14.4 kilowatthours over 30 days, or roughly $2.64 a month, and four of them about $10.55. An assumed 150-watt panel on the same schedule draws 2.4 kilowatthours a day, about 72 kilowatthours a month, or roughly $13.18 at the US average, about $24.20 in California and about $34.56 in Hawaii. Check the wattage printed on your own fixture, because listings often quote an equivalent rather than a draw.
- Read the actual wattage on the fixture, not an equivalent-to figure
- Put the hours on a timer, since hours are the only variable you control after purchase
- Price the schedule against your own state column, not the US average
- Prefer one fixture with published efficacy over several cheap ones if the monthly cost matters
Buy now or wait
Efficiency is the lever moving in the hardware. The DesignLights Consortium, which runs a qualified products list for horticultural lighting, says its HORT V4.0 technical requirements took effect April 18, 2025 and increased the photosynthetic photon efficacy threshold by 8.7%, putting the qualifying threshold 45% above the most efficacious non-LED option. DLC publishes no absolute threshold figure on that page and its list is aimed at commercial growers, but the direction of the change is the signal.
Buy now if you intend to grow through the dark months, because the hardware cost is one-time and the electricity cost starts when you switch it on. The case is strongest in low-price states, where a modest clip fixture costs a few dollars a month and a timer caps that. Wait if you are in Hawaii, California or New England and planning a large panel on a 16-hour schedule, at least until you have put your own wattage against your own state figure. EIA’s next Electric Power Monthly release was scheduled for October 23, 2026, which adds August data.
What to watch next
- The EIA Electric Power Monthly release scheduled for October 23, 2026, which adds August 2026 state-level prices
- Whether the fourth-quarter 2026 residential average lands near the 18.16 cents EIA forecast in October
- Whether DLC publishes an absolute photosynthetic photon efficacy threshold alongside the HORT V4.0 percentage change
Where to start
Paid links: we earn a commission if you buy through the buttons below, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases.
Grow light types compared on what drives the running cost
| Product type | Good fit for | Where to look |
|---|---|---|
| Clip-on full-spectrum grow light | Fits one or two plants | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
| Standing or shelf grow light | Fits a shelf of seedlings | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
| Outlet timer for a lighting schedule | Fits capping the hours | See listings on AmazonOpens Amazon search results, not one listing: check the model on the product page. |
Product types that fit the trend described above, not tested models. Check the exact listing before you buy. How we pick them.
Clip-on full-spectrum grow light
Where to look: Amazon
Suits one or two plants on a sill. At an assumed 30 watts and 16 hours a day, roughly $2.64 a month at the July 2026 US average price.
- Low wattage keeps the monthly cost small
- Easy to reposition
- Covers very little area
- Listings often quote equivalents
Standing or shelf grow light
Where to look: Amazon
Suits a tray of seedlings. Price the wattage against your own state column before committing to a 16-hour schedule.
- Covers a tray or a shelf
- Height usually adjustable
- Higher wattage, higher monthly cost
- Needs a dedicated spot
Outlet timer for a lighting schedule
Where to look: Amazon
Suits anyone running lights daily. The schedule, not the fixture, sets the bill.
- Hours are the variable you control
- Cheap next to the fixture
- Mechanical models drift
- Some lose the schedule in an outage
More: Garden and Backyard trends and how the Trend Signal is scored.
Sources
- Electric Power Monthly table 5.3, average price of electricity by end-use sector — US EIA
- Electric Power Monthly table 5.6.A, average price of electricity by state — US EIA
- Short-Term Energy Outlook, October 2026 — US EIA
- Bulletin 2751, Starting Seeds at Home — University of Maine Cooperative Extension
- Horticultural lighting technical requirements — DesignLights Consortium
Questions readers ask
How much electricity does a grow light use?
Multiply its rated watts by the hours it runs. A 30-watt fixture on 16 hours a day uses 0.48 kilowatthours a day, about 14.4 kilowatthours a month; a 150-watt panel on the same schedule uses about 72 kilowatthours. At the July 2026 US average residential price of 18.31 cents per kilowatthour reported by EIA, that is roughly $2.64 and $13.18 a month. Those two wattages are our examples, not measurements.
What is the US average electricity price right now?
EIA’s Electric Power Monthly, released September 24, 2026, reports a US average residential price of 18.31 cents per kilowatthour for July 2026, against 17.45 cents in July 2025. The January to July 2026 average was 18.19 cents against 17.01 cents a year earlier.
How many hours a day should a grow light run?
University of Maine Extension’s seed-starting bulletin recommends running the lights 16 hours a day for seed starting with basic fluorescent bulbs, with the lights 2 to 4 inches above the tops of the seedlings. That is the figure to use when estimating the monthly cost.
Will electricity get cheaper this winter?
EIA’s October 2026 Short-Term Energy Outlook forecasts a US annual average residential price of 18.21 cents per kilowatthour for 2026, up from 17.30 cents in 2025, and expects households that heat mainly with electricity to spend slightly more over the 2026–27 winter than the previous one.
