What permanent lights add to your electric bill

The short answer for a typical Macomb roofline

You can work out what permanent LED roofline lights add to your Michigan electric bill in a minute. Multiply the watts per foot by your lit footage, by the hours the lights run each night, and by your utility's price per kilowatt-hour. On a 100 ft roofline drawing 2 to 6 watts per foot, lit from dusk to 11 p.m. at full output, that comes to roughly $67 to $201 a year at a planning rate of 23 cents per kWh.

Those are ceiling figures. They assume every diode in every color channel runs flat out all evening. Dim the line, run a single color, or switch it off earlier, and the number falls with it.

A 100 ft line is a realistic local example. Ranches in Macomb Township usually measure 60 to 80 ft of front roofline and the smaller two-stories there 100 to 150 ft, while two-story colonials in Sterling Heights run 120 to 180 ft. The rest of this guide shows the method so you can price your own house.

How to calculate it: watts, hours, rate

Your electric bill is priced in kilowatt-hours. One kilowatt-hour (kWh) is 1,000 watts running for one hour.

1. Watts. Take the watts per foot from the fixture's spec sheet and multiply by your lit footage. That is the total draw at full output.
2. Hours. Multiply the total watts by the hours your schedule keeps the lights on, then divide by 1,000. That is kWh per night.
3. Nights. Multiply by 365 for an every-night schedule, or by the number of nights you actually plan to run.
4. Rate. Multiply by what your utility charges per kWh. The result is the added cost for the year.

For the first step, published datasheets for RGBW LED products give a useful range. A 30-LED-per-meter RGBW pixel strip is listed at 7.2 watts per meter, about 2.2 watts per foot. Two outdoor-rated RGBW linear fixtures are listed at 4.57 and 5.95 watts per foot. A dense 60-LED-per-meter RGBW strip, an indoor product, tops out at 21.8 watts per meter, about 6.6 watts per foot. Leaving out the indoor strip, the other three run from about 2 to 6 watts per foot; the indoor strip reaches about 6.6.

These are third-party figures used only as worked examples. They are not LightCast product specs and say nothing about which LED product goes on your house.

For the second step, the Detroit sky sets the schedule. The U.S. Naval Observatory puts sunset at about 5:00 p.m. in mid-December and about 9:10 p.m. in mid-June. A dusk-to-11 p.m. schedule therefore runs about six hours a night in December, under two in June, and just under four averaged across the year. Dusk to dawn averages just under 12.

What DTE charges per kilowatt-hour

DTE Electric's standard residential plan is the Time of Day 3 p.m. to 7 p.m. Standard Base Rate, known as D1.11. Peak hours are 3 to 7 p.m. on weekdays. Every other hour, including every hour after 7 p.m. and all weekend, is off-peak. The price depends on the hour, not on how much you use.

DTE's residential rate card, downloaded in September 2026, lists these base charges. The card's footer dates them as in effect February 6, 2025, so they may not include the increase that took effect March 5, 2026:

The card states that these rates do not include surcharges or taxes, so what you actually pay per kWh is higher than the base total. For a simple all-in planning number, the U.S. Energy Information Administration puts Michigan's average residential price at 22.99 cents per kWh for June 2026. The examples below use 23 cents. That is a statewide average across utilities, not a DTE quote, so treat it as a planning figure.

Rates move. Your bill shows the charges you actually pay. The Michigan Public Service Commission approved a DTE Electric rate increase that took effect March 5, 2026. Check the current card or your own bill before you run the math, and if another utility serves your house, use its rate. These are the utility's prices, not ours.

Worked examples at 100 and 200 feet

These worked examples use 2 watts per foot for a light-draw fixture and 6 for a heavy one, both inside the published datasheet range, at full output and 23 cents per kWh. Two schedules are shown: dusk to 11 p.m., just under four hours a night over the year, and dusk to dawn, just under twelve. Both are rounded up to whole hours, four and twelve, so the table leans high.

Worked by hand, the 100 ft light-draw line is 100 times 2, or 200 watts. Four hours a night makes 0.8 kWh, about 18 cents a night. Over 365 nights that is 292 kWh, about $67 for the year. The heavy-draw fixture on the same house uses three times as much, 2.4 kWh and about 55 cents a night.

For scale, the MPSC describes a typical residential customer as using 500 kWh a month. The 100 ft light-draw example adds about 24 kWh a month, under a twentieth of that. The 200 ft heavy-draw line lit dusk to dawn adds about 438 kWh a month, close to doubling that typical usage. That is the case worth avoiding, and the next section shows how.

A 200 ft line fits a big colonial with a three-car garage. Troy colonials usually carry 120 to 180 ft of front roofline, and West Bloomfield colonials 150 to 250 ft on the street side. To get your own footage, the LightCast measuring tool reads one straight-on photo from the street, takes a tap on your garage door for scale, and returns linear feet you can drop straight into the formula.

Brightness, color and schedule effects

Brightness

The datasheet number is a ceiling. Dimmed LEDs draw less power, so a line held below full output costs less than the table figure. Warm white trim light on an ordinary night seldom needs full output, and turning it down is also kinder to the house across the street, which our guide to brightness and glare covers.

Color

Draw depends on how many diode channels are lit and how hard. A single color lights one channel. White blended from red, green and blue lights three. An RGBW fixture carries a dedicated white diode, so warm white does not need every color channel working at once, which is one practical reason the white diode in RGBW matters. Treat the spec-sheet figure as everything on at once.

Schedule

Hours move the bill more than anything else you control. On the same house, dusk to dawn costs three times what dusk to 11 p.m. costs. Setting an on and off schedule from your phone is a one-time job, and our guide to phone control and schedules walks through it.

Michigan's seasons shape the bill too. A sunset schedule follows the sky, so the same dusk-to-11 p.m. setting runs about six hours a night in December and under two in June. A 100 ft heavy-draw line uses about 112 kWh in December and about 33 kWh in June. The added cost peaks with the holidays and nearly vanishes in summer.

DTE's peak window barely touches roofline lighting. From the March time change until early October the sun sets after 7 p.m., so an after-dark schedule never runs in peak hours. In the darker months, a weekday evening can put up to about two hours inside the 3 to 7 p.m. window at a base price about 1.6 cents per kWh higher. On a 200 ft heavy-draw line, that works out to under 4 cents a weekday evening.

Reading the spec sheet for your installed system

Every figure above is a worked example built from published third-party numbers, not a LightCast spec. The number that counts is the one printed for the system going on your house, so ask any installer for the fixture's spec sheet. Final details get checked at your house before any order is placed.

• Watts per foot or per meter. If the sheet lists watts per meter, divide by 3.28 to get watts per foot.
• Whether it is a maximum. Many sheets label the figure as maximum draw. If yours does not say, ask whether it was measured with every channel at full.
• Watts per pixel. Systems with spaced pixels sometimes list draw per node instead. Multiply by the number of nodes per foot.
• The power supply. Low-voltage LEDs run through a supply that converts household current, and every supply loses some energy as heat. Its efficiency rating tells you how much. For what that supply does and where it sits, read how permanent lights get power.
• Standby draw. Ask what the controller and supply use while the lights are dark, since they may stay powered around the clock.

If you are also weighing old incandescent strands against LEDs, that comparison lives in the MPWS guide to LED versus incandescent holiday lights. For the roofline itself, the four steps above are all the math you need.

Start with your footage. Measure your roofline with LightCast from a photo taken at the curb, multiply by the spec-sheet watts and your hours, and you will know the electric cost before anyone sets a ladder. When you want the installed price beside it, request an estimate and we will confirm within 24 hours.

Sources

1. DTE Energy, Residential Electric Pricing Options rate card (Standard Base Rate D1.11) dteenergy.com
2. Michigan Public Service Commission, DTE Electric rate order news release, February 19, 2026 michigan.gov
3. U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A (June 2026) eia.gov
4. U.S. Naval Observatory, sun rise and set data (Detroit, December 15 and June 15, 2026) aa.usno.navy.mil
5. Manufacturer listing: 12V RGBW pixel strip, 30 LEDs per meter, 7.2 W per meter superlightingled.com
6. Manufacturer spec: 12V RGBW pixel strip, 60 LEDs per meter, 21.8 W per meter maximum enttec.com
7. Manufacturer spec sheet: outdoor RGBW flexible linear light, 5.95 W per foot kelvix.com
8. Manufacturer data sheet: outdoor RGBW linear light, 4.57 W per foot docs.control4.com