A deer display, a plug-in wreath and a flagpole tree may follow different schedules. To estimate their seasonal electricity cost, calculate each set separately using its average input power, operating hours and your applicable electricity rate. Add the results only after those inputs are clear.
This guide covers plug-in decorations for homes and small shops. It provides a budgeting method, not verified running costs for any HOYECHI model. Battery-powered wreaths need a different assessment; this calculation does not estimate battery life or replacement costs.
AI-generated editorial illustration of an imagined household display; not a HOYECHI product photograph or a customer installation.
Start with the whole set and a reliable power figure
Give each set a name and record its exact model. Then find a documented average input power in watts for the complete set and the mode you intend to use. Record where that figure came from and its date. A product specification or manufacturer response is useful only if it identifies what the number represents.
- Average input power: a figure applicable to the complete set, operating mode and period can support a running-energy estimate.
- Rated or maximum power: keep the original description. It is not automatically the average draw. A calculation using it must be labelled as a rated-power scenario, not measured consumption or a proven upper limit.
- Adapter output capacity: do not treat this as the set's actual input power at the outlet. Likewise, multiplying an AC voltage label by an amperage label does not establish actual watts.
- No usable wattage: mark the input unknown. Height, LED count and apparent brightness cannot supply the missing number.
If a figure covers an entire deer set, count that set once. Do not add its individual pieces again. If a figure covers only part of a decoration, it cannot establish the complete set's cost.
Why individual LED wattage is not the whole-set figure
In a September 2026 interview, HOYECHI's representative described the individual LEDs in the light strings currently used by the company as approximately 0.025–0.03 W each. This is the representative's description of the LED components, not a measured average input-power specification for any complete decoration or individual product model.
The representative also identified power-adapter and wiring losses as factors to consider, but supplied no measurements for those losses. Multiplying an LED count by the stated component wattage therefore does not establish a decoration's actual input power or running cost. For the worksheet, use a supported average input figure covering the entire set. When that figure already covers the full set at its power input, do not add estimated adapter or wiring losses on top of it.
A small component wattage alone cannot tell you whether the electricity cost of a whole yard display will be low. The number of sets, each set's input power, operating hours and applicable tariff still determine the estimate.
Turn watts and hours into kilowatt-hours
Watts (W) describe power; kilowatt-hours (kWh) describe energy used over time. One kilowatt equals 1,000 watts. See the U.S. Energy Information Administration's explanation of electricity units.
Energy (kWh) = average input power (W) × total operating hours ÷ 1,000
Estimated variable electricity cost = energy (kWh) × applicable price per kWh
For an unchanged daily schedule, total hours equal hours per day multiplied by days used. If the schedule or operating mode changes, split the calculation into separate rows. The average power must describe the same period and equipment as the hours entered.
If you already have trustworthy energy data in kWh for the exact set and period, use that energy directly with the appropriate rate. Do not multiply it by hours again.
A worked example using hypothetical inputs
Every input below is an assumption for teaching the calculation. None is a HOYECHI product specification or a current local electricity rate. The example covers only the hours when the hypothetical decoration is operating.
| Input | Assumed value |
|---|---|
| Average input power while operating | 20 W |
| Daily operating time | 5 hours |
| Days used | 30 days |
| Single electricity rate | US$0.20 per kWh |
- Total operating time: 5 × 30 = 150 hours.
- Operating energy: 20 × 150 ÷ 1,000 = 3 kWh.
- Variable cost for those operating hours: 3 × US$0.20 = US$0.60.
The hypothetical US$0.60 excludes any unprovided standby consumption and other bill items. It is not a quote for running a real decoration for a season.
Keeping the same assumed power, 30-day season and rate, reducing operation from five to four hours a day gives 120 hours, 2.4 kWh and US$0.48. That is a 20% reduction in the calculated operating energy and its associated charge. It does not imply a 20% reduction in your whole electricity bill or total decoration energy, which may also include standby use.
Build a worksheet for your own display
Copy the following blank worksheet for each deer set, plug-in wreath or flagpole tree. Use a new row when a set has a different schedule, mode or tariff period. The dashes are blank fields, not zero consumption.
| Record | Set A | Set B | Set C |
|---|---|---|---|
| Exact model / included pieces / mode | — | — | — |
| Power source document and date | — | — | — |
| Average input W, or unknown | — | — | — |
| Hours per day and days, or total hours | — | — | — |
| Tariff period / rate source and date | — | — | — |
| Rate per kWh and currency | — | — | — |
| Calculated energy, kWh | — | — | — |
| Calculated variable cost | — | — | — |
| Excluded or unknown items | — | — | — |
Calculate each completed row before adding costs. A wreath lit only during shop opening hours should not inherit the schedule of a tree lit later in the evening. If one set's power is unknown, report the known subtotal and identify the missing set; do not present the subtotal as the complete display budget.
Match the rate to the hours you use
Use your own current tariff. Rates differ by location and customer type, and some tariffs vary by time of day, as explained in EIA's electricity pricing guide. A national average or a rate in an old lighting article is not a substitute for your tariff.
With time-of-use pricing, separate the energy used in each rate window: cost equals energy in window A multiplied by rate A, plus energy in window B multiplied by rate B. Extend this for every applicable window and decoration set. Only multiply all energy by one rate when that rate applies to all of it.
Use consistent currency units: convert cents or pence into dollars or pounds before multiplying if you want the answer in dollars or pounds. Record whether the chosen rate includes applicable taxes or usage-based charges. Fixed charges are outside this operating-cost calculation; dividing your whole bill by its kWh can mix those fixed charges into the resulting average. Small-shop tariffs may include additional items, such as demand charges, that this worksheet does not predict.
Keep standby and changing modes visible
A dark decoration is not sufficient evidence of zero consumption while connected. The U.S. Department of Energy explains standby power and describes averaging energy over time when power varies. That general guidance does not establish the standby draw or operating power of a particular decoration.
If reliable standby power and hours are available, calculate that period separately and apply its corresponding rate. If they are unknown, write “standby not included; consumption unknown.” When energy data already covers the full day, including standby, do not add the same standby period again.
A documented average for one lighting mode may not describe another. Keep estimates tied to the selected mode and schedule. Without evidence for the variation, do not invent a percentage error range or assume flashing always costs less.
What to do when a product's wattage is missing
Ask for the average input power for the exact model, complete set and intended mode, and whether the figure is measured, rated or maximum. Request the scope and conditions behind it. If only a rating is available, retain that label in any scenario; if the meaning is unclear, leave the cost unresolved.
For product selection, browse HOYECHI Christmas reindeer decorations, review how to choose an outdoor Christmas wreath, or read the HOYECHI flagpole Christmas tree guide. These links help identify the decoration you are considering; they do not supply verified running-cost figures for this worksheet.
Questions about Christmas lights running costs
Can I estimate cost from the number of LEDs?
No. Use a documented average input power for the whole set and intended mode. LED count alone cannot fill that field.
Can I add all the wattages first?
Only when the figures cover separate, non-overlapping sets with the same operating hours. The same rate must also apply if you want to calculate their cost together. Separate calculations are easier to check when schedules differ.
Does a battery wreath belong in this worksheet?
No. This is a plug-in electricity calculation. It does not establish disposable-battery costs, rechargeable-battery costs or runtime.
What is the most useful result if some inputs are unknown?
A labelled partial estimate and a short list of missing inputs. Keep a known subtotal separate from hypothetical scenarios. Once the missing power, hours or rate is confirmed, update the relevant row and recalculate.
