Calculate electricity cost as average watts divided by 1,000, multiplied by operating hours and your electricity price per kilowatt-hour. Rated power is useful for a planning scenario, but a plug-in energy meter provides a better account of an actual cycle. Keep purchase cost, consumables, and electricity separate.
Use the correct units
Watts describe power at a moment; kilowatt-hours describe energy used over time. For a constant-power example, a 100-watt load running for six hours consumes 0.6 kilowatt-hours. At an illustrative electricity price of $0.20 per kilowatt-hour, that would cost $0.12. These are example inputs, not a measured dryer result or a quoted local utility rate.
Use the variable electricity rate from your own bill. If your tariff changes by time of day, apply the relevant rate to each part of the cycle. Fixed monthly charges generally do not change because you ran one more drying cycle, so keep them separate from this incremental calculation.
Treat rated power as a scenario input
Creality's comparison page lists 145 watts for the original single-spool SpacePi and 160 watts for SpacePi Plus. Model names and revisions matter: verify the label on the specific machine rather than borrowing a number from a similar listing.
Using 145 watts continuously for six hours gives 0.87 kilowatt-hours. At the same illustrative $0.20 rate, that is $0.174, or about seventeen cents. This is a constant-rated-power calculation, not a claim about measured consumption. Actual draw can vary during warm-up and temperature control, so the calculation should remain labeled as an estimate.
Measure a representative cycle
Use an appropriately rated energy meter according to its instructions and the dryer's electrical requirements. Record total kilowatt-hours over the complete cycle, including the stages you intend to compare. Write down the load, selected temperature, duration, and room conditions so the reading has context.
Multiply the measured energy by your applicable electricity price. Repeat only when a meaningful variable changes, such as a different program or normal load. There is little value in collecting many nearly identical measurements if the decision is already clear. A small set of representative records is enough for most household planning.
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Comparing equipment? Review the documented limits before buying.
View SUNLU S4 on Amazon ↗A relevant option to investigate, not a diagnosis or a universal recommendation.
Compare cost per useful preparation
A two-spool machine's cycle cost and per-spool cost answer different questions. If both loaded spools receive a compatible required process, dividing that cycle's energy by two can help compare your workflow. If you usually load only one spool, use that actual pattern rather than assuming full capacity every time.
Do not shorten a prescribed cycle or mix incompatible materials merely to improve the arithmetic. A cheap cycle that does not meet the material's preparation requirements is not an equivalent result. Compare machines under the tasks you would actually ask them to perform, including the time they occupy your workspace.
Include ownership without inventing savings
List the purchase, any necessary storage supplies, recurring consumables, and your estimated electricity use separately. For an illustrative schedule of twelve measured 0.6-kilowatt-hour cycles per month at $0.20, electricity would total $1.44. Replace every input with your own before treating it as a budget.
Avoid assuming that every failed print would have been prevented by drying. Track observed reductions in waste over comparable jobs if you want to evaluate savings. Convenience can also matter: preparing tomorrow's spool while the printer is busy may be valuable even when electricity differences are small. A useful cost comparison states its assumptions and measures the workflow it claims to improve.
Sources and research notes
This guide synthesizes published guidance. It does not describe our own laboratory or hands-on product testing. Material instructions apply to the named manufacturer and grade.
