Garden Energy Use Calculator

Electric items

• Effective_W = Standby_W + (Power_W × Duty% ÷ 100) ÷ (Efficiency% ÷ 100)
• kWh = Effective_W × HoursPerDay × Days × Quantity ÷ 1000
• Cost = kWh × RatePerkWh
• CO₂(kg) = kWh × CO2Factor

Fuel items

• kWh_equiv = Liters × kWhPerLiter × Quantity
• Cost = Liters × CostPerLiter × Quantity
• CO₂(kg) = kWh_equiv × CO2Factor (uses your selected factor)

1. Enter your currency, electricity rate, and CO₂ factor.
2. Add each device or equipment item you want to track.
3. For electric items, provide watts, runtime, duty, and efficiency.
4. For fuel items, enter liters, kWh per liter, and fuel price.
5. Click Calculate to view totals above the form.
6. Use the download buttons to export CSV or PDF reports.

Garden systems often run quietly in the background, so small daily loads add up. Pumps, aerators, heaters, grow lights, timers, and charging tools can produce a noticeable monthly bill. Recording device watts, runtime, and quantities helps you plan upgrades and avoid surprise costs during peak watering or seed-starting periods.

This calculator uses power, standby draw, duty cycle, and efficiency to estimate effective energy. A pump that runs at 70% duty for 1.5 hours/day will consume less than a constant-load heater. Efficiency is important for inverters and motor-driven equipment: losses increase kWh even when watts look modest on a label.

Fuel entries convert liters to kWh-equivalent using your selected kWh per liter value. This allows side-by-side planning: for example, deciding between a small electric trimmer and a petrol trimmer for weekly edging. Costs remain separate by rate type, while energy totals show the overall intensity of your garden work.

Cost is calculated from kWh and your electricity rate, while CO₂ is estimated from the CO₂ factor you provide. If your grid is cleaner, reduce the factor; if you want a conservative estimate, increase it. Use the annual projection to compare scenarios such as shorter lighting schedules or a more efficient pump.

Start with the largest loads: pumps, heaters, and lighting. Reduce hours/day, trim duty cycle with better timers, and check standby watts for controllers and smart plugs. Swapping to high-efficiency LEDs, cleaning filters to reduce pump strain, and grouping watering cycles can cut kWh without reducing plant health.

1) What should I enter for duty cycle?

Use the percentage of time the device actively runs during the selected hours/day. If a pump cycles on and off, estimate the “on” portion. For continuous loads like grow lights, use 100%.

2) How do I pick a CO₂ factor?

Choose a value that matches your local electricity mix or your reporting goal. A lower value represents cleaner electricity. If you are unsure, keep the default and use it consistently for comparisons.

3) Why include standby watts?

Many garden controllers, smart plugs, and chargers draw power even when “off.” Standby consumption is multiplied by hours/day and days, so small numbers can become meaningful over longer periods.

4) What does efficiency change?

Efficiency accounts for losses in motors, drivers, and converters. If a device is 90% efficient, it needs more input energy to deliver the same output. This increases effective watts and therefore kWh.

5) Can I use “Days” for a season?

Yes. Days is your planning window. Enter 7 for a week, 30 for a month, or 120 for a season. The totals will reflect that window, and annual projection multiplies the total by 12.

6) How accurate are fuel kWh-equivalent totals?

They are a planning estimate based on the kWh per liter value you provide. It helps compare intensity across tools, but real-world efficiency varies by engine load, maintenance, and operating conditions.