Your result
Click Calculate
Enter your values, then click Calculate result.How this calculator helps
Calculate one appliance group's contribution to peak power and daily energy before building a complete solar load sheet. Repeat the calculation for fans, lights, televisions or computers and combine the results during system planning.
How to use it
- 1
Enter nameplate or measured watts for one appliance type.
- 2
Enter how many will operate and realistic daily hours.
- 3
Repeat for each appliance group, then combine peak watts and daily energy for system planning.
Formula and methodology
Peak load = appliance watts × quantity. Daily energy = peak load × operating hours. Energy units = watt-hours ÷ 1,000.
Uses editable energy demand, sunlight, equipment and loss assumptions. It is a planning model rather than a site survey or electrical design.
Worked calculation example
Six 80 W fans create a 480 W peak load. Used for eight hours, they require 3,840 Wh or 3.84 energy units per day.
How to interpret your result
Calculate peak load and daily energy for repeated appliances from watts, quantity and usage hours. Read the main result together with the supporting values rather than treating one number as a guarantee. The disclosed method is: Peak load = appliance watts × quantity. Daily energy = peak load × operating hours. Energy units = watt-hours ÷ 1,000.
Input guide
Enter nameplate or measured watts for one appliance type.
Enter how many will operate and realistic daily hours.
Repeat for each appliance group, then combine peak watts and daily energy for system planning.
Scenario comparison
| Scenario | What it demonstrates |
|---|---|
| Worked baseline | Six 80 W fans create a 480 W peak load. Used for eight hours, they require 3,840 Wh or 3.84 energy units per day. |
| Simultaneous use check | Peak load depends on which appliances actually overlap. |
| Variable power stress test | ACs, refrigerators, pumps and computers do not always draw one fixed wattage. |
Common mistakes to avoid
- Ignoring simultaneous use: Peak load depends on which appliances actually overlap.
- Overlooking variable power: ACs, refrigerators, pumps and computers do not always draw one fixed wattage.
- Failing to test startup surge: Motor loads require separate surge allowance beyond daily energy.
Check the result against equipment datasheets, a site survey and a written design from a qualified solar professional.
What can affect the result?
Simultaneous use
Peak load depends on which appliances actually overlap.
Variable power
ACs, refrigerators, pumps and computers do not always draw one fixed wattage.
Startup surge
Motor loads require separate surge allowance beyond daily energy.
Limits of this estimate
This page calculates one appliance group at a time and cannot automatically model surge, diversity, seasonal use or a full load schedule.
Sources and review information
Frequently asked questions
Is the solar load calculator free?＋
Yes. SolvePilot tools are free, work in your browser, and require no account.
Does SolvePilot store my values?＋
No. Calculations run locally in your browser and the values you enter are not sent to a server.
Should I treat the result as an exact bill or quotation?＋
No. Results are informed estimates. Final charges can vary because of taxes, tariffs, lender terms, usage patterns, or provider rules.
How can I improve the accuracy?＋
Use recent values from your own bill, statement or institution, review every assumption, and confirm important results with the relevant official source.
Should every appliance be assumed to run together?＋
Peak-load planning should include appliances likely to overlap; daily energy uses each appliance's realistic operating hours.