Guidelo

Interactive Energy & Solar Calculators

Accurate, client-side estimation tools designed with standard engineering formulas. Estimate appliance electricity costs in kWh and model rooftop solar payback periods without any backend data collection.

1. Home Electricity Cost Calculator

Calculate daily and monthly energy consumption (kWh) and costs for any electrical appliance. Select a preset or enter your custom wattage.

Quick Select Common Appliance:
Watts
Hours
Days
per kWh
Estimated Consumption & Cost
Total Estimated Cost
216.00
Daily Energy
9.60 kWh
Total Energy
288.00 kWh

This appliance consumes approx. 9.60 kWh/day (288.00 kWh over 30 days).

Formula: Energy (kWh) = (Watts × Hours) ÷ 1000
Cost = Energy × Rate per kWh
Note: Full utility bills may also include fixed charges, demand charges, fuel cost adjustments, and taxes.

2. Rooftop Solar Savings Estimator

Model solar generation, annual electricity bill savings, net capital investment, and simple payback periods based on realistic solar irradiation parameters.

kW
/ kW
Total
per kWh
Hours
%
Estimated Solar Economics
Simple Payback Period
3.0 Years
Gross Cost
₹165,000
Net Upfront Cost
₹87,000
Annual Savings
₹28,826/yr
Annual Generation
3,843 kWh
Monthly Generation
320 kWh/mo
Annual CO2 Offset
3.15 Tonnes
Assumptions: Calculations use a 78% Performance Ratio (PR) accounting for temperature, inverter conversion, dust, and wiring losses. Payback represents a simple estimate and does not constitute a guaranteed quotation or official subsidy commitment.
Step-by-Step Calculation Breakdown
Step 1 Net Investment
₹1,65,000 Gross − ₹78,000 Subsidy = ₹87,000 Net Out-of-Pocket
Step 2 Annual Solar Generation
3 kW × 4.5 hrs × 0.78 PR × 365 days = 3,843 kWh/yr (~320 units/mo)
Step 3 Annual Bill Savings
3,843 units × ₹7.50 = ₹28,826/year saved
Step 4 Simple Payback Period
₹87,000 Net Cost ÷ ₹28,826 Annual Savings = 3.0 Years (100% investment recovered)

3. Multi-Appliance Electricity Usage Calculator

Calculate the cumulative daily and monthly energy consumption of your entire household. Add or remove appliances, adjust runtime, and see which device drives the largest share of your electric bill.

per kWh
Appliance Name Watts Hours/Day Qty Daily kWh
9.60 kWh
1.28 kWh
2.70 kWh
0.36 kWh
0.50 kWh
Household Summary
Est. Monthly Electricity Cost
3,249
Total Daily Energy
14.44 kWh/day
Total Monthly Units
433 kWh/mo
Highest Energy Consumer: 1.5 Ton Inverter AC (9.6 kWh/day)
Formula: Total Monthly kWh = ∑ [(Watts × Hours × Qty) ÷ 1,000] × 30
Notice: Refrigerator compressor runs roughly 30% of plugged-in time. Enter effective compressor hours for cycling loads.

4. Solar System Size Estimator

Determine the exact solar capacity (kW), panel count, and shadow-free roof area required to offset your home's monthly electricity consumption.

kWh / mo
Hours
%
System Sizing Results
Recommended System Capacity
4.32 kWp
Total Solar Panels
8 Panels
Est. Monthly Generation
455 kWh/mo
Required Roof Area (Sq Ft)
432 sq. ft.
Required Roof Area (Sq Meters)
40 sq. m.
Sizing Formula: System Size (kW) = (Monthly kWh Target ÷ 30) ÷ (Peak Sun Hours × 0.78 PR)
Important Notice: Sizing assumes a south-facing unshaded roof. Professional site surveys must inspect roof azimuth, structural load limits, and local DISCOM net metering sanction thresholds before purchasing.
Step-by-Step Calculation Breakdown
Step 1 Daily Target
(450 units × 100%) ÷ 30 days = 15.00 kWh/day required
Step 2 Generation Rate
4.5 sun hrs × 0.78 PR = 3.51 kWh per kW/day
Step 3 Sizing Capacity
15.00 target ÷ 3.51 kWh/kW = 4.27 kWp required
Step 4 Sized Panels & Roof Space
8 panels × 540W = 4.32 kWp (432 sq ft roof space)