Electricity Supplier Comparator
Compare selected electricity offers with official market sources and an interactive annual-cost chart.
Compare suppliers →Estimate energy use, operating costs, payback and sizing with editable assumptions.
Compare selected electricity offers with official market sources and an interactive annual-cost chart.
Compare suppliers →Select a city, load PVGIS irradiation and specific yield, then estimate system size and payback.
Open calculatorCompare EIA residential prices and estimate cost by state.
Open →Estimate utility connection, line extension or trenching, meter, service entrance, main panel, permits and contingency.
Open calculatorWatts × hours × rate.
Open →Convert appliance power to kWh.
Open →Home charging vs gasoline.
Open →Estimate simple payback and 25-year savings.
Open →Estimate system kW and panel count.
Open →Compare N/E/S/W, any azimuth and tilt, then optimize annual plane-of-array irradiance with interactive 2D/3D charts.
Open solar orientation lab →Estimate gross and net project cost from size and local price per watt.
Open →Estimate battery capacity for essential-load backup.
Open →Compare electricity and gas operating cost.
Open →Estimate monthly and annual hot tub electricity cost.
Open calculator →Estimate annual savings and simple payback for an efficiency upgrade.
Open calculator →Calculate hourly, daily and monthly space-heater cost.
Open calculator →Estimate monthly and annual refrigerator operating cost.
Open calculator →Estimate HVAC energy savings and simple payback.
Open calculator →Estimate energy savings and simple payback for replacement windows.
Open calculator →Compare simplified annual heating energy costs.
Open calculator →Build an annual solar maintenance budget from your own assumptions.
Open calculator →Combine solar, HVAC, EV, electrical and efficiency project budgets.
Open calculator →Compare heat pump energy cost with gas, propane, oil or resistance heat.
Open calculator →Calculate stoichiometric oxygen, dry/wet combustion air, flue-gas composition and gas flow for coal, biomass and solid waste.
Open calculator →Model 1–7 wall layers, U-value, thermal resistance, heat flow, interface temperatures and target insulation thickness.
Open calculator →Learn the equations behind wall U-value, insulation thickness, combustion air and flue-gas calculations.
Read 10 engineering guides →Turn climate concerns into a practical home-improvement plan: identify relevant hazards, review protective upgrades, estimate your own local costs and connect each action to existing WattCostLab tools.
Adaptation guides →Start with the pages readers are using most often for cost planning and comparisons.