Energy & Environment

Solar panel, electricity cost, carbon footprint, and energy savings calculators.

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Solar Panel Savings Calculator

Estimate solar panel system cost, payback period, and 25-year savings with federal tax credit and state incentives.
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Electricity Bill Calculator

Calculate your monthly electricity bill by adding appliances and their usage. Find your biggest energy consumers.
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Carbon Footprint Calculator

Estimate your annual carbon footprint from driving, electricity, flights, and diet. Compare to the US average.
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Generator Size Calculator

Calculate generator wattage needed based on appliances. Accounts for starting watts on motor loads.
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Appliance Energy Cost Calculator

Calculate energy cost for individual appliances. Compare with efficient alternatives to find savings.
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HVAC Size Calculator

Calculate the right HVAC system size (BTU and tonnage) for your home based on square footage and climate.
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Water Heater Cost Calculator

Compare water heater types (gas, electric, tankless, heat pump) by purchase price and 10-year operating cost.
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Rain Barrel Calculator

Calculate rainwater collection potential from your roof. See water bill savings and barrels needed.
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Firewood Calculator

Calculate cords of firewood needed for heating season by home size and insulation quality.
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Solar Battery Calculator

Calculate batteries needed for solar backup from daily usage and backup hours needed.
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Heat Pump Calculator

Calculate heat pump size and savings vs gas furnace, electric, or oil heating.
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Water Usage Calculator

Calculate household daily water usage and monthly cost from habits and household size.
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Electric Bill Estimator

Estimate monthly electric bill from home size, climate, and heating type.
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Natural Gas Bill Calculator

Calculate monthly natural gas bill from therms used and rate.
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Propane Cost Calculator

Calculate propane heating and usage costs with tank size recommendations.
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Smart Thermostat Savings Calculator

Estimate savings from upgrading to a smart thermostat with payback period.
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Water Bill Calculator

Calculate monthly water and sewer bill from usage and rates.
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Trash Removal Cost Calculator

Estimate trash and recycling service cost by container and frequency.

About Energy & Environment Calculators

These tools help US households put a dollar figure on energy decisions before money or equipment is committed. The Electricity Bill Calculator breaks a utility statement into kilowatt-hours and your per-kWh rate so you can see what is actually driving the charge, while the Appliance Energy Cost Calculator estimates what a single space heater, dryer, or old refrigerator adds each month. Use them when a bill jumps or before replacing a major appliance.

Bigger one-time purchases get their own math. The Solar Panel Savings Calculator projects payback now that the federal 30% residential solar credit (the IRS Investment Tax Credit) expired December 31, 2025, so state and utility incentives carry more weight. The Heat Pump and HVAC Size calculators help you avoid an oversized system that short-cycles, and the Generator Size Calculator sizes backup power by running and starting watts. The Carbon Footprint Calculator, built on EPA emissions factors, is useful when comparing an EV, a flight, or a home upgrade.

Frequently Asked Questions

How is a kilowatt-hour different from a kilowatt, and which one am I billed for?
A kilowatt (kW) measures power, the rate at which a device draws electricity at any moment, while a kilowatt-hour (kWh) measures energy used over time. Your utility bills you for kWh, calculated as power in kW multiplied by hours of use. A 1.5 kW space heater running 10 hours uses 15 kWh, and that figure times your per-kWh rate is what shows up as the usage charge.
Why does an oversized furnace or heat pump cost more to run?
An oversized system reaches the set temperature quickly and then shuts off, a pattern called short-cycling that wears out components and leaves humidity and hot or cold spots behind. The fix is sizing to the home's actual heating and cooling load, which HVAC contractors determine with a Manual J load calculation rather than square footage alone. Bigger is not better here; a right-sized unit runs longer, steadier cycles and uses less energy.
What is the difference between running watts and starting watts when sizing a generator?
Running watts is the steady power a device needs once it is operating, while starting watts (also called surge watts) is the brief spike a motor demands at startup, often two to three times the running figure. Refrigerators, well pumps, and air conditioners all surge this way. Add the running watts of everything you plan to power at once, then add the single largest starting load, and size the generator above that total.
How are home carbon footprint estimates actually calculated?
They multiply your activity, such as kWh used, gallons of gasoline burned, or therms of natural gas, by published emissions factors that convert each unit into pounds of carbon dioxide equivalent. The EPA maintains these factors, and electricity figures vary by region because the grid mix differs, so the same kWh produces more CO2 in a coal-heavy area than in one running on hydro or nuclear. Estimates are directional, not audited measurements.
Is propane or electricity cheaper for home heating?
It depends on local prices and equipment efficiency, so the two have to be compared on the same energy basis. Propane is sold by the gallon (about 91,500 BTU each) and electricity by the kWh (about 3,412 BTU each), and a modern heat pump can deliver several units of heat per unit of electricity, which changes the comparison sharply. Pull your current propane price per gallon and your electric rate per kWh, then compare cost per delivered BTU rather than the sticker price of the fuel.