Home Energy & Utilities Savings Calculators
8 tools in this collection — free, instant, and private in your browser.
Home energy costs are one of the largest variable expenses in a household budget, and also one of the most actionable. This set of calculators is built to help homeowners and renters understand exactly where their energy dollars go and evaluate whether an upgrade — solar panels, a heat pump, an EV charger — will pay for itself over time.
A good place to start is understanding your baseline. The electricity bill calculator and the appliance energy cost calculator let you break down consumption by device and see which items are driving your monthly bill. The phantom load calculator surfaces the often-overlooked cost of standby power — the electricity consumed by electronics that are plugged in but not actively in use. For many households, phantom loads account for 5 to 10 percent of total electricity consumption.
Once you know your baseline, the savings calculators let you model specific upgrades. The solar panel savings calculator estimates how much of your electricity bill solar production could offset based on system size and local rates. The heat pump savings calculator compares the efficiency of a heat pump against a gas furnace or electric resistance heater. The EV charging cost calculator shows what it will actually cost to charge an electric vehicle at home compared to buying gasoline at current prices.
For resilience planning, the generator size calculator and home battery backup calculator help you size backup power systems appropriately for your home's critical loads — preventing the common mistake of buying a generator that is too small to run essential appliances or too large to be practical.
- Start with the Electricity Bill Calculator to establish your current cost baseline.
- Use the Solar or Heat Pump Savings Calculator to model the financial case for a specific upgrade.
- Use the Generator Size or Battery Backup Calculator when planning for outage resilience.
These tools do not replace a professional energy audit, but they give you the numbers you need to ask better questions and make more confident decisions about your home's energy future.
All home energy & utilities savings calculators
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| Tool | What it does |
|---|---|
| Appliance Energy Cost Calculator | Calculate how much energy an appliance uses and what it costs to run from its wattage, hours of use per day, and your electricity rate. |
| EV Charging Cost Calculator | Calculate what it costs to charge your electric vehicle for a given distance from its efficiency, your electricity rate, and charger efficiency losses. |
| Electricity Bill Calculator | Estimate your monthly electricity bill from average daily usage, the number of days, your per-kWh rate, and any fixed service charge. |
| Generator Size Calculator | Size a backup generator by adding your appliances' running watts and the largest single starting surge to find the running and peak (starting) wattage you need. |
| Heat Pump Savings Calculator | Compare the annual heating cost of a heat pump against electric resistance heating using your heating load, the pump's COP, and your electricity rate. |
| Home Battery Backup Calculator | Estimate how many hours a home battery can power your loads during an outage from its usable capacity and your average power draw. |
| Phantom Load (Standby Power) Cost Calculator | Calculate the yearly energy and cost of phantom (standby) loads — the power devices draw 24/7 while switched off or idle — from total standby watts and your electricity rate. |
| Solar Panel Savings Calculator | Estimate the annual electricity production, dollar savings, and simple payback period of a rooftop solar system from its size, your sun-hours, and your electricity rate. |
Frequently asked questions
- How accurate are the solar panel savings estimates?
- The estimates are based on the system size, local electricity rate, and average sun hours you provide. They do not account for shading, roof orientation, panel degradation over time, local utility net-metering rules, or installation costs, all of which significantly affect real-world returns. Use the calculator to get a directional sense of potential savings, then get formal quotes from at least two or three licensed solar installers for project-specific numbers.
- What is phantom load and is it really worth worrying about?
- Phantom load, also called standby power or vampire power, is the electricity drawn by devices that remain plugged in while not in active use. Common sources include televisions, game consoles, chargers, cable boxes, and older appliances. Individually the cost per device is small, but across an entire household the total can add up to 50 to 100 dollars per year. Smart power strips and unplugging seldom-used devices are the easiest fixes.
- How do I size a home battery backup system correctly?
- Sizing a home battery requires knowing two things: the total wattage of the appliances you want to run during an outage, and how many hours you want to run them between charges. Multiply those two numbers to get the kilowatt-hour capacity you need. The home battery backup calculator walks through this process. Keep in mind that battery systems are typically paired with solar so they can recharge during the day, which changes the math if you want more than one or two days of backup.