Standby is a sneaky appliance
“Vampire” standby loads can add 5–10% to a home’s annual electricity use—roughly the same as running a modern fridge.
Phantom watts
Home Energy Usage Calculator — kWh, Cost & CO₂
Household & Tariff
Appliances
Tip: For always-on devices (fridge, routers), set hours/day to 24 and days/week to 7, or use an average Watt value. For cycle-based devices (washer, dryer, dishwasher), use the cycle tab.
Results
How This Home Energy Calculator Works
This home energy usage calculator helps you estimate where your electricity goes and how much it costs. By adding appliances and entering how often you use them, you get an annual kWh total, an estimated bill impact, and an optional CO₂ footprint based on your local grid. It is a practical tool for budgeting, energy audits, and finding the biggest energy users in your home without needing a smart meter.
The math is simple. Each device uses power, measured in watts, over time. Multiply watts by hours of use to get watt-hours, then convert to kilowatt-hours (kWh), the same unit shown on your utility bill. The calculator sums each appliance to estimate a yearly total, then multiplies by your electricity rate to estimate cost. If you enter a grid emissions factor, it also estimates the carbon footprint of your home energy use.
To use the calculator, follow these steps:
- Add appliances using presets or create custom entries for the devices in your home.
- Choose a time-based input (watts and hours) or a cycle-based input (kWh per cycle).
- Enter how many hours per day or cycles per week each device runs.
- Set your electricity price and, if desired, the grid emissions factor for your area.
- Click Calculate to see annual kWh, cost, and CO₂ totals.
This is especially useful for comparing appliances. For example, you can see how a second refrigerator affects your annual bill, estimate the impact of a new heat pump versus electric resistance heaters, or check how much standby power adds up across electronics. Renters can use it to understand a monthly electricity bill, while homeowners can use it to plan upgrades like LED lighting or efficient HVAC.
The presets are starting points, not absolutes. Adjust wattage and usage to match your actual devices, and update the tariff if your utility has time-of-use pricing. For heating and cooling, the heat pump option lets you enter required heat (kWh) and a COP to estimate electrical use more realistically. With a few inputs, you get a clear picture of household energy use and where savings are most likely.
5 Fun Facts about Home Energy
Heat pump math feels like magic
A heat pump with COP 3 delivers 3 kWh of heat for every 1 kWh of electricity. That’s why cold-climate models crush resistance heaters on the bill.
COP superpower
Dishes on eco? Big savings
Switching a dishwasher from “normal” to “eco” often halves the water temperature and cuts energy use by 30–40% per cycle.
Cycle switch
LEDs pay back fast
Replacing a single 60 W incandescent with a 9 W LED saves about 90 kWh/year. Multiply by a dozen bulbs and it’s a free laptop’s worth of energy.
Lighting glow-up
Dryer lint = wasted kWh
A clogged lint screen can lengthen dryer cycles by 30%, burning hundreds of extra kWh annually. Cleaning it is basically free efficiency.
Maintenance win
FAQs
What if I only know annual kWh from the label?
Add a custom item and switch to the cycle tab using 1 cycle/week with kWh/cycle = annual kWh ÷ 52, or use the time tab with hours and Watts that match the label.
How do I include standby?
Use the standby Watts field and set hours/day it’s in standby. Standby is added on top of active use.
Can I change the currency?
Yes—set the currency symbol (e.g., £, $, €, ₹). Tariff is per kWh in that currency.