Simple calculators to find out how much each appliance costs to run, what battery you need for power cuts, or how many solar panels you need. Free, no sign-up, with the maths in plain sight.
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Energy use chart for 70 appliances: watts, kWh per hour and kWh per month for fridges, A/C, water heaters, lights and more, and how to work out yours.
Read the full article: Appliance energy use chart →The newest guides for your home.
How many watts a generator for your home needs: the math for running watts and starting watts, with three worked examples.
Read article: Generator size →
How many solar panels a 1,000 or 2,000 sq ft house needs, why square footage doesn’t decide it, and how to work it out from the kWh on your bill.
Read article: Solar panels for your home →
What size solar water heater you need for 2, 4 or 6 people: tank litres, collector area and why the number of tubes is misleading.
Read article: Solar water heater size →
How many solar panels it takes to run a 9,000 to 24,000 BTU air conditioner or mini-split, with the grid or with batteries, and why night changes everything.
Read article: Solar panels for an air conditioner →What happens if you plug a 110 V appliance into 220 V or the other way round, how to read its label to see if it works in your country, and when you need a converter.
Read: 110 V or 220 V: your appliances’ voltage →Why a circuit breaker or GFCI (RCD) trips, how to tell which one it was, what you can safely do yourself and when you need to call an electrician.
Read: Why a breaker or GFCI trips →What a watt, a kWh, a volt and an amp are, what a battery’s Wh and Ah mean, and what a deep-cycle battery is. Explained simply, with everyday examples.
Read: Beginner’s guide: watts, kWh, volts and amps →Energy use chart for 70 appliances: watts, kWh per hour and kWh per month for fridges, A/C, water heaters, lights and more, and how to work out yours.
Read: Appliance energy use chart →How much electricity a 9,000, 12,000, 18,000 or 24,000 BTU air conditioner or mini-split uses: watts, kWh per month, inverter or not, and how to use less.
Read: How much an air conditioner uses →Learn to read the energy label on your appliances: what the letter means, where to find the kWh you pay for, and how labels work in the EU, U.S. and Latin America.
Read: How to read an energy label →How many watts a generator for your home needs: the math for running watts and starting watts, with three worked examples.
Read: Generator size →What battery you need for a 500 to 6,000 W inverter: the amps it draws at 12, 24 or 48 V, how to work out Ah from hours of use, and common mistakes.
Read: Which battery for your inverter →LiFePO4, NMC, gel, AGM and lead-acid batteries compared: cycle life, weight, maintenance, safety and which one suits power cuts or solar panels.
Read: Home battery types compared →How many solar panels a 1,000 or 2,000 sq ft house needs, why square footage doesn’t decide it, and how to work it out from the kWh on your bill.
Read: Solar panels for your home →What size solar water heater you need for 2, 4 or 6 people: tank litres, collector area and why the number of tubes is misleading.
Read: Solar water heater size →How many solar panels it takes to run a 9,000 to 24,000 BTU air conditioner or mini-split, with the grid or with batteries, and why night changes everything.
Read: Solar panels for an air conditioner →