sust-it.net

To estimate what an appliance costs to run, find its power rating in watts (on the rating label or in the product specifications), convert that to kilowatt-hours (kWh) by multiplying kilowatts by hours of use, then multiply by your electricity unit price. For example, a 2,000 W appliance used 1 hour a day uses 2 kWh daily; at 30p per kWh that is about 60p a day. This works for any mains appliance where you know the wattage and can estimate usage hours. For vehicles and larger comparisons, Sust-it's databases and cost calculators cover electricals and vehicles, including running costs, fuel consumption and CO2 emissions.

Step 1: Find the power rating

Check these sources in order:

1. Rating label or plate — usually on the back, base or inside a door. Look for "W", "watts" or "kW".
2. Product specifications — manufacturer page, manual or retailer listing.
3. Energy label — for large appliances, annual energy use in kWh is often shown, which you can divide by 365 for a daily average.

Record the figure in watts. If it says kW, multiply by 1,000 (1.5 kW = 1,500 W).

Watch for range ratings

Some appliances list a range (e.g. 1,000–2,000 W) because power varies by setting. Use the setting you actually use most, or calculate both ends to see the spread.

Step 2: Convert watts to kilowatt-hours

The formula:

kWh = (watts ÷ 1,000) × hours used

For appliances that cycle on and off (fridges, ovens, heaters with thermostats), the label wattage is peak draw, not average. Use the annual kWh figure where available, or treat the result as an upper bound.

Step 3: Multiply by your electricity unit price

Running cost = kWh × price per kWh

Check your bill or tariff for the unit rate. Using the table above at 30p per kWh:

• Kettle: 0.75 kWh × 30p = 22.5p per day
• LED bulb: 0.05 kWh × 30p = 1.5p per day
• Fan heater: 4 kWh × 30p = £1.20 per day
• Fridge-freezer: 3.6 kWh × 30p = about £1.08 per day

Repeat with your own rate; the ranking of appliances usually stays similar even when prices change.

Step 4: Compare models before buying

Use the same method on candidate models so the comparison is like-for-like:

• Compare annual kWh from energy labels where both products have them.
• For products without labels, compare wattage at the same setting and multiply by the same usage hours.
• Check whether the rating is peak or average — a lower peak with a thermostat may still cost more over a year than a higher-rated appliance that runs briefly.

Sust-it's appliance and technology databases list energy usage and running costs across categories including refrigeration, washing and drying, dishwashers, cookers, small appliances, televisions, computers and printers, so you can compare before buying.

Step 5: Account for standby and real-world use

Label ratings rarely capture everything:

• Standby power — many devices draw 0.5–5 W when "off". A device at 3 W standby for 20 hours a day uses 0.06 kWh daily, roughly 1.8p at 30p per kWh — small per device but adds up across a home.
• Usage patterns — a kettle's 3,000 W matters little because it runs for minutes; a 150 W fridge matters more because it runs constantly. Always pair the rating with realistic hours.
• Heating and cooling — these usually dominate bills. Sust-it's heating and cooling calculators and price comparisons (halogen, fan, convector, ceramic, oil-filled and panel heaters) help compare options on running cost rather than purchase price alone.

Quick checklist

• [ ] Wattage found on label or specs
• [ ] Hours per day or week estimated realistically
• [ ] kWh calculated (watts ÷ 1,000 × hours)
• [ ] Unit price taken from your tariff
• [ ] Standby and cycling behaviour considered
• [ ] Same method applied to alternative models

Once you have running costs for your main appliances, target the largest contributors first — usually heating, cooling, wet appliances and refrigeration — before worrying about low-wattage items.

To estimate an appliance's running cost, find its power rating in watts (W) on the label or in the manual, convert that to kilowatt-hours (kWh) using the hours you actually use it, then multiply by your electricity tariff. For example, a 2,000 W heater run for 3 hours uses 6 kWh; at 30p per kWh that is about £1.80. This method works for any mains appliance and lets you compare similar models before buying. Sust-it's energy calculators and appliance databases are built around exactly this kind of comparison, alongside its running-cost data for electricals and vehicles.

Step 1: Find the power rating in watts

Check, in this order:

• Rating plate or sticker — usually on the back, base, or inside the door of the appliance. Look for "W", "watts", or "Wattage".
• Manual or spec sheet — often gives a range (e.g. 1,800–2,200 W) rather than a single figure.
• Energy label — for large appliances this gives annual kWh directly, which skips the maths below.

Two complications to watch for:

• Ranges and cycles. Washing machines, dishwashers, and ovens draw different power at different stages. Use the label's maximum for a worst case, or the energy label's annual kWh for a realistic average.
• Standby and always-on loads. Devices left on standby or running 24/7 (routers, set-top boxes, fridges) need their hours counted across the whole day, not just active use.

Step 2: Convert watts and hours into kWh

The formula:

kWh = (watts ÷ 1,000) × hours used

Worked examples:

For appliances you only use seasonally, multiply daily kWh by the number of days you actually use them rather than 365.

Step 3: Multiply by your electricity tariff

Running cost = kWh × price per kWh

Your price per kWh is on your bill or tariff summary. Using 30p/kWh as an illustration:

• LED bulb: 18 kWh/year × £0.30 ≈ £5.40/year
• Laptop: 142 kWh/year × £0.30 ≈ £43/year
• Fan heater at 3 h/day for a winter month (90 kWh) × £0.30 ≈ £27/month

Heating and cooling appliances dominate because their wattage is high and their run times are long. Lighting and small electronics are usually minor by comparison — Sust-it notes that lighting accounts for roughly 10–20% of a typical home's electricity bill, which is why switching to low-energy and LED bulbs is a common first step.

Step 4: Compare similar appliances before buying

Running-cost comparison only makes sense between appliances that do the same job. Use the same three inputs — rated power, realistic hours, tariff — for each candidate. Sust-it's appliance and technology databases list power ratings and running costs across categories, and its electricity cost calculators let you plug in your own usage and tariff rather than relying on averages.

A practical comparison: two kettles with the same capacity but different wattages. The higher-wattage one boils faster but uses broadly similar energy per boil; the bigger saving usually comes from boiling only the water you need, not from the wattage alone. This is why comparing kWh per task beats comparing watts in isolation.

Step 5: Target the high-consumption appliances

Rank your appliances by annual kWh from Step 2. The top of the list is where changes pay off:

• Heating and cooling — the largest loads; reducing run time, improving insulation, or choosing a more efficient model has the biggest effect.
• Wet appliances (washing machines, dishwashers, tumble dryers) — use full loads, lower-temperature cycles, and air-dry where possible.
• Refrigeration — runs continuously, so siting away from heat sources and keeping seals clean matters more than short-term habits.
• Standby loads — switch off at the plug where practical.

Common sticking points

• Using maximum wattage for everything overstates cost for cycling appliances; use the energy label's annual kWh where available.
• Forgetting the tariff includes standing charges — the per-kWh figure is what you multiply by, not the total bill divided by kWh.
• Assuming a higher wattage always costs more — run time usually matters more than the rating.
• Ignoring how you use the appliance — the same model can differ widely in annual cost depending on loads, cycles, and settings.

Once you have a ranked list in kWh and pounds, you can decide what to replace, what to run less, and what to leave alone.

To save energy at home, start by measuring what your appliances actually cost to run, then target the biggest loads first: heating and cooling, refrigeration, laundry, lighting, and standby power. Sust-it (sust-it.net) provides energy efficiency databases for household electricals and vehicles, plus running-cost and electricity-cost calculators, so you can estimate costs per hour, cycle, or year before you buy or change habits. This guide is for anyone who wants a practical, evidence-based way to cut electricity bills and CO2 without guessing.

Step 1: Find out what is costing you the most

The fastest savings come from the appliances that run longest or heat/cool the most. Use this order of attack:

1. Heating and cooling — electric heaters, immersion heaters, and kettles are high-power devices; even short use adds up.
2. Refrigeration — runs 24/7, so a small efficiency difference compounds over the year.
3. Washing, drying, and dishwashing — cycle costs depend on power rating and cycle length.
4. Lighting — Sust-it notes lighting accounts for 10–20% of a typical home's electricity bill.
5. Standby and small appliances — TVs, entertainment, computers, and chargers draw power even when idle.

Use power ratings and running-cost calculators

A power rating (in watts) tells you the maximum draw; running cost = power (kW) × hours used × your electricity price. Sust-it's electricity cost calculators and appliance databases let you plug in a product and see estimated running costs and energy usage, so you can compare "what it costs per hour/cycle/year" rather than relying on a label alone.

Example task: Before buying a new heater, look up the model's power rating, estimate hours of use per week, and calculate the weekly cost. Compare two models on the same basis — the lower-wattage model only saves money if it actually heats the room adequately.

Step 2: Compare products on the same dimensions

When choosing between products, compare like with like:

Sust-it's databases cover appliances and refrigeration, washing and drying, dishwashers, cookers, small appliances, TVs and entertainment, computers and monitors, projectors, printers, and low-energy lighting. For motoring, it covers electric, petrol, and diesel vehicles with emissions data, fuel consumption, and running costs, plus electric car journey calculators.

Lighting: a low-cost, high-return swap

Switching to low-energy and LED bulbs is one of the simplest savings. Use the LED bulb comparison pages to check power ratings and running costs before buying, and read the low-energy lighting guide to see how much of your bill lighting represents.

Step 3: Apply low-cost habits and home improvements

• Heat only what you need: use thermostats and timers; avoid heating empty rooms.
• Run full loads: washing machines, dryers, and dishwashers are most efficient when full.
• Cut standby: switch off at the plug where practical.
• Use the energy-proof-your-home tool: enter your postcode on Sust-it to get energy efficiency recommendations aimed at reducing bills, boosting home value, and cutting carbon emissions.
• Consider green finance: Sust-it's blog covers green mortgages and property-linked energy efficiency finance — check eligibility and terms before committing.

Step 4: Include motoring if it is part of your goal

If transport is a major cost, use the vehicle running-cost databases and electric car journey calculators to compare emissions, fuel consumption, and running costs between electric, petrol, and diesel options. Treat manufacturer and database figures as estimates; your actual costs depend on driving style, routes, and energy prices.

Common mistakes to avoid

• Relying on labels alone — an A-rated appliance can still cost more if it is larger or used more.
• Ignoring standby and heating — these are often the hidden loads.
• Comparing peak power only — use energy usage per cycle/year where available.
• Assuming a lower-wattage device always saves money — check whether it delivers the same result (e.g., heating performance).
• Skipping the postcode step — home recommendations depend on your location and property.

Where to start today

1. List your five most-used appliances.
2. Look up each in Sust-it's databases and note power rating and estimated running cost.
3. Calculate weekly/monthly cost at your electricity price.
4. Target the top two for replacement or habit change.
5. Enter your postcode for home-specific recommendations.

Sust-it also offers a free quarterly newsletter on energy-efficient electricals; subscribing is optional and separate from using the databases and calculators.

You can cut your home energy bill by working out what each appliance costs to run, then targeting the biggest and easiest-to-change loads first. The basic method: find the appliance's power rating in watts, estimate how many hours a day it runs, and multiply by your electricity price. Sust-it, a UK energy efficiency database for electrical products and vehicles, provides running-cost and energy-use data, CO2 figures, and calculators for appliances and vehicles, so you can compare before you buy or change habits. The steps below work for any household that knows (or can look up) its unit electricity price.

Step 1: Turn watts into a running cost

The formula is the same for every appliance:

Cost per hour = (watts ÷ 1,000) × price per kWh

For example, a 2,000 W fan heater on a tariff of 30p per kWh costs 0.6p per minute — about 60p for an hour of use. A 100 W television on the same tariff costs 3p per hour. The gap between these two numbers is the whole point of the exercise: it tells you where to spend your attention.

To build a quick picture of your home:

1. List your main appliances: heating and cooling, refrigeration, washing and drying, dishwashing, cooking, lighting, TVs and entertainment, computers, and anything left on standby.
2. Note the wattage from the rating plate or manual. If a range is given (many fridges and washing machines show annual kWh instead), use the annual figure where available.
3. Estimate daily hours of use honestly — a fridge runs intermittently but effectively all day; a tumble dryer might run twice a week.
4. Multiply out to a monthly or annual cost and rank the results.

Where the money usually goes

• Heating and cooling are typically the largest loads because of high wattage and long run times. Sust-it's calculators cover electric heaters specifically, which helps when comparing heater types.
• Refrigeration runs continuously, so even a modest wattage adds up over a year.
• Washing, drying, and dishwashing are high-power but intermittent; the number of cycles matters more than the minutes.
• Lighting accounts for roughly 10–20% of a typical home's electricity bill, according to Sust-it's low-energy lighting guide — a useful benchmark for judging whether a lighting swap is worth it.
• Standby loads are small individually but spread across many devices.

Step 2: Compare efficient replacements on the same basis

When an appliance is old or failing, compare candidates using consistent numbers rather than marketing claims:

Sust-it's product databases let you view running costs and energy usage for appliances and technology, and its vehicle section covers emissions, fuel consumption, and running costs if motoring is part of your budget. Use the same electricity price across all comparisons so the ranking is fair.

Step 3: Take the low-cost actions first

Before replacing anything, these changes usually pay back fastest:

• Switch to LED lighting. Sust-it's guide frames low-energy lighting as a direct route to lower bills; check the wattage difference between your current bulbs and LED equivalents and recalculate with the formula above.
• Lower wash temperatures and run full loads. The energy saving comes from fewer and cooler cycles, not from the machine's rated wattage alone.
• Cut standby power. Put entertainment and computer equipment on a switched extension lead and turn it off at the wall when not in use.
• Match heating to the room and the time. Use the heater comparison pages to check whether a lower-wattage heater run for the time you actually need beats a high-wattage one left on.

Step 4: Plan bigger upgrades with local data

For home-wide improvements, Sust-it's "Energy Proof Your Home" tool asks for your postcode and returns energy efficiency recommendations aimed at reducing bills, cutting carbon emissions, and boosting your home's value. Enter the postcode first, then review the recommendations against your own running-cost calculations — the tool gives direction, while your tariff and usage estimates tell you the likely saving.

Sust-it also publishes a free quarterly newsletter on energy efficient electricals if you want to track new products and offers; subscribing is optional and separate from using the databases.

Common sticking points

• Using the wrong hours. A 2,000 W appliance run for 10 minutes a day costs far less than a 200 W appliance run for 12 hours. Estimate time before judging wattage.
• Forgetting the tariff. The same appliance costs twice as much on a tariff twice as high. Recalculate when your price changes.
• Comparing labels instead of kWh. Two appliances with the same label class can differ in annual consumption; use the kWh figure.
• Treating one calculator result as a quote. Running-cost estimates are only as good as the inputs; use them to rank options, then verify against your actual bills.

Start with the three appliances you suspect cost the most, calculate their annual running cost, and change one habit or one product this month. That single pass usually reveals where the rest of your savings are hiding.