You’ve no doubt heard that switching your standard light bulbs to LED bulbs can save you money, with many LED manufacturers making some very bold claims (including us!).
These savings claims are of course based on averages and assumptions; but can you calculate how much you will really save by switching to LED lighting? This article provides the answer.
How LED light bulbs save you money
The cost saving provided by LED lighting is due to two factors:
- LEDs require much less electricity to power than both traditional incandescent and halogen light bulbs, and energy efficient light bulbs (CFLs).
- They last much longer than their incandescent, halogen and CFL equivalents.
For example, a 60W halogen light bulb would be replaced with a 9W LED. That’s a reduction of 85% in electricity consumption. The LED bulb will also last for over 20,000 hours, as opposed to 2,000 hours for the halogen – ten times longer!
What about CFL bulbs? Using the same example, a 60W halogen equivalent would be an 11W CFL bulb, so the reduction in electricity consumption from CFL to LED would be 18%. A good quality CFL should last for around 8,000 hours, which is still less than half of the LED equivalent.
Calculate the cost savings of LED light bulbs
Now that we know why LED light bulbs are cheaper to run, we can now look at how you can calculate the amount of money you can expect to save by switching to LEDs.
The information you need to work this out is:
1. The wattage of your current light bulbs and spotlights.
2. The average length of time each light bulb is in use for per day.
3. Your current electricity rate per kilowatt hour (kWh, kW-h or kW h). The UK average at the time of writing is 14.71 pence p/kWh if paying by direct debit.
4. The cost of replacing each bulb with an LED equivalent.
To help you organise all of the information we’ve created a spreadsheet that can be downloaded here (when it opens, click “File” then “Make a copy” or “Download as”). Simply go through your house room by room and put your numbers into the coloured cells.
By using the spreadsheet the calculations are done for you, but for information they are:
Current Cost per Month = (Current wattage / 1,000) x usage in hours p/day x cost p/kWh x 30 days
New Cost per Month = (New wattage / 1,000) x usage in hours p/day x cost p/kWh x 30 days
Monthly Saving = Current cost per month – new cost per month
Payback Period (Months) = Total cost of replacement bulbs / monthly saving
Real-life example of cost saving with LEDs
To illustrate, below is a screenshot of the spreadsheet I completed for my home. As you can see, despite having some energy efficient light bulbs already, and opting for some of the more expensive LEDs, the monthly cost saving is a substantial 87%, and the bulbs will have paid for themselves in a little over nine months.