Light Bulb and Fitting Register

Who this is for

Every light fitting in the house and the bulb it takes. The first page records the cap, shape, brightness and colour of each fitting's bulbs so the right replacement is bought first time, and the second works out what switching each one to LED saves a year at your own hours and price.

Anyone who has stood in a shop trying to remember which bulb the hall light takes, and households replacing older bulbs with LEDs who want to know what the change is worth.

What this helps you track

• Each fitting by room, with its cap type and bulb shape
• How many bulbs it takes, their brightness and colour temperature
• Whether a dimmable bulb is needed and whether a spare is held
• Old and new wattage for each fitting switched to LED
• The kWh and money saved a year at your own hours and price

How to use it

1. Write the home, your price per kWh from your bill and the date at the top.
2. Go room by room and fill a row for each fitting, copying the cap, lumens and colour temperature from the old bulb or its box.
3. Tick Dimmer for fittings on a dimmer switch and Spare when you have one in the cupboard.
4. On the second page, enter the old and new wattage and the hours a day each fitting is on.
5. The kWh and money saved are worked out in the browser and the workbook; on paper, multiply across each row and total.

Formats

• Printable PDF (A4 and US Letter)
• Fillable PDF with form fields
• Fill in online, saved in your browser
• Excel / Google Sheets workbook

The printable is laid out inside a box that fits both A4 and US Letter, so the two files are identical and neither one is scaled. The fillable PDF has real form fields. The workbook uses plain formulas only — SUM, IF, COUNTIF and the like — so it opens in Excel, LibreOffice and Google Sheets without anything breaking, and every calculated cell is grey so you can see which figures it worked out.

How to print

Download the A4 or US Letter file to match the paper in your printer, open it in a PDF reader and print at 100% — not "fit to page", which shrinks the writing space. Both files leave a 14 mm margin, which clears the unprintable edge on home printers. To print the online version with your entries in it, use the Print this sheet button, which prints only the sheet and none of the page around it. More on printing.

Questions

What is the cap and where do I find it?

The cap is the base that fits the lamp holder: screw, bayonet or pin types in several sizes. The code is usually printed on the bulb, the box or near the holder. Copy it exactly, because similar caps are not interchangeable.

Why record lumens rather than watts?

Lumens describe brightness, which is what you want to match when choosing a replacement. Watts describe the power drawn, which is what the saving is worked out from, so the sheet keeps both.

How is the yearly saving worked out?

Old watts less LED watts, times the number of bulbs and the hours a day, gives watt hours a day; times 365 and divided by 1000 gives kWh a year, which is priced at your own rate.

Does the sheet say which bulbs to buy?

No. It records what your fittings take and what you choose. Brightness and colour are your preference, and the sheet suggests no products, wattages or colour temperatures.