Swap your last few bulbs to LED — and forget about them for years
Most homes have a stray halogen or old bulb still burning money in a hallway or lamp. Replacing it with an LED cuts that bulb's power by roughly 80% and pays for itself in months.
LED lighting is the rare green swap with almost no catch: it costs a little upfront, then quietly saves money and energy for a decade or more while you forget it’s even there. The reason the saving is so large is that old incandescent and halogen bulbs are really tiny heaters that happen to glow — around 90% of the energy they draw leaves as heat, not light. An LED flips that ratio, which is why a 9-watt LED can match a 60-watt old bulb and run cool.
If you replaced most of your bulbs years ago, this hack is about hunting down the stragglers — the halogen spots over the kitchen counter, the dim bulb in the stairwell, the lamp you rarely think about. Those few are often the ones left precisely because they’re out of sight, and a cluster of halogen spotlights can quietly draw as much as a small appliance.
One honest nuance: there’s no point binning bulbs that still work just to feel virtuous, since the energy and materials to make them are already spent. The smart move is to replace each one with LED the moment it fails — and to bring forward the swap only for the real energy hogs, the old halogen spots, where the running-cost saving pays for the new bulb within a year.
How to do it
- Walk through every room (and the cellar, hallway, garage and outdoor lights) and note any bulbs that are warm to the touch, slow to brighten, or that you know are old halogens, incandescents or early CFLs.
- Check each fitting type before you buy — E27 (big screw), E14 (small screw), GU10 or GU5.3 spotlights — and snap a photo of any you're unsure of.
- Buy LED replacements, matching the brightness in lumens (not watts) — roughly 800 lm replaces an old 60 W bulb, 1500 lm a 100 W.
- Pick the colour temperature to suit the room: 2700 K (warm white) for living areas and bedrooms, 4000 K (neutral) for the kitchen or workspace.
- Swap them over with the power off, let any fitting cool first, and take the dead halogens and CFLs to a recycling point — never the household bin.
Pro tips & pitfalls
- Working bulbs aren't worth binning early on principle — but the moment one dies, replace it with LED rather than your last spare old one. Old halogen spotlights are the exception: they burn so much power that swapping them now usually pays back within a year.
- For dimmer switches, buy bulbs marked 'dimmable' — a standard LED on a dimmer can flicker or buzz.
What it's good for
Good for the planet
- Saves energy An LED draws roughly 80–90% less power than the halogen or incandescent bulb it replaces — a 9 W LED does the work of a 60 W old bulb.
- Cuts CO₂ Less electricity drawn means fewer kilos of CO₂ from the grid over each bulb's long life, with no behaviour change once it's in.
- Cuts waste One LED outlives a dozen or more cheap incandescent bulbs, so far fewer dead bulbs end up in the bin over the years.
Good for you
- Saves money Each swapped old bulb on a few hours a day typically saves €5–15 a year in electricity, and the LED itself lasts 15,000–25,000 hours — often 15+ years.
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