Do Dimmed Lights Use Less Electricity?

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Whether you already have a dimmer switch installed in your home, or you’re considering adding one, you might be wondering whether dimmed lights save you any money on your electricity bill.

After all, it might make the difference between whether you do decide to add that dimmer, or if you try to actively use it more and set the lights to be a little dimmer than you normally would if you end up making worthwhile savings.

dimmed house light

So, let’s take a look at just how dimmers work and if they’ll save you any money.

Does dimming lights use less electricity?

Dimming the lights does mean that the bulbs will consume less electricity. A dimmer works by switching the current on and off a huge number of times every second, so the lightbulb is essentially spending fractions of a second ‘off’, though you can’t tell.

So by design, the lightbulb will use less electricity because it isn’t always ‘on’. The power of the circuit isn’t affected – the voltage and the amps remain the same – but the current is instead just alternated between ‘on’ and ‘off’ extremely quickly.

It’s worth noting as well that this is only the case with modern electronic dimmers, which work much more efficiently.

Older dimmers used a resistor, rather than switching the current on and off, and so you didn’t save electricity – instead, the excess current was converted into heat energy.

Suggested read: Do Lamps Really Use Electricity When Turned Off?

dimmed light bulb on ceiling

Do dimmers lower wattage?

Dimmer switches do lower the number of watts being consumed. They don’t lower the demand of the bulb but instead make it so that the bulb is spending a percentage of time switched off, so the bulb isn’t drawing the necessary watts it needs all of the time.

As a quick example, say you’re using an LED bulb that uses 6 watts. That means that if it was switched on for a full hour, it would use 6 watt-hours in that hour. But if you dim the light by 20%, it will only be switched ‘on’ for the equivalent of 48 minutes.

You just can’t tell the difference because the current is being switched on and off so quickly, so the bulb looks like it is on for the full hour. But you’re only using 80% of the power and so you’d only use 4.8 watt-hours in the same hour.

dimmed ceiling light

How much energy do dimmer switches save?

A dimmer switch will save roughly the same amount of energy as the lights are dimmed. So if you dim the lights by 10%, you’ll save around 10% of the power. As you dim the lights more, the power savings get less – dimming by 50% will save around 40% of the power.

These aren’t exact figures because it’ll vary by the dimmer and the bulb in question, but as a guideline, you will save a roughly equivalent amount of energy as you dim the bulb.

But how much energy is that over a longer period of time? Let’s compare halogen bulbs and LED bulbs.

Halogen bulbs

BrightnessKilowatt-hours used daily (1.6 hours per day average)Daily cost ($0.14 per kWh)Kilowatt-hours used monthlyMonthly costKilowatt-hours used yearlyYearly cost

LED bulbs

BrightnessKilowatt-hours used daily (1.6 hours per day average)Daily cost ($0.14 per kWh)Kilowatt-hours used monthlyMonthly costKilowatt-hours used yearlyYearly cost

These are the stats for one bulb, and you will likely be dimming more than one bulb at once. But as a guide, using a dimmer on a halogen bulb saves you at most around $2 a year, while using one with an LED bulb saves you around $0.20.

If you’re using a dimmer switch with 20 halogen bulbs then you’ll save a decent amount of electricity, but otherwise, the savings are pretty minimal.

dimmer switch
Dimmer Switch

Are dimmable lights more expensive?

Old incandescent bulbs and halogen bulbs are ready to be dimmed as they are – you don’t need special versions. Dimmable CFLs and dimmable LEDs do cost more – and you’ll need special dimmers for each.

The cost difference isn’t huge between the two bulb types – you can normally get a pack of bulbs that are dimmable for just a few dollars more than the equivalent pack of non-dimmable bulbs.

Linkind A19 Non-Dimmable LED Light Bulbs

  • Last 10 times longer than incandescent and halogen bulbs
  • UL Listed and FCC certification to guarantee world-class quality
  • Energy-efficient light bulbs emit 800 lumens of 2700K soft white light

Linkind A19 Dimmable LED Light Bulbs

  • Compatible with most LED dimmers to have smooth dimming ranging from 10% to 100%.
  • Vivid color and close-to-sunlight quality light
  • Turns on instantly, no warm-up time
  • UL Listed and FCC certification to guarantee world-class quality

Those are the same brand, the same brightness, and same color temperature. The only difference is that one set is dimmable.

Can you leave a dimmer switch on all night?

It is usually fine to leave a dimmer switch on overnight provided you’ve bought a good quality one. Cheap dimmers are known to get hot when left running, which could become a fire hazard if left unchecked.

The other hazard would be if you leave older incandescent or halogen bulbs on dimmed settings for a long time. These bulbs produce a lot of heat, but switching on and off again will also wear them out faster and they could pop. This is only really a concern for older bulbs though.

LED lights don’t have the same issue and can be switched on and off as many times as you want without shortening their lifespan at all. As long as you’ve bought good quality bulbs and a reliable dimmer, you can leave your lights dimmed all night – ideal as a nightlight for the kids’ room.

LED bulb

Are dimmers worth it?

If you’re asking, does dimming save electricity? The answer is yes but not enough to justify installing a dimmer to lower bills. The difference is minimal. Dimmers won’t ever increase your bills though, and they are popular for creating a pleasant ambiance at home.

So don’t buy a dimmer in the hopes that it’ll save you a lot of money each year, but that doesn’t mean you shouldn’t consider one if you want to enjoy dimmed lights in the evening. Beyond the costs of the dimmer and of making sure your bulbs are compatible, there aren’t really any downsides to dimmers.

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