Many dimmer switches work by chopping the AC waveform, which can add high-frequency noise, sometimes called dirty electricity, to your wiring. Whether that noise has any effect on health has not been shown [1][2].
A dimmer controls brightness by letting through only part of each cycle of the alternating current. The abrupt start of each partial cycle is a sharp electrical edge, and sharp edges are what spread noise along the wiring to the rest of the house.
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Why a dimmer behaves differently from a plain switch
A standard switch is either closed or open. When it is closed, the full smooth wave passes and nothing is cut out of it. A dimmer sits in the middle and trims the wave, and the lower you set it, the more it trims.
A dimmer chops the waveform, which puts noise on the wiring
Dimmers are a common noise source.
Health effects of dirty electricity are not established; this shows the mechanism only.
Data table
| Step | Stage | What happens |
|---|---|---|
| 1 | Source | Dimmers, inverters, chargers and switching power supplies chop the waveform |
| 2 | On the wiring | High-frequency noise rides on the 60 Hz supply |
| 3 | Spread | It travels along circuits to other outlets in the home |
| 4 | Measure | Read it at the outlet with a line-noise meter, not a field meter |
| 5 | Reduce | Remove or replace the source first; filters treat what is left |
Chart: frequencyblockers.com: A dimmer chops the waveform, which puts noise on the wiring
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Worth knowing: a systematic review of dirty electricity found that the 50 Graham/Stetzer unit safety threshold used by filter sellers is arbitrary, and that the quantitative evidence for harm rests on self-reports in non-blinded interventions, ecological associations and one cross-sectional cohort study that does not point to dirty electricity as the cause [1].
So the reason for this swap is narrow: removing a known source of line noise. It is not a fix for a particular complaint, and the research above is a reason to approach it with calm expectations.
Swapping a dimmer for a standard switch
- Turn off the breaker for that circuit, then confirm the power is dead with a voltage tester before you touch anything.
- Photograph the wires on the old dimmer before disconnecting them, and note whether it is a single switch or one of a pair that controls the same light from two places.
- Buy a standard switch of the same type, and wire it the way the photo shows.
- If you are not comfortable working inside a wall box, or you rent, ask an electrician or your landlord to do it.
- For softer light in the evening, use a lamp or two on their own switches with lower-wattage bulbs, and leave the ceiling fixture on a plain switch.
One more check applies to the bulbs. Bulbs labeled for dimming are meant to be used with a dimmer, so once the dimmer is gone you can use ordinary bulbs of the type that suits you.
Seeing what changed
If you want to see what changes, measure outlets near dimmers with a Stetzer meter before and after removal, and treat any change as a reading of line noise, not of health risk [1].
A line-noise meter, the kind used for dirty electricity, is the right instrument. A magnetic field meter or an RF meter will not respond to a dimmer, so a flat reading on those proves nothing either way.
Take a reading at an outlet on the same circuit with the dimmer set to a low level, then at a middle level, then at full. Record the numbers. After the swap, read the same outlet again with the same lights on. The comparison is the point, not any absolute figure.
Incandescent Light Bulbs (Pack of 6)
Once a dimmer is replaced with a plain switch, a standard incandescent bulb in that fixture gives full light without any dimming electronics.
When this swap is not worth it
Not every dimmer produces the same amount of noise, and newer designs differ from older ones, so the only way to know what yours does is to measure it. If a dimmer reads quiet on your meter, leave it alone.
Other sources of line noise stay in the house after the swap, including chargers, inverters and the power supplies inside electronics. Treat the dimmer as one source among several and take the biggest one first.
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Frequently Asked Questions
Why should I replace dimmer switches with standard switches in my home?
Many dimmer switches add high-frequency noise (‘dirty electricity’) to your wiring by chopping the current. Replacing them removes that source of noise, but a systematic review concluded that the evidence for dirty electricity as a cause of human health effects does not stand up to scientific scrutiny [1].
Will replacing my dimmer switches actually reduce my EMF exposure?
It removes one source of high-frequency noise on your wiring. Whether that lowers any health risk is not established: studies that reported improvements in glucose, multiple sclerosis symptoms, asthma and insomnia after filtering this noise were judged too flawed to show cause [2][1].
Is it difficult or expensive to swap out dimmer switches for regular ones?
No, this is one of the easiest EMF reduction steps you can take. Standard switches are inexpensive and the installation process is straightforward, making it an accessible solution for most homeowners looking to reduce their electromagnetic field exposure.
How many dimmer switches should I replace in my home?
If you decide to replace dimmers, start with the rooms where you and your family spend the most time [1]. Conducting a walk-through of your rooms to identify all dimmers will help you prioritize which ones to replace first, starting with the areas where you and your family spend the most time.
References
- de Vocht F et al. Systematic Review of the Exposure Assessment and Epidemiology of High-Frequency Voltage Transients. Frontiers in public health (2016). PMID 27066469
- de Vocht F "Dirty electricity": what, where, and should we care?. Journal of exposure science & environmental epidemiology (2010). PMID 20336048
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
