Dirty Electricity: A Practical Guide

You plug a meter into the outlet beside your bed and it reads 800 GS units. You have no idea what that number means, but you've read it should be under 50. The number alone feels like a verdict, even though you don't yet know what it's measuring or whether it matters.

Maybe you've just installed solar panels and someone mentioned they could make your home's electrical noise worse. Or you've gone through the process of reducing RF, magnetic fields, and electric fields in your bedroom, and now you're wondering whether the wiring itself is radiating something you haven't addressed.

Dirty electricity is the least understood of the four EMF types assessed in building biology. High-frequency noise on your wiring is measurable and well-documented. Whether that noise matters for health, and whether plug-in filters might introduce problems of their own, is not settled. This guide covers what dirty electricity is, how to measure it, what the filters do, and where the evidence stands.

What Is Dirty Electricity?

Your home's wiring is designed to carry electricity at a single frequency: 60 Hz in North America, 50 Hz in most of Europe and Asia. That clean sine wave is what your utility delivers to the meter. By the time that current reaches your outlets, it has often picked up additional frequencies, voltage transients and harmonics in the range of roughly 2 kHz to 10 MHz, with the most commonly measured range being 10 kHz to 150 kHz. These high-frequency distortions ride on the 60 Hz waveform like static on a radio signal.

Electrical engineers call it conducted emissions, line noise, or electromagnetic interference (EMI). In building biology and environmental health circles, dirty electricity, microsurge electrical pollution (MEP), and electrical noise are more common. Same thing: frequencies on your wiring that shouldn't be there.

Your home's wiring was never designed to carry these frequencies. At 60 Hz, the wiring functions as a delivery system, current flows through the conductors to your appliances and back. At higher frequencies, the wiring begins to act as an antenna, radiating electromagnetic energy into the rooms around it. The higher the frequency and the stronger the amplitude, the more energy radiates. Every wire in your walls becomes an unintentional broadcaster.

What Creates Dirty Electricity?

Any device that chops, switches, or converts the 60 Hz power waveform introduces high-frequency noise back onto the wiring. The more of these devices in your home, the noisier your wiring gets.

LED and CFL Bulbs

Both LED and compact fluorescent (CFL) bulbs contain electronic driver circuits that convert 60 Hz AC to the DC or high-frequency AC the bulb needs. These switching circuits generate harmonics and transients that feed back onto the house wiring. A single bulb may not produce much noise. A home with 30 LED bulbs on multiple circuits can produce measurable elevation throughout the wiring. Not all LED bulbs are equal, some generate significantly more noise than others depending on the quality of their driver circuits. You cannot tell from the packaging.

Dimmer Switches

Standard dimmer switches work by chopping the AC waveform, they turn the current on and off many times per cycle, delivering only a portion of each wave to the bulb. This chopping creates sharp transients that propagate across the circuit. Dimmers are one of the most consistent sources of dirty electricity in residential settings, and the noise increases as you dim further from full brightness.

Solar (PV) Inverters

Solar panel systems generate DC power, which must be converted to AC before it can feed into your home's wiring or the grid. The inverter that performs this conversion is a significant source of high-frequency noise. String inverters, where a single inverter handles the output of many panels, tend to produce more dirty electricity than microinverter systems, where each panel has its own small inverter. If you have solar panels and elevated readings throughout the house, the inverter is the first place to look. Dirty electricity from solar systems can often be measured at the main panel and may affect the entire home.

Variable-Speed Motors

Modern HVAC systems, pool pumps, and appliances increasingly use variable-speed motors controlled by variable frequency drives (VFDs). These drives convert 60 Hz power to a different frequency to control motor speed, and the conversion process generates noise that feeds back onto the wiring. An older single-speed furnace blower produces negligible dirty electricity. A newer variable-speed blower may produce substantial amounts, especially during ramp-up and ramp-down cycles.

Switching Power Supplies and Chargers

Virtually every modern electronic device, laptops, phones, tablets, TVs, gaming consoles, uses a switching-mode power supply (SMPS) that converts AC to DC at high frequency. Each one contributes some noise to the wiring. Individually, these are minor sources. Collectively, in a home with dozens of SMPS devices plugged in, they add up.

Other Sources

Fluorescent tube lighting with electronic ballasts, treadmills and exercise equipment, battery chargers for power tools, and some models of refrigerators and washing machines with electronic controls also contribute. The common thread is any device that modifies or converts the power waveform electronically rather than using a simple resistive or inductive load.

How to Measure Dirty Electricity

Two plug-in meters dominate the market, and both are accessible to homeowners. For a comparison of these and other EMF measurement tools, see the EMF meters buying guide.

Stetzerizer Microsurge Meter

The Stetzerizer meter (~$100–150) plugs directly into any standard outlet and reads the level of high-frequency noise on that circuit in proprietary "GS units" (Graham-Stetzer units). It measures voltage transients in the 10 kHz to 150 kHz range, roughly corresponding to the frequencies where wiring radiates most effectively. The meter gives a simple numeric readout, higher numbers mean more noise. No setup, no interpretation of waveforms, no calibration. You plug it in, read the number, and move to the next outlet.

Greenwave Broadband EMI Meter

The Greenwave meter (~$130) performs the same basic function but reads in millivolts (mV) rather than GS units. It measures broadband EMI in a similar frequency range. Like the Stetzerizer, it plugs into an outlet and gives a direct numeric reading. The two meters use different measurement scales, so their numbers are not directly comparable, a reading of 200 on the Stetzerizer does not correspond to 200 mV on the Greenwave. Each meter has its own target values.

How to Use Them

1. Start in the bedroom. Plug the meter into every outlet in and near the sleeping area. Record each reading.
2. Move room by room. Test outlets throughout the house, paying particular attention to rooms where people spend extended time, home offices, living rooms, children's rooms.
3. Note which circuits are worst. Outlets on circuits that serve kitchens (with LED undercabinet lighting and multiple SMPS devices) and home offices (with computers and peripherals) often read highest.
4. Check with devices on and off. If you want to identify which device is driving the noise, unplug devices on the circuit one at a time and watch the meter. When the reading drops, you've found a contributor.

Target Values

The commonly cited targets come from the manufacturers of the meters and from building biology field practice, not from a formal regulatory standard:

• Stetzerizer meter: Below 25 GS units is considered low. Below 50 GS is acceptable for most areas. Above 50 GS indicates notable noise. Sleeping areas: aim for under 25 GS, ideally under 20. Living areas: under 40–50 GS.
• Greenwave meter: Below 25 mV is the manufacturer's target. Readings above 100 mV are considered elevated.

These are guideline values promoted by the meter manufacturers and adopted by building biology practitioners. They are not established with the same level of epidemiological research as, say, the magnetic field thresholds in the SBM-2008 standard. The SBM-2008 does include dirty electricity in its assessment framework, but it is the least extensively documented of the four EMF categories.

The Controversy: Does Dirty Electricity Actually Affect Health?

Most websites selling filters or meters skip past this. Whether dirty electricity is a meaningful, independent health concern is not settled, and the answer matters before you spend money on it.

The Case For Concern

The most-cited research comes from Dr. Samuel Milham and Dr. Lloyd Morgan, who published studies associating dirty electricity with cancer clusters in schools and with increased cancer risk among teachers working in environments with elevated microsurge levels. Milham's work includes an epidemiological analysis linking the historical rollout of residential electrification with increases in diseases of civilization, heart disease, cancer, diabetes, and suicide. His argument: dirty electricity (not just the 60 Hz power itself) is the biologically active component.

Some individuals who report electromagnetic hypersensitivity (EHS) describe symptom changes, headaches, sleep disruption, cognitive fog, when dirty electricity levels change in their environment. Building biologists working in the field report cases where reducing dirty electricity correlated with symptom improvement, though these are clinical observations, not controlled studies.

The plausibility argument: dirty electricity causes wiring to radiate at frequencies in the kilohertz to megahertz range. Some of these frequencies overlap with biological signaling frequencies, and chronic exposure could disrupt cellular processes. This is the same general argument applied to other EMF types, extended to a different frequency range.

The Case For Caution About the Claims

The evidence for dirty electricity as a distinct health hazard is thinner than for the other three EMF types.

• Limited controlled studies. Double-blind studies specifically isolating dirty electricity from other EMF exposures are scarce. Most of the published work involves observational studies or case reports. The Milham/Morgan school cancer cluster studies have been cited widely but have also been criticized for methodological limitations, including small sample sizes and difficulty controlling for confounding variables.
• Difficult to isolate. In practice, dirty electricity correlates with other EMF sources. A home with high dirty electricity levels typically also has more electronic devices, more switching power supplies, and more wiring carrying more current, which means more magnetic fields, more electric fields, and more RF emissions from those same devices. Separating the high-frequency noise on the wiring from everything else those devices produce is extremely difficult.
• Building biology's own positioning. Even within building biology, dirty electricity is treated as the least-established category. The SBM-2008 standard includes it, but practitioners generally acknowledge that the health research supporting the dirty electricity thresholds is less robust than the research behind the magnetic field or RF thresholds.
• Some researchers are skeptical. Not all EMF researchers agree that dirty electricity represents a biologically meaningful exposure separate from the other EMF types. The argument: if you've already addressed magnetic fields, electric fields, and RF in the sleeping area, the additional benefit of filtering dirty electricity is unproven.

A Reasonable Position

Dirty electricity is measurably real, a form of electromagnetic pollution you can quantify with commercially available meters. Whether it causes health effects independent of other EMF types is an open question. The precautionary approach suggests reducing it where practical and affordable, while being honest about how thin the evidence is. It should probably not be the first thing you address. Magnetic fields, electric fields, and RF radiation all have stronger research foundations and are typically higher-impact exposures in bedrooms.

Filters: How They Work

Plug-in filters are the most common fix. Two brands dominate the market:

• Stetzerizer filters (~$35 each): Plug into standard outlets. Designed by Dave Stetzer and based on the work of Dr. Martin Graham.
• Greenwave filters (~$30 each): Similar function, different manufacturer. Available in several form factors including models with a pass-through outlet so you don't lose the socket.

Both types work on the same principle: they contain capacitors that provide a low-impedance path for high-frequency noise, shunting it from the hot wire to the neutral wire before it can radiate from the house wiring. In electrical engineering terms, they act as low-pass filters, they allow the 60 Hz power frequency to pass through while diverting higher-frequency components. The filter doesn't eliminate the noise entirely; it reduces it by providing a shorter path for the high-frequency energy to dissipate.

How Many Do You Need?

Most homes require 10 to 20 filters to bring readings below target levels throughout the house. The number depends on how many noise sources are present, how the circuits are configured, and how high the readings are to begin with. The general approach is to plug a filter into the same outlet as the meter, read the resulting level, and add filters to the circuit until the reading drops below the target. Some outlets need one filter; some circuits need three or four distributed across multiple outlets on the same circuit.

At $30–35 per filter, outfitting a house with 15 filters costs $450–525. Not trivial, another reason to measure first and verify that you actually have elevated levels before buying filters for every outlet.

The Filter Concern: Magnetic Field Increase

The magnitude varies. In most installations, the additional current draw is small and the magnetic field increase is modest, detectable with a sensitive gaussmeter but not dramatic. When multiple filters are clustered on a single circuit near the bed, the effect can be more significant. The risk increases when wiring has existing issues (such as separated hot and neutral conductors) that prevent magnetic field cancellation.

What to Do About It

1. Measure magnetic fields before installing filters. Take a baseline reading at the bed with a gaussmeter or a 3-axis meter like the TriField TF2.
2. Install the filters.
3. Measure magnetic fields again at the same locations. If readings have increased notably, particularly if they've moved from the SBM "No Concern" range into "Slight Concern" or higher, reconsider the filter placement.
4. Prioritize filters away from the bed. Putting filters in the kitchen, living room, and hallway outlets may reduce dirty electricity on shared circuits without placing the additional current draw next to where you sleep.
5. Use only as many filters as needed. More is not necessarily better. Use the meter to verify the reading after each filter, stop adding them once you reach the target level.

None of this means avoid filters. It means approach them systematically, measure before, measure after, and make sure you're not solving one problem while creating another.

Solar PV Systems and Dirty Electricity

If you have rooftop solar panels, your inverter deserves specific attention. Solar inverters are one of the most significant sources of dirty electricity in residential settings, readings two to five times higher during daytime production than at night are common.

Inverter Types Matter

• String inverters are centrally located units (usually near the main panel or on an exterior wall) that convert DC from an entire string of panels to AC. They tend to produce more dirty electricity because they handle larger power flows through a single conversion point. The noise from a string inverter can propagate throughout the home's wiring.
• Microinverters are small units mounted under each individual panel. They convert DC to AC at the panel level. Because each unit handles a smaller amount of power, the high-frequency noise per unit is lower, and the noise tends to be better contained. Microinverter systems generally produce less dirty electricity at the home's outlets, though they are not noise-free.
• Power optimizers (like SolarEdge systems) use a centralized inverter but with DC-to-DC converters at each panel. Their dirty electricity profile falls somewhere between string inverters and microinverters.

What to Do

If you have solar panels and elevated dirty electricity readings, start by measuring at multiple outlets during peak solar production (midday sun) and again after sunset. The difference tells you how much the inverter is contributing. Filters can reduce inverter-generated noise, but you may need more of them, and the magnetic field concern applies here too, since the filters will be working harder to compensate for a larger noise source.

If you're planning a new solar installation, microinverters or power optimizers are the better choice from a dirty electricity perspective, all else being equal. If your system is already installed with a string inverter, line filters rated for higher current (installed at the panel by an electrician, not the plug-in type) may be more effective than trying to address the noise at individual outlets throughout the house.

A Practical Approach

Here is a measured approach, one that takes dirty electricity seriously without treating it as the most urgent EMF issue in your home.

1. Address the other three EMF types first. Magnetic fields, electric fields, and RF radiation all have stronger evidence bases and are typically higher-priority exposures in sleeping areas. The home EMF assessment guide covers the full protocol.
2. Measure dirty electricity. Buy or borrow a Stetzerizer or Greenwave meter. Test every outlet in the bedroom and the rooms adjacent to it. If readings are below 25 GS (Stetzerizer) or 25 mV (Greenwave), you likely don't need to do anything further.
3. Identify the sources. If readings are elevated, unplug devices one at a time to find what's driving the noise. Dimmer switches, LED bulbs on the bedroom circuit, and electronics with SMPS adapters are common culprits. Sometimes the fix is as simple as replacing a dimmer with a standard switch or moving a device to a different circuit.
4. Remove sources before filtering. If you can eliminate the source of the noise, by replacing a dimmer, switching to incandescent bulbs on the bedroom circuit, or unplugging a noisy charger, that's preferable to adding a filter. No additional current draw, no magnetic field increase, no ongoing cost.
5. Filter where necessary. If sources can't be eliminated (the solar inverter, the variable-speed HVAC, LED lighting you're not willing to replace), install filters at the outlets with the highest readings. Start with two or three and measure the result. Add more only if needed.
6. Check magnetic fields after filtering. Use a gaussmeter at bed level before and after filter installation. If magnetic fields have increased at the bed, move filters to outlets farther from the sleeping area or reduce the number of filters.
7. Re-measure periodically. Dirty electricity levels change as you add or remove devices, as seasons change (solar production varies), and as the utility's grid conditions shift. A quarterly check with the meter takes five minutes and confirms whether your setup is still working.

What the SBM-2008 Standard Says

The SBM-2008 standard includes dirty electricity (referred to as "high-frequency voltage transients") as one of the assessed parameters in sleeping area evaluations. It falls under electric field measurements and is evaluated alongside the other three EMF types. The standard includes it in the overall assessment framework, if it can be measured, it should be measured and reduced where possible.

The research backing for the dirty electricity thresholds is less developed than for the other categories. Practitioners treat the targets as reasonable precautionary guidelines rather than levels derived from strong dose-response data.

Common Questions

Do I Need to Filter Every Outlet?

No. Measure first. Many outlets will already be at acceptable levels. Focus filters on the outlets that read highest, usually those on circuits serving kitchens, home offices, and entertainment systems. The bedroom circuit is the priority if readings there are elevated.

Can Dirty Electricity Come from My Neighbors?

Yes. High-frequency noise can propagate along utility wiring from neighboring homes, particularly in dense housing where multiple units share a transformer. Plug-in filters are less effective here because the noise enters at the service panel rather than from a specific device inside your home. Panel-level filters (installed by an electrician at the breaker box) work better for noise entering from outside.

Are Some LED Bulbs Better Than Others?

Yes, but there is no reliable way to know from the packaging. The quality of the LED driver circuit determines how much noise the bulb produces. Some high-quality LED bulbs produce very little dirty electricity; some cheap ones produce a lot. The only way to know is to measure with a meter while the bulb is operating. If you find a brand and model that tests clean, buy several of the same one.

What About Whole-House Filters?

Whole-house EMI filters install at the main breaker panel and filter noise across all circuits. They can be effective, particularly for noise entering from the utility side or from a solar inverter. They are more expensive than plug-in filters ($200–600 for the unit, plus electrician installation) but address the problem at the source rather than at individual outlets. For homes with solar PV systems or significant external noise, a panel-level filter is often more practical than 20 plug-in units.

Next Steps

Dirty electricity is worth measuring as part of a home EMF assessment, but it's the last of the four types to worry about. The home EMF assessment guide walks through all four in the order that typically produces the most benefit. If you're just starting out, begin there. If you're choosing meters, the EMF meters buying guide covers dirty electricity meters alongside options for the other three types. For bedroom-specific guidance that brings all four EMF categories together, see the EMF bedroom guide.

If you want professional help, a certified building biologist can assess all four EMF types in a single visit, including dirty electricity, and can advise on whether filters make sense for your situation. For background on what building biology is and how it approaches these questions, see the building biology FAQ.

Dirty electricity is measurable and reducible, but it's the EMF type we know the least about. Don't spend hundreds of dollars on filters before you've checked your magnetic field levels or turned off your WiFi router at night. Address what matters most first. Come back to dirty electricity when the bigger issues are handled, and when you do, measure before and after every change you make.