HE detergent: why high-efficiency washers need it

If you have bought a washing machine in Canada in the last fifteen years, you almost certainly own a high-efficiency model, and its manual almost certainly told you to use “HE” detergent. Most people nod and buy whatever has the little circle on the label. Here is what that symbol is actually doing, why it matters for how clean and how well-rinsed your clothes are, and what it does and does not mean for your skin.

What makes a washer “high-efficiency”

The old top-loading washer filled its tub with water and swished clothes around an agitator, the central post that rubs the load back and forth. A high-efficiency washer does something different. Natural Resources Canada describes front-loaders as tumbling clothes through a small amount of water, and the newer high-efficiency top-loaders as flipping or spinning clothes through a stream of water rather than filling the whole tub.

The savings are large. According to ENERGY STAR, a full-sized certified washer uses about 53 litres of water per load compared with about 76 litres for a standard machine, and front-loaders use roughly half the energy and water of a top-load agitator washer. Natural Resources Canada puts the average for certified models at 25 percent less energy and 33 percent less water than a standard model.

Canada has changed accordingly. Natural Resources Canada’s shipment data show front-loaders went from 16 percent of washers shipped in 2001 to 60 percent in 2010, and the average water used per litre of tub capacity fell by 43 percent between 2005 and 2010 alone. Nearly every washer sold today cleans with far less water than the machine it replaced, and that is the whole reason HE detergent exists.

Why less water means fewer suds

Detergent foams because its surfactants, the molecules that grab grease on one end and water on the other, also trap air. In a tub full of water, foam is harmless: there is plenty of water to dilute it and carry it away in the rinse.

In a drum holding a few centimetres of water, foam becomes the problem. A cloud of suds cushions the clothes so they do not rub and tumble against each other, and tumbling is the mechanical action a low-water machine relies on. Foam also has to go somewhere at the end of the cycle, and with little water to dissolve it, it clings to fabric and to the inside of the drum. Many machines respond by sensing the suds and adding rinse cycles, which uses the water the machine was designed to save.

HE detergents are formulated to produce little foam and to disperse quickly in a small volume of water. That is the entire difference; the surfactants, enzymes and other ingredients are of the same families as any other detergent. We should note that the detailed explanation of how suds interfere with low-water washing comes mainly from appliance makers and the detergent industry rather than from independent studies. It is consistent with basic physics and with what people see when they use the wrong product, but it is not the kind of claim anyone has tested in a lab for publication.

The HE symbol

The symbol is a lowercase “h” and “e” inside a circle or oval. It is not a government certification; it is an industry mark that signals the formula is low-sudsing and meant for high-efficiency machines. Government energy programs have pointed consumers to it for a long time: a 2003 ENERGY STAR guide to qualified clothes washers already advised looking for “HE” on the detergent box or bottle for the best results, and noted that because these washers use less water, they need less detergent.

Two things the symbol does not tell you:

• Whether the detergent is fragranced or dyed. HE formulas come in every version, scented and fragrance-free, coloured and clear. The skin-relevant choices are separate from the HE question.
• How concentrated it is. Some HE detergents are several times more concentrated than others, so the correct dose varies from product to product. Read the label, not the cap.

Too many suds, more residue: the skin connection

For your skin, the interesting part of this story is residue. Rinsing is what removes surfactant from fabric, and rinsing works by dissolving what is on the fibres into water and draining it away. Suds are the opposite of dissolved: they are surfactant clinging to air bubbles and to whatever surface they touch. A load that finishes with foam in the drum has finished with more surfactant in the clothes.

Whether that residue matters for skin depends on the skin. A 2023 review in the journal Cutis found that true allergy to laundry detergent is rare, at most 0.7 percent of patients in the largest study. But the same review describes a model showing that surfactant residue, dilute right after the wash, becomes more concentrated at the fabric surface as clothes dry, potentially reaching irritating levels. For someone with eczema, whose skin barrier (the outer layer that keeps water in and irritants out) is already weakened, less residue is a reasonable goal even without a trial proving it prevents flares.

The American Academy of Dermatology’s self-care advice for atopic dermatitis says the same thing in practical terms: use only the recommended amount of detergent and make sure there is enough water for rinsing. In a high-efficiency washer, “enough water for rinsing” is exactly what a low-sudsing detergent at the right dose is designed to provide.

Dosing an HE detergent

The most common mistake with HE detergent is using too much. The formulas are concentrated, the machines use little water, and the measuring caps are often marked for the largest, dirtiest loads. Some practical habits:

• Start at the lowest line on the cap for an ordinary load, and only go up for heavy soil or a very full drum.
• Adjust for water hardness. Hard water, common across much of the Prairies and parts of Ontario, needs a bit more detergent to clean; soft water needs less.
• Fill, but don’t overfill. Natural Resources Canada’s own use tip. A packed drum cannot tumble or rinse properly, whatever detergent you use.
• Add an extra rinse for the laundry of anyone with reactive skin, if the machine offers one.
• Watch the end of the cycle. If you see foam on the door glass or a film in the drum after the final rinse, you are using too much.

If someone in your home has sensitive skin or eczema, combine the HE symbol with the two labels that matter for skin: fragrance-free and dye-free. You can browse the laundry products the panel has reviewed to see what those look like together.

What HE detergent will not do

It will not make a scented detergent gentler, it will not fix a rash, and it will not compensate for overdosing. If a persistent rash appears on skin covered by clothing, check the basics first: detergent dose, rinse, fabric softener, new unwashed clothes. If it lasts more than two weeks or keeps returning, see your doctor or pharmacist, because the cause is often something other than the laundry.

What to remember: high-efficiency washers use a small amount of water, and detergent that foams in that water does not rinse out well. HE detergent is simply the low-sudsing version, and the little circle tells you that and nothing more. Use the lowest dose that gets clothes clean, give the load room to rinse, and make the skin-related decisions, fragrance-free and dye-free, separately.