Read the test point before you believe the litre figure

The L/day number is a manufacturer claim at a stated point

Almost every compressor in this guide is sold as 10, 12, 20 or 25 litres per day. Those figures are not a promise of what will sit in the tank in a Leeds terrace in January. They are a laboratory extraction rate, and the laboratory is usually warmer and wetter than the room you will use.

Meaco publishes the rows that most brands hide. The MeacoDry Arete One 10L is 10.42 litres per day at 30 °C and 80 % relative humidity — the headline. At 20 °C and 60 % RH, which is closer to a heated British living room, the same official table is 4.34 litres. At 10 °C and 60 % RH it is 1.41 litres. The cooler rows are the ones a UK buyer should shop with.

The MeacoDry Arete One 12L follows the same pattern. The headline is 12.18 L/day at 30 °C / 80 % RH. At 20 °C / 60 % RH the table is 5.23 L/day — the everyday heated-flat figure. At 10 °C / 60 % RH it falls to 1.95 L/day.

We have not run our own laboratory tests. We are reading the manufacturer’s table out loud. If a brand does not publish the cooler rows, this site says so, and does not invent them. That is why Pro Breeze machines in this list are described as a litre class, not as a verified take at 16 °C.

Size by moisture load, then by temperature, then by the room

A studio with one occupant, a bathroom and no indoor washing is a different job from a three-bed that hangs two loads a day on an airer. The first job is often a 10 L compressor in a heated space. The second is a 12 L or 20 L compressor, or a desiccant if the drying room is cold.

Manufacturer room-size figures (42 m², 50 m², 80 m², 90 m²) assume a moisture load and a temperature that the brochure rarely spells out. Treat them as a starting band. If windows stream every morning, or you dry laundry indoors, shop one class up from the brochure’s small-room suggestion. If the room is unheated, change technology rather than buying a bigger compressor.

Compressor versus desiccant

A compressor dehumidifier is a small refrigerator. It cools a coil, water condenses, the tank fills. That loop is efficient in a heated home and it is why the quiet Meaco figures in the mid-30s dB(A) exist. It also has a floor, usually about 5 °C on the machines in this list. Below that, the coil ices, defrost cycles eat the day, and the published litre figure is a memory of a warmer test.

A desiccant dehumidifier uses a heated rotor that adsorbs moisture. EcoAir rates the EcoAir DD1 Simple MK3 at 7.5 litres per day at 20 °C / 60 % RH, and gives an operating range from 1 °C. That 7.5 L is not a smaller machine than a 12 L compressor in any simple sense: it was measured at a cooler, more realistic indoor point, and the machine will still run in a room where the compressor has given up.

The desiccant cost is electricity. The DD1 Simple MK3 is 300 W on economy. High / turbo is 580 W. An Arete One 12 L is 151 W at 20 °C / 60 % RH on Meaco’s sheet — several times less draw for a heated-room job. You buy a desiccant because the room is cold, or because you want the slim 6 kg body, not because it is cheaper to run in a heated lounge. High / turbo / laundry on a desiccant is a short, wet job. Daily background drying is what the low mode is for.

Continuous drain

Tank sizes in this list start at 600 ml on the Russell Hobbs mini and reach 5.5 litres on the Pro Breeze 20 L. A 2–2.5 L tank on a 12 L class machine will want emptying more than once on a wet laundry day if you rely on the bucket. Continuous drain is a hose from the back of the unit to a sink, gully or condensate pump.

Meaco Arete uses a 12.5 mm garden-hose fitting and does not pack the hose. Pro Breeze listings for the 12 L and 20 L typically include one. EcoAir’s DD3 usually includes a metre of hose; the DD1 can take one.

If the drain point is higher than the machine, gravity will not help. Meaco sells a separate pump for the taller Arete bodies. In a rented flat, a hose over the washing-machine waste is often the whole installation. In a garage, a bucket on a wet week is a worse plan than it looks on the Saturday you unbox the thing.

Noise and night

Published decibels are another manufacturer claim, usually at a stated fan speed, measured in a way you will not reproduce next to a skirting board. They are still useful for ranking. Meaco gives the Arete One 10 L and 12 L as 35 and 38 dB(A). The 20 L is 38 and 40 dB(A). The 25 L is 40 and 42 dB(A). Arete Two 12 L adds a third speed at 44 dB(A) for the faster laundry fan.

EcoAir quotes 34 dB(A) on low and 47 dB(A) on high for the DD1, and 36/47 dB(A) for the DD3. Pro Breeze 12 L listings cluster around 36–38 dB(A). The Pro Breeze 20 L is commonly listed around 42 dB(A), with laundry mode the louder setting.

Night mode, where it exists, usually dims lights and holds a lower fan. It is for a bedroom that needs humidity control, not for drying a duvet at 1 a.m. Laundry mode and night mode are different jobs. If you need both, you run laundry in the evening and night mode after the washing is down.

Laundry mode is still not a tumble dryer

On every machine in this guide that offers it, laundry mode means the unit keeps extracting instead of stopping at a humidity target, often with the fan on high. Wet clothes in a closed room then evaporate into air that is being dried. That is slower than a condenser tumble dryer, uses less heat than putting the central heating on for the same job, and still needs space around the airer. Towels and bedding take hours. A 12 L class compressor is a reasonable companion for a small household’s indoor wash. A 20 L is the size people buy when the airer is a daily fixture. Neither replaces a dryer if you need cupboard-dry school uniforms before breakfast.

Keep the door shut. A dehumidifier cannot dry the street. Empty the tank or fit the hose, because a full bucket stops the cycle. Aim any louvre at the washing if the machine has one (EcoAir DD1, Arete Two). Arete One has no louvre; put the unit close to the airer instead.

Cold rooms, and why the EcoAir DD1 is in this guide

Unheated utilities, porches, stone pantries, garages and holiday homes sit in the band where compressor take collapses. The EcoAir DD1 Simple MK3 is here because its published range starts at 1 °C and its 7.5 L figure is already at 20 °C / 60 % RH. The DD3 Classic MK3 is the same logic at 11 L, with a 4.2 L tank, for a larger cold volume. We do not put either in the Best 5 because the Best 5 is a heated-home shopping list. We do put the DD1 on the home page, because a UK buying guide that ignores cold rooms is writing for a climate we do not have.

What we will not do on this site

We will not invent a hands-on test we have not run. We will not freeze a pound price as if Amazon never moved. We will not give stars. Soft price bands in the data are a rough recent range, and every product page says so. The Amazon button is labelled See on Amazon, carries rel="nofollow sponsored", and is the only place a live price belongs.

The method page is the short version of how the list was built. The Best 5 is five roles, not five trophies.