Active electro-osmosis: costs, when it helps, and alternatives
What active electro-osmosis is, when it belongs with rising damp, and when it does not. No price list: the factors that move a quote.
Updated 2026-09-25 · 8 min read
Active electro-osmosis is a contractor job for rising damp: electrodes in the wall and a low continuous voltage, meant to oppose capillary rise. It is not a dehumidifier, not a fan, and not a fix for sweating glass.
When it can make sense
Only after a rising-damp diagnosis, not condensation. Typical signs: a band from the skirting, salts, crumbling plaster, a problem outside winter too. A contact meter compares low and high: it does not certify the building and does not by itself justify an installation.
When it does not
Condensation on glass or mould in a cold corner: that is air physics, not capillarity.
A windowless bath or indoor laundry: air the room first and, if RH stays high, a dehumidifier on the air.
A stain that appears after rain, in one spot: suspect a leak, not an electro-osmotic system for the whole house.
Cost: factors, not an invented price
We do not publish euros. We do not have a verified market price list to cite, and a “typical” number without a source would be a fake estimate. Ask the contractor, in writing, about:
Linear metres of wall, and how many storeys.
Access: furniture, finishes, chases to remake, basements.
Existing services (electrics, wall heating) and where the control unit can sit.
Region and firm: survey, written warranty, what is included (plaster, barrier, plant only).
Salt removal and replastering: a separate line, not included by default.
Alternatives, in diagnosis order
Ventilation removes vapour. Useful for condensation and a bath; not enough on its own for rising damp.
A dehumidifier lowers room RH. It does not dry a wall wetting from below.
A barrier or cut (physical or chemical) and drainage: masonry work, designed, not a catalogue item.
Plaster and salts: after the water is stopped, not before. Covering paint alone delays the stain.
IgroCasa does not publish a price list. A quote depends on metres of wall, access, existing services, region and contractor. Ask for a visit and compare written offers.
Does it help if the windows run?+–
No. Window condensation is moist air meeting a cold surface. Electro-osmosis does not treat dew point.
Can a dehumidifier replace it?+–
No. A dehumidifier treats room air. It does not stop water rising by capillarity in the wall.
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What may help (after diagnosis)
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25–45 €
Pinless wall moisture meter (e.g. RDINSCOS)
Example material moisture meter, no drilling. It helps compare “damp air” and “damp wall”: low vs high, stained vs sound. Absolute numbers are rough. Not a survey instrument.
When: Suspected rising damp or a leak; you want to see whether it starts at the skirting.
Not when: It does not certify a building, does not measure air RH, and does not replace a surveyor if there are salts, crumbling plaster or stains after rain.
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10–25 €
TempPro / ThermoPro TP50
Example desktop hygrometer for diagnosis. Without a relative-humidity number every tip is guesswork. Not a lab review.
When: Always, as the first diagnostic step.
Not when: It does not replace a moisture meter or a rising-damp survey.
Amazon.it affiliate link (tag qordac21-21): we may earn a commission, at no extra cost to you. A category example, not a lab review. Amazon.com is not used.
Sources
UNI EN ISO 13788
Prestazione igrotermica dei componenti edilizi. Soglia convenzionale di rischio muffa: umidità relativa superficiale 80%.