Compressor vs desiccant dehumidifiers
The one decision that actually matters when buying a dehumidifier — and it comes down to a single question: how warm is the room?
TL;DR
Heated home (10°C+): compressor — under half the running cost for the same water. Cold space (garage, conservatory, boat): desiccant — compressors lose their grip in the cold; desiccants don’t care and warm the air as a bonus.
Head to head
| Compressor | Desiccant | |
|---|---|---|
| How it works | Chills a coil; moisture condenses onto it | Moisture absorbed by a rotating desiccant wheel, driven off by a heater |
| Power draw | ~160–200W | ~300–700W |
| Cost/hour at 27p/kWh | ~5p | ~8–19p |
| Best temperature range | 10°C and above | 1–20°C, unbothered by cold |
| Output air | Room temperature | Noticeably warm |
| Weight | Heavier (compressor inside) | Light |
| Right for | Houses, flats, bedrooms, laundry | Garages, conservatories, boats, caravans |
The physics in one paragraph
A compressor unit is a small fridge: it chills a coil below the air’s dew point and the moisture condenses out. That works beautifully until the room itself is cold — then the coil struggles to get meaningfully colder than the air and spends its time defrosting. A desiccant swaps physics for chemistry: a moisture-absorbing wheel collects water and a heater bakes it off into the tank, identical performance at 3°C or 18°C — you just pay for that heater every hour it runs.
Our picks
Pro Breeze 20L OmniDry / Meaco ABC 12L
Both covered in depth in our dehumidifier guide — the OmniDry for whole-house and laundry duty, the Meaco for bedroom-quiet running.
£179.99 £149.95We don’t currently list a desiccant pick — the honest reason is that most readers asking this question have heated homes where compressor is the right answer. If you need one for a genuinely cold space, look at EcoAir’s desiccant range and apply the maths above.
Frequently asked questions
Which is cheaper to run, compressor or desiccant?
In a normally heated UK home, compressor — roughly 160–200W against a desiccant's 300–700W, so under half the pence-per-hour for the same water in typical conditions. Desiccant only pulls ahead in cold spaces below about 10°C where compressor efficiency collapses.
Which works better in a cold garage or conservatory?
Desiccant, decisively. Its chemistry doesn't care about temperature, while a compressor unit spends cold mornings defrosting instead of extracting. For boats, garages, caravans and unheated conservatories, desiccant is the right tool.
Do desiccant dehumidifiers really warm the room?
Yes — the regeneration heater means output air is a few degrees warmer, a genuine bonus in the cold spaces desiccants suit. In a heated home the same heat is just extra running cost.
Which is quieter?
The best compressor units (Meaco's ABC range, ~35dB) beat most desiccants, but desiccants have a smoother fan-only sound some prefer at night. For bedrooms in heated homes, a quiet compressor wins on noise and cost together.