Climatiseur sans évacuation : myth or reality ?
A portable air conditioner without evacuation is technically impossible according to thermodynamic laws. Discover real solutions to cool your home without renovation work.
# Air Conditioner Without Evacuation: Myth or Reality?
The search for a mobile air conditioner without evacuation is among the most frequent queries from French consumers seeking to cool their interior without undertaking work. Yet, this quest is based on a fundamental misunderstanding: a true air conditioner cannot function without expelling heat outside. This article separates fact from fiction and presents you with realistic solutions for your summer comfort.
What is an air conditioner without exhaust?
An air conditioner without exhaust does not exist in the strict sense: any air conditioning system must evacuate the heat extracted from indoor air to the outside. Products marketed under this term are actually evaporative air coolers or fans, which operate on a different physical principle. Unlike air conditioners, they do not produce cold through a thermodynamic cycle (compression/expansion), but cool the air through water evaporation, without rejecting concentrated heat outside.
The marketing trap
Advertisements deliberately use the expression "air conditioner without duct" to attract buyers, when they are actually coolers. This confusion maintained by certain online sellers deceives millions of consumers every year.
Standards and official definitions
According to the NF EN 12098-5 standard (individual air conditioners), an air conditioner must meet minimum cooling capacity and energy efficiency criteria. Air coolers do not meet this classification and are not subject to the same regulatory requirements.
Why an air conditioner cannot work without evacuation?
Thermodynamics imposes an inescapable rule: every extraction of interior heat generates an equivalent amount of heat to be rejected outside. A conventional mobile air conditioner operates according to the Carnot cycle: it compresses a refrigerant fluid that absorbs interior heat, then rejects this concentrated heat through a duct to the outside. Without this evacuation, heat would accumulate in the device and efficiency would collapse.
Energy balance of an air conditioner
An air conditioner that cools 10 kW of interior air must reject these 10 kW plus the energy consumed by the compressor (approximately 3-4 kW additional). In total, 13-14 kW of heat must leave the home. Without a duct, this heat remains partially inside, which neutralizes the cooling effect.
Studies and real measurements
A study conducted by [Que Choisir](https://www.quechoisir.org) in 2023 measured the actual efficiency of 15 mobile air conditioners sold "without evacuation". The results show that without a duct, the interior temperature only drops by 1-2°C instead of the expected 5-8°C with a properly installed duct.
Mobile Air Conditioner vs Air Cooler: The Real Differences
| Criterion | Mobile Air Conditioner | Evaporative Cooler |
|---------|-------------------|---------------------------|
| Principle | Thermodynamic cycle (compression) | Water evaporation |
| Cooling Power | 2,500-5,000 W | 500-1,500 W |
| Mandatory Duct | Yes (or window) | No |
| Installation | Easy | Very easy |
| Output Humidity | Reduces humidity | Increases humidity |
| Efficiency in Dry Climate | Excellent | Average |
| Efficiency in Humid Climate | Good | Poor |
| Consumption | 1,000-1,500 W | 100-300 W |
| Price | €400-800 | €100-300 |
Air Coolers: How They Work and Their Limitations
Evaporative coolers (or evaporative air conditioners) humidify the air by forcing it to pass through a wet filter. Water evaporation absorbs sensible heat, which lowers the temperature by 3-5°C maximum, depending on the initial ambient humidity. In Mediterranean regions (dry air), efficiency can reach 5-6°C. In Brittany or Île-de-France (humid air), it drops to 1-2°C.
Critical point: these devices increase indoor relative humidity, which can promote condensation and mold in poorly ventilated homes.
What are realistic use cases for ductless air conditioning?
There are a few contexts where the absence of ductwork remains acceptable, although results are moderate. An air cooler is suitable if you're looking for a light complement to a fan and not a complete solution. Realistic cases include small spaces under 20 m² in dry climates, covered terraces, or closed offices for a few hours. For a 40 m² living room or bedroom, only an air conditioner with exhaust guarantees lasting comfort.
Small space (< 20 m²)
An evaporative cooler may be sufficient in a small, well-oriented room with limited solar gains and good natural ventilation.
Dry climate (Provence, Languedoc)
In southeastern France, where relative humidity drops to 30-40% in summer, an air cooler offers acceptable efficiency (4-6°C drop).
Intermittent use (a few hours)
For an office used 4-5 hours a day, an air cooler may be suitable if internal loads (computers, people) are limited.
What are the real alternatives without heavy installation?
If you refuse a visible duct or construction work, several solutions exist to improve thermal comfort without a conventional air conditioner. These alternatives combine moderate efficiency and practicality.
Mobile air conditioner with sliding window
The sliding window kit (or window seal) allows you to evacuate the duct through a semi-open window, without drilling or permanent work. The duct remains discreet and installation takes 5 minutes. It's the best comfort/simplicity compromise: you keep the power of a real air conditioner (4-5 kW) while avoiding construction work.
High-performance air circulation fans
Modern ceiling or pedestal fans (variable speed, timer) consume little power (50-150 W) and create a noticeable cooling sensation. Combined with good insulation and external blinds, they are sufficient for moderate temperatures (< 28°C).
Reversible air conditioners (heat pumps)
Although more expensive (€3,000-8,000 with installation), reversible split air conditioners offer superior comfort, better energy efficiency (COP 3-4), and winter operation. They require a short and discreet external duct.
Passive cooling: blinds, shutters, night ventilation
External insulation (awning blinds, roller shutters) reduces solar heat gain by 60-80%. Combined with night ventilation (windows open between 10 PM and 6 AM), this strategy is often sufficient in central-west France. In Île-de-France, it limits peaks to 26-27°C instead of 32-35°C.
Real Efficiency Comparison Under French Conditions
For a 30 m² room facing south, outdoor temperature 32°C, humidity 45%:
- Mobile air conditioner with hose : 22-23°C reached in 45 min (consumption 1 200 W)
- Mobile air conditioner without hose : 28-29°C reached in 2h (consumption 1 200 W, heat partially returned)
- Evaporative cooler : 26-27°C reached in 1h30 (consumption 200 W, humidity +15%)
- Fan + blinds : cooling sensation, temperature unchanged (consumption 80 W)
Source : [UFC-Que Choisir](https://www.ufc-quechoisir.org) — comparative tests mobile air conditioners 2024.
Tempéra Recommendations for Your Situation
Choosing an air conditioner without evacuation is a matter of compromise between comfort and installation. Tempéra recommends:
1. If you tolerate a visible duct or sliding window → Classic mobile air conditioner (4-5 kW): guaranteed efficiency, moderate cost (500-800 €).
2. If you absolutely refuse a duct → Evaporative cooler (dry climate) or high-performance fan: limited efficiency, but zero installation.
3. If you seek comfort + energy efficiency → Reversible split air conditioner with discreet short duct (high initial cost, long-term savings).
4. For a small space (< 15 m²) → Evaporative cooler acceptable; for 30+ m² → air conditioner mandatory.
The real question is not "air conditioner without evacuation", but rather "what compromise between comfort, installation and budget".
Conclusion
A portable air conditioner without exhaust remains a physically impossible myth. Products sold under this name are air coolers, less powerful but simpler to install. Before buying, realistically assess your needs: area to cool, local climate, humidity tolerance, and acceptance of a discreet duct. For most French households, a portable air conditioner with sliding window kit offers the best comfort/installation ratio. Consult our [guide to types of air conditioners](https://tempera.fr/guide-types-climatiseurs) to explore all options suited to your region.
FAQ
Does an air conditioner without duct really consume less than a standard air conditioner?
No. An air conditioner without duct (cooler) consumes less (200 W vs 1,200 W), but only offers a temperature drop of 2-3°C instead of 6-8°C. A standard portable air conditioner without duct consumes as much as with a duct, but its efficiency drops drastically because heat remains partially indoors.
Can you use a portable air conditioner without duct in summer in Paris?
Not recommended. In Paris, average summer humidity is 60-70%. An evaporative cooler will be ineffective (drop < 2°C) and will increase humidity, promoting mold and discomfort. An air conditioner with duct (or sliding window) is necessary to reach 22-23°C.
What is the best compromise if I refuse a visible duct?
The sliding window kit for portable air conditioner. The duct passes through a thin slot in the semi-closed window, without work or drilling. You keep the power of a real air conditioner (4-5 kW) while maintaining aesthetics. Additional cost: €30-50.
Can an air cooler replace an air conditioner in Provence?
Partially. In Provence (dry climate, 30-40% humidity), a cooler offers 4-6°C drop, sufficient if temperature does not exceed 30°C. Beyond that, only an air conditioner guarantees lasting comfort. A cooler is a complement, not a replacement.
How much does an effective portable air conditioner really cost without work?
A standard portable air conditioner with sliding window kit costs €500-800 (unit + kit). An evaporative cooler: €100-300. A reversible split air conditioner with installation: €3,000-8,000. The best value for money remains the portable air conditioner + sliding window.
Mots-clés : climatiseur mobile, rafraîchisseur d'air, climatisation sans gaine, efficacité énergétique, alternatives climatisation