Monoblock vs Portable Split AC: The Honest Comparison
SplitClima editorial team
Updated on 1 August 2026
Walk into any Swiss electronics shop in July and you see two machines that both call themselves "mobile air conditioner". One costs CHF 300.–, the other CHF 800.– or more. The difference is not branding. It is physics, and it decides whether your bedroom sits at 24 °C or 28 °C at two in the morning. Here is the honest comparison, from a shop that sells the expensive kind and will still tell you when the cheap kind is enough.
What is a monoblock air conditioner?
A monoblock is the classic mobile air conditioner: one box on wheels with the entire refrigeration circuit inside, including the compressor. It dumps heat through a thick exhaust hose, usually 12 to 15 cm in diameter, hung out of a window or door. Price range in Swiss shops: roughly CHF 200.– to CHF 700.–. Setup takes ten minutes.
That simplicity is why monoblocks dominate the shelves at Galaxus, Fust and Interdiscount. It is also the root of every weakness that follows.
What is a portable split air conditioner?
A portable split works like a fixed split system: a quiet indoor unit and an outdoor unit carrying the compressor, connected by a thin refrigerant line. The difference from a fixed split: nothing is drilled or permanently mounted. The Midea PortaSplit made the category famous, and TIME listed it among its Best Inventions 2025; its connection line is 2.7 cm thin and fits through a tilted window.
You place the outdoor unit on the balcony or the window sill, route the line, seal the window opening, plug into a normal socket. No installer, no drilling, and as a mobile device generally no permit.
Why does the exhaust hose ruin monoblock cooling?
Negative pressure. The hose blows room air out; that air must be replaced, so warm outside air gets sucked back in through window gaps, door slits and the very opening the hose hangs in. The monoblock partly undoes its own work. Stiftung Warentest's verdict on mobile monoblocks sits right in the test title: flexible, but not very efficient.
A portable split has no exhaust air at all. The refrigerant carries the heat outside through a closed line, the room stays sealed, and the cooling stays where you paid for it. This one difference explains most of the efficiency gap below. It is also why single-hose monoblocks feel weaker than their kW rating promises, especially in flats with older, leakier windows.
Which is more efficient?
The portable split, by roughly a factor of two in practice. Typical monoblocks reach an EER around 2.6, measured at full load. The PortaSplit reaches SEER 6.1 and our SplitClima S12 SEER 5.6, measured across realistic part loads (SEER per EN 14825 weights part-load operation, exactly where inverter splits shine).
In francs, at the 2026 Swiss median tariff of 27.7 Rp./kWh (ElCom): about 11 Rp. per hour for the split against about 26 Rp. for the monoblock, or roughly CHF 55.– against CHF 130.– over a 500-hour summer. And the monoblock figure flatters it, because the negative-pressure effect is not captured by the EER. Full math and a per-canton table in our running cost guide.
Which is quieter?
No contest. The monoblock keeps the compressor in your room; typical models are specified between 55 and 65 dB(A), which is normal-conversation territory. Fine for an afternoon in the home office, brutal at night.
A portable split banishes the compressor to the balcony. What remains inside is mostly a fan: the PortaSplit runs at 39 dB(A) in silent mode, the PortaSplit Cool is specified at 38 dB(A), the S12 runs at 39 dB(A) in sleep mode. That is quiet-library territory, and it is the difference between sleeping with cooling and choosing between sleep and cooling. How those numbers feel in a real bedroom: our 39 dB guide.
Which is easier to install and move?
The monoblock wins on day one, the split wins every day after. A monoblock: roll it in, hang the hose out, done. It stores in one piece and moves between rooms easily, though "mobile" is relative at 25 to 35 kg.
A portable split takes 30 to 60 minutes the first time: place the roughly 45 kg main unit (owners on Reddit are clear that stairs need two people), position the outdoor unit on the balcony or sill, route the flat line through the tilted window and close the gap with a window seal. After that, daily use is plug and play. Moving it between rooms is possible but not something you will do weekly, and the 2 m line means the indoor unit stays near the window.
Are both allowed in a rental apartment?
Generally yes, because neither is fixed to the building. A plug-in device that changes nothing structural usually needs no building permit; the city of Zurich, for example, requires none for non-fixed mobile units. Fixed split systems are a different story: landlord approval plus, in many cantons, a building permit.
Two honest caveats. Geneva regulates air conditioning unusually strictly through its cantonal energy office, and outdoor units on balconies sit in a grey zone there, so ask before you buy. And noise rules apply everywhere, always: house rules and communal quiet hours do not care whether your device needed a permit. Homegate's tenancy advisory covers the tenant side; our renter guide goes deeper, canton by canton.
What do they cost to buy?
Monoblocks: from about CHF 200.– for no-name units to about CHF 700.– for branded models with app control; check live prices at Galaxus or on Toppreise. Portable splits: CHF 799.– for our S12 with the window kit included, CHF 1'090.– for the PortaSplit Cool, CHF 1'190.– for the PortaSplit (list price CHF 1'349.–; Swiss street prices ranged from CHF 999.– to CHF 1'349.– before the category sold out).
The gap looks big until you count seasons. Roughly CHF 75.– per summer in electricity savings, plus heating capability, plus noise you can sleep next to: if you cool more than a few weeks per year, the split becomes the cheaper machine over its lifetime.
Side-by-side comparison
| Criterion | Monoblock | Portable split |
|---|---|---|
| Compressor | In the room | Outside |
| Window | Hose in a half-open window | 2.7 cm line, window nearly closed |
| Room pressure | Negative, pulls warm air in | Neutral, room stays sealed |
| Efficiency | EER approx. 2.6 | SEER 5.6 to 6.1 |
| Cost per hour (2026 median tariff) | approx. 26 Rp. | approx. 11 Rp. |
| Noise indoors | 55 to 65 dB(A) | 38 to 39 dB(A) |
| Sleeping next to it | Hardly | Yes |
| Heating | Rarely | Yes, SCOP 4.0 |
| First setup | 10 minutes | 30 to 60 minutes |
| Weight | 25 to 35 kg, one piece | approx. 45 kg plus outdoor unit |
| Price | CHF 200.– to 700.– | CHF 799.– to 1'349.– |
| Building permit | Not needed (mobile device) | Not needed (mobile device) |
Which one should you buy?
Buy a monoblock if you cool two or three weeks a year, the budget is firmly under CHF 500.–, nobody has to sleep next to it, and you accept higher running costs as the price of a low entry price. That is a legitimate choice, and we say so although we do not sell one.
Buy a portable split if you want to sleep with cooling running, if you cool regularly from June to August, if your electricity is expensive (Basel-Stadt pays 33.25 Rp./kWh in 2026), or if heating a single room in spring and autumn adds value for you. It costs more once and less every hour after.
FAQ
Do dual-hose monoblocks solve the pressure problem?
Largely, yes: the second hose feeds outside air to the condenser, so room air is no longer blown out and no negative pressure builds. But dual-hose units are rare in Swiss shops, a recurring Reddit complaint, and they still keep the compressor in the room at monoblock noise levels. The portable split solves pressure and noise at once.
Can a monoblock cool a bedroom for the night?
It can cool the room before the night. Most owners pre-cool, switch off to sleep, and watch the temperature creep back up. At a specified 55 to 65 dB(A), sleeping next to a running monoblock is something few people manage long-term. If sleep is the goal, the split category is the answer.
Do both work with Swiss tilt-and-turn windows?
Yes, with a proper seal. The monoblock's thick hose needs a fabric seal spanning the whole window opening. The split's 2.7 cm flat line passes through the tilted corner, and the window seal kit closes the rest. No drilling in either case, which is exactly what a rental needs.
If the comparison points you at the split category, the Midea PortaSplit is the benchmark device: CHF 1'190.–, free delivery, a 2-year warranty handled in Switzerland and a 30-day return right. Like almost everywhere, it is sold out at the moment; the free waitlist gives you 48 hours of early access when the spring 2027 batch lands.