Air Conditioning for an Apartment or House: Portable vs. Built-in (Split). How to Choose the Best Option for You?

Portable (monoblock, “portable”): you’re renting, don’t want to cut into walls, want an immediate solution, and a lower upfront price. Expect higher noise and lower efficiency—especially with single-hose models (more below).
Built-in split (wall-mounted indoor unit + outdoor unit): you’re looking for a quiet, efficient, all-season air conditioner with the option of heating (heat pump) and a longer lifespan. It requires professional installation and work on the façade/exterior wall.

How to Read the Energy Label (A–G), SEER, and SCOP

Since 2021, the EU has used simplified A–G energy labels for most appliances (including air conditioners up to 12 kW). The label also shows seasonal efficiency:

SEER – efficiency in cooling (higher = better, lower consumption),
SCOP – efficiency in heating mode (applies to units with heating).
See an overview directly from the European Commission. (Energy Efficient Products)

Portable Air Conditioning: Pros, Cons, and What to Watch Out For

Advantages

quick setup with no HVAC/refrigeration work; you just vent the hose out a window,
you can move it as needed (home office/bedroom),
lower initial investment (typically a few hundred euros, depending on capacity and features).

Disadvantages and key facts

Noise – the compressor is in the room.
Efficiency – especially single-hose models create negative pressure (some cooled air is exhausted outside through the hose and is replaced by warm air drawn in from other rooms/gaps). This is one reason the U.S. introduced SACC/CEER ratings, which reflect real-world performance and losses more accurately—a useful reference even when choosing in the EU (the numbers on the EU label may differ, but the principle of comparing efficiency still holds). Learn more about SACC/CEER in the official DOE rule: Energy conservation standards for portable ACs. (Federal Register)
Recommendation – if you go portable, prefer a dual-hose design, which reduces negative pressure and usually cools faster.

Built-in (Split) Air Conditioning: Pros, Cons, and When to Choose It

Advantages

Quiet indoors (the compressor is outside),
High efficiency (SEER, and often heating with a solid SCOP),
Zoning – a multi-split can handle multiple rooms.

Downsides

Installation and admin (a penetration through the wall/façade, building manager approval),
higher upfront cost (unit + installation),
need for regular servicing.

You can find more on the principle and benefits of ductless mini-splits in the official U.S. Department of Energy guide: Ductless Mini-Split Air Conditioners. (The content is broadly applicable: with no ductwork, you avoid duct losses, which in centralized systems can reach tens of percent.) (The Department of Energy’s Energy.gov)

Refrigerants and the Future: What EU Rules Will Bring

The EU is tightening F-gas regulation: faster HFC reductions and phased bans on equipment with high GWP. For consumers, this means moving away from R410A to lower-GWP options (R32), and increasingly natural refrigerants (e.g., R290 – propane) in portable and small split units. Some standalone (monoblock) units using F-gases will be banned from 1 January 2032 (up to 12 kW), with milestones for higher capacities starting as early as 2027/2030. Detailed wording and exemptions are on the European Commission website:
Air conditioning – climate-friendly alternatives to F-gases (EU) and an overview of F-gas regulation: F-gas legislation. (Climate Action)

How Much Cooling Capacity Do I Need? A Practical Rule of Thumb (Quick Estimate)

As a rough rule of thumb, Natural Resources Canada suggests about 200 BTU/h per 1 m² of living space (about 60 W/m²). It’s a good starting point—then adjust for insulation, glazing, and orientation. Source and context here: Air Conditioning Your Home (NRCan). (natural-resources.canada.ca)

Examples (approximate):

15 m² → ~0.9 kW cooling
20 m² → ~1.2 kW
30 m² → ~1.8 kW
40 m² → ~2.3–2.5 kW
60 m² → ~3.5–3.6 kW
If you live under the roof, have lots of west-facing windows, or poorer insulation, add +10–20%. Conversely, in a shaded, well-insulated space, less may be enough.

Electricity Use and Running Costs: A Simple Calculator

Basic takeaway: the higher the SEER, the lower the consumption for the same cooling output.
Approximate example: if a unit typically draws 0.6 kW and runs 8 hours a day, it uses 4.8 kWh. At €0.20/kWh, that’s ~€0.96 per day.
The annual total depends on the number of “AC days” in your area (typically tens to low hundreds of hours per year here, outside extreme heatwaves).

Noise and Comfort

Portable: everything (including the compressor) is in the room, so it tends to be subjectively louder.
Split: the compressor is outside—indoors you mainly hear airflow from the fan, which is usually noticeably quieter. DOE also lists the advantages of ductless systems. (The Department of Energy’s Energy.gov)

Portable AC: How to Get the Most Out of It

Seal the window thoroughly (leaks = lost efficiency).
If possible, choose a dual-hose version.
Keep the hose short and as straight as possible (insulate it if the run is longer).
Modes: use the timer and sleep mode; in humid conditions, dehumidification helps.

Split AC: What to Consider Before Installation

Line set routing (wall penetration), condensate drain, placement of the outdoor unit (vibration, neighbors).
Power draw and electrical protection (a dedicated breaker, surge protection).
Service: regular cleaning of filters/coils, disinfection.

Selection Process in 5 Steps (Summary)

Measure the space (m²) and do a rough capacity estimate using the 200 BTU/h per m² rule; adjust by ±10–20% based on conditions. (natural-resources.canada.ca)
Choose between portable (fast, no building work) and split (quieter, more efficient, also for heating). (The Department of Energy’s Energy.gov)
Compare the energy label (A–G, SEER/SCOP, noise in dB(A), annual consumption). (Energy Efficient Products)
Check the refrigerant and future compatibility with F-gas rules (prefer lower GWP; R32/R290 will become more common). (Climate Action)
Calculate TCO (Total Cost of Ownership): purchase + installation + consumption + service. If you need to cool multiple rooms, consider a multi-split.

Frequently Asked Questions (FAQ)

Can I use a portable AC in a rental?
Yes—it’s one of the easiest options with no construction work. Make sure the window is well sealed and the exhaust hose is properly vented.

Can a split unit also heat?
Yes. Most split systems are air-to-air heat pumps (check the SCOP on the label). In the shoulder seasons, heating with a split is often cheaper than direct electric heating.

Is there a big difference between single-hose and dual-hose portable units?
In practice, usually yes. Dual-hose designs reduce negative pressure and use their capacity more effectively; the negative-pressure issue is also reflected in the fact that modern SACC/CEER efficiency tests account for real-world conditions and losses. (Federal Register)

Videos to Complement (Understanding Differences and Installation)

Why single-hose portable ACs are inefficient (negative pressure):

How installation works and the ductless mini-split principle (Ask This Old House):

Single vs. dual-hose portable (hands-on comparison):

Sources

European Commission – Understanding the Energy Label (A–G, SEER/SCOP, noise on the label) — https://energy-efficient-products.ec.europa.eu/ecodesign-and-energy-label/understanding-energy-label_en
European Commission – Air conditioning: climate-friendly alternatives to F-gases (overview of bans and timelines)— https://climate.ec.europa.eu/eu-action/fluorinated-greenhouse-gases/climate-friendly-alternatives-f-gases/air-conditioning_en
U.S. Department of Energy – Ductless Mini-Split Air Conditioners (principle, benefits, duct losses) — https://www.energy.gov/energysaver/ductless-mini-split-air-conditioners
Natural Resources Canada – Air Conditioning Your Home (rough sizing ~200 BTU/h per m²) — https://natural-resources.canada.ca/energy-efficiency/energy-star/air-conditioning-your-home