Short answer: for a bedroom of 15 to 25 m² choose a 9,000 BTU inverter air conditioner, for a larger bedroom or an attic room under the roof 12,000 BTU. Look at the indoor unit noise at the lowest speed: a quiet bedroom means about 19 – 22 dB. Mount it so that the airflow does not fall directly on the bed.
In the bedroom the air conditioner often runs all night, and noise and draughts bother you more than in the living room. Here are the size, the noise, where to place the unit and the night settings, with examples from the catalogue and prices as of 15.10.2026.
How many BTU for a bedroom
A typical bedroom is between 14 and 22 m². The formula is the area times 350 BTU: 18 m² gives 6,300 BTU, 25 m² gives 8,750 BTU. That is why a 9,000 BTU air conditioner covers almost any bedroom in a block of flats and is the standard choice for 15 – 25 m².
A 12,000 BTU air conditioner (25 – 35 m²) makes sense in three cases: the bedroom is larger than 25 m², it is on the top floor under the roof, or it has large south- or west-facing windows. A bigger unit in a small room is not better. It reaches the temperature quickly, stops, starts again and does not dry the air, so the bedroom becomes damp and cold. The calculation for all room sizes is in the guide how many BTU do I need.
| Bedroom | Size | Price in the catalogue |
|---|---|---|
| up to 25 m², normal conditions | 9,000 BTU | 85 models in stock, from 300 € |
| 25 – 35 m², top floor or south-facing windows | 12,000 BTU | 87 models in stock, from 315 € |
How quiet the air conditioner should be
The indoor unit noise is given in the specifications as several numbers, for example “39 / 34 / 25 / 19 dB(A)”. These are the levels at the different fan speeds, from the highest to the quietest. For the bedroom the last number matters, because at night the air conditioner runs at low speed or in SLEEP mode.
- 19 – 22 dB at the lowest speed is quiet. Most people do not hear the unit while they sleep.
- 25 – 26 dB is also acceptable, but people sensitive to noise may notice it on a quiet night.
- Every 10 dB more is perceived roughly as twice as loud, so a difference of 4 – 6 dB between two models can be heard.
In our catalogue noise is listed on about half of the 9,000 BTU model pages. Of those, 28 state a quietest level of up to 22 dB. The figures are manufacturer data measured in laboratory conditions, so in a room the unit sounds a little louder. The comparison between models, however, is fair.
| 9,000 BTU model | Quietest speed | Heats down to | Price |
|---|---|---|---|
| Nippon KFR 09 GLORY PRO | 19 dB | −25 °C | 510 € |
| Panasonic CS-BZ25ZKE | 20 dB | −15 °C | 676 € |
| Hitachi AirHome 400 RAK-DJ25PHAE | 20 dB | −15 °C | 715.30 € |
| Gree Pular GWH09AGBXB | 21 dB | no data | 540 € |
| Gree Clivia GWH09AUCXB | 22 dB | −25 °C | 630 € |
| Kaisai ECO KEX-09KTH2I | 26 dB | −15 °C | 469.88 € |
There are quiet models among the 12,000 BTU units too, for example Nippon KFR 12 GLORY PRO with 20 dB for 540 € and Panasonic CS-BZ35ZKE with 20 dB for 731 €. All models by size are on the pages 9,000 BTU air conditioners and 12,000 BTU air conditioners.
Where to mount the air conditioner in the bedroom
Where the indoor unit goes decides whether you sleep well more than the brand of the unit does. A few rules for the spot:
- Not above the head of the bed. The airflow falls straight on the pillow. It is better for the unit to be on the side wall or opposite the foot of the bed, so that the air passes over it.
- Not low down directly opposite the bed. Cold air sinks, so the unit is mounted high, close to the ceiling, and the louvres are set horizontally for cooling.
- Away from the wardrobe and curtains. An obstacle in front of the unit sends the air back to the sensor and the air conditioner stops before the room has cooled.
- The outdoor unit not under a bedroom window. Neither yours nor your neighbours’. The outdoor unit is louder than the indoor one and can be heard at night through an open window.
- Condensate away from the neighbours’ balcony. Water from the outdoor unit should be led where it will not drip onto someone else’s balcony or sill.
For a typical bedroom in a block of flats the pipes between the two units are up to 3 m and the installation is standard. For an air conditioner up to 14,000 BTU it costs 150 € if the unit is bought from us. What the price includes is on the page air conditioner installation in Varna.
Night settings
SLEEP (the icon is usually a moon) is the mode that makes a good remote worth having. It runs the fan at the quietest speed and gradually shifts the set temperature by 1 – 2 degrees during the first hours of sleep. The exact logic depends on the brand. The meaning of the other signs is in the article air conditioner remote symbols.
- In summer do not cool the bedroom sharply before going to bed. It is better to switch the air conditioner on an hour earlier at a moderate temperature and leave SLEEP running through the night.
- In winter 18 – 19 °C in the bedroom at night is enough. How to set up heating is described in the article setting an air conditioner to heat.
- The timer is useful if you do not want the air conditioner to run all night: TIMER OFF after 2 – 3 hours or TIMER ON half an hour before getting up.
- The display on the indoor unit can be switched off on many models with a LIGHT or DISPLAY button if the light bothers you.
Clean air in the bedroom
The indoor unit filters collect dust and in a bedroom they get dirty quickly. They are easy to clean at home, and once a year it is good to have the air conditioner serviced with the heat exchanger cleaned. A dirty unit is noisier, cools less and smells when switched on. With us servicing a standard wall-mounted air conditioner in Varna costs 42 €, details are on the page air conditioner servicing.
What to choose
For a bedroom up to 25 m² take a 9,000 BTU inverter with a quietest speed of up to 22 dB and SLEEP mode. For a larger or attic bedroom take a 12,000 BTU unit with the same requirements. If you also want heating in winter, check the lower heating limit in the specifications. Ready-made offers with price and installation are on the page air conditioners in Varna, and the full list is in the category inverter air conditioners.
Frequently asked questions
What air conditioner for a bedroom?
A 9,000 BTU inverter air conditioner for a bedroom up to 25 m² or 12,000 BTU for a larger, attic or very sunny bedroom. The quietest speed should be about 19 – 22 dB.
How many BTU for a 20 square metre bedroom?
9,000 BTU. The calculation is 20 × 350 = 7,000 BTU, and a 9,000 BTU unit covers rooms from 15 to 25 m².
How many dB is a quiet bedroom air conditioner?
19 – 22 dB at the lowest indoor unit speed. Look at the last number in the “indoor unit noise” specification.
Where should an air conditioner not go in the bedroom?
Above the head of the bed and low down opposite it. It is better on the side wall, high under the ceiling, so that the airflow passes over the bed.
Is it harmful to sleep with the air conditioner on?
The discomfort comes from airflow directly on the body and from sharp cooling. With the unit in the right place, SLEEP mode and a moderate temperature, an air conditioner in the bedroom is normal practice.
How much does a bedroom air conditioner cost with installation?
As of 15.10.2026, 9,000 BTU inverter air conditioners in the catalogue start from 300 € and 12,000 BTU from 315 €. Standard installation for a unit up to 14,000 BTU is 150 €.
