Cooling your apartment and rooms - Tips against heat for your home
Lowering room temperature indoors – summer heat and year-round aspects
Optimal room temperatures & health
The right room temperature is crucial for well-being, sleep quality and the prevention of mold growth.
Pleasant room temperatures increase well-being and health. The following guidelines are recommended year-round , wherever possible. :
Recommended optimal room temperatures in different rooms
| Space | Recommended temperature |
|---|---|
| Living room / study | approx. 20–22 °C (comfortable, without unnecessary overheating) |
| bedroom | approx. 16–18 °C (cool for restful sleep) |
| nursery | approx. 20–22 °C (similar to living room; babies and toddlers not too warm) |
| Kitchen | approx. 18–20 °C (slightly cooler, as cooking generates heat) |
| pantry | approx. 15–20 °C (dark, well ventilated; cool storage climate for food) |
| basement rooms | approx. 10–15 °C (unheated basement for storage; prevents condensation and mold) |
Mobile air conditioners: Technical solutions
Mobile air conditioners are a flexible option for cooling rooms, especially in rented apartments or where it is not possible to install fixed systems, air conditioners help to reduce the room temperature.
Here are important aspects:
Advantages
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Flexibility: Easy transport between rooms.
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Installation: No structural changes required.
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Functionality: Many devices also offer heating, dehumidification or air purification functions.
- Price advantage & mobility : Mobile systems are significantly more affordable than a permanently installed solution. Furthermore, a mobile device can be easily moved or relocated to other rooms.
Disadvantages
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Energy consumption: Higher power consumption compared to permanently installed air conditioning systems.
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Noise level: Can be louder than split units.
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Efficiency: Less effective at cooling large rooms.
Tips for use
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Exhaust hose: Ensure a good seal at the window to prevent warm air from flowing back.
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Ventilation: Ventilate briefly during the cooler morning and evening hours; keep windows and doors closed during operation.
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Maintenance: Regular cleaning of filters and water tanks to prevent germ formation.
Further measures for temperature regulation
In addition to the use of air conditioning units, there are other effective methods to combat heat in the home by lowering the room temperature:
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Sun protection: Roller shutters, blinds, awnings and curtains prevent rooms from heating up due to direct sunlight and increased outside temperatures.
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Evaporative cooling: Damp cloths placed in front of open windows can cool the room air through evaporation. An air cooler based on a similar system can also create a fresh and pleasant breeze and provide real cooling.
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Plants: Houseplants improve the indoor climate through evaporation and shade and usually keep rooms pleasantly cool.
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Electronic devices: Avoid unnecessary operation of devices that emit heat.
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Insulation: Good insulation protects against heat in summer and cold in winter. Insulation is always a good solution for heat protection.
FAQ block
Frequently asked questions about room temperature and air conditioning:
2. What is the optimal room temperature in living rooms and work rooms?
For living and working spaces , 20–22 °C is considered comfortable. This temperature ensures well-being without unnecessary overheating and simultaneously saves heating energy .
3. How does a mobile air conditioner work?
Portable air conditioners draw in warm room air, cool it using a refrigerant system , and then return the cooled air. The heat is usually expelled outside via an exhaust hose.
4 . Which is better: monoblock or split air conditioner?
Split units are quieter and more efficient, but more expensive. Monoblock units are cheaper and easier to install, but are louder and less efficient for larger rooms.
5. How can I cool rooms without air conditioning?
In addition to air conditioning, fans , evaporative cooling (e.g. damp cloths on the window), shutters and ventilation during the cool hours of the day also help.
6. How often should I clean my air conditioner?
Filters and water tanks should be cleaned at least once a month —more often with frequent use. This prevents germ growth and maintains efficiency.
7. Does it make sense to regulate the room temperature even in winter?
Yes, even in winter, don't overheat rooms. The recommended maximum temperature is 20°C in living areas . At the same time, temperatures should be avoided below 14°C to prevent mold growth .
Health effects of high room temperatures in summer
In high temperatures, our body can react with heat exhaustion or heat stroke – watch out for the first signs such as headaches or nausea.
High indoor temperatures in summer put a strain on the body and can cause a variety of health problems.
Circulation and heart : In order to maintain the core body temperature of ~37 °C, the body dilates the blood vessels in hot weather and sweats to cool down This lowers blood pressure and places greater strain on the heart and circulatory system, which can lead to dizziness, nausea, fainting spells and even circulatory collapse. Older people are particularly at risk because they feel less thirsty and start sweating later.
Sleep quality : If temperatures stay above 20°C at night, restful sleep is almost impossible – overheated bedrooms make it difficult to fall asleep and lead to restless sleep. The disrupted nighttime cooling increases fatigue the next day and reduces concentration and performance, creating a vicious cycle for well-being. .
Cognitive performance and concentration : From about 26 °C room temperature, the ability to concentrate decreases – you get tired more quickly and are less efficient In extreme heat, the body has to use so much energy to cool itself that less is left for mental tasks; attention and reaction times suffer, and thinking and memory skills decrease. Studies confirm that, for example, students in non-air-conditioned buildings performed worse in tests during heatwaves than those in air-conditioned rooms. Overall, many people complain of exhaustion, sleep disturbances, and headaches during heatwaves – according to a DAK survey, 59% of those affected had sleep problems and 66% had circulatory problems during the heatwave. Extreme indoor heat therefore poses a serious health risk, especially for vulnerable groups (seniors, children, chronically ill people).
Comfort standard (ISO 7730) Individual preferences may vary, but the general rule is: If possible, do not heat living rooms above 20°C if it is comfortable – every degree less saves heating energy. Bedrooms should be kept coolest year-round (16–18°C), which is beneficial for sleep quality. Relative humidity (40–60%) is also important, as air that is too dry irritates the mucous membranes and air that is too humid promotes mold.
Technical solutions for active temperature reduction (mobile air conditioning units)
Portable air conditioners are often used to effectively cool indoor spaces in summer. They offer flexible solutions, particularly in rental apartments without a fixed air conditioning system. Two types are common, differing in functionality and performance:
Porta-Split vs. Monoblock – Differences and Advantages
Monoblock air conditioners combine all components into one unit. They are positioned in the room and direct warm air outside through the window via a thick exhaust hose (usually ~15 cm in diameter). Advantages: easy installation (set up the unit, run the hose out the window) and relatively low purchase costs. Disadvantage: low efficiency – warm air constantly flows in through the open window gap Monoblocks consume more power and provide less cooling; in tests, they took approximately 30–45 minutes to cool a 14 m² room from 30 °C to 24 °C. They are also noisy because the compressor and fan are located in the room (noise levels often reach 60–65 dB).
Split air conditioners consist of an indoor and an outdoor unit, connected by narrow refrigerant lines (diameter ~3–5 cm). With portable split units (so-called porta-split units), the outdoor unit is simply placed in front of a window or on a balcony, without any permanent installation. The advantage: significantly higher cooling capacity and efficiency – the best split unit in the test cooled 14 m² to 24 °C in under 5 minutes. . The warm air is released directly outside, and the indoor unit blows only cooled air into the room . In addition, split units dehumidify the room air , which is pleasant in the humid summer climate. Another advantage: lower noise levels in the room , since the loud compressor is located outside – many mobile split units reach below 40 dB in silent mode. However, this is offset by higher costs and, with traditional split systems, installation work (specialist personnel, wall penetration). Mobile porta-split units avoid the need for fixed installation, but are also more expensive to purchase than monoblocks. Overall, split solutions offer the performance of a fixed air conditioning system with similar flexibility to mobile units. .
Conclusion : Those seeking maximum cooling efficiency and quieter operation will benefit from porta-split units with narrow connecting hoses. Monoblock units score points for their simplicity and low price, but are more suitable for smaller rooms or occasional use.
Current trends in mobile air conditioners : design, efficiency, smart features
Modern mobile AC devices are constantly evolving.
Energy efficiency is a key focus: Many units today use the environmentally friendly refrigerant R290 (propane) and improve efficiency with inverter technology, which controls the compressor speed and thus operates more efficiently and quietly. Some monoblocks achieve efficiency classes up to A+ or A++. In addition, some portable ACs have heating functions (heat pump mode), allowing year-round use (cooling in summer, heating in milder winter periods). .
Eco mode and intelligent temperature control are widely used – e.g. automatic adjustment of the temperature and control of the humidity for an optimal feel-good climate .
Noise reduction : Manufacturers prioritize quieter operation for bedroom use. Innovative airflow (“Air-Surround” or Wind-Free mode) distributes the cooled air without creating a strong draft, reducing the perceived noise level. The quietest monoblock devices can reach ~44 dB(A) in night mode, such as the EcoFlow Wave 2 in sleep mode.
Design : From bulky white boxes to sleek exteriors, modern appliances are often slimmer, with matte finishes or even black/silver, allowing them to blend in better with the home décor. Some models (e.g., from LG or Midea) are significantly more compact and easier to move without sacrificing performance.
Smart features : App control and Wi-Fi are almost standard. Many air conditioners can be operated via smartphone app, turned on or off remotely, and integrated into smart home systems. Voice control via Alexa or Google Assistant is also partially supported Timer functions and saving individual settings have become a matter of course These smart features allow you to activate the device before you return home or program automatic cooling times.
Additional functions such as air purification (filter against dust, pollen) and dehumidification mode make mobile AC multifunctional – in transition they can be used as
Dehumidifiers are used to combat damp rooms. Overall, the trends reflect increased comfort and efficiency: mobile air conditioners are becoming quieter, smarter and more environmentally friendly without sacrificing performance.
Suitable electrical appliances and models for different rooms (examples)
Depending on the location and needs, different types of mobile air conditioning units are best suited.
Note: In the bedroom , noise level is often more important than maximum cooling power – a quiet model or the use of a split unit is recommended here to stay below ~64 dB .
In a kitchen with a lot of waste heat (cooking, appliances), the air conditioner should have sufficient power reserve (high BTU); operating noise is less disturbing there than in the bedroom.
For persistently damp basements , an air conditioner with a powerful dehumidification mode can have a dual effect: It cools and keeps the air dry. Alternatively, pure dehumidifiers can be considered if moisture management is primarily needed.
Year-round view: regulate room temperature all year round
Smart temperature control in your own four walls is important not only in summer, but all year round.
In winter, it's important to avoid overheating – living spaces don't have to be tropically warm. As a rule of thumb, the Federal Environment Agency recommends keeping the temperature in living areas at a maximum of ~20 °C (if comfortable). Every degree less saves heating energy (approximately 6% per degree) and reduces CO₂ emissions. Of course, heating should not be too low either: Below ~14–15 °C, the risk of mold increases significantly. .
It's all about finding a balanced middle ground. During the colder months, proper ventilation helps: Regular, short bursts of ventilation (draft, air exchange) exchange moist indoor air for dry, cold outdoor air without significantly cooling the room. This keeps the room climate fresh and prevents mold, while saving heating energy.
Bedrooms should be kept cool year-round—ideally around 16–18°C, even in winter, with sufficient blankets. Elderly or those sensitive to cold can go down to 20°C in the bedroom, but should not fall below 14°C. During the day vs. at night : At night, you can lower the heating slightly (e.g. to 18 °C), which saves energy and corresponds to the natural needs of the body, which needs less heat at night . Modern thermostats or smart home heating controls facilitate such time-dependent temperature profiles In summer, on the other hand, you should try to prevent indoor spaces from heating up excessively (shading during the day, ventilating in the cool morning/evening hours) – this way, the air conditioning system has to work less.
Conclusion : The optimal room temperatures for health and well-being remain similar throughout the year (as recommended above). In winter as well as in summer, it is important to avoid extreme temperatures – neither too hot nor too cold – and to create a constant, comfortable indoor climate through adapted heating, ventilation, and cooling behavior. This not only promotes health (better sleep quality, less circulatory stress), but also protects your wallet and the environment through efficient energy use .
A good climate doesn’t have to be expensive:
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Expertise & Authorship
This article was created in collaboration with Stylies , the Swiss manufacturer of high-quality air conditioning units. Stylies has been synonymous with efficient and aesthetic solutions for humidification and air purification for years.
Daniel Gwerder , partner of Tavora Brands AG, has been an expert in health and indoor climate for over 20 years and shares his knowledge here free of charge. His goal is to provide preventative help through expert knowledge – sound, understandable, and practical – to as many people as possible. You can find out more about him on LinkedIn.
