Deep Dive into Cooling Your Home and Rooms
Tips for keeping your home cool:
Smart temperature control in your own home is important not only in summer but all year round. Pleasant room temperatures increase well-being and support health.
In winter, it is important to avoid overheating. Living spaces do not have to be tropically warm. As a rule of thumb, the German Environment Agency recommends keeping the temperature in living areas at a maximum of ~20 °C (if perceived as pleasant). Every degree less saves heating energy (~6% per degree) and reduces CO₂ emissions. Of course, it is also important not to heat too little: Below ~14–15 °C, the risk of mold increases significantly.
How can I lower the indoor room temperature? Both in summer heat and all year round?
The following guideline values are – where possible – recommended all year round:
Recommended optimal room temperatures in various rooms
| Room | Recommended Temperature |
|---|---|
| Living Room / Office | approx. 20–22 °C(comfortable, without unnecessary overheating) |
| Bedroom | approx. 16–18 °C (cool for restful sleep) |
| Children's Room | 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 (Storage Room) | approx. 15–20 °C (dark, well-ventilated; cool storage climate for food) |
| Cellar Rooms | approx. 10–15 °C (unheated cellar for storage; prevents condensation and mold) |
Mobile Air Conditioners:
Mobile air conditioners are a flexible option for room cooling, especially in rented apartments or when there is no possibility to install fixed systems, air conditioners help to lower 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, dehumidifying or air purifying functions.
- Price advantage & Mobility: Mobile units are significantly cheaper than permanently installed solutions. In addition, a mobile device can be easily moved to other rooms or stored.
Disadvantages
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Energy consumption: Higher power consumption compared to permanently installed air conditioners.
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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 in.
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Ventilation: Ventilate briefly in the cooler morning and evening hours; keep windows and doors closed during operation.
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Maintenance: Regular cleaning of filters and water containers to prevent germ formation.
Further measures for temperature regulation
In addition to using air conditioners, there are other effective methods to combat heat in the apartment and lower the room temperature:
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Sun protection: Roller blinds, blinds, jalousies, an awning and curtains prevent rooms from heating up due to direct sunlight and increased outside temperature.
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Evaporative cooling: Damp cloths in front of open windows can cool the room air through evaporation. An air cooler based on a similar system can also generate a fresh and pleasant breeze and cool effectively.
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Plants: Houseplants improve the indoor climate through evaporation and shade, usually keeping rooms pleasantly cool.
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Electronic devices: Avoid unnecessary operation of devices that generate heat.
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Insulation: Good insulation (thermal 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 offices?
For living rooms and offices, 20–22 °C is considered comfortable. This temperature ensures well-being without unnecessary overheating and at the same time saves heating energy.
3. How does a mobile air conditioner work?
Mobile air conditioners draw in warm room air, cool it via a refrigerant system, and return the cooled air. The heat is usually discharged to the outside via an exhaust hose.
4. What is better: monoblock or split air conditioner?
Split units are quieter and more efficient, but more expensive. Monoblocks are cheaper and easier to install, but louder and less powerful for large rooms.
5. How can I cool rooms without air conditioning?
In addition to air conditioners, fans, evaporative cooling (e.g., damp cloths at the window), roller blinds, and ventilating during the cool hours of the day can 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 formation and maintains efficiency.
7. Is it advisable to regulate room temperature in winter as well?
Yes, even in winter, do not overheat rooms. The recommendation is max. 20 °C in living areas. At the same time, temperatures below 14 °C should be avoided to prevent mold growth.
Health effects of high indoor temperatures in summer
At high temperatures, our body can react with heat collapse or heat stroke – watch out for first signs such as headaches or nausea.
High indoor temperatures in summer stress the body and can cause various health problems.
Circulation and heart: To maintain a core body temperature of ~37 °C, the body dilates blood vessels and sweats to cool down. This lowers blood pressure and puts more strain on the heart and circulation, which can lead to dizziness, nausea, fainting spells, and even circulatory collapse. Older people are particularly at risk, as their thirst sensation is lower and they start sweating later.
Sleep quality: If the temperature remains above 20 °C at night, restful sleep is almost impossible – overheated bedrooms make it difficult to fall asleep and lead to restless sleep. The disturbed nocturnal cooling increases fatigue the next day and reduces concentration and performance, a vicious cycle for well-being.
Cognitive performance and concentration: Above about 26 °C room temperature, the ability to concentrate decreases – one becomes tired more quickly and less productive. In great heat, the body has to expend so much energy on cooling that less remains for mental tasks; attention and reaction times suffer, and thinking and memory decline. Studies confirm that 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 heat periods – according to a DAK survey, 59% of those affected had sleep problems and 66% had circulatory problems during the heatwave. Extreme indoor heat thus represents a serious health risk, especially for vulnerable groups (seniors, children, chronically ill).
Thermal comfort standard (ISO 7730). Individual preferences may vary, but generally: do not heat living rooms above 20 °C if it is perceived as comfortable – every degree less saves heating energy. Bedrooms can be the coolest all year round (16–18 °C), which is beneficial for sleep quality. Also important is the relative humidity (40–60%), as air that is too dry irritates the mucous membranes and air that is too humid promotes mold growth.
Technical solutions for active temperature reduction (mobile air conditioners)
Mobile air conditioners are often used to effectively cool indoor spaces in summer. Especially in rental apartments without fixed air conditioning, they offer flexible solutions. Two designs are common, which differ in function and performance:
Porta-Split vs. Monoblock – Differences and advantages
Monoblock air conditioners combine all components in one unit. They stand in the room and direct warm air through a thick exhaust hose (usually ~15 cm in diameter) to the outside through the window. Advantage: easy installation (set up the unit, lead the hose out the window) and relatively low purchase costs. Disadvantage: low efficiency – warm air constantly flows back in through the open window gap. Monoblocks consume more electricity and cool less powerfully; in tests, they took ~30–45 minutes to cool a 14 m² room from 30 °C to 24 °C. In addition, they are loud because the compressor and fan are in the room (noise level often 60–65 dB).
Split air conditioners consist of an indoor and an outdoor unit, connected by narrow refrigerant lines (∅ ~3–5 cm). With mobile split units (so-called Porta-Split units), the outdoor unit is simply placed in front of the window or on the balcony, without fixed installation. Advantage: significantly higher cooling capacity and efficiency – the best split unit cooled 14 m² in less than 5 minutes to 24 °C in the test. The warm air is discharged directly outside, and the indoor unit only blows cooled air into the room. In addition, split units dehumidify the room air powerfully, which is pleasant in the humid summer climate. Another plus: lower noise level in the room, as the loud compressor is housed outside – many mobile splits achieve under 40 dB in silent mode. However, these come with higher costs and, for classic split systems, installation effort (specialized personnel, wall breakthrough). Mobile Porta-Split units bypass fixed installation but are also more expensive to purchase than monoblocks. Overall, split solutions offer the performance of a fixed air conditioner with similar flexibility to mobile units.
Conclusion: Those who want maximum cooling effect and quieter operation benefit from Porta-Split units with narrow connecting hoses. Monoblock units score with 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 units are constantly evolving.
Energy efficiency is a key focus: many devices today use environmentally friendly R290 (propane) refrigerant and improve efficiency with inverter technology, which operates the compressor at variable speeds, thus saving power and reducing noise. Some monoblocks achieve efficiency classes up to A+ or A++. Additionally, some mobile ACs feature heating functions (heat pump mode), enabling year-round use (cooling in summer, heating in milder winter phases).
Eco-mode and intelligent temperature control are widespread – e.g., automatic temperature adjustment and humidity control for optimal comfort.
Noise reduction: Manufacturers prioritize quieter operation for bedroom use. Innovative airflow ("Air-Surround" or Wind-Free mode) distributes cooled air without strong drafts, which reduces perceived noise levels. The quietest monoblock units sometimes achieve ~44 dB(A) in night mode, such as the EcoFlow Wave 2 in sleep mode.
Design: From bulky white boxes to appealing aesthetics – current devices are often slimmer, with matte finishes or even available in black/silver, allowing them to integrate better into living spaces. Some models (e.g., from LG or Midea) are significantly more compact and easier to move without compromising performance.
Smart Features: App control and Wi-Fi are almost standard. Many air conditioners can be operated via a smartphone app, turned on or off remotely, and integrated into smart home systems. Voice control via Alexa or Google Assistant is also sometimes supported. Timer functions and saving individual settings have become standard. These smart features allow, for example, activating the device before returning home or programming automatic cooling times.
Additional functions like air purification (filters for dust, pollen) and dehumidification mode make mobile ACs multi-functional – during transitional periods, they can serve as
Dehumidifiers for damp rooms. Overall, these trends reflect greater comfort and efficiency: Mobile air conditioners are becoming quieter, smarter, and more environmentally friendly without compromising performance.
Suitable Electrical Appliances and Models for Various Rooms (Examples)
Depending on the location and need, different types of mobile air conditioners are best suited.
Note: In the bedroom, noise level is often more important than maximum cooling power – a quiet model or 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 a bedroom.
For constantly damp basements, an air conditioner with a strong dehumidifier mode can have a dual effect: it cools and keeps the air dry. Alternatively, pure dehumidifiers can be considered if humidity management is the primary need.
Year-round consideration: Regulate room temperature throughout the year
Smart temperature regulation in your home is important not only in summer but all year round.
In winter, it's important to avoid overheating – living spaces don't need 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 found comfortable). Every degree less saves heating energy (~6% per degree) and reduces CO₂ emissions. Of course, you shouldn't heat too little either: Below ~14–15 °C, the risk of mold increases significantly.
It's about finding a balanced middle ground. In the colder months, proper ventilation helps: regular, short burst ventilation (draft, air exchange) replaces humid indoor air with dry, cold outdoor air without significantly cooling down the room. This keeps the indoor 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. Older or cold-sensitive individuals can go up to ~20 °C in the bedroom but should not go below 14 °C. Day vs. night: At night, you can lower the heating slightly (e.g., to 18 °C), which saves energy and corresponds to the body's natural need for less warmth at night. Modern thermostats or smart home heating controls facilitate such time-dependent temperature profiles. In summer, on the other hand, one should try to prevent indoor spaces from heating up excessively in the first place (daytime shading, ventilation during cool morning/evening hours) – this means the air conditioning has to work less.
Conclusion: The optimal room temperatures for health and well-being remain similar throughout the year (as recommended above). In both winter and summer, the goal is to avoid extremes – neither too hot nor too cold – and to create a constant, pleasant indoor climate through adapted heating, ventilation, and cooling behavior. This not only promotes health (better sleep quality, less circulatory stress) but also saves money and the environment through efficient energy use.
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. For years, Stylies has stood for efficient and aesthetic solutions for air humidification and purification.
Daniel Gwerder, partner at Salesbroker GmbH, has been an expert in health and indoor climate for over 20 years and shares his knowledge here for free. The goal is to provide preventive help through expert knowledge to as many people as possible – well-founded, understandable, and practical for everyday life. More about him can be found on LinkedIn
