Pleasant temperature versus heating costs and climate protection: Which indoor temperature is better, 20, 21 or 23 Grad?
Contents:
- Guideline: Temperature at home and workplace
- Good night
- Body heat and increasing resistance
- Fully utilising air in a heated room
- Summary
Guideline: Temperature at home and workplace
Do you know your ideal temperature that makes you feel comfortable or do you just set the heater to the highest setting out of habit? As soon as the colder season finds its way into the country people tend to overheat their homes. The same temperature that makes us put on a short T-shirt in the springtime feels much colder once the days get shorter. Over the past 20 years it has become more and more common to heat more than is actually necessary from a biological point of view. The body can become accustomed to the cold weather. Constantly dwelling inside warm rooms decreases this natural ability. Take a thermostat and measure which temperature is enough to make you feel comfortable.
The beginning of autumn and end of spring mark the time of increased heating. Usually, heating becomes an alleged nee das soon as the outdoor temperature goes below 12°C for three nights in a row, meaning even summer days can require heating. A cosy indoor temperature is achieved between 20 to 21°C.
It is recommended to keep the temperature at a level between 20 and 22°C in living areas between 06:00 and 23:00. At night at least 18°C should be measured, though the values can vary depending on the location.
The following specifications serve as a guideline
| Living room, dining room | 20 to 21°C |
| Child’s room | 21 to 22°C |
| Home office | 21 to 22°C |
| Bathroom, washroom | 21 to 23°C |
| Kitchen | 18 to 20°C |
| Bedroom | 16 to 17°C |
| Living space at night | 16 to 18°C |
| Hallway, storage room | 15 to 18°C |
| Time of absence, vacancy | 12 to 15°C |
| Cellar, basement | ca. 6°C |
| Turning the heater unit down by 1°C saves about 6% of heating energy. Source: co2online.com |
On average, bathrooms and living rooms are heated sparsely with 20.2 to 20.3°C. Bedrooms and kitchens however are heated to 19.5°C and 19.4°C respectively, which is more than enough since heat in the kitchen is also generated by the oven and stove. However, everyone has the right to decide themselves how and when they want to heat their homes. A few changes can save a lot in terms of heating costs. Building up resistance in the winter and heating less actually save quite a lot of money.
The heating system does not only inevitably result in costs, but also in environmental stress. CO2 emission varies depending on the fuel used. Coal, petrol and power coming from conventional sources have the highest CO2 values. Heat pumps, green electricity, solar cells and pellet stoves result in less emission. A recommended indoor temperature for residential buildings is 20°C. This temperature prevents the brickwork from cooling down and stops mould growth. However, the degree of humidity is a decisive factor, too.
Health and safety
The human body’s performance decreases below 12°C and over 24°C, accident risk increases by about 30%. The human body reaches a comfort zone and becomes less productive. Performance drops by about 12% under temperatures above 26°C.
Ideal room temperature about 20°C
Active metabolism
Fatburning
Body produces heat
Above 21°C
Metabolism slows down
Resistance decreases
Risk of catching a cold if air is dry
Above 24°C
Reduced concentration and performance
Fatigue
Headache
Risk of accidents increases
Good night
The thermal sensitivity and personal need for warmth are subject to periodical fluctuation. When sleeping, humans decrease their body temperature by 0.5 to 1°C. The body requires less heat during this time. Lowering the indoor temperature by 5°C to a level of 16-18°C (children’s room and nurseries 18°C) is sufficient for a restorative sleep. The sleep cycle is disturbed if the temperature is too high, think of hot summer days. However, if you prefer cosy heat and your sleep is not bothered by high temperatures, a heated room is not harmful to your health. However, keep energy costs and impact on our eco system in mind. Our tip for all those who like it hot: Turn the heater down one or two hours before going to sleep and use one more blanket instead.
People that are less susceptible to temperature change should not turn off the heater completely at night though. Sweating and breathing at night produces a high amount of humidity. Condensation water will appear on the cold walls, and could lead to mould in the worst case. Furthermore, it takes more energy to heat up a cold room than to keep a constant room temperature. The room temperature feels comfortable once the temperature difference between the walls (surfaces) and indoor air is very little. The difference between the air and temperature on the wall should be 3°C at most.
Apart from temperature and air movement, the humidity level is another factor that plays an important role when it comes to cosiness. The ideal indoor humidity level ranges from 45 to 60%, in the bedroom it should be about 50%. As long as the humidity stays at an acceptable value despite heating, there are no health risks. A humidity content below 30% means the air is very dry. Bacteria can affect the stressed mucosa. Excessive humidity however leads to an increase in mites and mould spores. A humidifier with thermostat is a good way to check the current conditions. Thanks to an automatic humidity sensor the device turns on and off once the ideal values are archieved.
A room thermostat and hygrometer combined into one device are available at low prices and help you gain an overview of the situation in your home. A programmable temperature controller on the heater reduces the temperature of air, for example at night or if residents are away for work. The thermostat also prevents bedrooms from cooling down too much at night: Temperatures below 15°C promote damp walls and mould. Furthermore, the energy required for heating up a cold room is higher than the energy required for keeping a consistent level.
Body heat and increasing resistance
Why do humans not feel cold as soon as the ambient temperature drops below the human body’s own temperature of 37°C? The human body produces heat simply because of the energy it draws from food intake and stored fat. This heat is mostly released through the skin (70-80%), in a resting position this equals about 80 Watt. Springtime outdoor temperatures of about 20-25°C feel most pleasing to humans. The emission of heat and the production of heat happen at the same time (thermoregulation), meaning the body feels neither too cold nor too hot.
The difference in the emission of temperature is caused by the subjective manner of perception of heat. Thin people and those with less muscles tend to feel cold sooner, the body heat is created from slight shivering and the little movements of the muscles. Women have about 15% less muscle mass than men, furthermore their skin is thinner. Low outdoor temperatures increase the blood flow in vital inner organs and in the lower part of the body. If the body does not have enough stored fat to transform energy, women will feel particularly cold on their limbs (cold feet). The following describes the process of increasing resistance to cold.
Resistance to cold is something everyone can achieve. Exercising and training blood vessels help to boost circulation and blood flow. A steaming hot bath and saunas have a long tradition. The heating and cooling of the body trains and stimulates blood flow as well as the immune system. In the winter you could gently rub snow in your face and on your arms. Even beginners will find this bearable. Cold temperatures constrict the blood vessels, the pores on the skin close, the human feels active and awake. However, taking ice cold baths is not a necessary measure. Hot and cold showers after a workout, talking a stroll around town in colder weather, opening all windows in the house to have a fresh breeze coming through or even a few rounds in the swimming pool are enough to help you get used to the cold.
The success of this “training“ is evident. Japanese pearl divers (Ama) descent into the depth of the ocean without any special insulation for cold. They only wear a suit made of neoprene, in the olden days they went naked. It is not unusual for the women to reach the noble age of more than 90 years. The tradition of the Ama women goes back as far as 2000 years in Japan. Medical research shows that they have a highly active metabolism: Cold activates the muscles of the blood vessels. The body adapts to changing temperatures upon repetition, the immune system is strengthened. The production of body heat becomes easier and faster the more the body has been trained. This proves that women do not have to suffer from cold despite a different pattern of muscles than men. The training is also beneficial for the volume of the lungs – these ladies dive without breathing gear.
Note:
Currently, there are no known studies proving that increased resistance to cold temperatures prevents illness.
Fully utilising air in a heated room
Warm air always rises upwards because it is lighter than cold air. That is why you will often find that the floor and lower area of the room are colder than the upper level at the ceiling. Even though the fireplace and heater are fueled constantly, there seems to be no effect at all. However, it is actually enough to fuel just a little and then utilise the warmth that is already there. A ceiling fan with reverse function recirculates heat until the temperature in the entire room has evened out. A TDA system with a temperature sensor on the other hand operates fully automated. The same effect is provided by a circulator, for example from the Vornado range. The patented “Vortex” system ensures whole room heat circulation with outstanding results.
It is not necessary to walk around in shorts at home if there is a blizzard going on outside. This picture is often painted in movies and advertisements, since the display of a naked pair of legs is used for a certain purpose. Try to keep the golden mean between a turned-up heater and goose bumps. Use two blankets instead of one and invest in cosy lounge wear. Light, high-quality textiles such as merino wool is perfect. This type of wool is incredibly soft, it does not become itchy and can oftentimes be washed in the washing machine. Cuffs made of wool also have a great effect. This one-time acquisition will save you further heating costs. You can also trick yourself: Candle light, red-orange interior decoration and a fluffy carpet make the room seem warmer.
Keep warm during sedentary and resting activities:
Fuzzy blankets
Woollen socks and cuffs
Slippers with a thick sole
Scarves
Warm lounge clothes, comfy jumper
Socks without tight elastic bands
Gloves, perhaps a headgear
Hot-water bottle, cherry pit pillow
Footbath, foot massage
Stretching, light workout
Eating properly, no dieting during the winter
Hot, warm tea for example ginger, cinnamon, chili
(Hot) chocolate stimulates blood circulation
Carpets cover the cold floor
Decorative stoppers placed in front of windows and doors to prevent draught
Vitalising creames and oils
And lastly, cuddling and warm thoughts
Summary
A heater on full power is not the only thing that will make the living space more agreeable in the winter. The thermal sensitivity is perceived subjectively by every person, but it can be trained. Humans and the climate are not affected if the heater is turned down a bit, which also saves heating costs. Rooms with excessively warm and dry air actually increase the risk of catching a cold, furthermore these conditions are unnatural for our body during the winter.
Temperatures above 17°C and controlled humidity levels (40 – 60%) are enough to prevent mould growth. The ideal indoor temperature ranges between 20 to 21 degrees Celsius, in the nursery and bathroom you should keep the maximum heat at 23 degrees. Try not to increase the temperatures above this level, particularly in the bedroom warmth impedes the sleep cycle. Instead it is more helpful to wear warm clothes and to mix the masses of cold and warm air, for example by using a ceiling fan.
Banner originator: Andrey Popov and pictworks, both fotolia.com
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