Relative Humidity and Temperature Monitoring

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Why monitoring conditions is important

Both temperature and relative humidity have a large impact on the comfort of our buildings. This matters both for working and resting area. Due to varying weather conditions, each day is different, although there are trends that occur along each season.

Monitoring is important since it creates a habit of taking decisions in similar situations and reinforcing good reasoning will be helpful in managing resources and energy consumption. It will also, just as importantly, establish a predictable environment for everyone.

Weather's influence

It does not matter how old or new a building is. It is still affected by exterior conditions and you should be highly aware of this. While newer or improved buildings are certainly less influenced by weather, the impact still manifests itself.

Weather conditions can change dramatically from one hour to another and this variability means that maintaining a proper balance of indoor spaces is much harder than you may have thought, particularly when you note the actual swings that occur. Keep in mind that indoor conditions change slowly and this inertia means that you should be aware of exterior ones.

Major external factors

The biggest influence comes, as you expect, from the sun itself. Places that are basked in the sunlight all day long will inevitably become hotter in the summer, and this can become unbearable. While altitude influences temperature and a higher altitude reduces the maximum heating that can be felt, the day to night swings are very large here as well.

Shading reduces the maximum impact of direct sunlight. However, shading raises other issues, such as rarely being adjustable or as effective as we may wish. While movable shades on windows reduce the impact of heating due to sunrays the building's exterior walls are still heated by the sun, so the impact depends on the covered area, and shades require some yearly maintenance.

Vegetation has a highly positive impact, especially if it is not with evergreen trees. Having trees that are covered in foliage from spring to autumn is a good choice for reducing the intense heat brought by the summer, especially in warmer climates or area or when a slightly cooler area is preferred.

Although largely beneficial, trees have to be trimmed from time to time to avoid reaching the building envelope and damaging it. Also, trees can be affected by extreme winds or frost so broken branches are not uncommon.

Vegetation also has a slight disadvantage in that it slightly increases local humidity as water is better trapped in the soil and below the planted area. This can promote mold growth, particularly in summer, when humid warm air exacerbates the impact of these conditions.

Rain, mist and humid air creates issues with maintaining proper indoor conditions. Since we must air our living spaces, the exterior air can be detrimental to our desired conditions. However, since airing is imperative, we have to ensure that humidity does not increase too much to create health risks and this means that we have to use air conditioning devices to limit humidity in a specific area.

Contrary to expectations, winter and dry weather are actually beneficial to indoor conditions. Since most of our activities release water vapours, airing indoor spaces is very easy and does require very little energy to do so. Heating dry, cool air is also less expensive than humid air.

Indoor areas specificities


Bathrooms are sometimes the last areas to be considered, although they should be the first. Just about any human activity requires cleaning and washing and this is regularly done to maintain a proper hygiene. Every time we use the washbasin or toilet we are inevitably spreading minute water droplets in the air.

Having a shower or bath spreads even more water droplets around us, no matter how careful we are. Hotter water tends to make the air temperature rise and humid but warmer air raises towards the ceiling. This means that a constant air circulation is created even with no ventilation.

When washing clothes, various items or taking care of our bodies, larger or smaller water spills do occur and they are spread in this room. This means that just about any activity increases humidity.

In general, bathrooms not facing the building's exterior and not designed with windows have the largest difficulty in keeping humidity on check. Not having a window that can be left open most of the year means that humidity has to be regulated using fans.

Enclosed bathrooms particular risks

Despite all building designer's assurance and years of experience in constructing buildings for residential or commercial purposes, enclosed bathrooms have serious humidity issues that can never be solved with forced ventilation. As we create better airtight buildings the efficiency of forced ventilation drops, and buildings with better airtightness are required for lower energy requirements on heating and cooling.

It is important to note that humidity can also influence nearby areas because temperature differences or air circulation mismatches may promote humid air to leave the bathroom, in some amounts, and get into other areas. This makes efforts at maintaining proper conditions nearby even more difficult.

Just as important is to note that since relative humidity is always higher in bathrooms any borderline condition in nearby spaces will become more severe in bathrooms since nearby air is always directed towards the bathroom for later extraction by the bathroom fan.

All of this means that in order to maintain a proper balance in the entire building, and particularly if the total area is not many times larger than the bathroom, the relative humidity should be kept lower on the entire interior to avoid high values in the bathroom.


Preparing food for own consumption or to cater to clients creates major challenges in itself. Many times, the available space may not be enough. When inevitable odours, steam and the occasional smoke is released due to cooking, it may be difficult to maintain proper conditions.

Considering how much the air is influenced and affected by cooking, ventilation is, realistically speaking, never enough. No matter how strongly you exhaust the air by forced ventilation, the balance is still skewed by the unavoidable heat and humidity that result from activities.

Encloses kitchens generally exacerbate poor air ventilation issues and affect even more the air quality of nearby spaces. Kitchens that have a window are generally much better but the air circulation may still be unsatisfactory due to winds or a location that promotes an inverse air circulation than the one intended.

Striving for an almost airtight kitchen with good door closing systems can bring benefits or reducing influence on nearby areas but it worsens conditions in the kitchen itself since humidity and vitiated air can linger longer in the kitchen itself.

All of this means that air admitted in the kitchen should be less humid and cooler since the inherent humidity and heat released there will amplify discomfort.


In general, bedrooms are not much considered except for temperature conditions, since we are mostly sensitive to temperature for proper sleeping. However, due to the nature of spending at least a couple of hours in the same place and up to 8 or 9 hours in some cases, the comfort of bedrooms matters a lot.

In cool days the bedroom has to be heated since our own body heat is rarely enough to reach a proper balance quickly enough. In very warm nights, it has to be cooled to avoid discomfort when sleeping. Even with all the advanced fabrics and products we may have, comfortable sleeping is not a given and we need cooling or heating.

However, even when cooling and heating may not be needed, there is always a major risk, increased humidity. Our respiration naturally releases some humidity. During sleep, a slight temperature discomfort or reaction to dreams may promote perspiration. When two or more persons sleep at the same time, the effect is compounded.

Until sleep ends, the humidity may already be way too high, due to perspiration and respiration, even if at the start of it, it was perfectly comfortable.

All of this means that monitoring and even keeping humidity lower before sleeping may be helpful to keep it acceptable until waking up. This is also important as most air conditioning devices are, by their nature, slightly noisy devices that can disturb sleep. Airing the room when unoccupied can alleviate most problems unless on warm humid days.

Dining areas

These areas areas do not have much different demands to office spaces or living rooms. By their nature, they may be slightly more crowded and warmer as well as slightly more humid, since cooked food, frozen delicacies and liquids promote them.

Living rooms and offices

Apparently simple living space, living rooms and offices have similar characteristics. Since most of the time is spent staying, drafts and lower temperatures should be avoided, as well as high humidity. Demands for cooling are slightly less than in kitchens or other intense activity areas.

Working and intense activity areas

Workshops and various spaces specially designed for work have a common similarity. They require frequent personal movement. This increases heat and humidity due to physical activity but is not as sensitive to cooling and drafts. Absent major specific requirements, working areas are not very demanding on humidity and temperature.

Corridors and halls

These areas are generally neglected, since persons spend little time on them. However, they do have a very important influence on the whole building's comfort. These areas are poorly temperature or humidity regulated. Since these spaces are in direct contact with all living, working or utility areas, they directly influence air flows.

Monitoring when temperature or humidity goes way higher than it should helps in maintaining a proper balance in other areas. During winter or cooler times of the year, such areas should have limited airflow but some airflow can be beneficial to keep in check other rooms.

It is important to note that airflows of such areas can be quite impactful in most conditions so knowing the main direction through the building is highly beneficial for decisions regarding the comfort of other areas. Monitoring conditions here can give early warnings in other premises.