Humidity
70° - 74° Very Humid, quite uncomfortable
65° - 69° Somewhat uncomfortable for most people at upper limit
60° - 64° OK for most, but everyone perceives the humidity at upper limit
55° - 59° Comfortable
Humidity varies with temperature. The higher the air’s temperature, the more water the air can hold. Temp isn’t the only thing that raises humidity.
Relative humidity is a percentage measurement of the humidity in relation to the maximum humidity for that temperature. Absolute humidity is a measurement of how much water is in the air depending on its temperature. The most common measurement for our homes is relative humidity, and it’s preferable to keep it between 25% and 55%.
The ideal relative humidity in a British home is around 50 to 55 per cent. Bathroom doors should be kept closed at all times, and when the room is in use the window should be open or an extractor fan running. Moisture generated by cooking is not just the steam rising off a pan of boiling potatoes, but also a by-product of the combustion of gas. Bedrooms also need ventilation, as the body can give off half a litre of moisture overnight through respiration and perspiration.
Many readers also report high internal humidity levels following the installation of cavity wall insulation, which appears to trap moisture in the cavity – despite industry claims that this can’t happen.
A humid environment is a breeding ground for all sorts of microscopic organisms that can harm your health. Mildew and mold spores thrive in it, and they can be highly toxic once they get into your body. Dust mites also love humidity. All sorts of bacteria can be found in spaces with high relative humidity. Relative humidity is the concentration of water vapour in the air relative to temperature.
One reason humidity makes hot weather more unbearable is that the higher the relative humidity, the higher the temperature actually feels. For instance, a temperature of 95° feels like 95° when the relative humidity is 30%. But bump that humidity up to 65% and that same 95° feels like a whopping 117°!The concentration of water in the air, relative to the temperature (relative humidity) determines the rate at which the water can evaporate from the skin. When the air is holding more moisture (relative to the total moisture it could hold at that temperature), it is harder for the air to absorb the sweat from our skin. The result? We sweat and sweat but instead of feeling any relief, we simply feel hot and sticky.
The problem with high humidity making us feel hotter is not just that we are more uncomfortable, but that our core temperature is actually rising, and our bodies compensate by working harder and harder to cool us down. When sweating doesn't work to cool us down and we continue to heat up, overheating results, which causes loss of the water, salt, and chemicals that the body needs. Overheating, or as it is more commonly known, heat exhaustion, can lead to dehydration and chemical imbalances within the body.
"Dehydration depletes the body of water needed for sweating and thickens the blood, requiring more pressure to pump it through the body, thus straining the heart and blood vessels." As blood goes to the external surface of the body, less goes to the muscles, the brain, and other organs. Physical strength declines, and fatigue occurs more quickly than under normal conditions. Mental faculties, such as alertness, may also be adversely affected."
Such effects are more pronounced, and more dangerous, depending on age and overall physical condition.
65° - 69° Somewhat uncomfortable for most people at upper limit
60° - 64° OK for most, but everyone perceives the humidity at upper limit
55° - 59° Comfortable
Humidity varies with temperature. The higher the air’s temperature, the more water the air can hold. Temp isn’t the only thing that raises humidity.
Relative humidity is a percentage measurement of the humidity in relation to the maximum humidity for that temperature. Absolute humidity is a measurement of how much water is in the air depending on its temperature. The most common measurement for our homes is relative humidity, and it’s preferable to keep it between 25% and 55%.
The ideal relative humidity in a British home is around 50 to 55 per cent. Bathroom doors should be kept closed at all times, and when the room is in use the window should be open or an extractor fan running. Moisture generated by cooking is not just the steam rising off a pan of boiling potatoes, but also a by-product of the combustion of gas. Bedrooms also need ventilation, as the body can give off half a litre of moisture overnight through respiration and perspiration.
Many readers also report high internal humidity levels following the installation of cavity wall insulation, which appears to trap moisture in the cavity – despite industry claims that this can’t happen.
A humid environment is a breeding ground for all sorts of microscopic organisms that can harm your health. Mildew and mold spores thrive in it, and they can be highly toxic once they get into your body. Dust mites also love humidity. All sorts of bacteria can be found in spaces with high relative humidity. Relative humidity is the concentration of water vapour in the air relative to temperature.
One reason humidity makes hot weather more unbearable is that the higher the relative humidity, the higher the temperature actually feels. For instance, a temperature of 95° feels like 95° when the relative humidity is 30%. But bump that humidity up to 65% and that same 95° feels like a whopping 117°!The concentration of water in the air, relative to the temperature (relative humidity) determines the rate at which the water can evaporate from the skin. When the air is holding more moisture (relative to the total moisture it could hold at that temperature), it is harder for the air to absorb the sweat from our skin. The result? We sweat and sweat but instead of feeling any relief, we simply feel hot and sticky.
The problem with high humidity making us feel hotter is not just that we are more uncomfortable, but that our core temperature is actually rising, and our bodies compensate by working harder and harder to cool us down. When sweating doesn't work to cool us down and we continue to heat up, overheating results, which causes loss of the water, salt, and chemicals that the body needs. Overheating, or as it is more commonly known, heat exhaustion, can lead to dehydration and chemical imbalances within the body.
"Dehydration depletes the body of water needed for sweating and thickens the blood, requiring more pressure to pump it through the body, thus straining the heart and blood vessels." As blood goes to the external surface of the body, less goes to the muscles, the brain, and other organs. Physical strength declines, and fatigue occurs more quickly than under normal conditions. Mental faculties, such as alertness, may also be adversely affected."
Such effects are more pronounced, and more dangerous, depending on age and overall physical condition.