Ideal Comfort Heat Temperature
It is generally accepted that the ideal comfort temperature to create “Comfort Heat” for the average human is in the region of 21 degrees centigrade, this assumes the person is non-active, in an enclosed environment and wearing everyday clothes. For example: Watching TV in a living room, eating supper in a dining room, or working in an office. The ideal comfort heat for sleeping is lower at around 18.5 degrees C , although we are OK at lower temperatures snuggled under the duvet.
In a conventional heating situation, the air temperature in the room is 21 degrees C which is great, and you are sitting in an armchair 1.5 meters from an outside wall which has a temperature of 15 degrees C. Do you feel Hot or Cold ? The answer is Cold, for the following reasons…
The air temperature is 21 degrees C, but of greater influence is the wall temperature of 15 degrees C. Your body heat will radiate out from you to the cold wall, resulting in your body feeling cold. This is because all objects (including humans and animals) absorb and radiate heat, and “emission” always flows from Hot to Cold. We feel absorption of heat as warming, and loss of heat as cooling.
Temperature Variations & Human Comfort Heat
Humans tolerate up to 5 degrees radiant heat difference under or over their ideal comfort heat temperature and still feel reasonably comfortable. Beyond the 5 degrees, people feel uncomfortable and take personal and environmental measures, by adding or removing clothes, increasing/reducing levels of activity, and increasing or decreasing air temperature via heating or window opening.
Radiant Temperature Imbalance = Loss of Comfort
None of these measures however combat the issue of the radiant temperature imbalance between the person and the environment, in this instance the cold wall. Cavity wall insulation or dry lining would raise the wall temperature but this may not be possible or economical. Layering clothes is a quick option but this is not ideal, exercise is good but not the ideal activity when working in an office or watching the TV. Ramping up the conventional Central Heating thermostat will warm the air but at the great expense of heating the whole property, and with the inevitable time lag. The conventional convection & plumbed CH systems will eventually warm the wall but this will take days at excessive expenditure of energy and £’s. This is because these systems actually radiate small amounts of heat relative to the emission of energy to the air.
Heating systems which positively radiate heat address this problem as they heat the objects in the environment (walls, ceiling, furniture, humans etc), this raises the radiant temperature of the room as a whole, and not just the air! The ideal type of infrared heating to produce Comfort Heat for humans within buildings is known as Far Infrared or Longwave . Far Infrared is the part of the infrared wavelength spectrum at which water begins to absorb heat specifically well for the least input of energy. It is therefore optimally absorbed by the skin surface, where the warmth is readily absorbed via conduction into the tissue and blood, and transported around the body. See Wave Length Analysis.
To conclude, if you like the sound of Comfort Heat then the ideal heating for you is a far infrared radiant heating system. When the RH system is operated via Smart Controls with individual heater thermostats, each room will be kept at the perfect temperature.