Lately I’m hearing with some frequency the claim that it would be good to lower the ceilings to save on air conditioning in the rooms and premises. The most common is to place a false ceiling of plaster laminate that reduces the space between floors and thus, save energy by having to heat or cool less air volume.
When I listen to this, I always think that there are too many supposed experts on climate control or too many opportunistic entrepreneurs willing to save on material and to leave us smaller and smaller living spaces at the same price.
It is interesting to note about the general ignorance or the little importance that is given to the circumstances that influence the welfare of the places we inhabit, such as humidity, speed and air quality, access to natural lighting, thermal uniformity, the isolation of the exterior and the absence of annoying noises. This invites us to reflect on how little we know about the human condition. Also, about what affects us for good or bad to health, something that we should consider important. After all, the most valuable thing we have is our life.
Those of us who dedicate ourselves to know many things regarding air conditioning are always startled when we take a tour of the world of advertising: blue heat, air deionizers, water magnets and other recipes of merchants eager to lighten the portfolio of the unsuspecting and wrongly informed. We are a society, little educated in the scientific method and in skepticism. It is much more comfortable to follow the shaman of the tribe to solve problems. I still remember the commercial success of the bracelets that balanced you and my astonishment of Obelix (They are crazy these Romans) when, to prove it, you found the subject balancing, usually next to the bar, with the bracelet on to demonstrate how well your life is going since you have it.
The roofs of the buildings that were built in the advanced cities of the early twentieth century had heights well above 2.5 m because hygienic criteria were applied.
A low ceiling makes a relatively small space and visually appreciated even when smaller.
The lower a ceiling, the lower the possibility of reducing polluted air due to occupation of people. The clean air content is lower.
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The high ceilings invite large windows that let light into the inhabited spaces, another of the elements that contribute to comfort.
My intention is to demonstrate the false premise that a low ceiling allows to save on heating or cooling because, having less air volume, the equipment will heat the rooms beforehand.
When we affirm that the equipment heats up a volume of air before we forget that the heating equipment is not designed to heat the air of a room. They are designed to compensate for the heat losses that occur in the enclosures (doors, windows, exterior walls, ceilings and floors).
Likewise, a conventional air conditioning equipment is designed to absorb the heat produced by the various sources of heat that we can find (indoor air is not the largest) such as lighting, motors, appliances, machines, people, exterior ventilation, solar radiation and external heat transmission.
The ceiling height is not going to influence, only these contributions of heat from the outside in summer or heat losses in winter. We will have the same contribution of heat in summer even if we have a high or low roof. If perhaps, a little less because we happen to line the top of this false ceiling with bad heat elements (fiberglass, rock wool or similar). However, we can do the same thing without lowering the roof or lowering it just enough to add to the insulation.
Also in winter, we have loss of heat to the outside and to the premises and rooms not heated by the enclosures. Isolating the roof is a good solution to avoid a significant part of losses. A 50 cm air chamber in the false ceiling will not allow the heat to pass through the thin sheet of plasterboard and suffer the same losses as when we did not have it.
When it refers to comfortable temperature in a room, it talks about operating temperature which is not the air temperature of the room. The operating temperature is an average between the temperature of the air, the temperature of the objects present, the walls, the floor and the ceiling, the appliances and the people who are in it. Therefore, to heat a room you do not have to heat the air. You have to raise the temperature of all the objects present in it.
That is why, we must always keep in mind two things:
Avoid Losses (Insulation) to the Outside.
Heating the interior elements more evenly (hot air split units are not a good solution because they heat the air, they are cheap and fast but not very effective).
I have traveled a lot in winter and I have had to sleep outside the house in hotels where it is usual for them to be heated by equipment that heats the air. It is a common experience to turn on the equipment so that the air in the room rises rapidly in temperature. The moment you turn off the equipment to avoid the annoying noise that occurs, you realize that the walls and furniture are still cold, the air has dried unpleasantly and after a short time, the temperature of the room has been reduced until it is necessary to restart the equipment.