Power of Psychrometric Chart Analysis…

It is much, much simpler than it sounds. Psychrometric chart analysis can be used, and in fact, recommended to be used if you are at the cross road.

Air conditioning, OR no air conditioning?

It is the first step in air conditioner buying guide.

I suggest, we go through psychrometric chart page, if you need to know more about it.

Moving on. A quick glance into the comfort zone.

Comfort zone is the area where most people will be comfortable.

The area, or region was concluded by ASHRAE, after gathering sample from a very large group of people.

We have to plot this area inside the psychrometric chart, before we can proceed further with the air conditioning, "million dollar question".

Air conditioning requirement analysis:

Let us use four major regions within a psychrometric chart, to simplify the analysis. These are stated RELATIVE to the comfort zone. Region with,

  • high dry bulb temperature, high relative humidity area.

    If the temperature and humidity plot of your local area falls within this region, then consider buying or renting an air conditioning unit.

    Reasons being, air conditioning unit will cool the air by lowering the dry bulb temperature.

    It will also remove humidity by condensing water vapour

  • high dry bulb temperature, low relative humidity area

    Your money will be best spent if you chose humidifiers, if this is the case.


    Humidifiers will introduce water vapour into your air. Since the relative humidity is low, the water vapour will absorb heat and occupy the air space.

    Relative humidity will increase to the comfort region and dry bulb temperature will decrease as a result of heat transfer

  • low dry bulb temperature, high relative humidity area.

    You have two options in this case.

    If the absolute humidity of the space is within the comfort region, then an air heater will do the trick. Air will be heated through sensible heating.

    If the absolute humidity of the air is higher than the comfort region, then a dehumidifier is the best option. Outlet temperature of the humidifier will be higher, at a lower humidity.

  • low dry bulb temperature, low relative humidity area.

    This should remind you of winter season.

    Air conditioner for heating, plus humidifying action is the best.

    As the temperature rises through sensible cooling, relative humidity will decrease. Thus, addition of water vapour into the heated air will increase its humidity.

Zone psychrometric chart, to determine the type of air conditioning you need

That’s it for psychrometric chart analysis for air conditioning. I promised you it’s simpler than it sounds.

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