Evaporative Cooling
or
Mechanical ??

A common question asked by customers and friends is should I install a Evaporative cooler (never refer to them as "Swamp Coolers - people have a negative view to the word "Swamp".) or Mechanical cooling.  If you live in a coastal or tropical region, you probably never hear this, because "evap' cooling is not very efficient when your ambient air is full of humidity. 

If your wet bulb temperature is around 60 % and higher, then mechanical cooling is the correct answer. 
In lower wet bulb regions a properly sized evaporative cooler can be a very cost- effective and comfortable choice.

Sizing is the key.
A good rule of thumb is to have 1 air change every 3 minutes in northern states, 1 air change every 2 minutes in the mid section and 1 air change every 1-2 in the southern states.

Example: A home that is 30' wide , 40' long 7'high has a total of 8400 cubic feet of area to be cooled.  30x40x7 = 8400 Using the factor two (for an air change every two minutes), divide 8400 by two to give you the CFM required, in this case 4200 CFM. In this case you would want to get a 4800 CFM cooler.

Another important factor is "Exhaust Air'.  A good cooler design is to exhaust slightly more air then your cooler is supplying, this can be done with windows or doors being open slightly or a sized exhaust fan inter-locked with the cooler. 

Having enough air exhausted is important so that there is negative air pressure in the conditioned space, positive air will cut down your blowers capacity.
A big advantage to evap coolers is that the capacity can be changed easily by adjustable pulleys to increase or de-crease air flow.  If you open your front door and the pressure slams it shut then, you need more exhaust openings, such as a window or another door.

Mechanical cooling cools no matter what the humidity is and usually increases your home value more then a evap cooler, but a well designed evap install, cost less to install and hardly noticeable on your utility bill.

A few notes for evaporative cooler maintenance:

• The more frequent pads are changed the better - don't try to get 2-3 years out of pads. Twice a season is good (although seldom done, even at my house).

• Water treatment - many types of cooler treatment tablets are available.  These tablets usually not only control corrosion but also freshen the air.

• Oil the motor and bearings - Most evaporative cooler motors do have oil
  ports.  Use SAE #20 non-detergent oil.

• Check for proper belt tension, and amp draw

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