How do you calculate sq. feet for air conditioning.width x length or do you include height ?

Question

How do you calculate sq. feet for air conditioning.width x length or do you include height ?

Answer 1

Normally an air conditioner is rated to cool a number of square feet, the volume of the area could also be a factor, but cold air tends to stay at floor level. if you use it i8n a high walled room don't use any fans.

Answer 2

Window air conditioners have designations of the size room that the unit will effectively cool. The room size is shown in square feet of floor space, or the dimensions of typical rooms is shown. This assumes an eight foot ceiling. This is a very rough generalization and will often lead to the over-sizing of a room window unit. Well, the manufacturers the stores and the A/C contractors are in the business of selling you the biggest unit they dare.

An 8000 BTU unit may work fine in a poorly insulated house trailer installed in the sun, but may be too big for the same size room of a well insulated masonry house with overhung eaves and shade trees.

But here we are speaking of around 100- 300 dollars for the usual range of window units.

When the big boys come out to play with the big bucks they calculate the actual cooling load based on the size, construction, climate, orientation, etc. This would be done for anything larger than a window unit, like for a whole house. And then experience can provide an A/C  contractor with his own guidelines (rules of thumb) in proper unit selection.

The people who put the sizing data on the box and the clerk at Walmart do not have a clue.

Answer 3

Area of the floor space is sufficient as the cooled air is more dense and will lie below the warmer air.

The packaging of room A/C units generally indicates the Btu's required for various room sizes in Square Feet.

For large buildings a combined Central A/C (and Heating Unit), is used that is graded in Tons of Refrigeration required for the Refrigeration section. In larger buildings, the volume to be cooled will be the more useful factor.

The Installers of such systems come along and calculate Volumes, Air Exchange Rates, Heat Exchange Rates, Fresh air make up quantities, expected quantity of Vented air..etc...all for Optimum Performance of the system.

1 ton of refrigeration is measured as 'The Number of Btu's required to freeze 2,000lbs of water at 0°C to ice at 0°C over a 24 hour period'.

This is expressed as 'Btu/Hr'.

2,000lb x 144Btu/lb = 288,000Btu / 24hrs = 12,000Btu/hr.

Answer 4

No, not for ordinary buildings like houses and offices.

When you are dealing with gymnasiums, auditoriums, large meeting rooms and ball rooms, you have to make life more complicated - it isn't just adding volume.