Support and Resources for the Domestic Energy Advisor

Single or double cant bays

On many of the properties that you assess you will almost certainly find bay windows to the front elevation of the dwelling usually to both the ground ( lowest ),and first( lowest+1 ) floors. These have to be included within the floor area calculations for each floor.

In arithmetical terms these shapes are known as trapeziums and to determine the areas of these bays we use the following calculation.

( Using some example dimensions )

Front of bay	Rear of bay	Average	Projection	Area
A	B	C ( A + B / 2 )	D	E ( C x D )
2.650	3.568	3.109	0.650	2.021sq metres

You can, of course,use the online calculator

Semi-circular bays

On many of the properties that you assess you will almost certainly find bay windows to the front elevation of the dwelling usually to both the ground ( lowest ),and first( lowest+1 ) floors.

These have to be included within the floor area calculations for each floor.

In arithmetical terms these shapes are known as semi-circles and to determine the areas of these bays we use the following calculation.

( Using some example dimensions )

Width of bay	Projection	Area
A	B ( A / 2 )	( 3.142 x B x B / 2 )
5.700	2.850	12.760 sq metres

You can, of course,use the online calculator

Segmental or curved bays

In arithmetical terms these shapes are known as segmental and to determine the areas of these bays we use the following calculation.

( Using some example dimensions )

Rear of bay	Projection	Area
A	B	(A x B x 2 / 3 )
2.850	0.550	1.045 sq meters

You can, of course,use the online calculator

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