Register. This is usually located in the wall about 12 inches above ground level, and will have a lever to adjust the vanes. The warmth to the room is delivered through the register.

Grille. This is usually sited high in walls or doors and does not have a lever for adjustment. Grilles allow circulation of air throughout the dwelling.

Diffusers. Sited in either the floor or ceiling, these are adjustable and deliver warmth.

Ceiling Diffuser

Floor Diffuser

What size replacement do you need?

‘Nominal sizes ‘ are the dimensions of the duct opening into which a register, grille or diffuser will fit.

REGISTERS & GRILLES
Sizing guidance

a) Register & Grille sizes are based on the duct they cover; therefore the best method of sizing is to remove the Register or Grille and to measure the duct. Measurements are normally taken in inches. Measurements are taken width (length) A x height B as diagram below. (Note, the measurement in inches in each case is usually an even number.)

DIFFUSERS
Sizing guidance

a) Diffusers sizes are based on the duct they cover; therefore the best method of sizing is to remove the Diffuser and to measure the duct. Measurements are normally taken in inches. Measurements are taken length (longest) A x width B as diagram below.
(Note, standard diffusers are usually 10,12 or 14 inches in length and 2 or 4 inches wide.)

b) Should removal of the Diffuser not be possible at the time of measuring, measure the opening / grille area of the Diffuser. Measurements are again taken length (longest) A x width B as diagram below, then add approximately ¾in to the length and ¼in to the width to find the nominal size of the replacement Diffuser.
(Note, standard diffusers are usually 10,12 or 14 inches in length and 2 or 4 inches wide.)

It is recommended that when ordering Registers, Grilles or Diffusers that you check with our sales department to ensure you have understood this guidance.