New homes with central heating and/or air-conditioning rely on ductwork that runs through the frame of a house and delivers warm or cool air to each of the rooms. Ductwork is broken up into components and functions much like a home's lungs: some ducts carry the warmed or cooled air (the supply duct); others return the old air back to the heating and air conditioning units for cleaning and reconditioning, (the return duct).

Ductwork is also needed to supply air to ventilation fans in bathrooms and above the kitchen stove.

Where a duct terminates at a wall or floor, the opening is called a register, which is usually covered by some kind of grill.

Proper placement of registers is critical to the efficiency of your new home's HVAC (heating, ventilation and air conditioning) system. Each room, from largest to smallest, will need to have at least one supply and one return duct. The ductwork runs through the home's framework eventually hidden beneath floors, behind drywall and above ceilings. The sub-contractor will cut, fit and install the duct on site.

Generally, the ductwork in your new home will be fabricated from sheet metal or insulated flexible fiberglass tubes.

The most important thing to check with your builder is that ductwork is tested for air leaks. Heating and air conditioning units account for 40 per cent of our energy bills, so they need to be as efficient as possible (not to mention the reduced comfort levels when the hot- or cool-air systems are not working to maximum efficiency).

Ducts can leak for many different reasons, such as a puncture from a nail, unsealed joints, or vents that are not properly attached.

To ease the risk of crimping or kinking, the builder will generally locate the heating, ventilation and air conditioning unit as close to the centre of the home as possible.

This will help to reduce the amount of ductwork needed to reach each room.

The ducts should also be checked for any kinking or sagging that could happen when a duct has to run around a tight space or corner.

Ducts in attics, walls and crawlspaces should be fastened and insulated.

The ducts should also be laid out with as few bends and turns as possible. Larger homes may require more than one HVAC unit.

It's important to have your "duct" in order; not only will the home be more comfortable, but you'll save money on your energy bills as well.

Cheryll Gillespie is a nationally syndicated Design and Décor columnist.