Ensure Effective Ductwork Design — The First Time Around

The federal Energy Star and Energy Savers programs state that the average home using forced-air heating and cooling loses 20 percent of conditioned air through leaks before it reaches the air-supply registers, and 60 percent of heat energy is lost in uninsulated ducts passing through unconditioned spaces. With that in mind, consider that the goal for ductwork design should be similar to that of the roof over your head – leak-free the first time around.

Ensuring efficient ductwork design

Sizing ducts is vital. A reputable contractor should calculate heat loss and heat gain, room by room, including details of window size, square footage, sun exposure and other factors. Ducts that are too small will put extra strain on the heating/cooling unit. Oversized ducts will compromise airflow and pressure.


A leaky duct may not drip water on your head, but it will put a drain on your wallet. Seal ducts securely at all connections with mastic and mesh, or aluminum tape (no duct tape!). If you ever notice a sudden and unusual increase in utility bills, or uneven heating and cooling in certain rooms, check for leaky ducts.


Insulation is primarily important for ducts located in unconditioned spaces of your home, such as the attic, basement or crawl space. Ducts in these areas should be insulated. Heat energy is easily lost through thin ductwork (or else infiltrates into the ducts during the summer).


Optimal airflow includes the unobstructed flow of air throughout your home, from the air-supply registers to the return grills, and back to the furnace. Obstructions may include kinked, leaky or damaged ducts, closed doors (sealing off air return), furniture, and dust and debris in the registers. Optimal airflow ensures neutral air pressure, helping to prevent outside air infiltration.


Ducts should take the straightest route from the air handler to the air-supply registers. Too many branches and turns hinders efficient airflow. Ducts shouldn’t be installed in unconditioned areas. If leaks occur or insulation falls away, air is quickly lost and energy is wasted.

If you take duct design seriously the first time around, this will help keep your family comfortable and save your household money for many years. Contact Geisel Heating, Air Conditioning & Plumbing today.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about ductwork design and other HVAC topics, download our free Home Comfort Resource guide.

Geisel Heating, Air Conditioning and Plumbing services Western Cleveland. Visit our website to see our special offers and get started today! For those Do it Yourselfers who would rather take control of your own indoor comfort, you can shop our online store for replacement parts, products and accessories!