According to the US Department of Energy, the average HVAC duct system is only 60-70% efficient. That means your HVAC system is not operating to its potential because air is not flowing through your space as it should. This leads to all kinds of undesirable consequences including energy inefficiency, higher costs and occupant discomfort. To make sure your HVAC system is working as it should, which includes a properly designed ductwork system, start by involving a knowledgeable HVAC design professional early in your design process. An experienced professional will work with the architect and contractor to do the following:

A DETAILED LOAD CALCULATION.

When your space has different rooms or areas with varying heating and cooling requirements, it’s important that load calculations be done for each room, rather than only for the space as a whole.

CHOOSE THE BEST LOCATION FOR HVAC EQUIPMENT AND DUCTS.

Ideally, the HVAC equipment will be centrally located to allow for the shortest possible duct runs. Ducts should be located in internal walls and ceilings to minimize the loss of conditioned air.

CHOOSE THE RIGHT DUCT SIZE AND LAYOUT.

Once all the system variables have been decided, your HVAC design professional can determine the most efficient ductwork design layout and calculate the correct duct size. Just like long runs impede air flow, bends in the ductwork that are too sharp or too numerous also decrease the amount of air that actually reaches the space to be cooled. To maintain balanced air pressure and air movement, your duct system needs return vents for air in the room to be pulled back into the HVAC system. Not providing enough returns is a common ductwork design flaw that leads to comfort complaints.

USE THE RIGHT MATERIALS, FITTINGS AND SUPPORTS.

Ductwork materials can vary depending on the requirements and the budget, but make sure your HVAC designer specifies the right materials for your needs. Flexible ducts (often called “flex”) made from reinforced plastic are less expensive and easier to install, but not as strong and durable as sheet metal. Ducts that are incorrectly supported can end up leaking cooled air into the walls where it won’t do any good to the occupants of your space.

ENSURE PROPER DUCTWORK SEALING.

Did you know that 30-40% of your conditioned air can be lost when duct joints are not properly sealed? The problem is compounded with high efficiency systems, which run longer at a lower capacity. Air is in the ducts for a longer period of time and so more can escape through leaky joints. Make sure your duct joints are sealed by experienced professionals to prevent leaks.

Select Mechanical can help with your Duct system design, fabrication and installation. To arrange a consultation, please call our offices at 925-447-1500 or send us a request for an estimate; bids@selectmechanical.net