5 Ductwork Design Mistakes to Avoid

duct system design

There are many considerations to make when designing a new residential or commercial property, but one of the things that will make a California, Nevada, or Arizona homeowner or business owner most happy is a heating and cooling system that works correctly and efficiently. But where should you start?

According to ENERGY STAR®, the average home or commercial building loses 20–30% of all air moving through its ductwork due to leaks and mistakes in the ductwork design. An underperforming ductwork system can lead to:

  • Increased energy costs

  • Hot and cold spots throughout the house

  • Unnecessary wear and tear on your HVAC system

  • Drafts and stuffy air

  • Poor indoor air quality

The initial planning—which includes both duct design and HVAC load calculation—before installing a ductwork system is very important, and the overall performance can be significantly impaired by subpar duct design. Here are five ductwork design mistakes and how to avoid them.

1. Duct Runs That Are Too Long

The further your conditioned air has to travel, the harder your system will have to work to get it there. It is also more likely that air will be lost through leaks in ductwork along the way, or that the conditioned air may not ever even reach its intended destination. HVAC protocol like manual D duct design is intended to make sure that ductwork and central HVAC elements are laid out in a location that minimizes long ductwork runs as much as possible.

2. Undersized Ducts

When paired with undersized ductwork, furnaces, air conditioners, and heat pumps have to work much harder than otherwise necessary to heat or cool a home. Think of it like trying to go for a run but only being able to breathe through a straw. HVAC duct sizing is crucial to a system’s high performance, and determined the correct size for your latest building project starts with a heat load calculation—in residential homes, you would use a manual J load calculation developed by ACCA (Air Conditioning Contractors of America); in commercial businesses, it’s a manual N load calculation—which will help calculate how much heating or cooling is needed for each room.

3. Air Leaks in Ductwork

Making sure that ductwork is sealed properly and preventing conditioned air from escaping into the walls and ceilings of a home or property is an essential component of a duct system’s efficiency. Duct sealing should be done with mastic gum or metal-backed tape, by an HVAC professional.

4. Sharp Bends in Ductwork

Similar to long runs, sharp bends or too many turns in a ductwork system will drastically increase how hard a system has to work to move conditioned air. Planning and laying out HVAC duct design in advance to minimize complex duct pathways will result in significantly better performance.

5. Not Enough Ductwork Returns

A properly-functioning forced air system results from a balanced loop of air being pushed out through the supply vents and then circulated back through the system via the return vents. But a common problem we see with existing systems is a lack of return ducts. When the furnace, air conditioner, or heat pump can’t get enough air back into the system, it can’t create more conditioned air to continue heating or cooling the house or building. 

Choose Balanced Comfort for Ductwork Done Right

The first steps involved in any forced air HVAC system should be accurately calculating how much heating and cooling power a home or business will need, as well as how the ductwork needs to be laid out to most efficiently supply conditioned air to the entire home or business. At Balanced Comfort, our engineering professionals conduct a number of detailed heat load calculations that will help create the best-sized and designed ductwork system for your project. 

Make sure you design the right ductwork for your building project. Call (559) 421-8814 or contact us today for expert engineering advice.

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