Good Ductwork Design: Some Guidelines

The way the ductwork in your house is designed is as important as the way it's built. You may not have thought about it, but good ductwork design can make a noticeable difference in your energy bills. Badly designed ductwork won't work efficiently, and it can wear out your HVAC system by making it work harder than it should. You'll also have trouble keeping your home at a comfortable temperature. 

Guidelines for good ductwork design:

• The ducts should be located inside the air conditioned or heated part of the house. Ducts in the non-conditioned areas will work less efficiently. When it's necessary to install a duct in the attic or crawlspace, use an insulation with a higher rating than required. This is also important when your home has a variable-speed furnace and air conditioner.

• All the joints between ducts need to be fastened together mechanically. They also need to be sealed with mastic (a type of putty) and fiberglass mesh. The installation crew should also check for air leakage after the install and confirm it doesn't exceed five percent of the total air flow rate.

• Hard ductwork is preferred over flexible styles. If you're retrofitting an older house, you may need to use flexible ductwork, but it's less efficient than hard ducts and easier to damage. It's also hard to install and seal correctly.

• Dampers (the device inside the duct that regulates airflow) work better when they're installed closer to the end of the duct instead of near the supply register. This allows you, or the installer, to more accurately balance the system. The dampers also need to be fixed in position after balancing.

• Supply outlets (the vents that supply conditioned air) should be on interior walls so the heated or cooled air has less distance to travel.

• If you have a larger two-story house, think about installing two separate heating and cooling systems with separate ductwork. Two systems, along with good ductwork design, will work more efficiently in two-story or large homes.

If you're building a new home, and need quality ductwork design, contact Air Assurance in Broken Arrow.

Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). 

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Good Ductwork Design Will Pay Off In Savings And Comfort

With new home construction, good ductwork design must begin with the blueprints for greatest energy efficiency, heating and cooling performance, and uncompromising comfort year after year. Follow these duct-design principles to maximize your investment.Principles of good ductwork design Balanced air flow throughout your home involves equal air movement through the supply and return ducts, which is made possible by correct duct sizing, location and sealing, and an unobstructed pathway for air circulation from registers to grilles.If these criteria are not met, problems often develop, such as pressure drops at the air handler, extra work for your heating and cooling systems, and moisture accumulation in walls, ceiling and/or floors that invites mold growth.

• To correctly size your new duct system, Manual J and D by the Air Conditioning Contractor of America must be used. Manual J is used to calculate heat gain/loss for each room of your home. With the measurements for heating and cooling requirements in hand, your HVAC professional uses Manual D to design the size and layout of your ducts.

• It’s important where ducts, registers, grilles and the heating and cooling systems are located in your home. The heating and cooling systems should be in a central location to allow for shorter, straighter duct runs. Registers and grilles should be installed on inner walls, preferably with a return grille in each room that contains a supply register. To minimize heat loss (wasted energy) through duct walls by conduction, ducts should be installed in conditioned areas like sealed chases, suspended ceilings, corners of rooms and raised floors. Utilize Y-branches for run-offs rather than T-branches for efficient air flow.

• Properly sealing ductwork is an essential component for good ductwork design. Mechanically seal metal duct joints with screws and mastic sealant. Mastic sealant and compression straps are used to seal flex ducts. Install an expansion collar at the trunk and plenum to minimize stress and noise.

If you have questions about good ductwork design, please contact Air Assurance. For more than 30 years, we've provided top-quality service and installation for the Greater Broken Arrow area homeowners.Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). Image courtesy of Shutterstock

Air-Conditioning Factors That Determine Correct Sizing Procedures

If you want optimal performance from your new high-efficiency air conditioning system over the long-term, ask a comfort consultant to perform a proper load calculation. If your system is improperly sized, your household comfort and annual energy costs are bound to suffer.Indications of improper sizing include:

• Inconsistent temperatures.

• Humidity fluctuations due to improper system cycling.

• Spiking energy costs.

To ensure that your cooling system is properly sized, insist that your comfort consultant do more than simply look at the nameplate of your existing air conditioner. In most cases, older systems are oversized for your current home because its cooling demands have been reduced by improvements in household energy efficiency such as weatherproofing, duct sealing and insulation upgrades. Plus, these days a smaller A/C can cool more efficiently than a comparably sized unit a decade ago. Thus, attempting to size a new air conditioning system based on the old model in your home can be highly inaccurate.TulsaorBroken Arrowarea residents should ask their comfort consultant to perform a load calculation based on a nationally recognized sizing method such as the Air Conditioning Contractors of America’s Manual J. Using this method, your comfort consultant will consider unique sizing factors such as:

• The climate of this part of Oklahoma.

• The size, layout, and orientation of your household.

• The adequacy of your insulation.

• Window location, type and size.

• Potential air leaks.

• Efficiency of ductwork design and installation.

• Duct sealing.

• Household occupancy.

• Family routine and comfort preferences.

• Efficiency ratings of light fixtures and major appliances.

These are just some of the factors your technician should consider when performing a proper load calculation.With every household being unique, checking the nameplate simply won’t cut it when it comes to the proper sizing of your new air conditioning system. If you’re in the market for a new air conditioner, let our trained comfort consultants personally assess the appropriate sizing needs of your household. For expert consultation, contact Air Assurance today.Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information, click here.Air Assurance services Tulsa, Broken Arrow and the surrounding areas. To get started, check out our website or see our current promotions.

A High-Efficiency HVAC System Calls For Expert Ductwork Design And Installation

As a homeowner, you most likely understand the importance of sealing and insulating your air ducts to reduce energy loss. Did you also know that ductwork design and installation plays just as important a role in your home’s efficiency? Unfortunately, the U.S. Department of Energy estimates, up to 75 percent of homes could be losing as much as $200 annually due to poorly designed ductwork.Ductwork design done right works hand in hand with your heating and air conditioning system. It should be able to distribute the conditioned air evenly throughout the house.Especially when combined with a high-efficiency system, ducts that aren’t correctly sized can compromise performance. If you’ve recently replaced your HVAC system with a higher efficiency unit, but haven’t updated your ductwork, you could be losing energy.Efficient ductwork design should take into account the floor plan of the house, including potential obstructions, roof hips, fire-walls, and the direction of joists. It should also cater to the specific airflow load required for each room. This helps maintain overall comfort and pressure levels throughout the house.Sheet metal is the most efficient material for ductwork, due to its smooth surface, which facilitates airflow. Another design factor contributing to performance are smooth curves as opposed to sharp angles. Sharp angles can cause the air to “wrinkle,” slowing it down in the system. It’s also important to maintain neutral pressure with return supply vents in every room, or at least one vent in a central location on each floor.As conditioned air moves away from the core of your high efficiency HVAC system, it loses energy. Because it has less energy, it needs a more compact space to move through. That’s why ducts should get smaller as they branch through your home. It keeps air flow circulating without becoming sluggish.Don’t compromise the performance of your high efficiency HVAC system with low efficiency ductwork. Call Air Assurance for expert ductwork design. We'll be happy to give you a professional evaluation, update your ducts, or simply to answer your questions.Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information, click here. Air Assurance services Tulsa, Broken Arrow and the surrounding areas. To get started, check out our website or see our current promotions.

Airflow Issues? Maybe Your Ductwork Design Needs A Look

Air ducts guide warm or cool air through your home from the HVAC system. Many people are aware that duct sealing is important for efficient air flow, but ductwork design also plays a key role. Ducts should keep each room in the home at relatively the same temperature, and keep air cycling through your house with return air flow preventing the build-up of too much pressure in some rooms and not enough in others. Proper air flow takes strain off your HVAC system and increases efficiency, yet the U.S. Department of Energy indicates that many US homes suffer from poor ductwork design, leaving air distribution lagging as low as 60 percent.How do you know if you have air flow or ductwork design issues? Some things to watch out for are unusually high utility bills, ductwork located in places like the attic or garage, and ducts with kinks or tears in them, which inhibit air flow. Other warning signs include rooms that always feel stuffy, and rooms are too warm or cold. If you are able, take a look at where your ducts attach to the furnace distribution box.  If you can feel warm or cold air coming from this area, you are paying to cool or heat your attic. Keeping your ducts well-sealed helps, but it won’t do much good if you’re also dealing with poor duct design, in fact sometimes, it can actually cause more harm in the areas of operation, safety, and indoor air quality.Good ductwork design must work hand in hand with your HVAC system, evenly distributing the same amount of air flow your system produces. If you’ve replaced your HVAC system, but not your ductwork, this could be an issue. The ducts should get smaller as they branch out from the core, like streams branching off a river. They naturally get narrower, enabling less water to flow with the same amount of energy. The angles of the duct design should be smooth and curving as opposed to sharp, which can cause air to “wrinkle” instead of flowing smoothly. The return duct system should have a vent in every room, or at least in central areas of the house and the size of that duct or opening is probably most important. Jumper ducts can be installed to increase the efficiency of your return system.Ductwork design and air flow issues in general can be difficult to diagnose and fix yourself. Give Air Assurance a call if you’re concerned about the circulation in your home!Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about ductwork and other HVAC topics, click here to download our free Home Comfort Resource guide. Air Assurance services Tulsa, Broken Arrow and the surrounding areas.  To get started, check out our website or see our current promotions.