load calculation

HVAC System

What Is a Manual J Load Calculation?

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Some HVAC terms are easy to understand while others may leave you scratching your head. For many Broken Arrow area homeowners, Manual J load calculation is definitely in the latter category. Not only is it the first step towards choosing the right HVAC system for your home, but it’s also an essential step.

Developed by the Air Conditioning Contractors of America, Manual J load calculation offers homeowners and contractors a way to properly size up a home’s HVAC needs and design an HVAC system that offers the best performance and efficiency match.

How Manual J Benefits Your Home

Different homes have different heating and cooling requirements and it’s easy to choose an HVAC unit that’s ill-equipped to handle your home. Depending on the age-old “rule of thumb” often results in an HVAC system that’s either underpowered or overpowered for the given environment. The former can make your home unbearable during the summer while the latter wastes energy while increasing overall discomfort.

Manual J lets contractors choose the right HVAC system by calculating a home’s precise heating and cooling needs. A typical Manual J calculation takes many of the following factors into account:

  • Square footage

  • Building materials

  • Location and directional orientation

  • Heat gain and loss throughout the entire home

  • Current HVAC system size and type

  • Insulation levels

  • Window types

  • Duct leakage

Using specially designed software, contractors can recommend an HVAC system that provides optimal comfort without using too much energy or wearing out early. Manual J load calculations are commonly done in conjunction with other ACCA design protocols, including Manual S equipment selection and Manual D ductwork design.

No HVAC system replacement should start without a Manual J load calculation. Contact Air Assurance today and let us take care of your heating and cooling needs, using the latest in modern HVAC technology.


How to Assess Your Broken Arrow Home's HVAC Needs

How to Assess Your Broken Arrow Home's HVAC Needs

Buying a new HVAC system for your Broken Arrow home is a significant investment. Apart from the initial costs, you'll need to consider additional costs such as the monthly energy bills, repairs, and maintenance. You'll want to invest in a system that best meets your home's HVAC needs.When it comes to heating and cooling systems, size matters a lot. An HVAC unit that's too big for your home will keep short-cycling and never achieve peak efficiency. It will drive up your energy bills. An undersized unit will run more frequently than needed, wasting energy in the process.So how do you know the right size for your HVAC needs? Here's what you should consider:

Square Footage

Determining your home's square footage is crucial to correct HVAC system sizing. You or an HVAC contractor can get it by measuring each room with a tape measure.

BTU Rating

To enjoy maximum efficiency, you should purchase a system with a suitable BTU (British Thermal Unit) rating. Follow the guidelines below to find out the BTUs you'll need for a room:

  • Under 150 feet – 5,000 BTUs

  • 150-249 feet – 6,000 BTUs

  • 250-299 feet – 7,000 BTUs

  • 300-349 feet – 8,000 BTUs

  • 350-399 feet – 9,000 BTUs

  • 400-499 feet – 10,000 BTUs

  • 450-549 feet – 12,000 BTUs

  • 550-699 feet – 14,000 BTUs

  • 700-999 feet – 18,000 BTUs

  • 1,000-1,199 feet – 21,000 BTUs

  • 1,200-1,399 feet – 23,000 BTUs

  • 1,400-1,499 feet – 24,000 BTUs

  • 1,500-2,000 feet – 30,000 BTUs

  • Over 2,000 feet – 34,000 BTUs

If an HVAC unit is to be used in your kitchen, increase its capacity by 4,000 BTUs. If a room is often occupied by more than two people, you should add 600 BTUs for each extra person. Increase the unit's capacity by 10 percent if a room is very sunny. Reduce the capacity by 10 percent for a heavily shaded room.

By purchasing an HVAC system that's properly sized and efficient, you'll enjoy maximum comfort as well as energy savings. For the best solutions to your HVAC needs in the Broken Arrow area, please contact us at Air Assurance.

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). For more information about HVAC needs and other HVAC topics, call us at 918-217-8273. Credit/Copyright Attribution: “geralt/Pixabay”

Duct System, Featured, Load Calculation, Service & Maintenance

Guide to Understanding Manuals J, D, and S

Guide to Understanding Manuals J, D, and S

During an HVAC system installation, there are several important technical elements that must be taken into account to ensure the system is correct for your home and that it will work at its best. The Air Conditioning Contractors of America (ACCA) publishes three technical references that provide all the guidance, procedures, and best practices that your HVAC professional will need for a successful installation. Here is a brief introduction to Manuals J, D, and S, and what they cover.

Manual J Residential Load Calculation

Manual J provides all the technical guidance necessary for a residential load calculation. Each building has a heating or cooling load, which is the amount of heating or cooling needed to keep the inside spaces at the temperature the residents prefer. A load calculation takes into consideration multiple thermal and physical characteristics of the building to determine its load. Once your HVAC professional knows the building's load, he can easily guide you to the type of HVAC equipment that has the functional capacity to satisfy that load.

Manual D Residential Duct Systems

Manual D covers the ductwork in residential settings. The HVAC system ductwork is the network of pipes that directs heated or cooled air from your HVAC equipment to the inside of your home. Ductwork must be properly designed, installed, sealed, and insulated to ensure it carries conditioned air without loss of energy and without wasteful air leaks.

Manual S Residential Heating and Cooling Equipment Selection

Manual S includes detailed technical specifications and performance information on multiple brands of air conditioners and heat pumps. This type of data helps your HVAC pro choose the best equipment for your particular needs. Manual S also provides additional information on equipment sizing, ventilation, and air distribution.

With more than three decades of experience in the HVAC industry, Air Assurance brings top-quality sales, installation, maintenance, and repair to customers in Tulsa and the neighboring communities. Contact us today for more information on Manuals J, D, and S and how these important technical references are used to ensure the best possible HVAC performance in your home.

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). Credit/Copyright Attribution: “Tang Yan Song/Shutterstock”


Confused About Furnace Efficiency Ratings? Here's Your Expert Guide

Confused About Furnace Efficiency Ratings? Here's Your Expert Guide

If you're in the market for a new furnace, one of the first things you'll encounter are furnace efficiency ratings. These ratings tell you how much of the fuel the system uses that goes directly into your home as heat and how much the furnace wastes. There's a close relationship between the ratings and the size and price of the furnace you need for your home.

The efficiency ratings for gas furnaces are called AFUE (annual fuel utilization efficiency). The minimum starts at 80 which means that the furnace uses 80 percent of the fuel it consumes for heating your home and it wastes 20 percent of the gas up the chimney or elsewhere. Systems are available with AFUE ratings as high as 99 percent, indicating they waste a mere 1 percent of the fuel they use.

Furnaces whose AFUE ratings are over 90 are usually condensing furnaces and they use a second heat exchanger to extract the heat from the water vapor burned gas creates. These systems have a slightly different configuration than the normal gas furnace and a higher price tag, but their efficiency promises significantly lower energy bills for years to come, offsetting the cost. Some units provide up to 98% efficient capabilities!

Mid-range furnace efficiency ratings have AFUE ratings in the mid-80s and if your home won't easily accept a condensing furnace, such a furnace is likely to provide you with higher efficiency than your current system offers. Some of these use two-stage heating, an energy saver when temperatures are milder and your home's heating needs are lower.

The size you need and the AFUE rating are related. Since a furnace with a higher AFUE puts out more heat, you may not need as large a system, which generally costs less. The HVAC contractor you work with should perform a load calculation using Manual J and S, both of which take into account the variables in your home that contribute to the system size you need.

To learn more about furnace efficiency ratings, contact the pros at Air Assurance, providing outstanding HVAC services for homeowners in the Broken Arrow area since 1985.

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

HVAC system

HVAC Contractor Hire Seem Daunting? It Needn't Be

HVAC Contractor Hire Seem Daunting? It Needn't Be

HVAC Contractor Hire Seem Daunting? It Needn't Be

Selecting the right HVAC contractor to install your new air conditioner or furnace is just as important as the equipment you choose. Proper installation is required for optimal safety, efficiency and reliability. Don’t be daunted by the task of hiring the right HVAC contractor. Instead, use this guide to aid you in your selection.

  • Ask friends and neighbors for recommendations: Their experience with a reputable contractor is a great place to start.

  • Call the contractor: Pay attention to how you’re treated on the phone. Reliable contractors are professional, prompt and courteous. Look for these features as they make their first impression.

  • Look for professional affiliations: North American Trade Excellence (NATE) is an organization that trains and certifies HVAC technicians. Trust the job to a NATE-certified tech for the best experience possible.

  • Seek estimates: This provides you with a price comparison. However, don’t give your business to a company that attempts to provide an estimate over the phone, since a load calculation must be performed before equipment size, and therefore cost, can be determined. In addition, think twice before accepting the lowest bid. Remember, you get what you pay for.

  • Ask about sizing techniques: With the cost estimate in hand, ask the HVAC contractor what sizing method they used to produce this estimate. If the contractor’s response is that they used the square footage alone to determine equipment size, wave them out the door. This rule of thumb is not accurate enough to give you the best results. Look for a contractor who uses formal sizing techniques found in Manual J.

  • Get everything in writing: A trustworthy HVAC contractor will provide a written proposal with details about the job at hand, such as the work to be done, labor costs and overall project price. The contractor will insist you sign a contract before work begins and ensures all changes are added and initialed as needed.

Please contact Air Assurance Heating, Air Conditioning & Plumbing to work with a qualified HVAC contractor who can meet or exceed your expectations in every way. We have proudly served the Broken Arrow community since 1985.

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

Service & Maintenance

How Manuals J and D Help You Get the Right Size HVAC

How Manuals J and D Help You Get the Right Size HVAC

How Manuals J and D Help You Get the Right Size HVAC

When HVAC professionals size the cooling and heating system for your home, they use software called Manuals J and D. These software applications eliminate the guesswork involved with HVAC sizing. Manual J covers the size of the equipment, while Manual D addresses the ductwork design and its capacity. The longevity of the system, your energy bills and comfort are driven by the correct size for both.Manual J takes into account the conditioning load of your home, which includes these factors:

  • Cubic footage

  • Floorplan layout

  • Number of windows, their orientation to the sun and efficiency

  • Insulation levels in the walls and attic

  • Air infiltration levels

  • Heat-producing appliances and your lighting types

  • Preferred indoor temperatures

  • Number of household members and their ages

  • Landscaping factors.

Once the contractor completes Manual J, he or she moves onto Manual D to determine the ductwork configuration and size you need. The layout of your home makes a difference in ductwork design, especially if you have an open floorplan or high ceilings. Another benefit of starting the HVAC replacement process with the load calculation using Manual J is seeing how improving insulation levels and sealing air leaks would lower the size of the HVAC system you need.Using Manuals J and D eliminates the risk of installing too large or small a system. When they're too small, they won't be able to keep up with the conditioning load during weather extremes. Systems that are too large short-cycle, which means they run for short periods more frequently.Short-cycling causes higher energy bills and more wear and tear on the system. During the summer, air conditioners that run for brief periods won't remove as much humidity or airborne particulates, like pollen, dust and pet dander. In the winter, the heating system won't run long enough to thoroughly warm solid objects in your home, which causes the furnace to turn on more frequently.If you're searching for a new HVAC system and would like to learn more about Manuals J and D, contact Air Assurance. We've provided HVAC services in the Broken Arrow and Tulsa areas since 1985.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

HVAC system

11 HVAC Terms Every Tulsa Area Homeowner Should Know


When it comes to heating and cooling a Tulsa-area home, homeowners are at a disadvantage. Why? HVAC terms require time to understand them, and heating and cooling is generally not an area of expertise for the average homeowner. With just a little knowledge under your belt, however, you can use these HVAC terms to effectively communicate with your HVAC technician the next time your equipment requires service or repair, or you’re ready to upgrade. Here’s what you need to know:

  • Seasonal Energy Efficiency Ratio (SEER), the cooling efficiency rating that reveals a unit’s performance capacity. This rating is used with central air conditioning and heat pumps

  • Annual Fuel Utilization Efficiency (AFUE), the rating used to show the efficiency potential for furnaces (and boilers)

  • Heating Seasonal Performance Factor (HSPF), the heating term used to show a heat pump’s potential for heating efficiency

  • Air handler, the unit that’s located indoors. Consisting of a motor and a fan, the air handler pushes conditioned air into the home

  • Condenser, or the heat exchanger, employed in air conditioning and heat pump systems to condense refrigerant into a liquid, which facilities heat transfer

  • Heat exchanger, a separate component of the furnace that helps to transfer heat that’s generated by the burners

  • Ductwork, the system of interconnected pipes that snake throughout your home to supply conditioned air to the living spaces

  • Ventilation system, a mechanical device that encourages air circulation in the home, and facilitates the equal exchange of outgoing and incoming air

  • Air filter, the device that filters out impurities from the air before that air supply moves into the heating/cooling system

  • Load calculation, a method for calculating the home’s unique heating and cooling load, which is used to help the contractor select the right-sized system

  • Manual D, the methodology employed when sizing ductwork

  • Manual S, the method used to size the heating or cooling system, used in conjunction with the load calculation

With a few HVAC terms under your belt, contact Air Assurance Heating, Air Conditioning & Plumbing for more information about installing, repairing or maintaining your home’s heating and cooling systems. We've served homeowners in greater Broken Arrow for nearly 30 years.

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