Manual J – Residential Calculations


Manual J – Residential Calculations

Manual J Load Calculations for HVAC Contractors


Outsourcing your manual J load calculations helps your business save time and money. The calculations for old homes and buildings help you plan the replacement HVAC system, and you can use calculations in a brand new building to create the right HVAC system. You must create a new business model that takes calculations from an outside vendor, and you will transform your business into a much more efficient operation. The business model explained below will help you get more work done accurately on every project you take.

When you buy a new air conditioning or heating unit to replace your old one, or if a completely new system is being installed in your new home, the installer needs to know how big or, more importantly, how small the unit should be. In order to know the proper size of the unit, the contractor needs to calculate how much cooling and heating capacity it must have to keep the occupants comfortable. This is called the load of the home.

The load of the home is partly dependent upon the home’s square footage. However, an accurate load calculation goes beyond that and includes:

icon-leaves  building construction

icon-leaves  orientation to the sun

icon-leaves  “R” value of the insulation

icon-leaves  number, size, and placement of rooms

icon-leaves  number, size, and placement of windows and doors

icon-leaves  types of windows and doors (thermal efficiency)

icon-leaves  number and arrangement of floors

icon-leaves  local climate

When determining residential load calculations, we take all these variables into consideration to help you make the best decision for comfort and efficiency.

What Is The Manual J Load Calculation?

The manual J load calculation is a systematic method of evaluation to estimate heat loss, sensible and latent heat gain; an account of the total heat flow into or out of a home (depending on time of year). The calculation covers the entire building, each floor of the building and each room in the building. You must have a calculation that explains where the heat loss or heat gain in the building is to be directed, and the calculation must be perfect. You will use calculations from the vendor to plan all your projects, and each calculation can be shared with the owner of the building. This sort of working partnership makes planning for each project much simpler, and you will feel confident knowing that you have made the right decision.

Why Not Do The Calculations Yourself?

The manual J load calculations that you take on your own take entirely too long, and your crew members may not have time in the day to do the calculations during a service appointment. Sending a third-party to the customer’s address will help your crew members move on to other locations. Your schedule is extremely tight, and you should not waste time doing a calculation that you can hire someone else to do for you.

Absolute Accuracy

The accuracy of each calculation is practically guaranteed when you start work on each new project. A company that does manual J load calculations all day can complete the job in a few moments, and you will learn quickly that the vendor will get the job done when you have no time to waste. One of your crew members may take too long to get the calculation done, but someone who does these calculations every day will get the job done when there is no time left.

Scheduling Your Appointments

You may work with your customers to create appointments for the calculations, and you can create appointments in a matter of moments. Each calculation is done at the leisure of the customer, and you are forwarded the paperwork when the job is done. You need not wait for the paperwork to come in the mail, and the customer will hold their own copy of the calculation. You may begin selling your customer the correct HVAC unit, and work on the installation can begin immediately.

Hiring another vendor to calculate your manual J load calculations will help you move to new projects every day. Your own technicians will not waste time on the calculations, and you are sure the job was done right. Design your HVAC systems using accurate calculations designed by a professional.

To schedule a Manual J Load Calculation or any other service, contact us!


(772) 263–3265



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