# Bright Hub Engineering

## What is HVAC Heat Load Calculations? Part 4: Process of Heat Load Calculations - 2

written by: Haresh Khemani • edited by: Lamar Stonecypher • updated: 11/27/2008

After surveying the building, the actual process of the heat load calculations will start. The actual heat load calculations can be carried out manually or using HVAC software.

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### 2) Carrying out actual heat load calculations

Let us continue with the process of heat load calculations:

2) Carrying out actual heat load calculations: After surveying the building, the actual process of the heat load calculations will start. The HVAC designer compiles all the data that has been collected during the building surveying. Thereafter lengthy process of complicated process of calculations will start. There are two possible methods of carrying out heat load calculations: manual and by using software. Let us see both of them

• Manual process of heat load calculations: In this method a number of readymade tables are usually used. The data taken from the building survey is manually written in these tables and various calculations are carried out manually. The heat absorbed from various sources like wall, roof, and windows is calculated by inputting their sizes and number. Similarly, heat released by electrical and electronic appliances calculated. Finally, the heat generated inside the room from various sources is calculated. Based on these calculations the HVAC designer recommends suitable type and tonnage of air-conditioning system required for the room.
• Using the software: Now-a-days most of the HVAC companies and designers use software for carrying our heat load calculations. With the HVAC software, all you have to do is to input the data obtained from the building surveying. All the heat load calculations are automatically done by the software and it also recommends the actual size of the air-conditioning system that will be required for the room.Some of the HVAC software can also be integrated with AutoCAD software so that all the data of the building can be taken directly in the HVAC software thus avoiding the long, time consuming and manual process of surveying the building. This facility is being provided by increasing number of the HVAC software, thus making the process of heat load calculations far easier and much faster.
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The heat load calculations are done for all the rooms of the building and also the total heat load of the whole building is calculated. Based on these calculations the HVAC designer or consultant recommends the air-conditioning system of proper size and type.

#### Heat Load Calculations: Important Role of HVAC Designer

The heat load calculations is very important part of the HVAC designer or HVAC consultant. Let us first try to understand what are heat load calculations?