The Complete Guide of Basic HVAC formulas in excel - (Online HVAC heat load calculator)

The science behind HVAC is complex and can be difficult to understand. By following the Basic HVAC Formulas & Equations and presenting them in live excel, you will have a better understanding of how your heating and cooling system works.

If you are an HVAC student or want to learn more about your current home’s heating/cooling systems, then this article is for you! You will learn some of the most commonly used basic hvac formulas in the HVAC industry that help calculate the amount of air needed in a room and how to calculate the temperature, humidity levels, and relative humidity inside a building. These hvac formulas are designed so that you can understand what they mean in easy-to-understand terms.

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Useful formulas with Live Excel Calculations

Ohm’s Law

Ohm’s law is a fundamental principle of electricity that states the current through a conductor between two points is directly proportional to the voltage across those points. This law is named after Georg Simon Ohm, who discovered it in 1827.

Ohm’s Law is a basic law that governs the flow of electricity in an electrical circuit. It can be used to calculate the power output of an electrical device or circuit, as well as how much resistance a wire has when it is being tested for current flow.

In essence, Ohm’s Law states that voltage (E) is directly proportional to the current (I) flowing through a resistor. The mathematical symbol for this law is E = I x R. When calculating the resistance of an object, it is important to use the correct units: ohms in SI units or watts in British thermal units (BTU). To calculate the power flowing through a circuit, use the power equation: P = VI x I

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Wattage Formula

The wattage formula is a calculation that can be used to determine how much power is needed for a task. It takes into account the voltage and current of an electrical circuit to calculate the wattage.

The wattage formula is used to calculate the power requirements for an electrical device. However, the multiplier needs to be adjusted depending on the elevation and temperature of the location. For example, if you are using the wattage formula in Denver (elevation 5,280 feet), you would use a multiplier of 1.073 instead of 1.0. Additionally, if you are using the wattage formula in Death Valley (elevation -282 feet), you would use a multiplier of 0.917 instead of 1.0

The wattage formula is also based on the weight of standard air (0.075 pounds of air per Cfm). This means that when you are calculating the wattage for a blower or fan, you need to know how much air it is moving. You can find this information in the product specs or on the manufacturer’s website.

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Three-Phrase Motor Voltage Imbalance


When an engine’s compressor experiences a voltage imbalance between the motor terminals, it can cause the compressor to overheat. To determine the magnitude of the imbalance, you need to measure the difference between each phase’s voltage and average voltage.

When an imbalance exists in a three-phase motor, the largest imbalance will be divided by average volts to calculate a percentage. This percentage will then be multiplied by two to determine an increase in winding temperature. In other words, a small voltage imbalance can lead to a large increase in winding temperature and potential compressor failure. Therefore, plant personnel needs to be aware of this issue when examining compressors.

Heat Load (BTU) calculator

The Heat Load Calculator is a formula given in excel that allows the user to input various parameters to calculate the amount of air needed in a room, how to calculate the temperature and humidity levels inside a building, and other related calculations. The calculator is simple to use and provides accurate results.

HVAC CFM Calculator, HVAC Labor Rate Calculator, HVAC Financing Calculator, HVAC EER Calculator

The HVAC CFM calculator can be used to determine your air conditioner efficiency and how much electricity you will need for it. The HVAC labor rate is the cost, in dollars per hour, of an HVAC professional doing the job. The HVAC Financing Calculator is used to calculate the cost of ownership based on estimated annual energy and utility usage. The HVAC EER Calculator is used to measure the efficiency of an HVAC unit.

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Hygrometric Data - Understanding Humidity Control

The HVAC (Heating, Ventilation, and Air Conditioning) industry is responsible for creating and maintaining comfortable and healthy indoor environments. One crucial aspect of this is controlling humidity levels, which can have a significant impact on both comfort and indoor air quality. Hygrometric data plays a crucial role in HVAC systems, allowing engineers to measure and control humidity levels in indoor spaces.

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HVAC Duct weight and flange drilling calculation

In the HVAC sector, airflow issues have always been a challenge. No matter how much you spend on a high-end HVAC system, the equipment won’t function at its peak without properly designed and installed ductwork. Poorly built ducts cause discomfort, high energy expenses, poor air quality, and elevated noise levels..

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HVAC duct work pressure loss calculation

The principal factor affecting air speed in the ventilation system is air resistance. Airflow increases air resistance in a direct proportion. Pressure loss is the name given to this phenomenon. A fan’s static pressure forces air to move in the ventilation system against some resistance. The lower the airflow in the fan, the higher the ventilation resistance in the system.

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HVAC Fan Laws

HVAC is a very important part of your home and you want to make sure that it’s always working properly. Fortunately, physics governs what happens to the fan curve when one factor, like speed, is changed. You may design your system to handle the change by using one of three fan law equations to forecast the impact of a potential or likely change.

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HVAC Pressure Relief Outlets Sizing and Door Air Loss in Excel

A pressurized vessel or system is protected by a pressure relief valve (PRV) in the event of an overpressure occurrence. Any circumstance that might raise pressure in a vessel or system over the designated design pressure or maximum permissible operating pressure is referred to as an overpressure event (MAWP). Relief valves should be independent and extremely dependable because they are the final line of defense.

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What types of math are used in HVAC?

HVAC formulas are used to calculate the temperature and airflow in an air conditioner or heating system. The most common formulas used in HVAC are for calculating the amount of air needed in a room, how to calculate the temperature and humidity levels inside a building, and how to calculate the BTUs needed for heating or cooling.

The formulas used in HVAC are based on fundamental mathematical principles. These principles underlie many of the calculations technicians use to determine airflow, temperature, and humidity levels in buildings. Understanding these formulas can help technicians improve their efficiency and growth as HVAC specialists.

Math is used extensively in HVAC to calculate a variety of factors. One such calculation is the amount of air needed in a room. This is calculated by multiplying the room’s volume by the desired airflow rate. Additionally, math is used to calculate temperature and humidity levels inside buildings. To do this, one must know the building’s dimensions, insulation values, and window characteristics.

To calculate the airflow needed in a room, the pressure and temperature levels inside a building, or other related factors, you will need to use some basic formulas and equations. Airflow is measured in cubic feet per minute (CFM), pressure is measured in pounds per square inch (PSI), and temperature can be measured in degrees Fahrenheit or Celsius.


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Do I need to be good at maths to be an HVAC technician?

There is no one-size-fits-all answer to this question, as the skills and abilities required for HVAC technicians vary depending on the specific field of work. However, some basic maths skills will come in handy when working with air conditioning and heating systems. You may also need to be able to read and interpret diagrams and schematics.

To be a successful HVAC technician, it is important to have a good understanding of mathematics and physics. The job of an HVAC technician revolves around calculating and measuring different variables to maintain the correct environment inside a building. While it is helpful to have strong maths skills, anyone can become an HVAC technician if they have the necessary skills and qualifications.

In addition to having a strong foundation in maths and science, it is important to have strong problem-solving skills. This is because oftentimes when something goes wrong with an air conditioning system, the technician will need to be able to troubleshoot the issue. Additionally, being able to use formulas, read schematics and understand diagrams is essential for being a successful HVAC technician.

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Electrical Formulas

Electrical formulas are mathematical equations that are used to calculate various electrical properties and values to HVAC work. Some common examples include the amount of current flowing through a circuit, the voltage across a component, or the power dissipated by a resistor. Many of these formulas can be combined with other mathematical concepts to solve problems more quickly.

Common HVAC Electrical Terms

When working with electrical circuits, it is important to understand the common terms. Voltage, or E, is the electrical pressure that pushes electrons through a wire. Amperage, or I, is the number of electrons moving through a wire per second. Resistance, or R, is the obstacle between voltage and current. And Power, or P, is the amount of energy used to produce an effect in an electric circuit.

Load (or load factor), also called U factor (U for “unit”), represents how much power a device uses compared to its rated wattage when working at full capacity with no losses in-between steps of its operation cycle (i.e., transformer step-down). It’s generally expressed as a percentage and can be found on product packaging or online. For example, if an appliance has a load of 50%, that means it’s using 1/2 the amount of power it’s rated for.

Farads (F), named after American electrical scientist Michael Faraday, is the standard unit of measure for electric capacity and voltage. 1 Farad is the amount of electricity that will flow through a conductor with a resistance of 1 ohm when it’s charged from 0 to 100 volts and discharged to 0 volts.

In addition, there are some common HVAC electrical terms that everyone should be aware of. Milliampere-hours (mAh) is an SI unit of energy storage equal to one-thousandth of an amp-hour. It can often be found on product packaging or online.

In the HVAC world, there are a variety of electrical terms that are important to know. These include terms for airflow and pressure, motors and controls, insulation, and wiring. By understanding these terms, you’ll be able to work with HVAC systems more effectively.

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The Mathematics Behind Measuring and Verifying Performance

When it comes to measuring and verifying performance, it is important to use the right metric. This will ensure that you are getting accurate results. Many different metrics can be used, but some of the most common ones are temperature, humidity, and airflow.

There is a lot of mathematics that goes into measuring and verifying performance. This includes understanding basic formulas for calculating the amount of air needed in a room, how to calculate the temperature and humidity levels inside a building, and more. By understanding these formulas, engineers can ensure that they are meeting or exceeding performance standards.

Several different metrics can be used to measure performance. The most common metric is throughput, which is the number of units of data that are processed per unit of time. Other metrics that can be used to measure performance include latency, which is the amount of time it takes for a request to be processed; errors, which are the number of incorrect requests that are processed; and response time, which is the amount of time it takes for a request to be serviced.

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What is the purpose of heat load calculation?

To understand how the airflow is being controlled and the temperature is regulated, it is necessary to perform a heat load calculation. The purpose of this calculation is to determine the rate of heat transfer by calculating the thermal resistance. The thermal resistance will be dependent on the density of air, which in turn will depend on the atmospheric pressure and temperature.

Heat load calculation is used to calculate the total cooling capacity of a piece of equipment. This information is used to determine the size and type of HVAC unit that is needed for a particular space.

The heat load calculation is used to determine the amount of heating or cooling required to maintain the desired temperature in a building. The calculation takes into account the ambient temperature, type of construction, and weather conditions. The results can be used to make decisions about heating and cooling systems, insulation levels, and other safety measures for the building.

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What are three important reasons why you need to know complete HVAC load calculations?

There are three main reasons why you need to be able to do complete HVAC load calculations. The first reason is that it can help with comfortable indoor conditions. If you know how much air needs to be circulated in a room and the correct temperature and humidity levels, you can create a more comfortable environment for people. The second reason is that it can save you money on your energy bills. By knowing how much air needs to be circulated, you can make sure that the fans and heaters aren’t working harder than they need to be. Finally, the third reason is that it’s required by law in some cases. To get an occupancy permit or other certification for your building, you may need to provide proof that you’ve done a load calculation.

HVAC load calculations are important because they help you to correctly diagnose and fix HVAC problems. Additionally, these calculations can help you to maintain the correct temperature and humidity levels inside a building. Finally, knowing how to complete these calculations will help you save energy and money.

To be able to work faster and more reliably, technicians and engineers need to have a strong understanding of HVAC load calculations. The calculations help them determine how much air is needed in a room, what the temperature and humidity levels should be inside a building and other factors that are necessary when it comes to maintaining an optimal environment.

This guide contains all the basic formulas needed to calculate HVAC loads. All the above listed HVAC formulas will be of great help to the technician in their day-to-day work.


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