Air duct calculator

The two most common insulated rigid ducts are supply air ducts and return air ducts used for air conditioning. Meanwhile, the fresh air ducts and exhaust air ducts in toilets and mechanical rooms can be uninsulated rigid ducts. In HVAC, main ducts and branch ducts are usually rigid ducts. They are more likely in a rectangular shape rather than ...

Aug 26, 2023 · About this app. This app is developed to Calculate Duct Size Required with available CFM & FPM. This app calculate Both Rectangular and Round Duct Sizes in Inches. This App is also Calculate Air Flow rate in CFM and this app is also calculate in Air Velocity in FPM. The application is designed for engineers HVAC working in the field of design ... QUICK-GUIDE. Select the duct material from the drop-down list (most duct sizing tools are typically based on galvanised steel ducting by default) Enter the air flowrate in cubic feet per minute (CFM) Enter an internal duct size in inches (this must be limited to a maximum aspect ratio of 5:1 for the results to be valid) The resulting velocity ... Jan 14, 2012 · The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct size, weight per linear foot of round duct, surface area in square feet per lineal foot of round duct ... Cleaning helps not only remove them, but may also remove blockages that can help make your system run more efficiently. Keep reading to learn more about the cost of duct cleaning services. 2024 Duct Cleaning Costs. Calculate local project costs by entering your zip code. Typical Price Range. $ 450 - $ 1,000.Air flow rates: information is provided on recommended air flow rates for each duct size. These flow rates are related to the volume of air needed for the HVAC system to maintain thermal comfort and air quality. Air speed: the graph illustrates the air speeds that can be obtained for the different dimensions of the ducts and air flow rates.The equivalent diameter is the diameter of a circular duct or pipe that gives the same pressure loss as an equivalent rectangular duct or pipe.. The table below can be used to compare equivalent diameters for rectangular and round circular ducts. The table is based on the ducts friction loss formula.. The rectangular dimensions and the air flow volume …

How Much Does an HVAC Replacement Cost in 2024? Average Cost Range: $6,465 - $11,877. Use the calculator below for a more accurate local estimate. Use Modernize's 2024 cost calculator to get accurate HVAC replacement cost. Get local price ranges by zipcode for cooling, heating or both!A duct size calculator, commonly known as a ductulator, depends on factors like the size of the space you’re heating or cooling, air flow …Example - Calculate Reynolds Number. A Newtonian fluid with a dynamic or absolute viscosity of 0.38 Ns/m 2 and a specific gravity of 0.91 flows through a 25 mm diameter pipe with a velocity of 2.6 m/s .. Density can be calculated from the specific gravity of the fluid and the density of the specific gravity reference water 1000 kg/m 3 - as. ρ = 0.91 (1000 …So, the duct design work is made simpler and easy. Since this is a web-based program, users can log in from any browser using an ID and password. Apart from duct designing, this software also helps in Duct sizing. With DuctQuote, you can. Calculate air flow for duct design; Draws 3D systems; Generate custom quotes using logo and …Diameter of Air Duct Sizing =√ ( (576 × 8) / (3.14 × 15)) = 9.8911 inch. Online ducting calculator to find the diameter of duct size. Sizing of air duct can be done using Velocity Method, Constant Pressure Loss Method and Static Pressure Recovery Method.Friction Loss per 100 Feet = (0.109136 * q 1.9 ) / (d 5.02 )* (l/100) Where, q = Air Volume Flow. d = Equivalent Duct Diameter. l = Duct Length. Online air duct friction loss calculation. Use this simple science air duct friction loss calculator to …Purpose and Learning Objectives. The purpose of this presentation is to introduce new and optimized techniques for designing high performing VAV systems at minimal cost. At the end of this presentation, you will be able to: Size VAV duct mains cost effectively. Select VAV boxes for minimum life cycle cost.

Duct Calculator Elite TM is an industry leading tool designed to simplify the job of duct sizing for HVAC professionals. This app allows users to calculate duct size, velocity, pressure drop, and flow rate for ductwork . Duct Calculator Elite TM features a highly intuitive interface which allows users to easily enter values with precision (without the … Rectangular sheet metal duct = .07" on most metal duct calculators. 2900. 40x12. 100 31/2 x14 2200 38x10 220 31/2 x30 2350 40x10. Rectangular sheet metal duct = .07" on most metal duct calculators. 3050. 42x12. Duct type: Metal Ductboard Flex Size by: Friction rate Velocity Friction Rate: per 100 ft. in/wg Duct TEL : ft. * include fittings in the Duct TEL Enter either: CFM: or Duct Size: …CFM (10×12 Duct, 500 FPM) = 500 FPM × 10 Inches × 12 Inches / 144 = 416.67 CFM. We can see that the 10×12 duct generates 416.67 CFM of airflow at 500 FPM air speed. Now, we did a huge amount of calculations for these rectangular ducts at 1 FPM, 500 FPM, and 2000 FPM, and gathered all the results in this feet per minute to cubic feet per ...

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Air Duct Calculator. Double-sided. Side 1 = standard ducloator with calculations for both round and rectangular duct. Side 2 = Continental vs competitive cross reference for some common GRDs and a Grille sizing chart. Qty 25/package. The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct size, weight per linear foot of round duct, surface area in square feet per lineal foot of round duct ...V = 0.408 Q/D 2. Components. = Air velocity inside the duct (feet/s) = Air flow rate inside the duct (GPM) = Air flow rate inside the duct (inches) Metric Equation. Determine the following formula, which can be used to calculate the air duct velocity: V …Air duct also termed as ductulator is a passage that is used to provide fresh air into rooms, buildings etc., Air ducts may be in circular, square and in rectangular shapes. This online air duct calculator is used to calculate the velocity of air flow feet per minute (FPM), and feet per second (FPS) through any shaped (circle, square or rectangle) ductulator with …Enter 6" into the Duct Height (Optional) field. The results table show a 10"x6" duct. This calculator can also be used to simply convert round to rectangular or vice versa. It is unnecessary to consider the duct material, length, or air volume since it is just a physical, geometric calculation. Assume we have an 18" round duct.

These calculations are divided in four areas: 1. Diameter converter, which allows converting circular to equivalent rectangular ducts. 2. Calculator of different ventilation parameters, with which will be able to obtain the diameter, the air speed, the airflow and the dynamic pressure of your installation. 3.The kinematic viscosity of air is determined by the properties of air, just like the density of air. However, both values are based on a set air condition. In the case of duct static pressure calculation, the properties of air are set at 1 atmospheric pressure at 20°C. Friction Loss Factor, f. The friction factor (f) is calculated using the ...Online Head Loss Calculator. The calculator below, which is based on eq. (2) , can be used to calculate the head loss in a duct, pipe or tube.The default values used in the calculator are for air flow 20 o C , 1.2 kg/m 3 and 6 m/s .The default density of water commonly used as reference fluid is 1000 kg/m 3.The friction coefficient is calculated …This article provides information on how to use the Ductwork Calculator for air flow CFM, friction loss and velocity. It explains the process of duct sizing diameter with accurate results when the right information is plugged into it. The article also gives a detailed explanation of each step in the process and what data … See moreCalculate velocities in circular and rectangular ducts - imperial and SI-units - online calculator. Ducts or Pipes through Steel Joists - Maximum Sizes. Maximum sizes of …PRODUCT DETAILS. AIR DUCT SLIDE RULE CALCULATOR. Size: 4"x9.25". Material: Heavyweight coated calculator board. Production: Each order is custom manufactured with your company information and in your choice of colors. AIR DUCT WIZARD DUCTULATORS. Size: 8.5"x11" card with a 7.25" wheel. Materials: Heavyweight coated …To calculate allowable leakage, you must know the system surface area, the required test pressure and the specified leakage class. System (or section) Surface Area. sq.ft. Test Pressure. (in.wg.) SMACNA Leakage Class*. Allowable leakage based on your input is: cfm. *SMACNA recommends using leakage classes in table below when the designer …Ductulator - Duct Diameter Calculator. Enter the required volume & velocity to see the necessary duct diameter. Required Air Volume. m³/sec m³/hr. Required Air Velocity. m/sec. Duct Diameter. mm. Health and Safety Executive recommended minimum duct …The duct weight can be calculated using the following formula: DW = ( (2* (H+W)) L T)*D. Where the variables are: The duct density for aluminum is 0.1 lbs/in^3. To calculate duct weight, simply multiply the sum of the height and width by 2, multiply the result by the length and thickness, and then multiply the final product by the density.Cleaning helps not only remove them, but may also remove blockages that can help make your system run more efficiently. Keep reading to learn more about the cost of duct cleaning services. 2024 Duct Cleaning Costs. Calculate local project costs by entering your zip code. Typical Price Range. $ 450 - $ 1,000.

Minor or Dynamic losses in duct systems are pressure losses caused by. Minor or dynamic pressure loss in air duct system components can be expressed as. Δpminor_loss = ξ ρ v2 / 2 (1) where. ξ = minor loss coefficient. Δpminor_loss = minor pressure loss (Pa (N/m2), psf (lb/ft2)) ρ = density of air (1.2 kg/m3, 2.336 10-3 slugs /ft3)

By multiplying air velocity by the cross section area of a duct, you can determine the air volume flowing past a point in the duct per unit of time. Volume flow is usually measured …ρ = 999.7 kg/m³. Find the dynamic viscosity: µ = 0.001308 kg/ (m · s) Compute the product of the density of water, the velocity of the flow, and L: ρ × u × L = 249.925 (m · s)/kg. Divide the result by the dynamic viscosity to find the Reynolds number: ReD = 249.925/0.001308 = 191,074 The flow is likely turbulent.Dec 20, 2016 · 20 Dec 2016; Atlanta; New Duct Sizing Calculator Available. Media Contact: Allen Haynes 404.446.1677 [email protected]. ATLANTA (Dec. 20, 2016) – A new duct sizing calculator from ASHRAE and the Air Distribution Institute (ADI) allows HVAC air distribution system designers to more accurately size ducts, especially flex ducts under varying amounts of compression, based on research results. The Digitized Ductulator is a free online calculator for sizing HVAC ducts. Use it in one of two ways; either enter the duct size to find the equivalent CFM, or input the CFM to find the right size of rectangular, round or flex duct. Click here to use the Ductulator. Use the right size duct. Duct that's too big, or too small can cause problems ... Purchase ADI Ductulator. The ADI - Air Distribution Institute, was formed in 1947 to promote the use of fabricated steel duct pipe and fittings for air distribution products. Today the alliance of ADI member companies produce steel duct pipe and fittings designed to efficiently deliver conditioned air in your home and office. Purpose and Learning Objectives. The purpose of this presentation is to introduce new and optimized techniques for designing high performing VAV systems at minimal cost. At the end of this presentation, you will be able to: Size VAV duct mains cost effectively. Select VAV boxes for minimum life cycle cost.Air duct pressure loss. Friction loss calculation is made in rectangular or round ventilation ducts. Fill in the form below. Unit system. : Duct type. : Duct position.mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load. While air duct cleaning and repair lengthens its life span, ductwork typically needs major replacement every 15 years to work properly. The national average cost for full ductwork replacement is $1,450–$8,000; however, the cost can range anywhere from $250–$12,000 depending on home size, system accessibility, and materials used. K-factor editor for local pressure loss. The program includes 2 procedures placed on customized command bar use to know the value of the coefficient K. 1° / - Module of imputation on the working sheet of the designation and the value of the K-factor. 2°/ - Data Visualization Module of the pressure loss coefficients according to the duct shape.

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How to design a duct system. In this video we'll be learning how to size and design a ductwork for efficiency. Includes a full worked example as well as usin...Download duct static pressure calculator excel sheet XLS. Free spreadsheet program for air duct friction loss calculation. Download Free MEP Calculation Excel Sheets, AutoCAD Drawings, and Training Courses for HVAC, Firefighting, Plumbing and Electrical Systems Design.Get free shipping on qualified Ducting & Venting products or Buy Online Pick Up in Store today in the ... resistant, 4-ply aluminum foil laminate that encapsulates a high density, corrosion resistant wire helix. This forms an air tight and easy to use air duct. View Product. Explore More on homedepot.com. Doors & Windows. 1 Panel 36 x 79 ...At 350-400 CFM per 12,000 BTUs of heating capacity, there’s enough airflow to circulate heated air through supply ducts and pull cool air back to the furnace or air handler through the cold air returns. A 3-ton unit, or 36,000 BTUs, would need a blower capable of moving 3 x 350-400 CFM, so a total of 1,050 to 1,200 CFM. A major friction loss diagram for air ducts - SI units. Air Ducts - Friction Loss Diagram A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm. Air Ducts - Velocity Diagram Air flow volume, duct size, velocity and dynamic pressure. Circular Ducts - Dimensions Standard size of circular ventilation air ducts. Duct ... Adjustable Absolute Duct Roughness. If selected, Flexible roughness is 0.003 ft when. straight and fully stretched tight at 0% compression. (adjusted at other compressions), otherwise the. original method of constant 0.01 ft roughness is used. Use ASH RAE 2013 Flex Compression. The average cost to replace ductwork is $1,400 to $5,600, depending on the home's size. Air duct replacement costs $25 to $55 per linear foot or $270 to $500 per duct for a crawl space, attic, or basement. New ductwork installation costs $2,400 to $6,600 for a house without HVAC ducts. Cost to replace ductwork by house size - chart. For 1000 CFM, we need 1650.12 FPM to 11,459.16 FPM, if we use 4-10 inch round ducts. This is quite an enormous air velocity (11,459.16 FPM is equal to 130 miles per hour (mph)). Now, let’s have a look at the 2nd part for rectangular air ducts, starting with the 2nd calculator: ….

The pressure losses in ducts are caused by friction between the air and the duct surfaces, as well as by fittings and bends in the duct system. How do you calculate CFM from pressure drop? CFM (Cubic Feet per Minute) can be calculated from pressure drop using the fan laws, which relate CFM, pressure, and fan performance.The Ductulator - Duct Sizing Calculator is a hand held rotating calculator used for sizing supply and return duct systems using the equal friction design method. This accurate, easy-to-use duct size calculator includes scales for friction loss per unit length, air volume, air velocity, round duct diameter and rectangular duct diameters. TO CALCULATE DUCT SIZE: Enter Air Quantity (Flow Rate) Enter either Friction Loss or Velocity. The software will automatically detect the calculation method. Click Calculate and refer to duct size box for results. Click Refresh for a new calculation. The Duct Size Calculator is a quick reference tool for approximating duct size and equivalent sizes of sheet-metal duct and flexible duct. A new duct-sizing calculator from ASHRAE and the Air Distribution Institute (ADI) allows HVAC air-distribution-system designers to size ducts more accurately, especially flex ducts under …A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm. Air Ducts - Major Friction Head Loss, Online Calculator Head loss or major loss in air ducts - equations and online calculator for rectangular and circular ducts - Imperial and SI units. Air Ducts - Sizing Required duct area vs. air flow. Air Ducts - Velocity ...Duct CFM @ .08 supply .05 return. This calculator does not replace good ACCA manual D or SMACNA principles. It does however provide basic duct sizes and CFMs based on these principles. This calculator can be used to estimate CFM or duct size using round Metal or Flexible "properly installed" typical duct runs.50°F (27.8°C) 2″ (50mm) Recommended Duct Insulation Thickness for Concealed Ducts. So, if my dew point is 77°F (25°C) and the supply air temperature is 59°F (15°C), the temperature difference is 18°F (10°C) which is below 30°F (16.7°C). Therefore, my duct insulation should be 1″ (25mm) thick.Duct Calculator Elite TM is an industry leading tool designed to simplify the job of duct sizing for HVAC professionals. This app allows users to calculate duct size, velocity, pressure drop, and flow rate for ductwork . Duct Calculator Elite TM features a highly intuitive interface which allows users to easily enter values with precision (without the … All Duct Calculator. An inclusive air duct calculator for diameter, velocity, CFM, and pressure drop of various types of duct. It will also determine round duct equivalents for rectangle, flat oval, and elliptical (flattened round) duct. Duct roughness and air properties are adjustable and includes a metric option. Open Calculator. Air duct calculator, ADI DUCTULATOR. Based on research conducted by Texas Tech University as well as Tennessee Tech University, to study the efect of compression in flexible duct on air flow efficiency, ADI created the Ductulator. This Duct Size Calculator's data is based on flexible duct laying in a straight line on a level surface,and nearly fully stretched (4% ..., Ducting Calculators and Air Volume Converter. Nordfab can offer technical assistance with determining whether our ducting is best for your application and with designing duct installations. Please contact us with your requirements. Input CFM Input Velocity (FPM) Ideal Round Duct Diameter Duct Friction in Straight Duct. Calculate., ρ = 999.7 kg/m³. Find the dynamic viscosity: µ = 0.001308 kg/ (m · s) Compute the product of the density of water, the velocity of the flow, and L: ρ × u × L = 249.925 (m · s)/kg. Divide the result by the dynamic viscosity to find the Reynolds number: ReD = 249.925/0.001308 = 191,074 The flow is likely turbulent., Ducting Calculators and Air Volume Converter. Nordfab can offer technical assistance with determining whether our ducting is best for your application and with designing duct installations. Please contact us with your requirements. Input CFM Input Velocity (FPM) Ideal Round Duct Diameter Duct Friction in Straight Duct. Calculate., Kurb Air Duct Calculator. ductulator.app. Calculation Method. Static Pressure Loss [inW/100ft] Air Flow [CFM] 3000 FPM. Round Duct Air Velocity. Infinity FPM. …, The velocity of an air duct with area 16 sq.ft and air flow of 10 CFM would be : V = 10 / 16 = 0.625 FPM. When converted to FPS, it is 0.0104 FPS. Air duct also termed as ductulator is a passage that is used to provide fresh air into rooms, buildings etc., Air ducts may be in circular, square and in rectangular shapes. , The smallest return air grille is usually starts at 4 inches by 4 inches. So, the next corresponding return air grille size includes 4×6, 6×6, 6×4, 8×6, 4×8 and so on. The largest return air grille is typically stops at 48 inches by 24 inches. Here are some examples of a standard return air grille: 4×4. 6×6., Nov 7, 2022 · To calculate the speed of air in the ducts, we use a duct velocity calculation (you can find the calculator below). Let’s first look at how to calculate the air velocity in the ducts. We have to use this air velocity formula in restricted spaces (such as ducts): V (Air Velocity) = Q (Airflow) / A (Duct Cross-Section) , Formula. The formula for air duct sizing involves the calculation of air velocity (V) and duct cross-sectional area (A) to determine the air volume flow rate (Q), expressed in cubic feet per minute (CFM). Q = A × V. This equation comes from the principle of continuity in fluid mechanics which states that for incompressible flow, the product of ... , Enter the air flowrate in litres/second (can change to cubic metres/second by use of drop-down to the right of the input) Enter an internal duct diameter (this can be any number, it doesn’t need to be standard duct size) To get an idea of the equivalent rectangular duct size, adjust the aspect ratio. Note that only aspect ratio up to 5:1 are ..., A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm. Air Ducts - Major Friction Head Loss, Online Calculator Head loss or major loss in air ducts - equations and online calculator for rectangular and circular ducts - Imperial and SI units. Air Ducts - Sizing Required duct area vs. air flow. Air Ducts - Velocity ..., Step-3 Calculate Fresh Air Considering People outdoor air rate & Area area outdoor air rate as per ASHRAE 62.1: ... Normally, fresh air duct is not insulated, however, if there is a chance of heat gain from outside or there is any heat source near to that duct, insulation can be considered., TO CALCULATE DUCT SIZE: Enter Air Quantity (Flow Rate) Enter either Friction Loss or Velocity. The software will automatically detect the calculation method; Click Calculate …, In April 2024 the cost to Install a Duct starts at $12.13 - $21.39 per linear foot. Use our Cost Calculator for cost estimate examples customized to the location, size and options of your project.. To estimate costs for your project: 1. Set Project Zip Code Enter the Zip Code for the location where labor is hired and materials purchased.. 2., The two most common insulated rigid ducts are supply air ducts and return air ducts used for air conditioning. Meanwhile, the fresh air ducts and exhaust air ducts in toilets and mechanical rooms can be uninsulated rigid ducts. In HVAC, main ducts and branch ducts are usually rigid ducts. They are more likely in a rectangular shape rather than ..., Air duct also termed as ductulator is a passage that is used to provide fresh air into rooms, buildings etc., Air ducts may be in circular, square and in rectangular shapes. This online air duct calculator is used to calculate the velocity of air flow feet per minute (FPM), and feet per second (FPS) through any shaped (circle, square or rectangle) ductulator with …, DUCTULATOR. Sizing air ducts is essential task for HVAC Engineers, it requires quick tool to aid HVAC designer to determine air duct dimensions while drafting AC layouts. DUCTULATOR Software, uses two methods to size air ducts based on velocity or static regain method, taking into account the air properties at given temperature and elevation ..., A duct size calculator, commonly known as a ductulator, depends on factors like the size of the space you’re heating or cooling, air flow …, Kurb Air Duct Calculator. ductulator.app. Calculation Method. Static Pressure Loss [inW/100ft] Air Flow [CFM] 3000 FPM. Round Duct Air Velocity. Infinity FPM. …, Purpose and Learning Objectives. The purpose of this presentation is to introduce new and optimized techniques for designing high performing VAV systems at minimal cost. At the end of this presentation, you will be able to: Size VAV duct mains cost effectively. Select VAV boxes for minimum life cycle cost., Rectangular duct is rounded up to the nearest 1/4 inch. Calculations are for 60°F dry air at sea level, from 5 to 3000 cfm (approximately standard air which is 0.075lb da /ft³). If "ASHRAE 2013" is selected, Flexible roughness is 0.003 ft when straight and fully stretched tight at 0% compression (adjusted at other compressions), otherwise the ... , VariTrane Duct Designer streamlines duct design and improves calculation precision, letting you optimize your designs while obtaining a minimum pressure system. VariTrane Duct Designer enables you to organize the layout structure of your duct system and provides detailed engineering information on a section-by-section …, HVAC Charts - Your Source for Heating & Air Conditioning Charts and Supplies. Duct Sizing Calculator. The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct ..., VariTrane Duct Designer streamlines duct design and improves calculation precision, letting you optimize your designs while obtaining a minimum pressure system. VariTrane Duct Designer enables you to organize the layout structure of your duct system and provides detailed engineering information on a section-by-section …, FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. , About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ..., The cross-sectional area of the duct is: Then the mass flow rate of air through the duct and the rate of heat loss become. therefore, or 5688 kJ/h. The cost of this heat loss to the home owner is. Conversion: 1 Therm = 105,480 kJ. Conclusion: The heat loss from the heating ducts in the basement is costing the home owner 4 cents per hour., The kinematic viscosity of air is determined by the properties of air, just like the density of air. However, both values are based on a set air condition. In the case of duct static pressure calculation, the properties of air are set at 1 atmospheric pressure at 20°C. Friction Loss Factor, f. The friction factor (f) is calculated using the ..., Feb 16, 2023 · Calculate for each individual room. To calculate CFM, you need to know the size of your heating or cooling unit in tons. Multiply this number by 400, which is the average output of an HVAC unit. Then divide by the total square footage of your home. This will give you the multiplier for all your rooms’ CFM. , The chart below can be used to estimate velocities in air ducts. The default values are for air flow 400 cfm (680 m3 /h) , duct size 8 in (200 mm) and velocity 1150 fpm (5.8 m/s) . Download and print Air Ducts - Velocity …, TO CALCULATE DUCT SIZE: Enter Air Quantity (Flow Rate) Enter either Friction Loss or Velocity. The software will automatically detect the calculation method; Click Calculate …, At А+ AIR SERVICES Cleaning, our excellent customer service has earned us loyal customers throughout our 20 years in business. With a wide range of services, we are experienced at mold remediation, ductwork installation, cleaning kitchen exhaust systems, air ducts, dryer vent and chimney, as well as taking on corporate and commercial …, The Engineering ToolBox (2004). Air Duct Calculator. [online] Available at: https://www.engineeringtoolbox.com/air-duct-calculator-d_813.html [Accessed Day …