The h2x Blog
We publish practical guides, top tips and trends, latest news, and more stories related to the mechanical, plumbing and fire industry.
Latest Articles
How to Calculate Air Changes Per Hour
Learn the ACH formula, how to calculate air changes per hour from airflow and room volume, and...
Do Heat Pumps Work in Cold Weather? How They Extract Heat From Air Below 0°F
Yes, heat pumps can work below 0°F (-18°C). Here's how cold-climate systems extract heat, maintain capacity, and...
CFM Calculation Formula: 4 Ways to Calculate Required Airflow
Four CFM calculation formulas for ventilation, cooling load, and duct sizing, with a fully worked example.
How to Read a Psychrometric Chart (Without Losing Your Mind)
This psychrometric chart guide breaks down every property, process, and worked example in plain English.
Latent Heat vs. Sensible Heat: What Every Mechanical Engineer Needs to Know
Find out how to differentiate latent heat vs. sensible heat and work them into real projects.
Air-to-Water Heat Pump System Design: 5 Key Principles for Peak Performance
Most air-to-water heat pump systems underperform because of how they're designed, not what they're made of. Here...
HVAC System Selection for Any Building Size
A practical guide for mechanical engineers on when and why to specify each HVAC system selection type.
How to Eliminate Data Entry Errors in Plumbing Design
Why disconnected tools and manual data transfer create calculation errors in plumbing design, and how engineers can...
Hydronic Snow Melt Systems: How to Size & Design Them Correctly
A complete technical guide to hydronic snow melt design for HVAC engineers: what to calculate, what to...
Gas Pipe Sizing Guide: How to Size Natural Gas and LPG Pipework
A practical gas pipe sizing guide using International Fuel Gas Code (IFGC) equations, with metric and imperial...
MEP Design and Estimating: Bridging the Gap
A look at how design and estimating function in MEP projects today, where the process breaks down,...
What Is Air Film Resistance and Why Does It Matter for Load Calculations?
A technical guide to surface air film resistance: what it is, how it forms, and how it...
Featured (Must-Read Blogs)
How to Calculate Duct Size for HVAC Systems
Learn how to calculate duct size from airflow, velocity and friction rate, with a worked example for...
What Are Cv and Kv? Flow Coefficient Formulas & Valve Sizing Explained
Learn how flow coefficient (Cv) impacts valve sizing. Explore their calculation, importance in fluid dynamics, applications, and...
Calculating Heat Loss: A Step-by-Step Guide
Learn how to calculate heat loss using U-values, surface areas, temperature differences, ventilation and thermal bridging.
Darcy-Weisbach Equation vs Hazen-Williams for Pipe Friction Loss
Compare the Darcy-Weisbach equation and Hazen-Williams formula, when to use each and how they calculate pipe friction...
How to Size Water Pipes
To size water pipes correctly is critical for the performance of your design. Below, we will explore...
How to Calculate Residual and Static Water Pressure
Learn the difference between residual and static water pressure, how to calculate both through a plumbing system,...
Highlights (Free Downloads)
Duct Sizing Chart for CFM, Velocity and Friction Rate
A duct sizing chart for round and rectangular ducts, showing airflow capacity and velocity at common friction...
FREE Pipe Volume Spreadsheet
Access h2x's free pipe volume spreadsheet to streamline calculations, optimise design, and enhance efficiency in piping projects.
Hardy Cross Method – Sizing a Ring Main (FREE Spreadsheet)
Flow rate and friction loss in a pipe network system can be difficult to calculate. When the...