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Latest Blogs
Data Center HVAC Design Guide to Cooling Loads and Systems
A data center HVAC design guide: calculate the cooling load, choose air or liquid cooling, size the chiller plant and benchmark PUE.
Data Center Liquid Cooling Design for Direct-to-Chip Racks
How data center liquid cooling works, from CDUs and the three water loops to direct-to-chip flow rates, water temperatures and pipe sizing.
Hydronic Piping Design Guide for Layouts and Pipe Sizing
A hydronic piping design guide to layouts, direct and reverse return, primary-secondary piping and pipe sizing, with worked examples for heating and chilled water.
Latest Charts
Plumbing Fixture Units, Explained: Charts for Every Code
Supply, Drainage, and a Chart for Every Major Code
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.
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 rates, with imperial and metric units.
Latest Formulas
Hydronic Piping Design Guide for Layouts and Pipe Sizing
A hydronic piping design guide to layouts, direct and reverse return, primary-secondary piping and pipe sizing, with worked examples for heating and chilled water.
How to Calculate Air Changes Per Hour
Learn the ACH formula, how to calculate air changes per hour from airflow and room volume, and typical values by room type.
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.
Latest Spreadsheets
FREE Pipe Volume Spreadsheet
Access h2x’s free pipe volume spreadsheet to streamline calculations, optimise design, and enhance efficiency in piping projects.
h2x vs. Spreadsheets
Since its launch back in 1985, Microsoft’s spreadsheet application Excel has gone on to become accepted as the leading program for the management and calculation of data.
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 pipe network is in a ring main (also known as a closed-loop) formation, the calculations are extra difficult.
This difficult calculation is very common for fire hydrant ring main size designs and the ring main design calculations.
Latest Calculators
Heat Loss Calculator
FREE HEAT LOSS CALCULATOR Heat Loss Calculator Use this free heat loss calculator to work out how much…
Water Flow Rate Calculator
Water Flow Rate Calculator Use this free Water Flow Rate Calculator to estimate flow rates from plumbing fixtures…
Ductulator
Ductulator Use our free online Ductulator to calculate velocity, pressure drop, Reynolds number, and friction factor based on…
Resources
Heat Loss Calculator
FREE HEAT LOSS CALCULATOR Heat Loss Calculator Use this free heat loss calculator to work out how much…
Data Center HVAC Design Guide to Cooling Loads and Systems
A data center HVAC design guide: calculate the cooling load, choose air or liquid cooling, size the chiller plant and benchmark PUE.
Data Center Liquid Cooling Design for Direct-to-Chip Racks
How data center liquid cooling works, from CDUs and the three water loops to direct-to-chip flow rates, water temperatures and pipe sizing.
Hydronic Piping Design Guide for Layouts and Pipe Sizing
A hydronic piping design guide to layouts, direct and reverse return, primary-secondary piping and pipe sizing, with worked examples for heating and chilled water.
How to Calculate Static Pressure in an HVAC System
Calculate static pressure at design stage, measure TESP at commissioning and compare the two to diagnose excess resistance.
Plumbing Estimating Software for Faster, Accurate Tenders
How to turn a partial floor plan into an accurate bid before the deadline hits.
Plumbing Fixture Units, Explained: Charts for Every Code
Supply, Drainage, and a Chart for Every Major Code
RIBA Plan of Work Stages: How They Shape Construction Projects
Every RIBA stage exists to answer a specific question at the optimal time to prevent project delays or extra costs.
What Is Thermal Lag? Understanding Time Lag and Thermal Mass in HVAC Design
Why heat arrives hours after the temperature peaks, and what that means for cooling loads, plant sizing, and comfort.
Designing to BS EN 12831-1:2017 in h2x: A Step-by-Step Guide
A practical guide to configuring BS EN 12831-1:2017 heat loss calculations, ventilation inputs, and system settings in h2x.
Commercial Plumbing Design Software: Five Takeaways for MEP Engineers
Review insights from a recent h2x live session on designing domestic water systems.
Best MEP Software in 2026: 10 Tools Compared
Compare the leading MEP design, calculation and BIM platforms to find the right software for your engineering workflow.