The Pipe is a collection of fast, reliable HVAC calculators for ventilation, water and heating — designed to save you from Excel sheets, old PDF tables and "what was that formula again?".
Built for everyone who works with HVAC — from professional
plumbers and design engineers to apprentices,
hobby users and industry-adjacent (salespeople, project managers).
🧰 CALCULATORS
Ventilation
• Volume flow and air volumes per room (TEK17 minimum)
• Pressure drop in ducts (Darcy-Weisbach)
• Duct dimensioning against Spiro standards
• Air change (n/h)
• SFP — specific fan power
• Heat recovery — efficiency and supply air temperature
• Equivalent diameter (Huebscher)
Water and sewage
• Pipe sizing
• Circulation line
• Pressure test and pressure drop
• Sewer sizing
• Frost insulation
• Pump and pressure tank sizing
• Expansion vessel
• Septic tank
Heating
• Heat loss (NS-EN 12831)
• Energy calculation
• Snow melting system
🤖 AI ASSISTANT
Use voice or text to navigate the app and find the right calculator quickly. Get help understanding what a value means or which standard applies.
📐 BASED ON NORWEGIAN STANDARDS
Values and references are based on TEK17, NS-EN 12831, NS-EN 16798-1, NS 3031 and industry standard practice.
📤 EXPORT
Create PDF reports from your calculations — perfect for
project documentation or to send to a customer.
🔒 PRIVACY
Your projects are stored locally on your device. We do not have a
user account and do not collect personal data
to identify you.
⚠️ IMPORTANT
The pipe is an auxiliary tool — not a replacement for
projecting by a qualified person. Always
verify
results against applicable regulations before using them in
real projects.