HVAC Condensate Drain Calculator
Estimate HVAC condensate-drain pipe sections, planned fall, support clips, fittings and material cost from horizontal run, vertical drop, editable slope and stock length.
Default project preview
5 pipe sections
Planned horizontal fall
4.5 in
Base pipe length
44 ft
Purchased pipe length
50 ft
Support clips
10
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Horizontal drain run
Enter this project assumption in ft. The current imperial default is 36 ft.
Vertical drain drop
Enter this project assumption in ft. The current imperial default is 8 ft. Minimum: 0.
Planned fall per horizontal length
Enter this project assumption in in/ft. The current imperial default is 0.125 in/ft. Minimum: 0.
Pipe stock length
Enter this project assumption in ft. The current imperial default is 10 ft.
Support-clip spacing
Enter this project assumption in ft. The current imperial default is 4 ft.
Elbows and directional fittings
Enter this project assumption in a unitless value. The current imperial default is 5. Minimum: 0.
Cleanouts or service tees
Enter this project assumption in a unitless value. The current imperial default is 2. Minimum: 0.
Cuts and routing allowance
Enter this project assumption in %. The current imperial default is 12 %. Minimum: 0. Maximum: 50.
Price per pipe section
Enter this project assumption in a unitless value. The current imperial default is 9. Minimum: 0.
Average price per fitting
Enter this project assumption in a unitless value. The current imperial default is 3.5. Minimum: 0.
Price per support clip
Enter this project assumption in a unitless value. The current imperial default is 1.2. Minimum: 0.
How to read the outputs
Planned horizontal fall
0.125 in/ft. Default preview: 4.5 in.
Base pipe length
horizontal run plus vertical drop. Default preview: 44 ft.
Purchased pipe length
full stock sections. Default preview: 50 ft.
Support clips
4 ft spacing. Default preview: 10.
Elbows and service fittings
5 elbows + 2 cleanouts. Default preview: 7.
Drain material cost
pipe, fittings and support clips. Default preview: $81.50.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Pipe order length = horizontal run + vertical drop, plus routing allowance. Sections, supports and fittings are rounded to whole purchasing units; total fall uses the entered slope.
Related tools
Continue planning the project
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
HVAC Condensate Drain Calculator questions
Does this calculate condensate flow rate?+
No. Condensate production varies with equipment, load and humidity. The calculator estimates drain materials and planned fall.
When is a condensate pump needed?+
A pump may be required when a continuous gravity route to an approved termination is not available.
Why include cleanouts?+
Condensate drains can collect biological growth and debris. Accessible service points make inspection and cleaning easier.