HVAC takeoff and estimating, duct to diffuser
Momo reads your M-sheets, verifies scale, measures ductwork by size, counts air devices and equipment, and builds the priced estimate with sheet metal weight and insulation from visible formulas. Nothing counts until you commit it.
- Counts · Lengths · Areas
- Duct, air devices, equipment and piping
- Every line sourced
- Sheet, scale and formula on each quantity
- $0 until committed
- Momo's work stays a proposal until you review it
What does a full HVAC takeoff in DrawScale include?
A full HVAC takeoff in DrawScale measures every duct run by size and counts every air device and piece of equipment. Momo traces supply, return and exhaust duct on the mechanical plans as lengths tagged with their dimensions. Your formulas turn length and size into surface area, sheet metal weight by gauge, and duct wrap or liner. Momo counts diffusers, grilles and registers by schedule tag, and reads the equipment schedule for rooftop units, VAV boxes and fans. Hydronic and refrigerant piping is measured by size. Everything carries into the priced estimate, and gauge tables and rates are labeled assumptions for you to confirm.
New to the process? Read the construction takeoff guide or see how Momo runs a full takeoff and estimate.
Sheets Momo reads
- M-001 legend and abbreviations
- M-101 to M-104 HVAC duct plans
- M-201 to M-204 HVAC piping plans
- M-301 roof plan and equipment
- M-501 details
- M-601 equipment and air device schedules
Typical CSI sections
- 23 07 13 Duct Insulation
- 23 21 13 Hydronic Piping
- 23 31 13 Metal Ducts
- 23 36 00 Air Terminal Units
- 23 37 13 Diffusers, Registers and Grilles
- 23 74 13 Packaged Rooftop Units
The full takeoff
What Momo takes off for hvac contractors
Every item is measured on the sheet as a count, a length or an area. Formulas then turn that measurement into the quantities you price. The sheets listed are typical; Momo reports the exact sheets it used for every quantity.
| Takeoff item | Measured as | Typical sheets | Outputs and formula |
|---|---|---|---|
| Rectangular and round duct by size | Length | M-101 to M-104 | Duct SF = LF × perimeter; weight by gauge per labeled table |
| Duct insulation and liner | Length | M-101 to M-104, M-501 | Wrap or liner SF from the same duct runs |
| Diffusers, registers and grilles | Count | M-101 to M-104, M-601 | Air devices by schedule tag and neck size |
| VAV boxes, fans and rooftop units | Count | M-301, M-601 | Equipment by tag, with curbs and connections |
| Hydronic and refrigerant piping | Length | M-201 to M-204 | Pipe LF by size and system; insulation LF |
| Fire and smoke dampers | Count | M-101 to M-104 | Dampers by type and size at rated walls |
Ductwork
- Rectangular supply, return and exhaust
- Round and spiral duct
- Flexible duct runouts
- Duct wrap and liner
- Fire and smoke dampers
Air devices and terminals
- Supply diffusers
- Return and exhaust grilles
- VAV and fan-powered boxes
- Exhaust fans
- Louvers
Equipment and piping
- Rooftop units and curbs
- Split systems
- Chilled and heating hot water piping
- Refrigerant piping
- Condensate drain piping
Every number shows its work
Worked example: Level 1 main supply trunk
This is an illustrative example of how a DrawScale quantity is built. Each line shows its formula, and anything that depends on a rate, factor or spacing is marked as an assumption for you to confirm.
24" × 12" galvanized rectangular supply duct, externally wrapped
M-101 Level 1 HVAC Plan at 1/8" = 1'-0", scale verified from the dimensioned grid
| Line | Formula | Result |
|---|---|---|
| 24 × 12 supply traced | Sum of traced run lengths on M-101 | 180 LF |
| Perimeter | 2 × (24" + 12") ÷ 12 | 6.0 ft |
| Duct surface | 180 LF × 6.0 ft | 1,080 SF |
| Gauge for 24" max dimension | Labeled assumption, confirm per spec 23 31 13Assumption · confirm | 24 ga |
| Sheet metal weight | 1,080 SF × 1.156 lb/SF (24 ga)Assumption · confirm | 1,248 lb |
| Duct wrap | Same surface as the duct | 1,080 SF |
Meet Momo
How Momo runs an HVAC takeoff
Duct, devices, equipment and piping, measured and priced with the work shown.
- 01
Measures duct by size
Each duct run is traced as a length and tagged with its dimensions, so a size change starts a new line instead of hiding in an average.
Size on every run - 02
Turns length into area and weight
Formulas turn length and size into surface area, pounds by gauge and insulation. The gauge table and weights are labeled assumptions you confirm.
Visible formulas - 03
Counts devices and equipment by tag
Diffusers, grilles, VAV boxes, fans and rooftop units are counted by schedule tag and carry the schedule's size and model.
Schedule-driven counts - 04
Hands you a reviewable proposal
Momo's work stays a proposal until you accept it. Review the riskiest items first, fix anything by hand, then commit.
You commit
What Momo checks for
Where HVAC takeoffs go wrong
Ductwork errors compound: a wrong size changes area, weight, gauge and insulation at once.
Size changes along a run
A trunk steps down from 30 × 14 to 24 × 12 to 18 × 10 across one floor. Measure it as one size and the sheet metal weight is wrong.
Duct plans and piping plans on different sheets
Duct lives on M-101, piping on M-201 and equipment on the roof plan. A takeoff that stops at the duct plan misses the rest.
Air devices that don't match the schedule
Diffuser tags on the plans reference a schedule with different neck sizes. Counting by symbol alone prices the wrong device.
Weight and insulation carried as a guess
Pounds of sheet metal and square feet of wrap follow from the duct runs, but they are often estimated separately with no link back.
From quantities to a bid
The priced estimate, schedule and export
Committed quantities flow into the estimate worksheet through visible formulas, and every unit rate, waste factor and production rate is labeled as an assumption to confirm. Nothing Momo proposed counts toward a total until you review and commit it.
Bid-stage schedule
The bid-stage schedule groups quantities into activities such as duct rough-in by floor, piping, set equipment, air devices and start-up. Each duration is installed quantity divided by a labeled production rate you confirm, leveled to your crews, with a critical path and P50 and P80 finish dates.
Coming from another takeoff tool?
If you take off today in Bluebeam Revu, PlanSwift, QuickPen or a spreadsheet, DrawScale opens the same PDF plan sets in the browser with nothing to install. Manual count, linear and area tools always work, and changing a sheet’s scale flags every quantity that depends on it.
What you hand your chief estimator
- A ledger of committed quantities, each linked to its sheet, scale and traced geometry
- A priced estimate worksheet with visible formulas and every rate labeled as an assumption to confirm
- A bid-stage schedule built from installed quantity divided by a labeled production rate
- An Excel or CSV export with audit columns that contains committed quantities only
HVAC takeoff and estimating FAQ
Direct answers for hvac contractors.
Yes. Duct weight comes from a visible formula: traced length times the duct perimeter gives surface area, and area times the weight for the gauge gives pounds. The gauge table is a labeled assumption you confirm against the spec.
Yes. Momo tags each duct run with its dimensions, so every size change starts a new line with its own length, area and weight.
Yes. Momo counts air devices by schedule tag and carries the schedule's type and neck size, so each device prices correctly.
Yes. Momo measures piping on the piping plans by size and system, and your formulas add insulation and supports from the same runs.
No. Everything Momo produces is a proposal that counts for nothing until you review and commit it. Your own drawn or edited geometry is never overwritten by a later run.
You get committed quantities linked to their sheets, a priced estimate worksheet, a bid-stage schedule and an Excel or CSV export with audit columns. The export contains committed quantities only.
Takeoff and estimating for related trades
See every trade DrawScale coversPlumbing takeoff and estimating
Fixtures, drains and piping by system and size, with hangers, insulation and fittings from visible formulas.
Electrical takeoff and estimating
Devices, fixtures, gear, conduit and homeruns from the E-sheets, priced with labeled assumptions.
General Contractor takeoff and estimating
Concrete, framing, doors, finishes and specialties across the set, with a priced estimate and bid-stage schedule.
Send Momo your next mechanical bid set
Bring an M-set you have already bid. We will run the full takeoff and estimate with you so you can check duct, devices and equipment against numbers you trust.