The HVAC Study Module 4
🧱 Module 4: Material Costs & Assemblies
Price materials with confidence, build reusable assemblies, and flow vendor quotes into a clean, defensible estimate.
HVAC Estimating & Plan Reading CourseOverview
In this module, you’ll calculate HVAC material costs, create assemblies that mirror real installation packages, and implement a quote-leveling process. You’ll also stack delivery/tax/escalation the right way so your numbers match buyout reality.
🎯 Learning Objectives
- Define material categories, units of measure, and cost drivers (size, gauge, pressure class, insulation).
- Build reusable assemblies for duct, piping, and typical equipment connections.
- Request, record, and level vendor quotes (price, freight, lead time, terms, scope).
- Apply waste, delivery, tax, and escalation properly to raw costs.
- Map assemblies to your takeoff so quantity changes update the estimate quickly.
📦 Common HVAC Materials & Units
| Category | Examples | Typical UOM | Cost Drivers |
|---|---|---|---|
| Sheet Metal (Rect/Round/Oval) | Straight duct, elbows, tees, reducers, boots, end caps | LF (straight), EA (fittings), SF (insul/liner) | Gauge & class, size/SF, liner/insulation, shop/field labor split |
| Flex & GRDs | Flex duct, diffusers, grilles, registers | LF (flex), EA (GRDs) | Neck size/CFM, acoustic spec, finish |
| Piping & Fittings | Copper/steel/PVC, valves, unions, strainers | LF (pipe), EA (fittings/valves) | Size/schedule, metallurgy, valve type, joining method |
| Insulation & Accessories | Duct wrap/liner, pipe insulation, jacketing, hangers/strut | SF (duct), LF (pipe), EA (hangers) | Thickness/type, jacket, spacing/bracing reqs |
| Equipment & Controls | AHUs, RTUs, FCUs, VAVs, EF, actuators, sensors, panels | EA | CFM/tonnage, electrical, accessories, factory options, lead time |
UOM sanity: Keep LF/SF/EA consistent across takeoff and assemblies to avoid conversion errors.
🧩 What is an Assembly?
An assembly is a bundle of materials (and often labor units) that repeats across projects. It speeds estimating and reduces misses. Name by System_Size_Attributes and store the component list.
Examples (Airside)
- RECT_DUCT_30x18_CL2_LIN1_EXT2 → 1 LF 30×18 duct (24ga CL2) + hanger + 1" liner + 2" wrap
- FLEX_BRANCH_6IN_STD → 12 LF 6" flex + 2 clamps + mastic allowance
- VAV_BOX_1500CFM_ELEC_RHT → VAV box + reheat coil + control valve kit + flex to 2 GRDs
Examples (Wet/Ref)
- REF_LINESET_3/8x7/8_PER_LF → suction/liquid pair + insulation + fittings allowance
- CHWSR_2IN_PER_LF → 2" pipe + standard fittings factor + 1.5" insulation + hangers
- COND_DRAIN_1IN_PER_LF → 1" PVC + fittings + supports + neutralizer (if required)
Do not bury scope: Keep accessories explicit (FD/SD, access doors, curbs). Assemblies are for repeatable content, not a place to hide unique items.
📚 Starter Assembly Library (Template)
| Assembly Name | Components (UOM × Qty) | Notes |
|---|---|---|
| RECT_DUCT_30x18_CL2_LIN1_EXT2 | Rect duct 30×18 (LF×1); Hanger (EA×0.125); Liner 1" (SF×(2×(2.5+1.5))); Wrap 2" (SF×(2×(2.5+1.5))) | Assumes hanger @ 8' spacing; W/H in feet for SF calc |
| ROUND_SPIRAL_18IN_PER_LF | Spiral Ø18 (LF×1); Hanger (EA×0.125); Insul 2" (SF×(π×1.5)) | SF per LF ≈ π×Dft |
| FLEX_BRANCH_6IN_STD | Flex 6" (LF×12); Clamps (EA×4); Misc mastic (LS×0.05) | Limit flex length per spec (often ≤6–8') |
| CHWSR_2IN_PER_LF | Pipe 2" (LF×1); Fittings allowance (EA×0.2); Insul 1.5" (LF×1); Hanger (EA×0.125) | Adjust fittings factor by drawing density |
| REF_LINESET_3/8x7/8_PER_LF | 3/8" liquid (LF×1); 7/8" suction (LF×1); Insul (LF×1); Fittings (EA×0.1) | Include line hide/jackets if exterior |
Naming standard: SYSTEM_SIZE_ATTRIBUTES (e.g., RECT_24x12_CL2_LIN1) so filters/pivots work in Excel.
🏷️ Vendor Pricing Strategy & Quote Leveling
- Identify primary vendors: sheet metal shop, pipe/valves, insulation, equipment, controls.
- Send clear RFQs with tagged drawings, schedule pages, and a scope checklist.
- Log price, freight, tax, lead time, terms, warranty, and exceptions. Pick a preferred and a vetted backup.
- Apply escalation to long-lead items and note validity dates in the proposal.
Quote Leveling Template
| Vendor | Base Price ($) | Freight ($) | Tax (%) | Lead (weeks) | Terms | Scope Exceptions | Landed ($) |
|---|---|---|---|---|---|---|---|
| — | |||||||
| — | |||||||
| — |
Landed = Base + Freight + Tax% × Base. Lead time and scope exceptions still need judgment.
🧮 Applying Costs in Your Estimate
- Pull totals from your takeoff (e.g., LF duct by size, #VAVs, LF pipe by size).
- Map each line to an assembly or unit cost. Keep a reference column for the source (vendor quote # / date).
- Add waste (5–10% typical depending on complexity and shop standards).
- Add delivery, tax, and escalation (for buyout lag or volatile commodities).
- Flow into your pricing template and reconcile totals after every update/export.
Stack order reminder: Direct Material → Waste → Delivery/Freight → Tax → Escalation → Overhead → Profit (margin) at the summary level.
🧰 Mini Tools
🧩 Assembly Builder (Unit Cost)
Assembly Unit Cost: —
Use for per-LF duct/pipe or device kits. Add labor separately if you keep labor out of assemblies.
🚚 Landed Material Cost
Subtotal (w/ waste): —
Tax: — | Total Landed: —
📈 Escalation Forecaster
Forecasted Cost: —
Simple compounding: Base × (1 + r)months
🔁 Quick Level — Pick Low
Lowest Landed (w/ penalty): —
Adds a soft penalty for long lead times to help your decision.
🗃️ Mapping — From QTO to Assemblies to Estimate
| QTO Field | Assembly/Item | UOM | Multiplier/Notes |
|---|---|---|---|
| SA 30×18 LF | RECT_DUCT_30x18_CL2_LIN1_EXT2 | LF | Hanger 1/8 EA per LF; liner & wrap via SF per LF |
| Spiral Ø18 LF | ROUND_SPIRAL_18IN_PER_LF | LF | Insul SF per LF = π×Dft |
| CHWS 2" LF | CHWSR_2IN_PER_LF | LF | Fittings factor 0.2 EA/LF (adjust by detail) |
| VAV Box (EA) | VAV_BOX_1500CFM_ELEC_RHT | EA | Include reheat kit; controls by who? |
| Condensate Drain 1" LF | COND_DRAIN_1IN_PER_LF | LF | Include neutralizer if spec’d |
Excel flow: Use one tab for QTO, one for Assemblies, one for Rates, and a Summary tab. XLOOKUP the assembly unit cost and multiply by QTO.
🧪 QA/QC — Before You Price
- Units consistent (LF/SF/EA) and conversions documented in Notes.
- Waste factors justified (complex routing, tight ceilings, rework risk).
- Freight/delivery captured for heavy/oversized shipments and roof cranes.
- Tax applied to taxable materials only per jurisdiction; exemptions documented.
- Escalation used for long-leads; quote validity and buyout month noted.
- Quote leveling table saved with vendor emails and date/time stamps.
🧠 Practice & Exit Ticket
- Build an assembly for RECT 24×12 CL2 with 1" liner & 2" wrap. Show the unit cost and components.
- Compute landed cost for 180 LF of Ø18 spiral with 8% waste, $400 freight, 8.75% tax, 2% escalation.
- Level three vendor quotes (enter in the table) and pick a preferred + backup with notes on scope gaps.
- Map SA 30×18 (120 LF) and CHWS 2" (220 LF) from QTO into assemblies and show extended costs.