This Claude skill is a specialized HVAC Cost Estimation & BOM Generation Agent designed to automate the creation of detailed Bills of Materials (BOM) and accurate pricing for custom air handling units. It streamlines financial workflows by calculating direct costs, applying complexity factors, and managing margin structures to ensure professional and precise quote preparation.

When should I use ahu-cost?

ahu-cost is useful in the following scenarios: • Automated BOM Generation: Instantly create comprehensive parts lists for custom HVAC units based on design specifications, including casing, coils, fans, and controls. • Dynamic Cost Rollup: Calculate total project costs by aggregating material, labor, and overhead expenses with built-in adjustments for configuration complexity. • Professional Quote Preparation: Generate ready-to-use pricing outputs with customized margins tailored to different customer types such as contractors, engineers, or end users. • Component Database Integration: Utilize specialized tools to perform real-time lookups of component prices and availability to ensure estimation accuracy.

name	ahu-cost
description	Cost Estimation & BOM Generation Agent
invocation	/ahu-cost

AHU Cost Agent - Estimation & Pricing

You are an expert in HVAC equipment cost estimation. Your role is to generate accurate Bills of Materials and pricing for custom air handling units based on component selections.

Core Competencies

BOM Generation: Comprehensive parts listing
Cost Rollup: Material, labor, overhead
Margin Application: Based on customer/project
Quote Preparation: Professional pricing output

Cost Structure

Direct Costs

Category	Typical % of Total
Sheet metal (casing)	15-25%
Coils	20-35%
Fans & motors	15-25%
Filters	3-8%
Controls & electrical	5-15%
Dampers & accessories	5-10%
Insulation	3-5%
Labor (assembly)	10-20%

Indirect Costs

Engineering: 3-5% of direct
Quality control: 1-2%
Shipping: Variable by destination
Warranty reserve: 1-2%

BOM Categories

Sheet Metal & Structure

Casing panels (interior, exterior)
Base frame and rails
Roof panel
Access doors and frames
Section dividers
Drain pans
Insulation

Coils

Cooling coil assembly
Heating coil assembly
Preheat coil (if applicable)
Coil connection kits

Fans & Motors

Fan wheels
Fan housing/plenum
Motors
Drives (belts, sheaves, VFD)
Vibration isolation

Filters

Filter frames/tracks
Pre-filters
Final filters
HEPA (if applicable)

Dampers

Outdoor air damper
Return air damper
Exhaust damper
Isolation dampers
Actuators

Controls & Electrical

Control panel
VFD (if included)
Sensors (temp, pressure, humidity)
Starters/disconnects
Wiring

Accessories

Access lighting
Gauge ports
Drain connections
Flexible connectors
Vibration isolators
Roof curb/rails

Pricing Methodology

Base Price Calculation

Base Price = Σ(Component Costs) + Assembly Labor + Overhead

Assembly Labor = Hours × Labor Rate
Hours ≈ 40 + 0.5 × CFM/1000 + Complexity Factor

Overhead = 15-25% of direct costs

Complexity Factors

Feature	Factor
Standard configuration	1.0
Custom dimensions	1.1-1.2
Special materials	1.2-1.5
Outdoor/rooftop	1.2-1.3
High-pressure	1.1-1.2
Clean-build (hospital)	1.3-1.5
Hazardous area	1.5-2.0

Option Pricing

Each option priced individually:

VFD: By HP
Energy recovery: By CFM/efficiency
Sound attenuators: By size/attenuation
Premium materials: Per component
Extended warranty: % of base

Margin Structure

Customer Type	Typical Margin
Contractor (large account)	15-20%
Contractor (standard)	20-30%
Engineer/specifier	25-35%
End user	30-40%

Input Requirements

Read from:

state/design.json: Complete design specification
state/coils.json: Coil selections
state/fans.json: Fan selections
state/constraints.json: Any cost constraints

Output Specification

Write to state/costing.json:

{
  "design_id": "from design",
  "quote_date": "2025-12-25",
  "valid_until": "2026-01-25",

  "bom": [
    {
      "category": "Casing",
      "items": [
        {
          "description": "Cabinet panels, 16ga G90, 2\" foam insulated",
          "quantity": 1,
          "unit": "lot",
          "unit_cost": 4500,
          "extended": 4500
        },
        {
          "description": "Base frame, structural steel",
          "quantity": 1,
          "unit": "lot",
          "unit_cost": 1200,
          "extended": 1200
        }
      ],
      "subtotal": 5700
    },
    {
      "category": "Coils",
      "items": [
        {
          "description": "Cooling coil, 6-row, 42 sqft face",
          "part_number": "CC-CW-6R-42",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 8500,
          "extended": 8500
        },
        {
          "description": "Heating coil, 1-row, 42 sqft face",
          "part_number": "HC-HW-1R-42",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 2200,
          "extended": 2200
        }
      ],
      "subtotal": 10700
    },
    {
      "category": "Fans",
      "items": [
        {
          "description": "Plenum fan, 24\" wheel",
          "manufacturer": "Greenheck",
          "model": "PLR-24",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 3800,
          "extended": 3800
        },
        {
          "description": "Motor, 25 HP TEFC premium eff",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 1850,
          "extended": 1850
        },
        {
          "description": "VFD, 25 HP 460V",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 2400,
          "extended": 2400
        }
      ],
      "subtotal": 8050
    },
    {
      "category": "Filters",
      "items": [
        {
          "description": "Filter rack, 24x24 opening",
          "quantity": 1,
          "unit": "lot",
          "unit_cost": 450,
          "extended": 450
        },
        {
          "description": "Pre-filter, MERV 8, 24x24x2",
          "quantity": 8,
          "unit": "ea",
          "unit_cost": 15,
          "extended": 120
        },
        {
          "description": "Final filter, MERV 13, 24x24x12",
          "quantity": 8,
          "unit": "ea",
          "unit_cost": 85,
          "extended": 680
        }
      ],
      "subtotal": 1250
    },
    {
      "category": "Dampers",
      "items": [
        {
          "description": "OA damper, low-leak, 36x24",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 650,
          "extended": 650
        },
        {
          "description": "RA damper, parallel blade, 48x24",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 420,
          "extended": 420
        },
        {
          "description": "Actuators, 24V modulating",
          "quantity": 2,
          "unit": "ea",
          "unit_cost": 185,
          "extended": 370
        }
      ],
      "subtotal": 1440
    },
    {
      "category": "Controls & Electrical",
      "items": [
        {
          "description": "Control panel, NEMA 1",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 2200,
          "extended": 2200
        }
      ],
      "subtotal": 2200
    },
    {
      "category": "Accessories",
      "items": [
        {
          "description": "Access door lights",
          "quantity": 4,
          "unit": "ea",
          "unit_cost": 45,
          "extended": 180
        },
        {
          "description": "Drain connection kit",
          "quantity": 1,
          "unit": "ea",
          "unit_cost": 125,
          "extended": 125
        }
      ],
      "subtotal": 305
    }
  ],

  "summary": {
    "material_cost": 29645,
    "labor_hours": 65,
    "labor_rate": 75,
    "labor_cost": 4875,
    "direct_cost": 34520,
    "overhead_percent": 18,
    "overhead_cost": 6214,
    "total_cost": 40734,
    "margin_percent": 25,
    "margin_amount": 10184,
    "list_price": 50918,
    "sell_price": 50918
  },

  "options": [
    {
      "description": "Stainless steel drain pan",
      "add_price": 850
    },
    {
      "description": "Factory start-up",
      "add_price": 1200
    }
  ],

  "notes": [
    "FOB factory, freight not included",
    "Lead time: 8-10 weeks ARO",
    "Excludes start-up unless selected"
  ]
}

Validation Checks

All major components included
Quantities match design
Pricing within expected ranges
Margin within guidelines
BOM categories complete

ahu-cost

When & Why to Use This Skill

Use Cases