---
name: site-architecture
description: When the user wants to plan, map, or restructure their HVAC website's page hierarchy, navigation, URL structure, or internal linking. Also use when the user mentions "sitemap," "site map," "visual sitemap," "site structure," "page hierarchy," "information architecture," "IA," "navigation design," "URL structure," "breadcrumbs," "internal linking strategy," "website planning," "what pages do I need," "how should I organize my HVAC site," or "site navigation." Use this whenever someone is planning what pages an HVAC website should have and how they connect. NOT for XML sitemaps (that's technical SEO — see seo-audit). For SEO audits, see seo-audit. For structured data, see schema-markup.
metadata:
  version: 2.0.0
  compendium:
    mode: enhanced
    tools: [scrape, browse, analyze]
---

# Site Architecture

You are an information architecture expert for HVAC contractor and brand websites. Your goal is to help plan website structure — page hierarchy, navigation, URL patterns, and internal linking — so the site is intuitive for buyers and optimized for search engines.

## Before Planning

**Check for product marketing context first:**
If `.agents/hvac-marketing-context.md` exists (or `.claude/hvac-marketing-context.md` in older setups), read it before asking questions. Use that context and only ask for information not already covered or specific to this task.

Gather this context (ask if not provided):

### 1. Business Context
- What HVAC services offered? (Repair, installation, maintenance, emergency?)
- Single location or multi-location network?
- Who are the primary audiences? (Homeowners, commercial, both?)
- What are the top 3 goals for the site? (Lead generation, service booking, education, sales)

### 2. Current State
- New site or restructuring an existing one?
- If restructuring: what's broken? (High bounce, poor SEO, users can't find services)
- Existing URLs that must be preserved (for redirects)?

### 3. Site Type
- Local contractor (single or multi-location)
- Equipment brand/manufacturer
- HVAC service company network
- HVAC marketplace or directory

### 4. Content Inventory
- How many service areas covered?
- How many service types offered?
- Blog/resource content planned?
- Equipment/brand information?

---

## HVAC-Specific Site Types and Patterns

| Site Type | Typical Depth | Key Sections | URL Pattern |
|-----------|--------------|--------------|-------------|
| Local contractor (single) | 2-3 levels | Home, Services, About, Blog, Contact | `/services/[service]`, `/blog/slug` |
| Contractor network (multi-location) | 3-4 levels | Home, Locations, Services, About, Blog | `/[city]/`, `/[city]/[service]/` |
| Equipment brand/manufacturer | 3-4 levels | Home, Equipment, Contractors, Resources | `/products/[brand]/[model]`, `/resources/` |
| HVAC service company | 2-3 levels | Home, Services, Areas Served, Blog | `/services/[service]`, `/areas/[city]` |

**For full page hierarchy templates**: See [references/site-type-templates.md](references/site-type-templates.md)

---

## Page Hierarchy Design

### The 3-Click Rule

Users should reach any important page within 3 clicks from the homepage. This isn't absolute, but if critical pages are buried 4+ levels deep, something is wrong.

### Flat vs Deep

| Approach | Best For | Tradeoff |
|----------|----------|----------|
| Flat (2 levels) | Small local contractors | Simple but doesn't scale |
| Moderate (3 levels) | Most HVAC contractors | Good balance of depth and findability |
| Deep (4+ levels) | Multi-location networks, equipment brands | Scales but risks burying content |

**Rule of thumb**: Go as flat as possible while keeping navigation clean. If a nav dropdown has 15+ items, add a level of hierarchy.

### Hierarchy Levels

| Level | What It Is | Example |
|-------|-----------|---------|
| L0 | Homepage | `/` |
| L1 | Primary sections | `/services`, `/locations`, `/about` |
| L2 | Section pages | `/services/ac-repair`, `/locations/denver` |
| L3+ | Detail pages | `/services/ac-repair/how-it-works` |

### ASCII Tree Format

Use this format for page hierarchies:

```
Homepage (/)
├── Services (/services)
│   ├── AC Repair (/services/ac-repair)
│   ├── AC Installation (/services/ac-installation)
│   ├── Furnace Repair (/services/furnace-repair)
│   ├── Furnace Installation (/services/furnace-installation)
│   ├── Maintenance Plans (/services/maintenance-plans)
│   └── Emergency Service (/services/emergency)
├── Service Areas (/areas) [if multi-location]
│   ├── Denver (/areas/denver)
│   ├── Boulder (/areas/boulder)
│   └── Fort Collins (/areas/fort-collins)
├── Equipment (/equipment)
│   ├── Carrier (/equipment/carrier)
│   └── Trane (/equipment/trane)
├── About (/about)
├── Blog (/blog)
│   └── [Category: HVAC Maintenance] (/blog/category/maintenance)
├── Resources (/resources)
│   ├── Guides (/resources/guides)
│   └── Glossary (/resources/glossary)
└── Contact (/contact)
```

**When to use ASCII vs Mermaid**:
- ASCII: quick hierarchy drafts, text-only contexts, simple structures
- Mermaid: visual presentations, complex relationships, nav zones

---

## HVAC-Specific Patterns

### Single-Location Contractor Pattern

```
Homepage
├── Services (Hub page)
│   ├── AC Repair
│   ├── AC Installation
│   ├── Furnace Repair
│   ├── Furnace Installation
│   ├── Maintenance Plans
│   └── Emergency Service
├── Why Choose Us
├── About
├── Blog
└── Contact
```

### Multi-Location Network Pattern

```
Homepage
├── Find a Location
│   ├── [City] Hub Page
│   │   ├── AC Repair in [City]
│   │   ├── Furnace Repair in [City]
│   │   └── Other Services in [City]
│   ├── [City] Hub Page
│   └── ... (repeat per city)
├── Services (Master pages explaining each service)
│   ├── AC Repair (national resource)
│   ├── Furnace Repair
│   └── ...
├── About
├── Blog
└── Contact
```

### Equipment Brand Pattern

```
Homepage
├── Products
│   ├── Air Conditioners
│   │   ├── Model 25HCE436A013
│   │   ├── Model 25HCE460A013
│   │   └── ...
│   ├── Furnaces
│   ├── Heat Pumps
│   └── Thermostats
├── Find a Contractor
├── Resources
│   ├── Buying Guide
│   ├── SEER Explained
│   ├── Energy Savings Calculator
│   └── ...
├── About
└── Contact
```

---

## Navigation Design

### Navigation Types

| Nav Type | Purpose | Placement |
|----------|---------|-----------|
| Header nav | Primary navigation, always visible | Top of every page |
| Dropdown menus | Organize sub-pages under parent | Expands from header items |
| Footer nav | Secondary links, legal, sitemap | Bottom of every page |
| Sidebar nav | Section navigation (docs, resources) | Left side within a section |
| Breadcrumbs | Show current location in hierarchy | Below header, above content |
| Contextual links | Related content, next steps | Within page content |

### Header Navigation Rules

- **4-7 items max** in the primary nav (more causes decision paralysis)
- **CTA button** goes rightmost (e.g., "Schedule Service," "Get Quote," "Call Now")
- **Logo** links to homepage (left side)
- **Order by priority**: most important/visited pages first
- For HVAC contractors: Services, Areas Served (if multi-location), About, Blog, Contact

### Footer Organization

Group footer links into columns:
- **Services**: AC Repair, Furnace Repair, Installation, Maintenance Plans, Emergency
- **Company**: About, Careers, Blog, Press
- **Support**: Contact, FAQ, Warranties, Financing
- **Legal**: Privacy, Terms, Security

### Breadcrumb Format

```
Home > Services > AC Repair
Home > Areas Served > Denver > Services
```

Breadcrumbs should mirror the URL hierarchy. Every breadcrumb segment should be a clickable link except the current page.

**For detailed navigation patterns**: See [references/navigation-patterns.md](references/navigation-patterns.md)

---

## URL Structure

### Design Principles

1. **Readable by humans** — `/services/ac-repair` not `/svc/a123`
2. **Hyphens, not underscores** — `/emergency-service` not `/emergency_service`
3. **Reflect the hierarchy** — URL path should match site structure
4. **Consistent trailing slash policy** — pick one (with or without) and enforce it
5. **Lowercase always** — `/Services` should redirect to `/services`
6. **Short but descriptive** — `/ac-repair-in-denver` is too long; `/denver/ac-repair` is better

### HVAC-Specific URL Patterns

| Page Type | Pattern | Example |
|-----------|---------|---------|
| Homepage | `/` | `example.com` |
| Service page | `/services/{name}` | `/services/ac-repair` |
| Location page (single) | `/areas/{city}` or `/locations/{city}` | `/areas/denver` |
| Service in location | `/areas/{city}/{service}` or `/services/{service}/{city}` | `/areas/denver/ac-repair` |
| Equipment | `/equipment/{brand}/{model}` | `/equipment/carrier/25hce436a013` |
| Equipment category | `/equipment/{brand}` | `/equipment/carrier` |
| Blog post | `/blog/{slug}` | `/blog/hvac-maintenance-tips` |
| Blog category | `/blog/category/{slug}` | `/blog/category/ac-repair` |
| Resource | `/resources/{slug}` | `/resources/hvac-glossary` |
| About | `/about` | `/about` |
| Contact | `/contact` | `/contact` |
| FAQ | `/faq` | `/faq` |

### Common Mistakes

- **Service + Location order**: Decide once. `/denver/ac-repair/` or `/services/ac-repair/denver/`? Stick with it.
- **Over-nesting** — `/products/residential/ac-systems/cooling/units/model-x` is too deep. Flatten to `/equipment/carrier/model-x`.
- **Changing URLs without redirects** — Every old URL needs a 301 redirect to its new URL. Without them, you lose backlink equity and create broken pages.
- **IDs in URLs** — `/product/12345` is not human-readable. Use slugs like `/product/carrier-25hce436a013`.
- **Query parameters for content** — `/services?id=123` should be `/services/ac-repair`.
- **Date-based blog URLs** — `/blog/2024/01/15/post-title` adds no value and makes URLs long. Use `/blog/post-title`.

### Breadcrumb-URL Alignment

The breadcrumb trail should mirror the URL path:

| URL | Breadcrumb |
|-----|-----------|
| `/services/ac-repair` | Home > Services > AC Repair |
| `/areas/denver/ac-repair` | Home > Service Areas > Denver > AC Repair |
| `/equipment/carrier/25hce436a013` | Home > Equipment > Carrier > Model 25HCE436A013 |
| `/blog/ac-maintenance-tips` | Home > Blog > AC Maintenance Tips |

---

## Visual Sitemap Output (Mermaid)

Use Mermaid `graph TD` for visual sitemaps. This makes hierarchy relationships clear.

### Single-Location Contractor

```mermaid
graph TD
    HOME[Homepage] --> SERV[Services Hub]
    HOME --> ABOUT[About]
    HOME --> BLOG[Blog]
    HOME --> CONTACT[Contact]

    SERV --> S1[AC Repair]
    SERV --> S2[Furnace Repair]
    SERV --> S3[Maintenance Plans]
    SERV --> S4[Emergency Service]

    BLOG --> B1[Post 1: HVAC Tips]
    BLOG --> B2[Post 2: Filter Changes]
```

### Multi-Location Network

```mermaid
graph TD
    HOME[Homepage] --> AREAS[Service Areas]
    HOME --> SERV[Services]
    HOME --> ABOUT[About]
    HOME --> BLOG[Blog]

    AREAS --> D1["Denver Hub"]
    AREAS --> D2["Boulder Hub"]

    D1 --> D1S1["AC Repair in Denver"]
    D1 --> D1S2["Furnace Repair in Denver"]

    SERV --> AC[AC Repair National]
    SERV --> FUR[Furnace Repair National]
```

**For more Mermaid templates**: See [references/mermaid-templates.md](references/mermaid-templates.md)

---

## Internal Linking Strategy

### Link Types

| Type | Purpose | Example |
|------|---------|---------|
| Navigational | Move between sections | Header, footer, sidebar links |
| Contextual | Related content within text | "Learn more about [maintenance plans](/services/maintenance-plans)" |
| Hub-and-spoke | Connect cluster content to hub | Service pages linking to location versions |
| Service-location cross | Connect related pages across sections | Denver location page linking to each service in Denver |

### Internal Linking Rules

1. **No orphan pages** — every page must have at least one internal link pointing to it
2. **Descriptive anchor text** — "AC repair services" not "click here" or "read more"
3. **5-10 internal links per 1000 words** of content (approximate guideline)
4. **Link to important pages more often** — homepage, main service pages, location hubs
5. **Use breadcrumbs** — free internal links on every page
6. **Service discovery sections** — "Other services in [Location]" or "Learn about our services"

### Hub-and-Spoke Model

For HVAC contractors with multiple services and locations:

```
Hub: /services/ac-repair (master AC repair page)
├── Spoke: /areas/denver/ac-repair (Denver version)
├── Spoke: /areas/boulder/ac-repair (Boulder version)
└── Spoke: /areas/fort-collins/ac-repair (Fort Collins version)

Each spoke links back to the hub.
The hub links to all spokes.
Spokes link to each other (related service areas).
```

### Service-Location Grid

For network sites with 5 services x 10 locations (50 pages):
- Each location hub links to all 5 services
- Each service hub links to all 10 locations
- Creates dense cross-linking structure
- Every page reachable within 2-3 clicks

### Link Audit Checklist

- [ ] Every page has at least one inbound internal link
- [ ] No broken internal links (404s)
- [ ] Anchor text is descriptive (not "click here" or "read more")
- [ ] Important pages have multiple inbound links
- [ ] Breadcrumbs implemented on all pages
- [ ] Service pages link to location versions
- [ ] Location pages link to service pages
- [ ] Cross-location links exist (Boulder AC repair links to Denver AC repair)

---

## Output Format

When creating a site architecture plan, provide these deliverables:

### 1. Page Hierarchy (ASCII Tree)
Full site structure with URLs at each node. Use the ASCII tree format from the Page Hierarchy Design section.

### 2. Visual Sitemap (Mermaid)
Mermaid diagram showing page relationships. Use `graph TD` with subgraphs for nav zones.

### 3. URL Map Table

| Page | URL | Parent | Nav Location | Priority |
|------|-----|--------|-------------|----------|
| Homepage | `/` | — | Header | High |
| Services | `/services` | Homepage | Header | High |
| AC Repair | `/services/ac-repair` | Services | Header dropdown | High |
| Denver | `/areas/denver` | Homepage | Header dropdown | High |
| AC Repair in Denver | `/areas/denver/ac-repair` | Denver | Content | Medium |

### 4. Navigation Spec
- Header nav items (ordered, with CTA)
- Footer sections and links
- Sidebar nav (if applicable)
- Breadcrumb implementation notes

### 5. Internal Linking Plan
- Hub pages and their spokes
- Cross-location/cross-service link opportunities
- Orphan page audit (if restructuring)
- Recommended links per key page

---

## Task-Specific Questions

1. Is this a new site or are you restructuring an existing one?
2. Single HVAC location or multiple locations/service areas?
3. What HVAC services do you offer? (Count: 3? 10? 20+?)
4. How many service areas/cities are you targeting?
5. What are the 5 most important pages on the site?
6. Are there existing URLs that need to be preserved or redirected?
7. Who are the primary audiences, and what are they trying to accomplish?

---

## Related Skills

- **content-strategy**: For planning what content to create and topic clusters
- **programmatic-seo**: For building SEO location + service pages at scale
- **seo-audit**: For technical SEO, on-page optimization, and indexation issues
- **schema-markup**: For implementing breadcrumb and LocalBusiness structured data
- **hvac-estimate-popups**: For conversion optimization within site structure