By Sagar Shankaran, Founder of CallSphere
HVAC companies miss 40–60% of inbound. Build a 4-agent dispatch (intake, scheduling, parts, emergency) that integrates with ServiceTitan in 600 lines.
Key takeaways
TL;DR — At $2,500–$5,000 average ticket, missing 5 calls/week is $50–100k/year in lost revenue. Build a 4-specialist HVAC dispatcher (intake, scheduling, parts/quote, emergency) on OpenAI Realtime + ServiceTitan API. Per-minute cost: ~$0.07 vs. 0.30–0.80 for vendor stacks.
A 4-agent HVAC dispatcher: triage → (new-job intake | reschedule | parts/quote | emergency). Books to live ServiceTitan capacity, SMSes confirmations with tech name + ETA window, and pages the on-call for after-hours emergencies.
openai-agents[voice], fastapi.flowchart TB
C[Caller] --> TR[Triage]
TR --> NEW[New Job]
TR --> RES[Reschedule]
TR --> PQ[Parts/Quote]
TR --> EM[Emergency]
NEW --> ST[(ServiceTitan)]
RES --> ST
PQ --> ST
EM --> PAGE[On-call page]
```python triage = RealtimeAgent( name="triage", instructions="""You're dispatch for ABC Heating. Identify intent in 2 exchanges: new-job, reschedule, parts/quote, emergency. Emergencies (no heat in winter, gas smell, water leak) hand off to emergency immediately.""", handoffs=[new_job, reschedule, parts_quote, emergency], ) ```
```python @function_tool async def find_open_slots(zip_code: str, day: str, urgency: str) -> list[dict]: techs = await st.techs.list_by_zip(zip_code, skill_set=["hvac"]) slots = await st.dispatch.aggregate_slots(techs, day, urgency_score=URGENCY_MAP[urgency]) return slots[:5]
@function_tool async def create_job(name: str, phone: str, address: str, slot_id: str, problem: str, system_type: str) -> dict: j = await st.jobs.create(customer={"name": name, "phone": phone, "address": address}, slot_id=slot_id, summary=problem, tags=[system_type]) ref = f"HV-{datetime.now():%Y%m%d}-{j.id:03d}" await sms.send(phone, f"Tech {j.tech_name} arriving {j.eta_window}. Ref {ref}") return {"ref": ref, "job_id": j.id, "eta": j.eta_window} ```
Hear it before you finish reading
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```python @function_tool async def lookup_existing_job(phone: str) -> dict: j = await st.jobs.find_active(phone) if not j: return {"found": False} return {"found": True, "job_id": j.id, "current_slot": j.slot_iso}
@function_tool async def reschedule_job(job_id: str, new_slot_id: str) -> dict: j = await st.jobs.reschedule(job_id, new_slot_id) await sms.send(j.customer.phone, f"Updated to {j.eta_window}. Ref HV-{j.id}") return {"ok": True} ```
```python @function_tool async def get_diagnostic_quote(zip_code: str, after_hours: bool) -> dict: z = await st.pricing.zone(zip_code) return {"diagnostic_fee": z.diag_fee + (z.after_hours_premium if after_hours else 0)}
@function_tool async def check_part_in_stock(model_number: str, part: str) -> dict: return await st.inventory.find(model_number, part) ```
```python @function_tool async def page_oncall(summary: str, address: str, phone: str) -> dict: oncall = await rotation.who_is_oncall() twilio.calls.create(to=oncall.phone, from_=BUSINESS_NUMBER, url=f"https://you/page?summary={summary}") j = await st.jobs.create_emergency(summary=summary, address=address, phone=phone) return {"job_id": j.id, "paged": oncall.name} ```
Standard Realtime bridge. Add CSAT IVR ("press 1 if booked correctly") at end-of-call to populate quality metrics.
Still reading? Stop comparing — try CallSphere live.
CallSphere ships complete AI voice agents per industry — 14 tools for healthcare, 10 agents for real estate, 4 specialists for salons. See how it actually handles a call before you book a demo.
Track: book-rate (booked / total), AHT, average revenue per booking, after-hours emergencies/night, missed-call rate (always 0 with AI). Replace your old IVR dashboard.
OneRoof Property runs 10 specialists over WebRTC + Pion + NATS — same shape, scaled. Healthcare's FastAPI :8084 ships 14 HIPAA tools. Salon emits GB-YYYYMMDD-### references the way the HV-YYYYMMDD-### pattern above mirrors. 37 agents · 90+ tools · 115+ DB tables · 6 verticals. Pricing $149/$499/$1499 flat — no $0.30–$0.80/min surprise. Start a 14-day trial or check /pricing.
ServiceTitan tier needed? "Marketing Pro" or higher for full API.
TCPA? Inbound is fine; outbound recall to cell phones needs PEWC.
After-hours pricing? Tool returns the surcharge so the AI can quote correctly.
Multi-trade (HVAC + plumbing + electric)? One trade parameter on every tool.
Voice tone? Use ElevenLabs for warmer voice for residential calls.
Written by
Sagar Shankaran· Founder, CallSphere
Sagar Shankaran is the founder of CallSphere, where he builds production AI voice and chat agents deployed across healthcare, hospitality, real estate, and home services. He writes about agentic AI, LLM engineering, and shipping voice agents that handle real calls in production.
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