AI Voice Agents vs Human SDRs: The 2025 Cost-Benefit Analysis

Reading time: 12 minutes

Introduction: The $50,000 Question

A SaaS company hired us with a straightforward problem: their two SDRs were burning out, making 50-80 calls per day each, and still missing 60% of inbound leads because they couldn't keep up with volume.

The VP of Sales asked: “Should I hire two more SDRs at $75,000 each, or try this AI voice agent thing?”

We ran the numbers. Here’s what we found:

Option A: Hire 2 more SDRs

• Cost: $150,000/year in salary + benefits
• Capacity: 160 calls/day total (4 SDRs × 40 calls)
• Training time: 3-6 months to productivity
• Turnover risk: 35% annual turnover

Option B: Deploy 1 AI voice agent

• Cost: $48,000/year ($4K/month all-in)
• Capacity: 1,000+ calls/day, unlimited concurrent
• Training time: 2-3 weeks to optimization
• Turnover risk: Zero

They chose Option B. Six months later: 1,200+ agent hours saved monthly, 85% Tier-1 inquiries resolved, 3x more qualified appointments for the remaining SDRs, ROI: 8.7x.

The True Cost of Human SDRs in 2025

Base Compensation

• Salary: $45,000-65,000
• Commission: $15,000-30,000
• Benefits: 20-30% of salary ($12,000-19,500)
• Payroll taxes: 7.65% ($5,000-7,500)

Total compensation: $77,000-122,000 per SDR/year

Hidden Costs

• Recruiting: $3,000-8,000
• Onboarding: 2-4 weeks at full salary
• Training: 8-12 weeks to 50% productivity; 16-24 weeks to full
• Tools/Software: $2,400-6,000/year
• Management overhead: 15-20% of sales manager ($12,000-18,000)
• Office space (if applicable): $6,000-12,000/year

Hidden costs: $23,400-52,000 per SDR/year

Turnover Costs

Average SDR tenure: 18 months. Turnover: 35-40%.

• Lost productivity: 2-3 months
• Recruitment: $3,000-8,000
• Training: $15,000-25,000

Annualized turnover: $15,000-25,000

Total Cost of Ownership: Human SDR

Year 1: $115,400-199,000 | Year 2+: $100,400-174,000 | 3-year total: $316,200-547,000

The True Cost of AI Voice Agents in 2025

Initial Setup

• Platform selection/config: $2,000-5,000
• Script dev/optimization: $1,500-3,000
• CRM & lead source integration: $1,500-4,000
• Voice persona: $1,000-2,000
• Testing & QA: $500-1,500

Total setup: $6,500-15,500 (one-time)

Monthly Operating

• Platform: $500-1,500
• AI usage: $0.10-0.30/call
• Telephony: $200-500
• Maintenance/optimization: $500-1,500
• Human oversight (PT): $800-1,500

1,000 calls/month: $2,100-5,300 | 5,000 calls/month: $2,500-6,500

Annual Cost of Ownership

Year 1: $31,700-79,100 (incl. setup) | Year 2+: $25,200-63,600 | 3-year total: $82,100-206,300

Bottom Line

Conclusion: AI voice agents cost 74-82% less over 3 years.

Performance Comparison: 50+ Implementations

Volume & Capacity

Speed & Response

Consistency & Quality

Cost Efficiency

When to Use Human SDRs: 5 Scenarios Where Humans Win

1. Complex enterprise sales ($100K+ deals, 6+ month cycles)
2. High-touch relationship building
3. Strategic account management
4. Highly technical/consultative sales
5. Brand-building & thought leadership

Best practice: AI handles contact/qualification/scheduling; humans handle discovery, demos, objections, closing, and strategy.

When to Use AI Voice Agents: 8 Scenarios Where AI Dominates

1. High-volume lead qualification
2. Instant lead response
3. After-hours & weekend coverage
4. Appointment setting & reminders
5. Repetitive qualification questions
6. Outbound cold calling at scale
7. Follow-up & nurture sequences
8. Seasonal/promotional spikes

Typical ROI: 4-20x in year one, depending on volume and average deal size.

The Hybrid Approach: Best of Both Worlds

For ~80% of businesses, hybrid delivers the best results.

How It Works

AI: instant contact (10-20s), qualification (BANT), scheduling, after-hours, follow-ups, reminders.

Humans: discovery, demos, objections, closing, relationships, technical depth.

Results