Alternative Fuel Conversion Cost Comparison: HHO vs LPG vs CNG vs EV

HHO Supplementation

Upfront cost: $150–$500. Ongoing cost: electricity (included in existing charging system). Expected savings: 10–20% fuel reduction. Payback period: 3–18 months at typical driving levels. Infrastructure: none required — uses existing gasoline infrastructure. Best for: high-mileage drivers in standard gasoline vehicles wanting simple, low-risk supplementation.

LPG Propane Conversion

Upfront cost: $2,500–$5,000 installed (bi-fuel conversion). Ongoing cost: LPG fuel (typically $0.70–$1.50/gallon equivalent less than gasoline where available). Expected savings: 20–40% per mile when running on LPG. Payback period: 2–4 years at average mileage. Infrastructure: LPG stations less common than gasoline, varies significantly by region. Best for: high-mileage drivers in areas with good LPG infrastructure.

CNG Conversion

Upfront cost: $3,000–$8,000 installed. Ongoing cost: CNG significantly cheaper than gasoline per equivalent gallon ($1.50–$2.50 CNG vs $4.00+ gasoline). Payback period: 1.5–4 years for high-mileage drivers. Infrastructure: limited public stations; home fueling possible with Phill unit. Best for: vehicles that drive predictable routes near home or depot fueling.

EV Conversion

Upfront cost: $8,000–$25,000 for quality conversion. Ongoing cost: electricity at $0.10–$0.20/kWh equivalent vs gasoline. Payback period: 5–15+ years depending on conversion quality and electricity prices. Infrastructure: home charging available; DC fast charging expanding. Best for: dedicated local-use vehicles with consistent charging access and high daily mileage.