Calculate energy savings from an ERV or HRV ventilation system. Compare heat recovery ventilation costs to standard exhaust-only ventilation.
Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRVs) are balanced ventilation systems that exchange stale indoor air for fresh outdoor air while recovering 60–85% of the heating or cooling energy from the exhaust stream. Without heat recovery, ventilation energy is simply lost.
In a climate with 6,000 HDD, ventilating a home at 100 CFM without heat recovery costs $400–$600/year in heating energy alone. An HRV with 75% efficiency recovers $300–$450 of that — paying for itself in 4–8 years. ERVs also transfer moisture, making them ideal for humid climates.
This calculator compares the annual energy cost of ventilation with and without heat recovery, showing your savings and payback period for ERV/HRV installation.
This measurement provides a critical foundation for energy auditing and sustainability reporting, helping organizations meet regulatory requirements and voluntary environmental commitments. Integrating this calculation into regular energy reviews ensures that conservation strategies are grounded in measured data rather than assumptions about building performance and usage patterns.
Mechanical ventilation is essential in tight homes but costly without heat recovery. This calculator quantifies how much an ERV or HRV saves based on your climate, ventilation rate, and energy costs. Regular monitoring of this value helps energy teams detect usage anomalies early and address equipment malfunctions or operational issues before they drive utility costs higher.
Ventilation Heating Cost = CFM × 1.08 × HDD × 24 / (Heating Efficiency × 100,000) × Fuel Cost Recovery Savings = Ventilation Cost × Recovery Efficiency Payback = Install Cost / Annual Savings
Result: $340/year savings, 8.8-year payback
At 100 CFM and 6,000 HDD: ventilation heating cost ≈ $454/year. ERV at 75% efficiency recovers $340/year. At $3,000 installation, payback is 8.8 years. Over 20-year lifespan, net savings exceed $3,800.
The ERV/HRV core contains thousands of thin channels where incoming and outgoing air streams pass close together without mixing. Heat transfers through the channel walls from the warm stream to the cool stream. In an ERV, moisture also transfers through permeable membranes. The result: 70–85% of the energy that would be lost is recovered.
Cold dry climates (zones 5–7): HRV is usually preferred because you want to exhaust moisture (from showers, cooking) rather than retain it. Hot humid climates (zones 1–3): ERV is preferred because it pre-dehumidifies incoming air. Mixed climates (zones 3–4): ERV is often the better all-around choice.
In mild climates (under 3,000 HDD), the energy savings from heat recovery may not justify the $3,000–$5,000 installation cost within a reasonable payback period. In these areas, simpler exhaust-only ventilation may be more cost-effective.
An HRV transfers only heat (sensible energy). An ERV transfers both heat and moisture (sensible + latent energy). In humid climates, ERVs prevent excess humidity from entering. In dry cold climates, ERVs retain indoor moisture. HRVs are simpler and slightly cheaper.
A residential ERV or HRV costs $1,000–$2,000 for the unit and $1,500–$3,000 for professional installation with dedicated ductwork. Simplified installations using existing bathroom and return ducts cost less. Total: $2,500–$5,000.
Yes. In summer, the ERV pre-cooks incoming hot air using the cool exhaust air, reducing air conditioning load. An ERV also reduces incoming humidity in summer, which is a significant benefit in the Southeast and Gulf Coast.
With proper maintenance (filter cleaning, core cleaning, motor lubrication), ERVs and HRVs last 15–25 years. The heat exchange core is the most durable part. Motors may need replacement at 10–15 years.
A simplified installation (exhaust from bathrooms, supply to living area) is feasible for handy homeowners. A fully ducted system with dedicated supply and exhaust to multiple rooms is more complex and usually requires a professional.
An ERV can serve as the whole-house ventilation system, including bathroom exhaust, if the ductwork is designed for it. Many installations use the ERV exhaust as the bathroom exhaust, eliminating separate bath fans.