An ERV (Energy Recovery Ventilator) and an HRV (Heat Recovery Ventilator) both provide controlled mechanical ventilation for tight homes — introducing fresh outdoor air while recovering 70–80% of the energy from exhausted indoor air. An HRV recovers only heat. An ERV recovers both heat and moisture — making it the right choice for Utah’s dry climate, where it retains indoor humidity during dry winters instead of exhausting it. Modern homes built to current energy code are tight enough to require mechanical ventilation per ASHRAE 62.2. Without it, indoor CO2, VOC levels, and air quality degrade. RainFire Builders installs ERV systems as the standard ventilation solution for new construction in Utah.