Sign in | Free 10-day GBA Pro Trial

Use a heat-recovery ventilation system

Tags: New construction, Gut rehab, Home performance & weatherization, Gut rehab, Home performance and weatherization, Other Mechanical Systems, cold, hot_humid, mixed_humid

Saving energy while providing fresh air
Heat-recovery ventilation(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. (HRV) transfers heat from exhaust air to incoming fresh air, meaning that the heating system doesn't have to work as hard to keep the house comfortable. In summer, exhaust air cools incoming air before it enters the house. Energy-recovery ventilators (also called enthalpic heat recovery ventilation or EHRV), transfer moisture as well as heat. Among the choices for ventilation, these two are the most expensive.

Green points

LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. : 2 points for installing a system that provides heat transfer between incoming and exhaust air, such as an HRV or ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV.; 1 point for third-party testing for ventilation (EQ 4).
NGBSNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. /ICC-700: 15 points for heat-recovery ventilation; 17 points for energy-recovery ventilation (902.2.1).