Talking with any experienced carpenter, you have probably heard the phrase “a house needs to breath, you don’t want to build it too tight.” This is common folklore that has been passed down from generation to generation. Your builder tells you he is doing something that is good for your home by letting it leak a little to get fresh air and allow the building materials to dry out. These concepts need to be addressed, but a leaky house is not the solution. You do want to bring fresh air into your home, but you should do it through a planned ventilation system. You also want to allow materials to dry out so you need to know the permeability of those materials and verify that you are not creating a surface that reaches dew point in the assembly.
An Energy Recovery Ventilator (ERV) is the system used for energy recovery by exchanging the energy contained in air exhausted from the building and using it to treat (pre-conditioned) the incoming outdoor ventilation air in residential and commercial HVAC systems. (So it is basically a spinning hamster wheel working to make your home more comfortable.) During the warmer months, the system dehumidifies and pre-cools while humidifying and pre-heating in the cooler months. The benefits of using energy recovery is the ability to meet the ASHRAE ventilation and energy standards, while improving indoor air quality, and reducing total HVAC equipment capacity. It does not make your home more energy-efficient, this is used with a focus on comfort and indoor air-quality.