Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Whole house continuous mechanical ventilation nearly always result in higher energy use than having no such system. After all, you are bringing in outdoor air that needs to be conditioned to the thermostat setpoint. Mechanical ventilation systems are designed to improve indoor air quality, not save energy. Even systems with heat recovery will result in higher energy use than no system, though "less high" than systems without heat recovery.
In general, it only makes sense to optimize across mechanical ventilation systems that provide the same level of indoor air quality. In your example above, that would mean deselecting the None option, so that the optimization is evaluating different HRVs/ERVs that all provide the same amount of airflow (100% of ASHRAE 2010 requirement).
| | 2 | No.2 Revision |
Whole house continuous mechanical ventilation nearly always result in higher energy use than having no such system. After all, you are bringing in outdoor air that needs to be conditioned to the thermostat setpoint. setpoint (plus using fan energy to do it). Mechanical ventilation systems are designed to improve indoor air quality, not save energy. Even systems with heat recovery will result in higher energy use than no system, though "less high" than systems without heat recovery.
In general, it only makes sense to optimize across mechanical ventilation systems that provide the same level of indoor air quality. In your example above, that would mean deselecting the None option, so that the optimization is evaluating different HRVs/ERVs that all provide the same amount of airflow (100% of ASHRAE 2010 requirement).
| | 3 | No.3 Revision |
Whole house continuous mechanical ventilation nearly always result in higher energy use than having no such system. After all, you are bringing in outdoor air that needs to be conditioned to the thermostat setpoint (plus using fan energy to do it). Mechanical ventilation systems are designed to improve indoor air quality, not save energy. Even systems with heat recovery will result in higher energy use than no system, though "less high" than not as high as systems without heat recovery.
In general, it only makes sense to optimize across mechanical ventilation systems that provide the same level of indoor air quality. In your example above, that would mean deselecting the None option, so that the optimization is evaluating different HRVs/ERVs that all provide the same amount of airflow (100% of ASHRAE 2010 requirement).
