Crawl space vents.

[john vicari]

What are the suggested conditions for opening or closing crawl space vents?

[Ron C]

The recommended solution is to condition the air in the crawlspace and encapsulate the floor and walls to prevent air infiltration. If this can not be done because of job conditions then a vent would be necessary. If you have a combustionable appliance like a furnace or a gas water heater that needs fresh air, a vent or direct intake would also be necessary.