To be on the safe side, you would have to keep the bed bugs at 0 degrees Fahrenheit for at least 4 days. This applies to adults and nymphs. Bed bug eggs are more resistant to the cold and you would need to keep them at 0 degrees for almost two months. If your freezer is capable of holding that temperature consistently, then this could work for you.
While this tactic won’t work for large items, it could be a practical (and cheap) method of treating smaller items that are infested with bed bugs. Items like certain electronics, books, clothing and accessories that can’t be washed and children’s toys.
You will have to use good judgment. But this could be a workable piece of a larger bed bug extermination effort.