There is no one definitive answer to this question. Depending on how long you have been proofreading, how fast you read, and how well you know the language, it could take anywhere from a few minutes to an hour.
If you are just starting out, or haven't proofread in a while, it might be a good idea to take a few practice runs. You can find practice texts online, or in books. Once you have a good feel for how long it takes you to proofread, you can estimate how long it will take you to proofread 1000 words.
Remember, everyone is different. Some people can proofread very quickly, while others take a bit longer. The important thing is to proofread carefully, and not to rush through it.
