A crawlspace is the narrow area that gives access to the home's plumbing, electrical, and heating systems. A crawlspace is typically found in homes where there is not a basement. An important part of any crawlspace is the ventilation system, which keeps the air moving under your home. Ventilating your crawlspace will keep it from holding moisture that causes mildew and rot.
Crawlspace ventilation is often created by using windows that can be opened to allow for air to travel between them. This system can be inconvenient as you have to keep opening and closing the windows manually.
Some people will say that windows are not enough to keep your crawlspace ventilated. They recommend the use of a fan ventilation system. Fan ventilation operates with electric power. One fan sucks air into the crawlspace, while another fan pushes it out.
If you live in an area that is not susceptible to extreme fluctuations in temperature, then a very basic option is available. Using hinges, attach a piece of lattice work to the opening of your crawlspace. This way you can ventilate your crawlspace, maintain access to the crawlspace, and can keep out animals.