A fixture is a once-movable item that, by virtue of its attachment to realty, reflects the intention to permanently improve that realty. Common examples of fixtures include heating systems, custom-made storm windows, furnaces and lighting installations.
Unless otherwise agreed, a tenant must not remove a fixture, even if the tenant installed it. Fixtures pass with ownership of the land.
How does one know whether a given tenant installation qualifies as a fixture? First, the landlord and tenant’s express agreement on the matter is binding. In the absence of such an agreement, a tenant may remove an item that she has installed so long as removal does not cause substantial damage to the premises. If removal will cause significant harm, then the tenant, in objective judgment, has demonstrated the intention to install a fixture. As a general matter, the fixture must stay put.