I am not a legal expert, and real estate laws can vary depending on your location. However, I can provide some general information on this matter.
The legality of the situation and who owns the central heating and air conditioning system may depend on several factors, including the terms of the lease agreement, local laws, and whether the installation was done with the landlord's knowledge or consent.
Lease Agreement: Review the lease agreement between the landlord and the tenants. It should specify the terms regarding alterations or improvements to the property. If the lease explicitly prohibits tenants from making modifications without the landlord's permission, the tenants may be in breach of the lease agreement.
Consent and Communication: If the tenants installed the central heat/air system without the landlord's knowledge or consent, the legality of the situation may be questionable. Generally, tenants are required to seek permission from the landlord before making significant changes to the property.
Fixtures and Chattels: The legal concept of "fixtures" versus "chattels" comes into play here. Fixtures are items that become permanently attached to the property and are considered part of it. Chattels, on the other hand, are movable personal property. If the central heat/air system is deemed a fixture, it would likely remain with the property, even if the tenants installed it. However, if it's considered a chattel, the tenants may have the right to remove it since they paid for it.
Local Laws: Real estate laws can vary by jurisdiction, and some areas may have specific rules regarding tenant improvements, alterations, and property ownership rights. It's essential to consult local laws and regulations to understand how they apply in your situation.
Mediation or Legal Advice: If there's a dispute between the landlord and tenants regarding the central heating and air conditioning system, it might be best to seek mediation or legal advice to resolve the matter. A real estate attorney or local housing authority can help clarify the rights and responsibilities of both parties.
Ultimately, the resolution will depend on the specific circumstances, the terms of the lease, and the applicable laws in your area. It's crucial for both parties to communicate openly and, if necessary, seek legal guidance to determine the best course of action.