Sunroom are a great addition to many homes. They will add useable square footage to the home. As someone who was a licensed realtor for many years, this isn’t something I’d recommend for a home that has a dated bathroom or kitchen. These are going to be the first place that potential buyers will look so adding a super nice sunroom to a home that needs a remodel won’t produce nearly the same return it will on a fully modernized home.
Another perk of sunrooms is that they are a differentiator when potential buyers are deciding between similar properties. Additionally, there are some people who specifically seek out homes with a sunroom.
When adding a sunroom to a home, I think you should look at the addition shouldn’t be more than 10% of the value of the home. If the home is worth $300k then $30k is the absolute most I’d consider investing into a sunroom.