How do we upgrade the heating system in our sun room?
We have a 12x12 approx sun room built onto our family room and kitchen with two french doors opening into it from the house. There is no central heating or cooling system in the room and it is essentially unusable in the winter. How can we heat the room in the most energy efficient and cost efficient way? The room itself had large floor to ceiling windows and six sun lights overhead. Under the floor, there is a concrete base, but it is not part of the foundation of the house and there is a 3-4' crawlspace underneath with no insulation and a downward slope of the land away from the house. There is also a very small vent and apparent duct going from the sunroom into the HVAC under the family room, but no airflow is felt during normal operation.
In order to seriously answer your question, you need a diagnostic energy audit done which should at least include duct testing and some modeling work.
As for a quick fix, I would track down that duct and make sure it is tied into the forced air system. My guess is it became disconnected or a damper is closed.
If neither is the case you are going to need an HVAC company to get the problem resolved properly. This may just require some duct sealing, or it may require some substantial fixes to the distribution system as it wasn't designed or installed properly.
For more information:
Read Mark Schrieber's "We're adding a sunroom to our home. Can you suggest strategies for natural heating and cooling?" for more information on designing an energy efficient sun room.