What Type of HVAC System Needed for Sun PorchWhat Type of HVAC System Needed for Sun Porch  - We added a 300 sq.ft. of living space to our home as a sun porch. How do we effectively, efficiently heat/cool this space? We’ve been pitched several options. 1) Use existing with a manual duct damper to the new sun porch. 2) same as above but use a zoned approach. Zoned w/auto dampers for main house 1st floor and sun porch plus separate thermostats. 3) HVAC with new units for sun porch (e.g., radiate, forced air, etc)

Sun Porch and What Type of HVAC System Needed?

The Sun Porch or Florida Room: What Type of HVAC System Needed for Sun Porch

Parameters - Sun porch is a 15×20 fully enclosed insulated space with 6 ft. casement windows on three sides. The fourth side is the main house wall. Main house is 2 story, 1600 sq ft. per floor, gas heated with 2 Trane furnaces. It’s cooled with 2 Trane central air units. The Trane equipment is new being installed in 2007.

We really do not know much about any of this and that is why we turn to you to help us. My wife found your website on the internet seeking the answer to our predicament. We appreciate any help you may be able to offer us. Thanks for your help in advance. Paul and Debbie

The Answer to What Type of HVAC System Needed for Sun Porch

This is Richard from High Performance HVAC responding to your question. The question concerning your sun porch and the type of HVAC equipment you need to keep it comfortable. The first thing I thought for your dilemma was a mini-split heat pump. I’ve seen many of these systems used successfully on sun porches. However, I see you reside in Illinois and I don’t believe heat pumps can take the cold winters there. Heat pumps do not provide effective heating for constant temperatures less than 38 degrees F. A mini-split heat pump with backup heat strips would work. Consequently, the electric heat backup for the heat pump is expensive to operate but it works.

Electric heat is expensive for the utility bill. However, the installation cost for the mini-split is cheaper than a full sized HVAC unit. (minimum sizes with these units are 1.5 tons which is too much for what you need). Additionally, it’s ductless so you don’t need ductwork with the mini-split. You could get a straight AC mini-split with heat strips in the air handler portion. And for back-up heat on really cold days a gas fired radiant heat. Lastly, this would not require ductwork which is good because their are no future problems with replacing or repairing the duct work.

What Type of HVAC System Needed for Sun Porch - Other Factors and Considerations

I’m not a big fan of the automated duct dampers in residential systems. I’ve seen too many problems and heard too many complaints about them. Some contractors swear by them but I will not recommend something that I don’t have confidence in and I don’t have confidence in these systems. The other problem which arises when thinking of using this type of system (automated damper system with two thermostats) is the size of the unit. Is the other parts of the house going to suffer or is the unit going run too hot when only one zone is calling.

It will probably have a bypass damper so you only get the required amount of BTU airflow to the sun porch. However, where does the bypass bypass to? Back to the furnace where it will cause the furnace to short cycle. (which is the common method of doing it in a system like this)? Does the furnace have staging to prevent short cycling. If so does the contractor have the talent necessary to hook up the controls properly to make it work right?

Finally, another option for heating and cooling the sun porch is to install a PTAC unit. PTAC units are through the wall heating and cooling units that most people will recognize from hotel rooms and is pictured above. PTAC is an acronym of portable terminal air conditioner.

 What Type of HVAC System Needed for Sun Porch

High Performance HVAC

What Type of HVAC System Needed for Sun Porch


Resource, Learn More HVAC and About the Author

To learn more about heating systems and HVAC use this resource.

See the About the Author page for information about the author of this article.

Share your HVAC Photos or ask a question about your HVAC System by uploading a photo of it.

Photo Uploads
Enter your name so we can credit you
If you have a website enter your website URL for additional credit
If you want to include a description then do so here.
Drop a file here or click to upload Choose File
Maximum upload size: 33.55MB
jpe, jpeg, jpg, gif, png, bmp, docx, doc, txt and PDF files allowed to be uploaded. Limit 15 files total and 100 mb/s max size.