Thanks for the reply. The current windows and door are simply not doing their job. My idea was to do just that, remove the paneling and install more insulation as you mentioned.
The floor I believe it is concrete. It does not have basement under it. I am attaching photos for you to take a look at the steps. As for the heating, I am not sure how to go about it. I will be researching my options and then post more questions about it.
I am about to measure the patio door. I saw one at Lowe's that was in the clearance because it was discontinued. It is made by Pella and has shades in between the glass panels. I liked it a lot, but am not sure if it is the right size.
Anyway, please share your opinions and experiences. Thanks. Be well
Miriam
As you can see there are actually 2 steps to go into the house.
This is the steps coming from the outside into the sunroom. The door is covered with insulated fabric right now.
The door and one window. There are 3 more
The heater. There are 2 of them. My idea was to remove the paneling and make the frame to go all the way to where the heater is.