Need just a little more info...
What do you plan on growing?
What type of system do you plan to utilize?
What are your temp extreams?
Which direction will this addition be facing? and are there any trees that may block the sun?
You will find there are a lot of "it depends" and at some point you just have to jump in and give it the ol' college try. There are lots of resources out there and I learned a ton of of youtube. The most important thing with hydroponics is the root/resouviour temps. The roots do not like to be too cold or too hot. There will be lots of opionions but I try to stay in the 65 to 82 degrees range so for me that means heating in the winter and cooling in the summer. Again, there are lots of options from home made, off the grid ideas to expensive store bought systems. I just use frozen containers in the nutes to keep them cool and insulating the resoviour in the summer. For winter, I am looking at a sawdust barrel stove.
The other thing is the right plant for the right spot... Don't plant a tomato plant in a 4" horizonal tube, I learned the hard way! However I did grow a pumpkin plant in a 15 gal rubbermaid tote
Good luck! Hydro is a great way to feed your family.