Is the sunroom part of your interior space - does it have insulation, proper windows, heating/cooling?

Are you experienced with making structural changes such as opening a wall?

A lovely idea to expand your kitchen!! Exciting and I am sure a little nerve wracking too.

You wrote....

We are looking to convert our 370 sqft sunroom into living space. How can we achieve this conversion?

Renovation, have you ever renovated a kitchen or home before? It can be challenging. I agree with the questions from Design Fan

The sunroom is a step-down area from the dining room. We are seeking an economical way to repurpose this area, possibly transforming it into a family room and bedroom

Economical? You may want to sit down and study the cost of the materials, labor, and time. For some this could be $20,000 for others this could be $100,000 Its a good idea to sit down and see what you can afford and does it match your needs and even wants. Are you removing the tile floors? Keeping them?

PS

2)We are thinking of opening up the kitchen and close the door and window in the kitchen to the sunroom. We may have to provide a pillar to support the current beam ,when we open up the kitchen. Is it advisable to do that ?

Sure, but I would meet with a structural engineer to find out if this could work.

Now to a few questions...

Is that your current kitchen?

What is your budget?

What are the zoning rules in the bay area?

The bay area has some crazy taxes so you may need to do this reno in small pieces to avoid the surcharge of anything over $50 grand or the taxes could be crushing.

Could you draw with measurements of all the walls, windows, doorways on to graph paper and then post that on this thread?

Are you willing to move water? Electric?

Could you move your kitchen to the sunroom?

So many things to consider as you tackle this space.

Enjoy

This is not a diy project unless you own a construction company, and sq feet are essentially meaningless. Traffic patterns, entries, exit, define space along with the feet and inches and where those are located.

You need a hard measure of the alllllll the spaces involved.

Every wall, window, etc. as it exists n.o.w: )

I'll add that nothing about a project like this will be "economical" . No renovation is- it is nail for nail often more expensive than new construction.

Sunrooms are not built to be interior spaces. You will have to redo the foundation, walls, and roof, to meet current building codes. Rebuilding half hour house is certainly NOT any DIY job, unless you are an experienced contractor.

What everyone else said is true. Sounds like a job for a professional.

Why do you need a bedroom in the sunroom? Is it for guests or kids or aging in place?

Perhaps, a guest room could be fashioned by simply adding a wall, but it would only be useful during the summer (assuming this is a three season room.)

I guess we need context and a floor plan.

Where are you OP ?

I agree with what other posters have said. This isn't a diy project unless you are very experience with construction. It would be a good idea to have a contractor or even a structural engineer examine your sunroom to see if it will support the kinds of changes you are looking to do. I'm assuming your expansion of the kitchen will be elsewhere than the sunroom as the sunroom steps down and you wouldn't want a two level kitchen. As far as adding a bedroom you would either have to access it from your new family room or connect it with another portion of your house. Access off the family room isn't the most desirable but could be acceptable. Is the current sunroom conditioned? I don't see any floor, wall or ceiling vents. If you are going to convert the space you would certainly have to expand your hvac system into the new spaces. Also, what is your budget? This isn't a small space. Will take some $$$ to make this conversion even if you are able to do it yourself.

Btw, I came across this cool rotating summerhouse from Scotts of Thrapston (https://www.scottsofthrapston.co.uk/rotating-summerhouses/) that could totally add a unique touch to your sunroom, giving it that wow factor without breaking the bank!