Take up the floor? Back porches usually have a crawlspace under them, which gives you access to go under and add batts without removing flooring--that is what I did to my pantry/porch on my house built in 1908.
Why not blow in insulation from the outside for the walls (cellulose is good for this, and you can rent the machine to do it yourself).

Good idea. The entire house has nasty vinyl siding. :-( even on the front and back porches, all the way to the ground. It might take some doing to remove it all, but would be easier than demo-ing everything! I'm so new to home reno...what cost would you say this might be? ballpark estimate?

Rethink removing the windows, especially if they are original to the house, instead think about adding storms to them.
Do some reading on the board here and you will see why.

If you are going to be doing some plumbing so you can move the laundry do it now when everything is down to barebones. It will make the job easier in the long run even if you don't actually move everything till a later time.

Same with adding outlets or lighting fixtures. Do it before you insulate.

Prices will vary greatly depending on where and what time of year you are having the work done and how fast you want it done. It also makes a huge amount of difference if you are having demo work done if you do that yourself or if you have to pay to have it done too.

With a new-old house it's best to look for a contractor that is use to dealing with old houses as a specialty rather than getting one that deals primarily with rip and repair. Again do some reading on this board and you will understand why.

Infact I'd suggest doing lots of reading thru the old post here. You will learn much that can help you save money and time.

Carol, great advice. Thank you. I might not get any housework done this weekend, because I will be reading the old posts! I'm not sure about the windows. I don't think they are original. They look aluminum, and my guess is 50's? Also, the wall material doesn't strike me as early century, but 50's. I could be very wrong, as I'm new to all of this.

Hi, Kindred. A house built in 1916 or thereabouts will have issues with lead, so approach demo with that in mind.

When we did a temporary fix on our back porch (in south Alabama so not too too cold)which was built in 1950 with stucco exterior, no insulation, and only screening on the top, we took off the wall board and replaced it with sheetrock after putting in some fiberglas batts. We also removed the screening and added some Lexan which was not the really thick kind. At least it kept out the raccoons. We also replaced the hollow core back door. The floor was in terrible shape, but since this was a temporary job, my DH first moved the power connections and the water supply lines for the laundry hookups. Then he laid 3/4" plywood over the floor for stability. Our crawl space is enclosed and we did not insulate beneath the floor nor in the shed roof--because we will eventually tear this porch off. Even with the addition of plywood flooring and sticky-back tiles on top of that, the porch floor is about 3 inches lower than the present kitchen.
That is why we did this job only temporary, for a couple of years, until we tear off the whole thing and expand the kitchen into its footprint with new everything.

Before YOU launch a full redo of your back porch, decide if, like us, the porch is really a pigs ear and will never become a silk purse. :)

Depending on what the floor is made from, it may be difficult to make a real room out of your porch. If it's wood, you are in better shape. If concrete, it will be difficult to ever have it really warm. For washing machine placement, it must be level. If a wood frame, check o see that the structure hasn't sagged at the foundation. Porch footings are rated for porches, not rooms. Any settling has to be addressed at the ground level.
Yes strip the walls. Spray foam on all exterior surfaces is going to giove the best result IMO. Upgrade to a good grade of window like Anderson 400 or A series. They are custom-sized for the existing openings, and perhaps the 1950's aluminum windows were not sized to complement the older house windows, which could be addressed at this time as well.
So; level, insulated floor, walls & ceiling, upgraded wiring & plumbing (for W/D), new efficient windows, (new entry door?), vapor barrier, a light and some outlets, drywall, paint, molding, all for less than 10 grand? Maybe if you do most of the grunt work ursef.
Casey

Thank you so much for responding. I was thinking this might be more than a little $$. My 20 year plan (as I call it) would be to expand the house off the back by about 20 ft (up and down). This would mean tearing off the porch, so I don't want to spend a ton to do it. If I could get away with a grand or two, I might. But not $10,000. When I build off the back, it would enable the 2 upstairs bedrooms that currently have no closet to finally have one. And it would enable me to have a family room off the back (complete with fireplace) and a 1st floor laundry and mudroom. Thanks for the info, though. It helps to put things in perspective and set my priority list accordingly! :-)

I think it's going to cost a lot more than you want to spend. Maybe get a few contractors to come out and give you some free estimates...make sure they're free, too. Tell them what you want to do...with maybe a few different options.

There are so many variables, it's almost impossible to tell, without seeing the porch, in person. Hope that helps :)

Thank you. Yes, it does. I was thinking of turning it into usable space (coats,shoes,recyclables even). Right now it's like walking outside when it's winter. I don't keep stuff out there because it's too cold to go out and get it without putting on a coat and boots! And then the stuff is too cold to wear! It's OK. I'll appreciate the addition even more when I finally do it! :-)