I am looking for some suggetions on how to get a few rooms in our house warmed

We have an old house (+100 years) that had a 10x20 addition added approx 60-80 years ago. The addition is only a first floor addition and consists of a mud room, bathroom and office. These rooms are freezing in the winter. The bathroom and the office each have a forced air vent in the floor, but that doesn't seem to cut it. I think this is an insulation problem.
Here is my insulation status:
1.Their is no insulation in any of the first floor walls (addition or main house)
2. Under the addition a full basement was never dug, and the crawl space is barely 2 ft tall. There is no insulation in the floor joists or on the foundation walls of the addition.
3. Above the addition is a porch that someone started to tun into finished space. They added a roof and storm windows, but nothing else. I have posted regarding this space before, here is a link with some pictures: http:/www.askmehelpdesk.com/construction/sister-unsupported-rafters-375602.html#post1860475 (https://www.askmehelpdesk.com/construction/sister-unsupported-rafters-375602.html#post1860475)


My questions are:
1. Is this an insultation problem?
2. Where am I going to get the most bang for my buck, the walls, ceiling or crawlspace?
3. If I do the ceiling, can I just clean out the enclosed proch and unroll R-38 or do I have to open up the porch floor?
4. If I do the crawl space, should I insulate the joists or the foundation walls. The crawl space has a very small access hole that and I am not sure I can get a lot of insulation on the walls as the crawl space is not 2ft everywhere.

Thanks for the help

To simplify this

Any insulation you add is of benefit. Usually the ceiling since hot air rises is the best to insulate first.

Air leaks are a real pain to caulk or repair but seal up the envelop of the rooms and that will help also.

You mentioned crawl space and here you want to install a plastic vapor barrier on the dirt covering the entire crawl space dirt floor. Do the vapor barrier AFTER you insulate the floor joists since moving around to do the insulation of the floor joists will mess up the plastic you install on the crawl space floor area.

Remember any vapor barrier material should face the warm side of the room.

I have a section of crawl space that had to be done many years ago and there was no way I would fit down there so I got a real small thin guy to do that work for me. Do you have any skinny friends? This could be a solution to your crawl space work.

hvac1000-
Thanks for the reply.

If I insulate the ceiling can I just unroll insulation in the porch area, over the porch floor? It stays dry in the porch, so I am not concerned about moisture, but I want the insulation to be effective.

Do I need to worry about the foundation walls? Most sites say I need to insulate the walls because I have a vented crawl space. What is your opinion?

To start with if you have the plastic vapor barried in the crawl space then in most cases you can close off the crawl space vents in the winter which will make the floors warmer.

Yes you can unroll the insulation in the porch roof area but becareful since it needs to be supported. I noticed you have a open style ceiling or vaulted ceiling and whenever you finish it off special attention will need to be given to that ceiling for ventilation or moisture can be trapped there.

If you are heating an area BELOW the floor then you could on a temporary basis unroll the insulation on the top of the floor is this is what you mean.