There are several view points on how crawl spaces should be dealt with. Your pictures are very helpful for a couple of reasons.
Open exterior vents ( Some say close them period, Some say open in summer, closed in winter) Some say stupid to have period.
Solid concrete floor ( Great! Stop/ slow down Radon)
Ducting in un- insulated ( Heating supply ducting un- insulated… DUM! )
Open heat register ( Positive pressure, Some say good idea with a small register open and exterior venting sealed) Keeping this non living space pressurized is acceptable by some. What do you do for summer time?
No insulation period on foundation walls or floor joists. ( Do you see a moisture problem you need to deal with first? Oh Ya!) But a good polyurethane insulation works great!
Depending on where you live / inspect you hear , read, see different methods of dealing with Crawl spaces… Believe me I have been battling with some people on some other BBS’s with this “situation” … Now if you check with: http://www.buildingscience.com or North American Insulation Manufacturers Association (NAIMA)
DOE Building Technologies Program: Insulating Your Home
You can get some ideas.
Here is one. positive pressure supplied by a small heat register open in the crawl space with the "exterior vents closed is a new way of thinking.
Some believe that a crawl space should be completely sealed to begin with ONLY with the floor sealed, covered with heavy 8 mil plastic sealed at the foundation walls. Then insulate ( in a couple of ways to do that) type of insulation and where to do it, foundation walls, floors or under joist… Beware the “vapor barrier”… I cannot tell you guys how many arguments on vapor barriers, moisture permeable, air barriers, I have been in … UGH! Toward the warm side some say BAD others say YES… ARRRGHHHH… Trap moisture… I have some Pdf that are too large to attach. If any of you guys want more links or pdf’s just private email me and I will be glad to send you some…
I live in a heating / cooling climate of the midwest (Chicago). I also have one of the most complex crawl spaces in the Chicago area. My house dates back to 1890’s with a vented wall and crawl space vents 7 feet high on my exterior double /triple brick walls. Sand floor and brick foundation walls… Wood joist resting on brick … Venting tell me about venting … I deal with extreme drafts in the winter …possibly Radon too…
Original heating …was a wood burning stove… No ducting no radiators nothing in them early days… How the folks lived back then puts me in awe! Talk about a home lab… So here is what I did … Laid heavy multi layer 7 mil plastic on the sand floor, Sealed it at the foundation walls. Closed the high exterior vents. Insulated with “Reflectix” underside of the joists see. Reflectix Inc. : Products & Industries : Building Materials : Crawl Space
I am still working on saving heat but it is getting better all the time…