We have a house built in 1984 (we bought 4 years ago) with single pane + [questionable] storm windows. Some do a sorta-OK job, some do a meh job. But if I was spending the money, I would get all new windows. Why? Well, in the winter, some of our windows have condensation, and I never had that with houses with double-pane vinyl windows. That, in itself, is telling me that single pane + storm windows is not sufficient for our area in the winter. I also like the idea that the new low-e can block infrared on our southwest side, which cooks in the spring before the leaves come out on the trees. I live in Fairfax county, so same metro region.

From the photo - That is not black trim. That is the storm window frame with a black accent paint around it. I can guarantee you that when you remove the storm window, the fin of the aluminum window beneath it will not be exposed. With vinyl siding, it is NEVER correct to install exterior trim on top of the siding. I don't know what your original siding was, underneath the vinyl. Do you? But with aluminum windows, I can almost guarantee you that the siding butts up against the window frame. IF there was a casing trim of some kind, it was most likely removed when the vinyl siding was installed. You remove the storm window. Then you remove the sashes/glass and mullions (if any) from the window, leaving just the frame. Then you pry the frame into the opening, pulling out the nails. You also hope at this point that the vinyl "J" channel was not nailed through the window fin. If so, the "J" will come off with it. When the frame is out, you then have the opening you will be dealing with. You can have the new window made to slip between the "J" and cutting back the sheetrock, or you can have the new window made to fit sheetrock to sheet rock, and trim the outside appropriately. You'll be able to see where the studs are, and the window cannot be bigger than the rough stud to stud opening. The problem is the vinyl siding. I hesitate to recommend cutting that back. Perhaps someone else here has a suggestion on how to do that without risking cracking/chipping and ruining the siding. The other problem with cutting it back to reveal the window fin is that you no longer have the right "J" channel - though maybe they can find some and slip it around the siding cut. But then you also cannot nail it properly after the fact. This is why I recommend leaving the "J" and siding alone. What abosolutely MUST be done in your situation is that the proper drip cap/flashing MUST be applied above the window. It must go up behind the sheathing, and turn out over the window, extending past the "J" channel, and then a downward bend of app 1/2". In your case, you have to have someone custom bend that on site. The addition of vinyl siding will make any pre-made drip cap unusable. It must start from up behind the sheathing or original siding, NOT the vinyl siding. Also make sure that the new windows are fully injected around the frame with low expanding insulating foam. This will be an absolute must for your application. That's probably clear as mud. But I did my best for you. Keep in mind, this is a standard every day job for any competent window company, and I did thousands of windows like this that never leaked. But if you get a crew in there that takes short cuts and depends on caulking for shedding water, you're going to be in big trouble down the road. Hope that answers your question. What the other guys here said is more true than you can know. "Contractor" guys are clueless about this kind of stuff, and it shows in the end results, and we've seen it a million times. I also want to tell you that if you chince on this, you will get a chince result and look. The money has to come out of somewhere. You don't want it to be the product or the workmanship. Pay for a good job done right, and you won't be doing it again in less than 10 years. Ignore this advice, and you will. It's not an insult to your intelligence, which I'm sure is adequate. It's just the fact of it. And unless you do this for a living for years, you cannot know, and I don't mean to offend, but that's the reality.

Cost can be an issue relative to the value of your home. With heating bills increasing in recent years, the energy savings can justify the cost of new windows. However, putting 25,000 worth of new windows in a $75,000 house just doesn't make sense unless you plan to live there forever and the rest of the house is sound. With a 25 yr old house, I doubt you have the very old lead weight counterbalances. One option that can save you money is what they call a "sash pack". Several manufacturers offer this. If the frame of you window is square and level, it could be an option. Basically, you take the existing sashes out. This generally requires a wooden stop to be removed. The sash liners maybe be vinyl or aluminum that is flexible on both sides. There also maybe a cord to hold for counterbalance with a spring. The sash liners, cord and spring must all be removed. Several manurfactures offer this product. Kolbe, Eagle, Semco, Marvin come to mind. There are probably more. Get the measureing instructions and follow them closely. What you get is a pair of sash liners that install on both sides. The new sashes can have insulated, lowe glass. Installation will also include some kind of adjustable head or foot too. Keep in mind with sash paks you are not replacing the entire window unit and I don't think it qualifies for tax credit. Ironically, if you go to a vinyl window company, they have replacement windows which is really a window that fits inside you existing window after you remove the sash and liners. There are dozens of companies selling this kind of installation. They have it down to a science and can yank your sashes out, stick the replacements in and caulk them in a very short time. Even though many of these replacement windows qualify for tax credit, they are generally very cheaply made. What that means is they meet tax credit performance in a factory test but after a few years in the sun, vinyl can sag, letting in wind and cold. That doesn't mean all replacements are made cheaply but you do have to do your homework. If you have Tom, Dick, Harry or Jack come out and do you windows as a package deal, be careful. Ask to see a cross section of the window and go to a long term window dealer or lumber yard and compare what you are getting.

Larson's Gold Series is a nice storm window that is avaiilable through Menard's. It is available in a flush mount or recessed style, low-E coaing is available and in 4 colors. If you need more colors Sugar-Creek/Pro-Via (I think) is available in 16 colors recessed style only through limited dealers.