Doors and Windows - Replacement or retrofit?

I am a little confused on the terminology. I have wood sash windows that I want to replace. The house is a two story and has aluminum siding (which will not be replaced at this time).

I want to just replace the window and not the frames. Is this a replacement or a retrofit? Can it be done from inside? What is the difference between single hung and double hung windows too while I am at it.

I realize that at some point the outside might need to be caulked or nailed and that isn't a problem but to get the window up to the second level probably will require two people, maybe scaffolding or something to lift the window up to that level.

I feel that I am relative handy and would like to save the labor cost if possible.

Thanks for the advice.

Pete

Retrofit is defined as "putting a replacement window inside an existing frame." So generally speaking, "replacement and retrofit" refer to the same thing. The thing that confuses some people is that replacement windows can also come with a nailing fin, and in some cases, the entire old window frame (sill and jambs) can be removed so that this new "replacement window" with a nailing fin can be installed right into the rough opening.

In your case, if you just want to replace the old wood sashes and not disturb the exterior and interior trim, you should order a replacement window that is 1/4" narrower and 1/4" shorter than the interior side of your window opening... a retrofit installation. You should have window stops that will be removed (interior), parting stops that will be removed (middle), the old sashes, the ropes & pulleys or steel coil springs, then the new window will get caulked to the blind stops, which usually appear to be the 1/2" x 7/8" stop (exterior side). Provided you have removable interior stops, you can do it all from the outside, as long as you plan to continue to paint the wood exterior. If your windows are already "clad" with aluminum trim coil, you will likely need to bend and install a "stop cover" over your exterior blind stops because usually that part (behind your current storm windows) will be uncovered.

Regarding the difference between a single hung and a double hung, single hungs have only one sash that operates since the upper one is fixed. On a double hung, both sashes operate. Single hungs are generally more efficient that double hungs since they have half the leakage potential. One thing you will want to check, however, is how thick the single hung frame is. Most replacement windows frames are 3 1/4" wide, which is the perfect thickness for most window openings. Some single hungs that I have run into will be 2 3/4" thick, which means you need to add a filler onto the exterior blind stops before you install a custom made "stop cover".

It doesn't hurt to run another bead of caulk around the outside when you are done. Some windows will have a snap-on sill expander also, and sometimes this is easier to install off a ladder. Don't forget to tuck some insulation under the window before snaping it on, and before reinstalling your stops you should shim and screw the window in place according to the manufacturer's instructions.

You said "Provided you have removable interior stops, you can do it all from the outside, as long as you plan to continue to paint the wood exterior."

I would like to do this all from the inside. Is that possible? I think I saw a DIY Weekend handyman program and that is what they did.

And thanks for that very thorough response.

Pete

my mistake. What I meant to say was "you can do it all from the inside."

Thanks. I guess I will still need to climb to caulk but that will be easy compared to lifting the window up on the outside.

Pete