New windows

I hate having moisture on the windows.

I'll agreee though, if it's not a tested, reasonble quality manufactured and a thermally broken extrusion profile that the window is built from, it's most likely junk. The manufacturing process has to be top notch for these, when the machines and tooling for these kind of windows get sloppy or have problems, it can easily put a damper on the products performance. Usually tested in 2 ways, window by itself, and the window installed into a common or unique substrate, to determine how each performs, the latter being dependent on the installers work.

Long winded, but interesting stuff, don't let those amateur outfits fool you, some of the best windows made are aluminum, having been installed into buildings all over the country where there is no subsitute for meeting rigorous performance criteria.

Charles

"Correct me if I'm too wrong but, 1 inch of wood is equivalent to R12+-." Wood that it were true (sorry, that was bad.) You misplaced the decimal, unfortunately. Softwoods and plywood have an R-value of 1.25 per inch, hardwoods .91 per inch. Sawdust is R 2.5 per inch and I used to find it occasionally in the exterior walls of old houses in Seattle I would buy to renovate and resell. More commonly, houses built before 1950 had no insulation in the walls, and black rock wool amounting to maybe R-8 in the attic. I can't figure out whether people then wasted heating fuel because it was cheap, or they just didn't expect the whole house to be toasty warm all the time.

All the best, Stan

Air and water infiltration are about the 2 most important other performance aspects, besides the thermal performance. Check the listed performance criteria, I believe that all these manufacturers are subject to getting their products certified by various manufacturers associations or reference standards. I used to work in the metal and glass industry, and we started building exterior doors in our shop, and had to get them certified prior to making the line available. It was quite the process to get that done and get all the bugs out of them. One of the most impressive testing facilties I've ever seen was ATI in York P.A., have done several mock ups there and tested same, very interesting place to walk around.

See what reference standards and or manufacturer association criteria it's been tested to, ask the sales rep. Look at the jamb, head and sill in section, and have the rep. explain to you how the system works, have them explain the entire window system, including the glazing (glass) etc.

That is one half the battle, the rest is the installation, you could get the most expensive top of the line, highest performing window unit and the installer does a poor job installing it in the rough opening. The installation must be quality workmanship as well for it to perform.

If you want to let the air out of the sales people, do some research and have a list of important questions, like mentioned above, as well as all particular details, in section, plan, elevation, fastening, flashing, sealant and sill details, this will give you a good understanding of what they are selling. Also for residential, the window balance system is also important, as well as the operational functions of the window.

I'm sure they don't like construction savvy people asking questions, much rather prefer the deer in the headlights, similar to when people go to an repair shop or dealer for work, too funny when it turns out to be a mechanic and they look foolish.

• ATI