New windows. How to tell if they insulte well?

BigSteve · Forum Member Joined: 31 Jan 2010 Posts: 3

Hi,
Hope someone can clue me in a little. I live in SW Florida. We had old, leaky single pane crank-out windows all over the house. I had them replaced with Vinyl impact glass sliders, that meet the requirements to qualify for the $1500.00 tax reduction.

It's been about 3 weeks, so it has not been enough time to see if the windows have affected my heating bill. However, on a cold night, the glass seems as cold as the old windows. During the afternoon with the sun beating down on a window, the glass seems as warm as the old windows.

How can I tell if the windows are really doing their job or if something is amiss? I was expecting them to feel more temperate than the old windows. But of course, I really don't know anything about it. Wondering if there is some kind of formula or something that takes into account outside and inside temps or something?

The windows tags read:

Fixed: L 2A-A LE/C 7/8 OA: (1/8" ANN-7/16" ARGON 5/16"
LAM (1/8" ANN .090" PVB 1/8" ANN)
SASH: L 2A A LE/C 7/8" OA: (1/8 ANN 7/16" ARGON 5/16"
LAM (1/8" ANN .090" PVB 1/8" ANN)

Also another tag says: "Clear/LOW E 270"

The windows are made by Custom Window Systems in Florida. The contractor was a local long timer held in high regard around town. The contractor came back for something else, and I asked him the same question. He really couldn't give me a straight answer.

Thanks in advance for any input.

Steve