We have a home that is a modified A-frame. The A-Frame was built in 1968, is about 2 stories in height, and has only single pane windows. The problem is that this provides no insulation and the house is cold in the the spring and fall.

We are considering replacing the windows but we don't know what to do. We had a window company bid the replacement. They want to replace the windows and put in Low E double pane windows. They would remove the current panes and place the new ones in the existing frames. I don't know much about the process of windows and question wether this will solve the problem of lack of insulation the current windows have. I don't want to spend thousands to replace windows and there is little change. The other options are to put in metal or fiberglass windows that have their own frames. I don't know how doing this will differ from just replacing the panes utilizing the original frames.

Of course the installer said that insulation will improve as I go up in price/solution but I don't understand the difference and if it makes sense to spend twice as much. I need some feedback from someone that understands the process that isn't making money on my decision. Thanks for any feedback you can offer.