I knew I wanted the Simonton and was looking specifically for that brand, so I did not look at the Harvey's. When I went into the showroom, I do recall that Jim took me over to a Harvey window on display and showed me something about it that was not as good as the Simonton. He was not showing me this difference to get me to buy the simonton, as I had already made the decision. He was showing me the "flaw" (again I can't remember what it was) to reinforce to me that the Simonton was a better window. I'm sure the Harvey's are good windows also, and if your windows are as bad as ours were any new window will make a difference.
Ours made quite a difference. We were able to keep our 3 season porch open all year, using an electric heater and a ventless propane heater as required. Even on the coldest nights, the porch would only get 8-10 degrees colder than the house with no heat source on. The new sliders (for about 5k) gave us a year round room, so they were worth it to us. I really can't say if we used less oil, because we were heating the pouch thru the open slider all year, with no heat source at all at night.
The double hungs also have been great. No issues at all, and we do think that they made a difference with not only heating but also with sound (less road noise) and possibly with allowing less sun heat thru in the summer.
One thing I remember reading on this and the other window board I was on; the install is just as important as the window. We did find that the sliders in particular had some installation issues. When winter came we could feel major drafts around the moulding. When I pulled the moulding off, I found they had not insullated the gaps between the window and the sill. I had to pull all the mouldings off and do this. Now I will say that this is a 3 season pourch, but it turns out I found out later that the main install guy was fired by Keddie at the end of the summer for "performance issues", so maybe he was cutting corners. I had the same issue with a few of the double hung, though not as pronounced, and in the case of the double hung it was not leakage from the outside of the house but from the center of the wall where they had to "smash" thru the stop on the old window frame to make the opening for the new window. When they broke off the stop they broke the frame behind it also and this allowed cold air to come thru the center of the wall and into the room from behind the moulding. I feel this Should have been done by them.
I would still recommend this place, but as I said, there may be cheaper places for installed simontons in the area, I don't know. And again, Harvey's will probably make just as big a difference if your windows suck as ours did.
Rick
NH
800-399-4623