On Wed, 12 Dec 2007 17:07:40 -0500, John Albert
wrote:
snip

I've been checking out something the Marvin windows company
offers called "Tilt Pac". Not a replacement "insert", this
is a double-hung replacement kit that replaces your old
sashes with new wood/thermal glass, and has jamb liners that
once installed, allow the new sashes to tilt inward.

The end result is a "reconstructed" traditional window that
uses the old casings.

I was wondering if anyone out there has tried these, and can
offer opinions on them.

They aren't cheap. They cost about the same as Marvin's
"Integrity" double-hung FULL window assemblies. The sales
guy said there might be extra installation cost involved
with full windows due to trim removal/reinstallation on the
outside, however.

I haven't used Marvin's, but have used similar kits by another
manufacturer whose name escapes me at the moment.

They work as advertised, and after I got the hang of it, took maybe 30
minutes per window to install. The major effort was staining and
varnishing them (mine were wood inside, AL clad outside). They operate
nicely and seal very well.

As you say, they cost as much as good quality full windows. IMO, the
only reason to use them is avoid the siding work and inside trim work
that comes from doing full replacements, and wanting to avoid the kind
of replacements that slip inside the old frames. Since you are redoing
siding anyway, that reason evaporates. If you really want to do the
windows, go with full new. Once the old siding is off, they will be
easy to do. If you are careful, and the old windows are standard
sizes, you can reuse the inside trim.

HTH,

Paul F.