The replacement window industry spends a lot of money making the choice sound simple: old windows are inefficient, new windows are better, replace them. The actual cost and performance data tells a more complicated story — one that almost always favors restoration for pre-1950 homes in Baton Rouge.
What's It Cost To Get Your Historic Windows Operational & Efficient Again?
If functionality and energy efficiency is all you're looking for, a mechanical rehabilitation may be just what you need. Mechanical Rehab is making sure the window operates as it was originally intended, sash ropes, pulleys, free & balanced motion in the guides. Couple that with added or repaired period appropriate weatherstripping and your historic window, with all the original glass, long-lasting dense wood species, and all the charm and design that matches you home, all in runs in the range of $300-$550.
What Restoration Costs
Professional restoration of a historic wood window runs approximately $1,300 to $1,500 per window, all in. That includes assessment, materials, and labor — stripping old paint, probing and repairing any rot with epoxy, re-glazing the glass with fresh compound, replacing broken sash cords, adding weatherstripping, and painting.
A window in reasonably good condition — sound wood, minor glazing failure, one broken cord — is toward the low end. A window with significant rot in the sill and bottom rail that requires full epoxy rebuild is toward the high end. On a house with 15 windows, a complete professional restoration typically runs $22,000 to last the lifetime of the house.
A restored original window, properly maintained, should last the life of the house. The material in a pre-1940 Baton Rouge window — old-growth longleaf pine, grown slowly over centuries — has already proven itself for 80 to 100 years. It will outlast what comes after it if it is kept sealed. When your windows were installed, part of the culture home owners belonged to was this periodic maintenance: paint your house, repoint you bricks, tend to your windows, and your home will last for centuries.
What Replacement Costs
A vinyl double-hung replacement window runs $300 to $800 per unit, depending on size and quality. Installed — with labor, disposal, and trim work to close the gap between the new unit and the old opening — budget $700 to $1,400 per opening. Unusual sizes, second-story work, and any structural issues the new installation reveals push that number higher.
For 15 windows: $10,500 to $21,000, before addressing anything the installation uncovers.
The service life of a standard vinyl replacement window is 15 to 25 years before the insulated glass unit seals fail and the glass fogs. At that point the unit cannot be repaired — it must be replaced again. Another $21,000 at today's prices. What will it be in 20 years? Replace again. The cost clock resets.
The Energy Efficiency Claim
Replacement windows are sold hard on efficiency. The actual performance data is more complicated than the marketing implies.
A single-pane historic window by itself rates approximately R-1. That sounds poor until you understand where heat actually transfers in a residential window assembly: the U.S. Department of Energy and the National Trust for Historic Preservation have both documented that the majority of energy loss in old windows happens through air infiltration around the sash and frame — not through the glass itself.
A properly weatherstripped historic window — with bronze V-strip in the sash channel and an interior or exterior storm window — achieves R-2 to R-3, equivalent to a standard double-pane replacement. The gap between restored original windows and vinyl replacement windows, in real-world performance, is substantially smaller than the sales pitch suggests. A window that seals well performs well. The glass type matters less than whether the window actually closes tight.
The practical implication: the energy argument for replacement is strongest when the existing windows are in genuinely poor condition and leaking badly. For a house with properly maintained historic sash, the efficiency case for replacement essentially disappears.
Historic Tax Credits
For properties listed on the National Register of Historic Places — or contributing to a listed historic district — original windows are often designated character-defining features. Removing them can disqualify the property from the federal Historic Tax Credit, which covers 20% of qualified rehabilitation expenses, and the Louisiana State Historic Tax Credit.
These are real numbers. On a $200,000 rehabilitation project, the combined federal and state credits represent significant value. Restoration work, properly scoped and documented, supports a tax credit application. Replacement work generally does not.
Baton Rouge has multiple historic districts — Beauregard Town, Spanish Town, Mid City, and others — with local preservation overlay zoning. In some of these districts, replacing original windows with vinyl or aluminum requires approval from the preservation commission or may be prohibited outright. Restoration is the path of least resistance in regulated areas, and often the only path for owners who want to maintain historic designation.
What Gets Permanently Destroyed
Replacement is irreversible. Once original windows are removed, several things are gone permanently.
The glass. Original historic sash windows contain cylinder glass — hand-rolled or mechanically drawn in ways that are no longer commercially manufactured. This glass has subtle waves and irregularities that give old houses their characteristic quality of light. You cannot buy it new. Once removed, it goes to a landfill.
The wood. Old-growth longleaf pine from a pre-1940 window grew over 150 to 200 years. Its growth rings are tight, its resin content is high, and it is genuinely rot-resistant in ways that plantation-grown lumber is not. The sash in a 90-year-old Baton Rouge window is better raw material than what you can buy in a lumber yard today. When that sash is replaced with a vinyl unit made from fast-grown pine, you have traded something irreplaceable for something that will need replacing again in two decades.
The proportions. Historic windows were designed to the house — their size, height, and profile were part of the original architectural intention. Standard replacement windows come in manufacturer sizes that rarely match the existing opening exactly. The gap is filled with casing, and on a Craftsman bungalow or a shotgun double, the result is visible. Buyers who understand historic properties notice it immediately.
When Replacement Is the Right Answer
Replacement is appropriate in specific circumstances: the original frame is so severely compromised — full-depth structural rot in the jamb or head — that no repair is viable. The opening requires a size change. The owner has no interest in preservation and the property is not in a regulated district.
These circumstances exist, but they are less common than the replacement industry suggests. Most historic windows in Baton Rouge, even ones that look rough, are candidates for restoration rather than replacement. The starting point is an honest assessment of what each window actually needs.
— we'll talk about your windows, how many, condition, etc., and see how you can get started toward keeping your historic home beautiful & efficient. Want an in-depth window-by-window Assessment? We can do that, too! Ask how.