# Window Performance: Old Windows vs. Window Replacements - Link: https://www.oldhouseguy.com/window-replacements/ - Published: 2014-12-07T14:21:00-05:00 - Author: Ken Roginski **Windows are the eyes of a house**—the most important character-defining feature creating the greatest visual impact on the overall appearance of a house. So should you replace your old wood windows? Should you consider restoring old windows? And if you require window replacements, do you know what to shop for based on the design and style of your house? **The public has been brain-washed by marketers.  ** Even an eight year old’s mind has been contaminated into believing one must replace old wood windows to save energy and lower your heating bill. What else can you expect with all the advertisements and promotions manipulating the public? **This post may be long but remember this information can save you thousands of dollars greatly affecting the life of your family forever**, not to mention the appearance of your house which is in another important article here, so pay attention. I may quiz you later! [⌊historic window victorian⌉⌊historic window victorian⌉[ As eyes to a human, Windows are the most important feature on a building. Please understand, this is big business and big sales commissions are paid to highly trained people to convince you that you need window replacements.  Their livelihoods depend on these sales. The TV show This Old House may agree to save old windows but the money they get from advertisers force them to promote false claims made by the manufacturers. Additionally, with the trend of saving energy at home and making everything “green”,** misinformation from the current sustainability movement has embedded in our minds that all old windows are NOT efficient and NOT green.** **Financial incentives such as tax credits for home efficiency improvements, have escalated the situation to a frightening degree, making old windows the most vulnerable element of a building.  ** **The result? You spend money that will never be regained – a very bad investment. Additionally, the character of your house is destroyed forever.** _**Note: ** The term historic window may be used to represent an original window– one that is wood and original to the house.  It does not have to be 100 years old or be ornate to be valued and worth preserving._ [⌊georgian window twelve over twelve⌉⌊georgian window twelve over twelve⌉[ Circa 1750 window has character. [⌊ranch house window⌉⌊ranch house window⌉[ 1950’s window also has character. ## Windows Replacements are NOT Green⏎ and will NOT Lower Your Heating Bills as You Think With global warming imminent, you cannot escape the talk of this and LEED (Leadership in Energy and Environmental Design). Replacement **manufacturers anxiously take advantage of this opportunity as a salesperson selling snake oil as a cure to everything.** Window manufacturers easily convince homeowners of great energy savings associated with their product. A replacement window seems to be the logical “green” choice. While this claim may correspond to newly-constructed, LEED-certified buildings, ** the argument that window replacements are “greener” than restoring old windows is 100 percent (not 99%) FALSE**. A common and often exaggerated reason for window replacements is that new windows will significantly reduce heating costs.  This is wrong! * > **Studies indicate that in most cases, approximately 10% of the a buildings > heating loss is through windows.  ** > **The remaining 90% is lost through gaps** in roofs, walls, floors, and chimneys, > with roofs being the greatest culprit. These other areas of heat loss can be > resolved at a much lower cost and result in much more savings on your heating > bill than replacing windows. * > Following this model, **reducing the heat loss through windows by 50% will > only result in a 5% decrease in the overall heat loss** in the building and > your heating bill. > Pay close attention to ads claiming, a 50% reduction in your heating bill.  > It is all a tactic to get you excited and interested to save heating expenses. > It is NOT a 50% savings of your heating bill. > **IT IS a 50% savings of the 10% heat loss through all of your windows, which > will save you only 5% off your heating bill **if you’re lucky. The 50% they > may tell you is not a lie but merely a manipulation of words to trick a homeowner. Even with this in mind, keeping the heat in and the cold out are still prime wintertime goals. Both goals can be met with your existing original old wood windows! Keeping the heat in, means insulation measured in R-value (measurement of a materials resistance to heat flow). **Old windows coupled with a storm window with [LOW E glass coating ](https://web.archive.org/web/20250324011525/https://www.energy.gov/energysaver/storm-windows) will give you an equal or higher R-value than a double-glazed replacement window.** This is because there is more air space between the storm window and the inside window than between the two tightly squeezed panes (double pane) of glass in a replacement thermo-pane window. Believe it or not, AIR is one of the best insulators. Since molecules are so far apart in air, heat cannot be transferred. On top of this, there is no seal that will ever break or leak that contains the gas between the double-paned insulated glass. [⌊un-insulated window casement⌉⌊un-insulated window casement⌉[ Therefore, the **three inches of air space you have between the two pieces of glass performs as a very good insulator.** Let’s look at this in another way. * One measure of heat transfer is the U-value – the number of BTU’s per hour transferred through a square foot of material.  When comparing thermal performance, the LOWER the U-value the BETTER the performance (opposite of R-value). * According to ASHRAE (American Society of Heating, Refrigeration and Air-conditioning Engineers), the U-value for single glazed old wood windows ranges from 0.80 to 0.99.  **The addition of a storm window proudly reduces these figures to a range of 0.44 to 0.49.** * A double-glazed metal window has a U-value of about 0.60 and a double-glazed wood window ranges from 0.51 to 0.55. **Therefore, if you do not presently have storm windows, install them instead of window replacements.  You will spend much less money, receive much more insulation, and not add to the landfills.** If you do the math you may not live long enough to get back your investment in energy saving. Before you could ever get back your investment you will need to replace the replacements. **This U-value CAN be lowered further, but at this point we are slicing peas.**  With windows accounting for only 10% of heat loss, you really do not need to look further.  However, if you do, **with a Low-E-Coating Storm Window you can lower the U-value to a .32 level.** Adding storm windows is a less costly investment and, more importantly, you save your original old wood windows (and the beauty of your house). You will not be responsible for adding to the landfill and destroying our planet. You can also add INTERIOR storms for even more insulation but windows are not the source for loss of energy as you are told. [⌊demolition of historic buildings by contractors⌉⌊demolition of historic buildings by contractors⌉[ Historic windows end up in the landfill. Replacement windows will too in 15-20 years. Photo by Mexi Lane ### You Must be an Educated Consumer. **Are your old windows draining your wallet—or is that just a myth?!** ✅ **Complete Research**: Packed with verified data and studies on window efficiency ✅ **Practical Solutions**: Real-world techniques to improve historic window performance ✅ **Cost-Saving Analysis**: Detailed breakdown of restoration vs. replacement economics ✅ **Climate-Specific Guidance**: Tailored recommendations for both northern and southern regions ✅ **Myth-Busting Facts**: Evidence-based answers to common window replacement claims ✅ **DIY-Friendly Options**: Affordable improvements anyone can implement In _The Case for Historic Windows_, restoration experts Scott Sidler and Stacy Grinsfelder reveal how to transform your drafty old windows into energy-efficient treasures. Save money, boost your home’s value, and preserve its timeless charm—all without the waste of replacement. Backed by scientific studies, industry testing, and real-world experience, this book is your key to smarter, greener living. [You really should buy this book to save yourself from making a foolish financial mistake. Click here now. ](https://www.amazon.com/Case-Historic-Windows-Energy-Efficiency/dp/B0DXVMF1NQ/kenroginskihisto) [⌊window restoration⌉⌊window restoration⌉[ There are two co-authors of this book. Scott has the best How-To websites called– [The Craftsman Blog. ](https://thecraftsmanblog.com/) Stacy has a podcast which is also on Youtube discussing various topics of owning a historic home called [True Tales from Old Houses. ](https://www.truetalesfromoldhouses.com/) I cannot stress enough the potential harm in speaking to a window manufacturer. One may say they have no intention of buying but would just like to hear options available. This may sound logical but remember these people are super high-pressure and it will be almost impossible to get them to leave without a commitment. They also usually offer a discount to allow them to use your house as a model. To be an educated consumer first you must keep in mind your source of information. Does your information come from someone with a financial benefit? Are the statistics weighted?  Are they geared for new construction? Don’t be blinded by the lure of tax credits when you can save ten times more money making an educated decision. Energy Star tax credits are now available for storm windows. **As with nutrition labels, there is some misrepresentation of U-value measurements.** See the following link where the author advises window shoppers to make an informed decision: > Traditional Building Magazine – [Do You Replace or Restore Historic Windows ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/Trad-Bldg-Replace-or-Restore.pdf) ### Old Wood Windows vs Window Replacements Energy Analysis **This is important folks**. Here are three insightful documents that discuss the cost of window replacements versus historic wooden windows. These reports are not outdated for the results remain the same. > [Saving Windows, Saving Money: Evaluating the Energy Performance of Window Retrofit and Replacement ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/saving-windows-saving-money.pdf) > by The National Trust for Historic Preservation > _This report analyzes do-it-yourself solutions such as window films and weather > stripping to replacing older windows with new ones. This study builds on previous > research and examines window options comparing the relative energy, carbon, and > cost savings in various climate regions._ > [A Comparative Study of the Cumulative Energy Use of Historical vs Contemporary Windows ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/Study-replacement-vs-historic-window-Frank-Shirley.pdf) > by Frank Shirley Architects. > _This link is a summary so scroll down and click on the links for an extremely > through report. This study compares the life-style costs of two residential window > systems in a pre-1940 house in Boston, Mass. One is an original double-hung window > with a triple track storm window. The other is a new, vinyl double-hung replacement > window. _ There are two co-authors of this book. Scott has the best How-To websites called– [The Craftsman Blog. ](https://thecraftsmanblog.com/) Stacy has a podcast which is also on Youtube discussing various topics of owning a historic home called [True Tales from Old Houses. ](https://www.truetalesfromoldhouses.com/) I cannot stress enough the potential harm in speaking to a window manufacturer. One may say they have no intention of buying but would just like to hear options available. This may sound logical but remember these people are super high-pressure and it will be almost impossible to get them to leave without a commitment. They also usually offer a discount to allow them to use your house as a model. To be an educated consumer first you must keep in mind your source of information. Does your information come from someone with a financial benefit? Are the statistics weighted?  Are they geared for new construction? Don’t be blinded by the lure of tax credits when you can save ten times more money making an educated decision. Energy Star tax credits are now available for storm windows. **As with nutrition labels, there is some misrepresentation of U-value measurements.** See the following link where the author advises window shoppers to make an informed decision: > Traditional Building Magazine – [Do You Replace or Restore Historic Windows ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/Trad-Bldg-Replace-or-Restore.pdf) ### Old Wood Windows vs Window Replacements Energy Analysis **This is important folks**. Here are three insightful documents that discuss the cost of window replacements versus historic wooden windows. These reports are not outdated for the results remain the same. > [Saving Windows, Saving Money: Evaluating the Energy Performance of Window Retrofit and Replacement ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/saving-windows-saving-money.pdf) > by The National Trust for Historic Preservation > _This report analyzes do-it-yourself solutions such as window films and weather > stripping to replacing older windows with new ones. This study builds on previous > research and examines window options comparing the relative energy, carbon, and > cost savings in various climate regions._ > [A Comparative Study of the Cumulative Energy Use of Historical vs Contemporary Windows ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/Study-replacement-vs-historic-window-Frank-Shirley.pdf) > by Frank Shirley Architects. > _This link is a summary so scroll down and click on the links for an extremely > through report. This study compares the life-style costs of two residential window > systems in a pre-1940 house in Boston, Mass. One is an original double-hung window > with a triple track storm window. The other is a new, vinyl double-hung replacement > window. _ > [Studies and Experts Prove Window Saving is Better ](https://web.archive.org/web/20230602014544/http://historichomeworks.com/forum/viewtopic.php?t=1600) > _If you haven’t read enough and still don’t believe the Replacement Window Myth, > here are some more links to random energy savings studies at Historic Home Works. > [saving-windows-saving-money ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/saving-windows-saving-money.pdf)_ ### The Science of Drafts and Where They Come From What about drafts? **You can feel the same draft with brand-new, “top of the line” windows**, as well as with your old windows.  **The culprit? Convection.**  Glass is a great conductor.   The warm air in your house contacts a cold window glass, where it cools and then draws more warm air to it.  This continues on and on until convection currents are created throughout the room and perhaps through the entire house. This draft feeling is created only because the product GLASS is used in a window. If you really want to prevent drafts, you can use wood plywood to cover your window instead, however you will not be able to see outside. Use of interior shutters, shades, or curtains can solve the draft problem by blocking off the glass from the warmed room air. An additional layer of glass (storm window) which creates an air space between the two glasses will help; however, you are still using glass, and heat will still be drawn to it, although not as much. ## Extreme Energy Savings. The window at the right shows a piece of plywood attached to the blind stop of the window. This is where one would screw in a storm window. The plywood is painted to look like a 6/1 window with curtains. From the street, one would think this is a real window. On the interior you if artistic or an artist can paint a scene of your street, Egyptian pyramids or any scene you would like to see out your window. **This is probably the best way to save heat in the winter.** [⌊insulated windows⌉⌊insulated windows⌉[ This window sash is plywood painted to look like a real window, ### Energy Saving Information Specific to the Older Home **The National Park Service** – Department of Interior, provides a Technical Preservation Service. Highly qualified experts working under contract with the federal government have assembled more than 40 booklets designed to help owners and developers of historic buildings recognize and resolve common preservation and repair problems. **These links from the National Parks Service can help you understand how to improve energy efficiency:** * [Conserving Energy in Historic Buildings – Preservation Brief #3 ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/preservation-brief-03-energy-efficiency.pdf) * [The Repair of Historic Wooden Windows – Preservation Brief #9 ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/preservation-brief-09-wood-windows.pdf) _The National Trust for Historic Preservation is a great resource for any information you would need for an older home. They also have a good section on weatherization. However their webmasters constantly move around information which results in bad links for you the reader. This is bad business. OHG and other sites would like to direct you to these links to help you but NTHP is not a team player. I have therefore removed all their links to specific articles._ ### Window Replacements Are NOT Maintenance Free **A big myth is that replacement windows will eliminate maintenance.  In a way this is true because they are disposable.** You install them; 10-20 years later, you throw them out and, again, buy new windows. Even so, the public has been sold on the myth of no maintenance, but there will ALWAYS be maintenance. * For appearance sake alone, you certainly will be painting those windows even if they are vinyl.  They too will fade over time, just as aluminum sided homes, which were once touted as “maintenance-free” are being painted. * **When wood is continually maintained, its life expectancy can be about 200 years to indefinite.  **On the other hand, according to studies, **vinyl has a life expectancy of only about 20 years.** The plasticizers in vinyl will evaporate over time, making the vinyl brittle and subject to cracking. And what cost are you imposing on future owners or your poor unsuspecting children when your venture doesn’t last?  Go with time-tested materials: paint on wood. * How are you going to replace a double-glazed pane of glass when it breaks?  Manufacturers frequently modify their product line and technology quickly changes.  You may, therefore, need to replace the entire sash and frame.  Many other components of replacement windows deteriorate relatively quickly. * The seal around double glazing can fail within 10 years, resulting in condensation between the panes of glass.  This will require replacement, too – not repair. Many of the plastic and neoprene seals, which hold the glass in place in vinyl and aluminum and new wood windows, also degrade in ultraviolet light**.** * **“[Insulated glass typically lasts from 10 to 25 years ](http://en.wikipedia.org/wiki/Insulated_glazing), with windows facing south often lasting less than 12 years”.**  Try to imagine locating a replacement vinyl gasket 10 years from now, or the problem of replacing a bent aluminum channel.  With your original window you can always get parts at a local hardware store. **Maintenance Free MEANS Cannot Be Maintained.** ## What are My Options to Save Energy? ### Interior or Exterior Storm Windows. * [Install an Exterior Storm Window with low-e glass or an Interior Storm Window. ](https://www.oldhouseguy.com/storm-windows-screens/) * Consider Low-E glass for your exterior storm window. ## What if the Previous Owner Already Replaced the Original Historic Windows? This is sad. If you are very lucky the previous homeowner would have saved the original windows in the attic or basement in hope a future homeowner will actually care for and respect the history of the house. The windows can then be restored and re-used. * **Check locally to see if there is a [carpenter that can build a window ](https://www.oldhouseguy.com/wood-window-restoration-companies-carpenters/). You can search by state here.** * **Heirloom Windows makes a [reproduction window with vacuum insulated glass ](https://www.oldhouseguy.com/replica-windows/).** * **Brent Hull makes a [100 Year Window ](https://100yearwindow.com/) with wavy glass.** ### What You Need to Know About the Types of Insulated Glass. Technology has improved and there are not better option for energy saving windows: [Insulated Glass & Historic Windows: What Finally Works ](https://www.oldhouseguy.com/insulated-glass/). The following video from 2026 discusses the problems using Insulated Glass (IG) to replace the original historic glass in a window. This insulated glass is much thicker than the improved Vacuum Insulated Glass (VIG) now available. Pilkington Spacia once a leader now falls behind other manufacturers making the thinner VIG glass.   ## Additional Information You Should Know. ![](/wp-content/uploads/2014/12/icon1.jpg) [Repair or Replace – The Visual Impact ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/repair-or-replace-natl-trust.pdf) **Appearance is Important**. The National Trust for Historic Preservation addresses the following questions with **great pictures in living color** to really show comparisons. * Should I repair my old windows? * When are Window Replacements Necessary? * Do the Benefits Outweigh the Costs? * What Not to Do When Replacing My Windows? * Do Window Details Matter? ![](/wp-content/uploads/2014/12/icon1.jpg) [Should Your Old Windows be Saved? ](https://www.finehomebuilding.com/2010/03/11/should-your-old-wood-windows-be-saved) This article comes from Fine Home Building and there is a subscription fee. A first timer may access articles for free. The article focuses on common problems with old windows and what you can do. Options of replacing old windows are weighed against the cost, complexity, efficiency, and preservation of historic character with a problem-and-solution approach. A Visual Guide to Historic vs Replacement Windows. ![](/wp-content/uploads/2014/12/icon1.jpg) [Window Myths ](https://web.archive.org/web/20251210202238/https://www.traditionalbuilding.com/opinions/window-myths) Replacement windows are not what you are led to think they are. ![](/wp-content/uploads/2014/12/icon1.jpg) [NTHP Wood Window Tipsheet ](https://www.oldhouseguy.com/wp-content/uploads/2014/12/NTHP-Wood-Window-Tipsheet-2008.pdf) A window tip sheet from The National Trust for Preservation ![](/wp-content/uploads/2014/12/icon1.jpg) [Old Wood vs New Wood video by Brent Hull ](https://www.youtube.com/watch?v=cWX4PgCFk7c) What does old versus new wood mean and how does it effect wood products today? **Now that you understand how to avoid being influenced by the false claims of window replacement marketing, it is very important to understand how windows effect the appearance of your house.** ![old windows design](https://www.oldhouseguy.com/wp-content/uploads/2014/12/windowicon. jpg) More About Windows 1- The Truth About Windows 2- Window Energy Performance 3- Wood Window Repair 4- Window Design vs Curb Appeal Storm Window Options & Screens Window Restorers List& Blog articles [Windows MENU ](http://www.oldhouseguy.com/windows/) ![wood window repair](https://www.oldhouseguy.com/wp-content/uploads/2014/11/wood- window-repair.jpg) Part 3: Wood Window Repair Learn how you can take apart a window, Fix Sash Chains, and Repair Rotted Windows to last an additional 200+ years. [NEXT PAGE ](http://www.oldhouseguy.com/wood-window-restoration/)