There are few products as misunderstood as a replacement window. Drenched in mis-information and double speak the replacement window myth is alive in an industry awash with more fake news then the media is accused of today. In my opinion, this double speak is just as detrimental to homeowners.
The marketing juggernaut that is the replacement window industry is interested in selling you a product and selling it often. Somehow they have transformed what should be a one time purchase (a traditional window) and turned it into a consumable item that is meant to be purchased over and over again at regular intervals.
What is the myth you ask? It’s quite simple:
Myth: Replacement windows will save you money and are good for the environment.
Sounds reasonable, but the truth is that in most cases they accomplish the exact opposite of what they promise. How is that possible? I’ll break it down for you below in simple terms the way I always do.
Exposing the Replacement Window Myth
Let’s take this myth apart and break down its claims into the two major points so we can discuss and analyze each part. At the end of all this you can tell me in the comments if this makes sense to you or if you disagree with my analysis. If you disagree with me I really want to hear your take on it.
Myth #1 Replacement Windows Save Money
Do they really? Let’s take a look at it. Like so many things these days a half true statement when taken out of context of the whole can create a lot of obfuscation. Here’s where the replacement window industry as a whole seems to make their case.
If you have two identical houses, one with single-pane historic wood windows and the other with double-pane vinyl windows, which one will have lower energy bills? Clearly the second one. Just like that same house with triple-pane windows will be more efficient and result in lower energy bills than the house with double-pane windows. This is simple math and science that no one should question, but that is not the whole story.
How much do those replacement windows cost and what is the Return on Investment (ROI) for that cost? This is where things get sticky. According to Angie’s List the average cost of a replacement window is between $175 and $1,200. That’s a wide range so let’s go with an average of $700 (the real average is $687.50 but we’re going to use nice round numbers for simplicity).
I’ll use my own house as an example which is 1700 SF and has 25 windows. That would equate to a $17,500 bill to have my windows replaced. My average monthly energy bill for 2019 was $205 which equates to an annual cost of $2,460.
How long will these replacement windows last? That is a challenge since their lifespan largely depends on the manufacturer, location, type, and price point. The more expensive window lasts longer than the cheaper ones. I scoured the internet and according to a variety of window manufacturers own websites the average lifespan of a vinyl double-pane window was between 5 and 25 years. So, as before, let’s use the average of 15 years.
How much will these windows be saving me? According to EnergyStar.gov the national average you can expect to save for a house about my size with a similar number of windows is $348 per year by switching from single-pane to double-pane. So that equates to a 14% reduction in my energy costs. Not bad. Note: Upgrading from older double-pane windows to newer ones doesn’t create nearly the savings.
How long until my investment of $17,500 is paid back and I can begin enjoying the savings I really want? Well, if I am saving $348 per year then that will be 50 years and 3 months before I make my money back. Ummm, I have to wait until I’m 92 to have these window pay for themselves?
I’m a pretty steady guy but I don’t know that my wife and I will still be living in the same house in 50 years let alone if we will still be living at all. So I think we can safely say that replacement window do not save money, but the financial ridiculousness doesn’t end there.
Remember that the average lifespan is only 15 years. I’m going to be kind and give the windows the benefit of the doubt and say that I got really lucky and my windows lasted longer than average. Way longer! Let’s say they lasted 25 years. That means I’ll have to pay another $17,500 (plus inflation!) to replacement them again in 2044. Now the breakeven point is nowhere in site.
Myth #2 Replacement Windows are Good For the Environment
It’s clear that replacement window don’t make sense financially, but not everything we do needs to be based on finance calculations. We need to consider our planet and protect it. Even if it doesn’t make financial sense it makes moral sense to do so.
Since replacement windows clearly cause my house to consume less fossil fuels in energy use they must provide a benefit to the environment. Let’s try to figure that out and quantify it. The average cost per kilowatt hr in the US is $0.13 so with my $348 a year savings that means I am saving 2,638 kilowatt hrs every year in energy use.
According to BlueSkyModel one kilowatt hr is about equivalent to one pound of CO2 released into the atmosphere. That means every year I am contributing 1.25 tons less (2,638 lbs) CO2 than with my single-pane windows. That a definite improvement! Over the 25 year (very generous) lifespan that’s almost 33 tons or 65,950 lbs of CO2 removed from the air.
Right now it sounds like a huge win for the environment, but we’re not done with the math yet. It takes some energy to produce these new windows and some raw materials to be pulled out of the earth as well. What does that look like? This is tough to calculate exactly but a Swedish study can give us some ideas of what this looks like. This study claims that it takes about 1,244 lbs of CO2 to produce a single double-pane vinyl window. That means my 25 new windows generate 31,108 lbs (15.5 tons) of CO2 while being manufactured.
How about transporting them from the factory to the store and then to my house? Assuming these windows travel a total of 1,000 miles in their lifetime that comes out to about 6,480 more lbs of CO2 according to the Environmental Defense Fund. That now gives us a total of 37,588 lbs of CO2 for my new windows giving us a net gain of about 13 tons of CO2 saved over 24 years. Why 24 years? Because in year 25 we’ll be replacing the windows again which generates another 15.5 tons of CO2. That means at the end of 25 years we have produced 2.5 additional tons of CO2 by replacing our windows.
Lastly, my old windows will end up in the landfill and so will my new window in 25 years when they need replacing again and again 25 years after that as the cycle continues. How do we calculate the embodied energy in all the windows that end up in the landfill? Currently, there isn’t a good way to do this so we can’t really answer this. I think we can all agree that while CO2 production is important to calculate it is equally important to check ourselves for how much waste we create.
Filling the landfills with replacement windows is not good for anyone except window companies who get a steady stream of new customers.
I know this has been a lot of math and there are plenty of sources quoted here so you don’t think I am playing fast and free with my numbers. Check them out. Do your own research! I think I’ve easily dispelled the replacement window myth. We’ve concluded that it doesn’t not make financial sense to replace your windows nor does it make environmental sense to replace them. So why would you do it?
Don’t be fooled by clever marketing. The truth is out there we just need to make it known to more people. This is just a small DIY blog not a media empire (yet). So if you want people to know the truth then you have share this post around. Generate conversations. Talk about the truth because the truth will set you free.
Founder & Senior Editor
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.