PreservationNation Blog

I have been mulling over Patrice’s vinyl sadness since last week which probably explains the violence with which I responded to a Building & Grounds Manager from one of our 29 historic sites today when he called to ask if I would approve “vinyl replacement” windows in one of our rental houses (I am the Director of Architecture for the National Trust’s 29 historic sites). “No vinyl” I said. “But vinyl lasts longer and doesn’t need any maintenance,” he responded. Why does this misperception continue in the general public and bleed over into those of us who should know better? As Mike Jackson (Chief Architect of the Illinois SHPO’s office) says, “No Maintenance required” really means “can’t be repaired” - so they end up in the landfill much sooner than say a wood window which can be repaired and repaired and repaired, or recycled. Vinyl can’t be repaired, and it can’t be recycled. So, maybe you don’t need to repaint it every 10 years, but within 20 years you will need to buy new windows yet again, and the heavy imprint on the environment starts all over.

To quote my colleague Patrice’s recent "White Paper on Sustainability": There is a common perception that windows are a major source of heat loss and gain. Yet retaining historic windows is often more environmentally friendly than replacement with new thermally resistant windows. Government data suggests that windows are responsible for only 10% of air infiltration in the average home. Furthermore, a 1996 study finds that the performance of updated historic windows is in fact comparable to new windows. Window retention also preserves embodied energy, and reduces demand for environmentally costly new windows, typically constructed of vinyl or aluminum… There is the widespread perception that air leakage through windows is responsible for the majority of heat gain or loss in historic buildings. Yet information from the U.S. Department of Energy indicates that windows are responsible for only 10% of air escape in the average American home. Floors, ceiling and walls are responsible for 31% of heat loss and gain, while ducts and fireplaces are each responsible for about 15% of heat loss and gain.

Now this assumption is only true for traditional windows, typically in buildings built before 1920. All the tables are turned when looking at buildings built after World War II, or even earlier International Style or mid-century modern buildings. Many of these windows and/or curtain wall systems were experimental, and most of the energy loss in these buildings is attributed to the curtain wall system.

So, what sage advice did I give our Building and Grounds Manager after I stopped hyperventilating? First, absolutely no vinyl. It doesn’t matter that this building is not the National Historic Landmark that the site is known for. It’s the vinyl in all the good sound background buildings that are contributing to the problems in our environment. Second, maybe the perceived energy loss is not from the windows (or the windows alone), so let’s get an energy audit first before we jump to conclusions. And third, get me options for repairing the windows or replacing with new wood. Yes, they will probably be more expensive than the vinyl, in the short term. But as stewards for the site we need to always be looking at the long term and the big picture. And so that means, NO VINYL!!

UPDATE, November 15th, 2007: The Building and Grounds Manager from the offending site called me yesterday to tell me he got prices for new wood windows that match the badly deteriorated ones, as well as prices for vinyl and clad windows. Guess what, the difference was pretty minimal, so he thanked me for the recommendation and now we'll be staying away from the vinyl!!