For the protection of wooden windows

A book on the history of windows in Hungary

European Union

European Working Group on EU Directives and Cultural Heritage (pdf)
(read the section about window: from page 4 on)


Windows – A guide to the repair of historic windows (pdf)


Guidelines for Preservation and Replacement of Historic Wood Windows in Cambridge, Cambridge Historical Commission

“… historic wood windows were milled from old-growth lumber that can last centuries, even when not properly maintained. Their sustainability is complemented by the fact they were carefully constructed with mortise and tenon joinery to fit tight into the window openings of a house with extreme care and craftsmanship. Mass-produced wood replacement windows are typically constructed of new-growth lumber, often with glued-together finger joints and are highly susceptible to rot. …”

“…it’s not surprising that property owners are often inclined to do away with old wood windows. “Maintenance-free,” however, is a misleading claim. Any product that is in constant operation and is susceptible to seasonal fluctuations and weathering will need maintenance. Replacement windows typically have plastic and metal parts that become outmoded over time, making them difficult (if not impossible) to repair. Vinyl windows are prone to denting, warping and fading in high temperatures. …”

Much like sustainability, energy efficiency is an important factor in the “green” discussion, and is often the primary reason homeowners look to replace their windows. The generally erroneous notion is that older wood windows are not as energy efficient as today’s double-glazed replacement models. However, window replacement companies will often compare their product to an unrestored wood window with little or no weatherstripping. …”
“Another major claim of the window replacement industry is insulating glass. Insulating glass involves two panes of glass with an inert gas sealed in the space between them; these windows are called “double-glazed.” Their design, however, does not lend to sustainability. Windows with insulating glass come with only a 15 to 20 year warranty; when the sealant fails, the window will lose its insulating quality, the glass will fog, and the entire window may have to be replaced. Historic wood windows with a single pane of glass can be repaired (…) and will last up to 10 times longer than a replacement model.”

“An optional feature of replacement windows is “low-e”
(low emissivity) glass, a microscopically thin, virtually invisible,
metal or metallic oxide layer deposited directly on the surface of one
or more of the panes of glass.”

The Building Conservation Directory, 2008

“The inclusion of exemptions came as a surprise, being introduced very late in the day by government.
(…) In addition, work specifically permitted for historic buildings
includes replacing lost elements such as windows where these are
important in maintaining the building’s character.” 

Windows of Opportunity: Repair – Don’t Replace – Those Older Wood Windows
by Rebecca Williams, National Trust for Historic Preservation

“Repairing historic windows is more economical and environmental than you might think”

The Repair of Historic Wooden Windows
by John H. Myers

“Technical Preservation Services recommends the retention and repair of original windows whenever possible.”

Dedicated to the preservation of historic wood windows

A Homeowner’s Guide to Preserving and Enhancing the Character of Your Conservation Area
Bradford City Council
(Windows & doors from page 25)

“high-solids alkyd or waterborne alkyd. These types of paint are least harmful to the environment and human health and are micro-porous (allowing the timber to breathe’ rather than sealing it)”

Top Ten Reasons to Restore or Repair Wood Windows
Restoration Alliance of NEWRA

“10. Because the greenest building is one that is already built.”

In the words of Richard Moe, President of the National Trust for Historic Preservation
“We can’t build our way out of the global warming crisis. We have to
conserve our way out. That means we have to make better, wiser use of
what we have already built.” “Repairs and restoration work are done by
local craftspeople paying local taxes. The use a minimum of materials
and resources and a maximum of labor. Restoring windows is the best use
of existing materials and the best way to support the local economy.” 


Sverre Fossdall: Windows in existing buildings – maintenance, upgrading or replacement? (pdf)


The Practice of Upgrading Windows in Germany with Natural Materials and Old Technologies (in German Language)

A store of used building materials in Germany


Where Contemporary Windows are Few – the Old Ones are Sold as Expensive as Gold


Why Shouldn’t I Replace My Windows {Yapp B.} pdf
National Trust for Hist. Prez. Washington DC

“… homeowner’s think they need to replace their windows is that the
window industry spends tens of millions of dollars a year to convince
homeowners to buy their inferior products. (…) If retrofitting energy
efficient glass into an old sash is something you feel must be done. ”

Replacement windows are often an irresponsible environmental choice

“… Life cycle assessment studies conducted in the U.K. and Norway
indicate that, over a building’s life cycle, the overall environmental
impact of retrofitting existing windows may be smaller than those
associated with the manufacturing of new windows. [4]

“Replacement windows typically fail 10-20 years after installation, and
usually after the warranty period has ended. Once replacement windows
fail, they cannot be repaired and typically end up in
already-overcrowded landfills. New windows are then required, and the
wasteful cycle of disposal and replacement continues. Unlike the vast
majority of replacement windows, components of historic windows can be
repaired, thus extending the life cycle of the entire window unit.
Furthermore, historic windows are generally constructed of old growth
wood, which is far more durable than modern wood from new growth
sources. [5] …”

Albany’s Historic Preservation Program

“The style of windows and pattern of openings in a building is one of
the single most important elements in defining its character and the
date of construction. Retaining and celebrating authenticity applies to
windows, too. Replacement windows, no matter how accurate, never
reflect the nuances of the original.”

Standards for Window Replacement – a guide to applying for a window replacement permit 2010, San Francisco (PDF) 

John Leeke’s Historic HomeWorks Forum

Windows forum

National Trust for Historic Preservation

Window Know-How – A Guide to Going Green
Helping people protect, enhance and enjoy the places that matter to them.

“Older is Better:  Old windows were fabricated from old wood. It’s generally denser and lasts longer than the new wood used for modern windows.”

Revised Window Tip Sheet

“Historic window systems are usually built with good attention to detail (such as weather shedding) and with good quality materials (such as old-growth timber). Problems related to wear over time – peeling paint, broken glass and missing putty – can look unsightly but are easily put right.
Residential wood windows can be in service for 100 years before requiring a major retrofit to remain in service for a second 100 years. Similarly, it is not unusual for modern windows to experience major, non-repairable failures to sealed units, vinyl welds, caulk joints and wood joints within 10 to 25 years. Today, most sealed units carry warranties of only 8 to 10 years. …

In the name of energy efficiency and environmental responsibility, replacement window manufactures are convincing people to replace their historic wood windows. The result is the rapid erosion of the building’s caracter, the wast of historic resource, and a potential net loss in energy conservation.”

Kansas State Historical Society, preservation Techniques (video introductions)

“Replacement windows have been marketed as energy efficient, and therefore environmentally friendly, and economical, by saving the homeowner money over the lifespan of the window.”


Repair or Replace – Windows in Historic Buildings: Arriving at a Sustainable Solution
by Craig Sims and Andrew Powter

“Life-cycle cost analysis has shown that replacing historic windows in order to reduce heating costs is largely a myth.” 

Life Cycle Analysis of Windows for North American Residential Market

Research of  University of  British Columbia (Dr. Taraneh Sowlati, P.Eng.)

“The analysis showed that more than one-third of greenhouse gas generated during the life cycle of each window is related to the energy use during the manufacturing stage”

Life Cycle Assessment of PVC and of principal competing materials – Summary of overall life cycle impacts of PVC polymer

”Environmental impact: The amount of
primary energy required for the production and recycling of a PVC
window frame is considerably larger than that for a wooden window

How wood products help slow Global Warming

PVC – the waste crisis, Greenpeace

GREEN PAPER environmental issues of pvc (A pvc környezeti hatásai)

”… Assuming that the maximum potential of
PVC recycling is achieved, incineration of PVC waste would still
increase more than fourfold to 2.2-2.5 million tonnes in 2020. Current
recycling rates are at less than 3%. (…) Almost all PVC wastes
contain hazardous additives.”

Environmental Impacts of Polyvinyl Chloride (PVC) Building Materials

“Toxicity. The feedstocks, additives, and
by-products produced and released during the lifecycle of PVC have been
shown to cause a range of health hazards, in some cases at extremely
low doses, including:

  • Cancer
  • Disruption of the endocrine system
  • Reproductive impairment
  • Impaired child development and birth defects
  • Neurotoxicity (damage to the brain or its function), and
  • Immune system suppression.

Dioxins. Among the most important by-products of the PVC lifecycle are
dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) and a large group of
structurally and toxicologically related compounds, collectively called
dioxins or dioxin-like compounds.”

Environmental Impacts of Polyvinyl Chloride, by Joe Thornton, Ph.D.

”Building MaterialsMetal stabilizers are
highly toxic. Lead is an exquisitely potent developmental toxicant,
damaging brain development and reducing he cognitive ability and IQ of
children in infinitessimal doses. Cadmium is a potent neurotoxin and
carcinogen, and organotins can suppress immunity and disrupt the
endocrine system. ”

(…) PVC products can release heavy
metals into the building environment. Metal stabilizers, particularly
lead, cadmium, and organotins, can be released from vinyl products.
Significant quantities of lead have been found to be released from
vinyl window blinds into air and from PVC pipes into water.
Toxicological effects of these substances include neurological,
development, and reproductive damage.

(…) In the European Union, 60 percent
of vinyl is used in building and construction applications, with an
additional 25 percent in appliances, electronics, and furniture.

(…) The PVC lifecycle begins with the production of chlorine gas in the chlor-alkali process.

(…) But recent data indicate that even the most modern chlor-alkali plants produce dioxin-like compounds.

” … Dioxin is a known human carcinogen and has been linked to reproductive disorders, immune suppression, and endometriosis, and other diseases in laboratory animals.”

(…) Mercury is an extremely toxic, bioaccumulative global pollutant.
Mercury compounds cause irreversible health damage to wildlife and
Humans – especially to developing children, resulting in birth defects,
impaired neurological development, kidney damage, and severe
neurological destruction. ”

„The PVC lifecycle presents one opportunity after another for the formation and environmental discharge of organochlorines and other hazardous
substances. When its entire lifecycle is considered, it becomes
apparent that this seemingly innocuous plastic is one of the most
environmentally hazardous consumer materials produced, creating large
quantities of persistent, toxic organochlorines and releasing them into
the indoor and outdoor environments. PVC has contributed a significant
portion of the world’s burden of persistent organic pollutants and
endocrine-disrupting chemicals – including dioxins and phthalates –
that are now present universally in the environment and the bodies of
the human population."

"Vinyl is all around us, but no other plastic poses such direct
environmental and human health risks. All the most essential
information about the hazards of vinyl have been culled from the web
and placed in this one site. "



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