�

�

Historic windows are among the most impor-tant elements of a b u ilding. S imple repairs and routine maintenance coupled with storm win-dows make for energy efficiency that in most cases matches, if not exceeds, the efficiency of replacement windows. W orkshops throughout the region have taught b u ilding owners easy ways to care for their historic windows. A t the W oodlawn M useum in E llsworth, M E , a grant from the N ational T rust for Historic P reserva-tion helped fund a window repair workshop. Photo courtesy of the Woodlawn Museum

HIS T O R IC WO O D WIN D O WS

A t ip sheet from the N at ional T ru st for Histor ic P reserv at ionA t ip sheet from the N at ional T ru st for Histor ic P reserv at ionA t ip sheet from the N at ional T ru st for Histor ic P reserv at ionA t ip sheet from the N at ional T ru st for Histor ic P reserv at ion

T here is an epidemic spreading

across the country. In the name of

energy efficiency and environmental

responsib ility, replacement window

manufacturers are convincing people to

replace their historic wood windows. The

result is the rapid erosion of a b u ilding’s

character, the waste of a historic resource,

and a potential net loss in energy

conservation. T ypically replacement

windows are vinyl, aluminum, or a

composite with wood, and none will last as

long as the original window. R epairing,

rather than replacing, wood windows is

most likely to b e the “greener option” and

a more sustainab le b u ilding practice.

R esearch shows that most traditionally

designed wood-frame b u ildings lose more

heat through the roof and un-insulated

walls than through the windows.1 A

historic wood window, properly

maintained and fitted with a storm

window, can b e just as energy efficient as

a new window.2 R eplacing a historic single

-pane window also may not save you

much money in the long run. W hile the

exact figure will vary depending on the

type of window installed and whether or

not a storm window is used, studies have

found that it could take 10 0 years or more

for a replacement window to pay for itself

in energy savings.3 A ccording to

information pub lished in a recent O ld

H ouse Journal article, it could take 240

years to recoup the cost of replacing a

single-pane window-storm window

comb ination with a low-e glass doub le-

pane thermal replacement window.4 A lso,

a historic wood window can easily last

more than 10 0 years, while a new window

may not last 25.

N ot every wood window can b e

repaired and there are situations where

replacement is appropriate. However,

many historic wood windows can and

should b e repaired, especially if the

windows were manufactured b efore about

1940 . W ood windows made b efore this

Intro d uctio n N ational T ru st for Historic N ational T ru st for Historic N ational T ru st for Historic N ational T ru st for Historic P reservationP reservationP reservationP reservation 1785 M assachusetts A ve, N W

W ashington, D C 20 0 36 (20 2) 588-60 0 0 (20 2) 588-6462 (fax) info@ nthp.org www.P reservationN ation.org

This tip sheet on historic wood windows was developed as part of the N ational T rust for Historic P reservation’s Sustainab ility Initiative. A b ou t the Initiative:A b ou t the Initiative:A b ou t the Initiative:A b ou t the Initiative: Historic preservation can – and should – b e an important component of any effort to promote sustainab le development. The conservation and improvement of our existing b u ilt resources, including re-use of historic and older b u ildings, greening the existing b u ilding stock, and reinvestment in older and historic communities, is crucial to combating climate change. Learn more ab out Learn more ab out Learn more ab out Learn more ab out P reservation and P reservation and P reservation and P reservation and S u stainab ility on the web : S u stainab ility on the web : S u stainab ility on the web : S u stainab ility on the web : www.preservationnation.org/issues/sustainab ility F or more information, F or more information, F or more information, F or more information, contact:contact:contact:contact: P atrice F rey, D irector of P atrice F rey, D irector of P atrice F rey, D irector of P atrice F rey, D irector of S u stainab ility R esearchS ustainab ility R esearchS ustainab ility R esearchS ustainab ility R esearch (20 2) 588-6255 P atrice_F rey@ nthp.org B arb ara A . C ampagna, B arb ara A . C ampagna, B arb ara A . C ampagna, B arb ara A . C ampagna, A IA , L E E D A P , G raham A IA , L E E D A P , G raham A IA , L E E D A P , G raham A IA , L E E D A P , G raham G und A rchitectG und A rchitectG und A rchitectG und A rchitect (20 2) 588-629 1 B arbara_C ampagna@ nthp.org

R eb ecca W illiams (author R eb ecca W illiams (author R eb ecca W illiams (author R eb ecca W illiams (author of this pub lication), F ield of this pub lication), F ield of this pub lication), F ield of this pub lication), F ield R epresentative, N ortheast R epresentative, N ortheast R epresentative, N ortheast R epresentative, N ortheast O fficeO fficeO fficeO ffice (6 17) 523-0 885 R ebecca_W illiams@ nthp.org

time were constructed with individual

parts, each of which can b e repaired or

replaced. The wood itself is denser and of

higher q uality than what is grown today,

and it is generally more rot- and warp-

resistant than modern wood.

These are just some of the practical

reasons to repair rather than replace

historic wood windows. In addition,

repairing the historic window helps

maintain a b u ilding’s authenticity. O nce

original material is removed from a

b u ilding, it is gone forever. There are many

more b enefits to repairing your wood

windows, so keep reading.

——————————————— 1. R ypkema (20 0 6 ); James et al (199 6 ); K lems

(20 0 2). 2. James et al (199 6 ); K lems (20 0 2). 3.

Sedovic (20 0 5); e.g . research b y K eith Heberern,

calculations availab le at

www.historichomeworks.com/hhw/education/

windowshandout/windowenergyanalysis.pdf. 4.

“Let the N umbers C onvince Y ou: D o the M ath.” O ld

House Journal 35 no. 5 (September/O ctober

20 0 7).

�

�

page 2 Historic W ood W indows

M y Wind ow s A re O ld and D rafty, Why Sho uld n’t I B uy N ew O nes?

1. M ore heat is typically lost though you r roof and M ore heat is typically lost though you r roof and M ore heat is typically lost though you r roof and M ore heat is typically lost though you r roof and unununun----insulated walls than through you r windowsinsulated walls than through you r windowsinsulated walls than through you r windowsinsulated walls than through you r windows. A dding just 3 and 1/2 inches of insulation in your attic can save more energy than replacing your windows.1

2. R eplacement windows are called “replacement” R eplacement windows are called “replacement” R eplacement windows are called “replacement” R eplacement windows are called “replacement” for a reason. for a reason. for a reason. for a reason. M anufacturers often offer lifetime warrantees for their windows. W hat they don’t make clear is that 30 % of the time, a replacement window will b e replaced within 10 years.1

3. R eplacement windows that contain v inyl or R eplacement windows that contain v inyl or R eplacement windows that contain v inyl or R eplacement windows that contain v inyl or P V C are toxic to produce and create toxic b yP V C are toxic to produce and create toxic b yP V C are toxic to produce and create toxic b yP V C are toxic to produce and create toxic b y ----products. products. products. products. Installing these in your house is not a ‘green’ approach.2

4. If you r wood windows are 6 0 years old or older, If you r wood windows are 6 0 years old or older, If you r wood windows are 6 0 years old or older, If you r wood windows are 6 0 years old or older, chances are that the wood they are made of is chances are that the wood they are made of is chances are that the wood they are made of is chances are that the wood they are made of is old growthold growthold growthold growth—dense and durab le wood that is now scarce. E ven high-q uality new wood windows, except for mahogany, won’t last as long as historic wood windows.

5. S tudies have demonstrated that a historic wood a historic wood a historic wood a historic wood window, properly maintained, weatherstripped window, properly maintained, weatherstripped window, properly maintained, weatherstripped window, properly maintained, weatherstripped and with a storm window, can b e ju st as energy and with a storm window, can b e ju st as energy and with a storm window, can b e ju st as energy and with a storm window, can b e ju st as energy efficient as a new windowefficient as a new windowefficient as a new windowefficient as a new window.2

6 . A ccording to studies, it can take 240 years to it can take 240 years to it can take 240 years to it can take 240 years to recoup enough money in energy sav ings to pay recoup enough money in energy sav ings to pay recoup enough money in energy sav ings to pay recoup enough money in energy sav ings to pay b ack the cost of installing replacement b ack the cost of installing replacement b ack the cost of installing replacement b ack the cost of installing replacement windowswindowswindowswindows.3

7. E ach year, A mericans demolish 20 0 ,0 0 0 E ach year, A mericans demolish 20 0 ,0 0 0 E ach year, A mericans demolish 20 0 ,0 0 0 E ach year, A mericans demolish 20 0 ,0 0 0 b u ildings. T hat is 124 million tons of deb ris, or b u ildings. T hat is 124 million tons of deb ris, or b u ildings. T hat is 124 million tons of deb ris, or b u ildings. T hat is 124 million tons of deb ris, or enough waste to construct a wall 30 feet high enough waste to construct a wall 30 feet high enough waste to construct a wall 30 feet high enough waste to construct a wall 30 feet high and 30 feet thick around the entire U .S . and 30 feet thick around the entire U .S . and 30 feet thick around the entire U .S . and 30 feet thick around the entire U .S . coastline.coastline.coastline.coastline.4 E very window that goes into the dump is adding to this prob lem.

8 . W ith a little b it of practice, it can b e easyit can b e easyit can b e easyit can b e easy—and and and and inexpensiveinexpensiveinexpensiveinexpensive————to repair and maintain you r wood to repair and maintain you r wood to repair and maintain you r wood to repair and maintain you r wood windows.windows.windows.windows.5

9 . N ot a D IY -er? There are people near you who can do it for you . Hiring a skilled tradesperson to Hiring a skilled tradesperson to Hiring a skilled tradesperson to Hiring a skilled tradesperson to repair you r windows fuels the local economy repair you r windows fuels the local economy repair you r windows fuels the local economy repair you r windows fuels the local economy and prov ides job s.and prov ides job s.and prov ides job s.and prov ides job s.1

10 . Historic wood windows are an important part of Historic wood windows are an important part of Historic wood windows are an important part of Historic wood windows are an important part of what gives you r older b u ilding its character. what gives you r older b u ilding its character. what gives you r older b u ilding its character. what gives you r older b u ilding its character.

———————————

1. R ypkema (20 0 6 ). 2. Sedovic (20 0 5). 3. e.g . C alculations b y K eith

Heberern availab le at www.historichomeworks.com/hhw/education/

windowshandout/windowenergyanalysis.pdf. 4. Hadley (20 0 6 ). 5.

e.g . www.historichomeworks.com

Wood Wind ow B asics

A c. 1846 wood window in the former R ob b ins and Lawrence A rmory, now the A merican P recision M useum in W indsor, V T .

Meeting Rail or Check Rail (the rail where the two sash come to-gether)

Muntin (horizontal, vertical, diago-nal, or curved pieces that frame and provide mounting surface for the lights) The shape, or profile, of the muntin provides a clue to the win-dow’s age.1

Sill (exterior, horizontal piece at the bottom of the window frame, com-monly wood, stone, or brick) Stool (interior shelf-like board at the bottom of a window against which the bottom rail of the sash rests)

Rail (horizontal part of sash)

Stile (vertical part of sash)

Jamb (the wood that frames the window opening)

Bottom Sash (lower section of win-dow, typically slides up to open)

Top Sash (upper section of win-dow, may slide down to open)

U sing this 12-over-12, doub le-hung wood window as our example, here are the b asic terms used for wood window parts. This window is called 12-over-12 b ecause there are 12 panes of glass in each sash. B oth sashes are moveab le so it is called doub le-hung. If only the bottom sash moves, it is called single-hung.

Light/lite/pane (glass, held in place by glazing putty and metal glazing points)

——————————— 1. Garvin (2002).

�

�

page 3 Historic W ood W indows

T here are many good, practi-

cal books and magazine arti-

cles to gu ide a handy person

in the b asic maintenance of wood

windows. Several pub lications are

listed in the references section of

this tip sheet. To get you started,

here are some of the keys to many

years—and generations—of life

with older wood windows.

1. K eep the exterior surfaces

painted, including the glazing

putty. P aint protects the wood and

putty from water and extends their

service life. B e especially attentive

to horizontal surfaces where water

may collect.

2. G lazing putty will eventually dry

out and is meant to b e periodically

replaced. Y ou can do spot repairs

initially, b ut eventually it will b e

easier to re-glaze the whole sash.

3. K eep movab le surfaces, such as

the inside jamb, free of paint b u ild-

up so that the sash can slide freely.

4. If your sashes are hung with

cord, keep the rope free of paint.

This will improve the window’s op-

erab ility. C ord will eventually dry

out and b reak b ut can b e replaced.

W hen replacing the cord you can

also re-hang the weights so that

the sash will b e b alanced.

Winter Tip s

What A b o ut Lead ?

I f your windows retain paint that

was applied prior to 19 78,

chances are there is lead paint

on them. Just b ecause there may

b e lead paint on the windows does

not mean they are unsafe or that

they need to b e replaced. There

are steps you can take to protect

yourself and others if you suspect

lead paint may b e present. B efore B efore B efore B efore

b eginning work, consult you r b eginning work, consult you r b eginning work, consult you r b eginning work, consult you r

local or state ordinance to local or state ordinance to local or state ordinance to local or state ordinance to

determine the legaldetermine the legaldetermine the legaldetermine the legal method for method for method for method for

handling andhandling andhandling andhandling and disposing of lead disposing of lead disposing of lead disposing of lead

paint in you r area. paint in you r area. paint in you r area. paint in you r area.

• C hildren and pregnant women should not b e allowed in the work area.

• D o not smoke or eat or drink in the area you are working in and wash your hands and face b efore doing so.

• W ear disposab le gloves and eye protection.

• U se a respirator if there is friab le paint, or if you are scraping or sanding paint.

• U se a wet sanding techniq ue to minimize dust.

• V acuum using a HE P A filter.

• W ash your work clothes separately from your household laundry. Y ou can also wear a tyvek su it to protect your clothes. T ake it, and your shoes, off b efore you leave your work area.

• P lace tarps under your work surface to collect loose paint. Seal off the work space from other rooms and from HV A C systems. C over any furniture and other items in the work area with

(C ontinued on page 4)

M ost of the heat transfer occurs around the perime-

ter of the sash rather than

through the glass. So the tighter

the seal around the window and

between the upper and lower sash,

the more energy efficient the win-

dow will b e. Here are some tips to

help you save on your heating b ills.

C heck the lockC heck the lockC heck the lockC heck the lock. M ost people think

the sash lock is primarily for secu-

rity. It does help with security, b ut

the lock’s most important job is to

B asic M aintenance ensure that the meeting rails are

held tightly together. A tight fit

greatly reduces air infiltration.

W eather strippingW eather strippingW eather strippingW eather stripping—add it or re-

new it. A dding weather stripping

to your window can increase the

window’s efficiency b y as much

as 50 % . It’s an inexpensive way

to boost your window’s effi-

ciency. There are many different

kinds from which to choose. R e-

fer to the articles listed at the

end of this tip sheet. The staff at

your local hardware store should

also b e ab le to assist you .

S torm windowsS torm windowsS torm windowsS torm windows—use them!

There are many styles from which

to choose, including storms that

can b e fitted on the interior of

the window. M any studies have

shown that a wood window in

good condition fitted with a

storm window can be just as en-

ergy efficient as the more expen-

sive replacement window. D ue to

the thermal exchange properties

of wood, there is also a growing

interest in traditional wood-

framed storm windows as they

transfer less heat than metal-

framed storms.

C ondensationC ondensationC ondensationC ondensation. If you find con-

densation on the inside of your

primary window, cold air leaking

through the storm window is

likely the culprit. If the condensa-

tion is forming on the inside sur-

face of the storm window, warm

air from the b u ilding interior is

leaking in around the primary

window. W hen warm and cold air

are present on opposite sides of

glass, condensation forms (think

of a cold glass of lemonade on a

hot day). W hen condensation

forms on your window glass, wa-

ter can collect on the horizontal

wood parts of the rails, muntins,

and sill, which can lead to paint

failure and rot. To reduce con-

densation, you need to limit the

amount of leaking air. A dd or re-

place weather stripping, make sure

the sash are meeting properly and

that the sash lock is tight, and

check the seal around the exterior

of the storm window and caulk if

necessary. W hen caulking around

the perimeter of exterior storms it

is important to leave weep holes at

the bottom so that any condensa-

tion or infiltration that does occur

can drain out.

�

�

“Testing the E nergy P erformance of W ood W indows in C old C limates.” A R eport to the S tate of V ermont D ivision for Historic P reservation. 30 A ugust, 19 96 . www.ncptt.nps.gov/P D F files/19 9 6 -0 8 .pdf Jordan, S teve. “S trips and S torms: Techniq ues for tuning up sash windows for winter.” O ld House Journal (N ovember/D ecember 20 0 4): 46 -51. www.oldhousejournal.com Leeke, John C . Save Y our W ood W indows: an alternative to vinyl replacement windows and vinyl windows. 20 0 4. Sample pages availab le at www.historichomeworks.com/hhw/reports/reports.htm. K lems, Joseph H. "M easured winter performance of storm windows." U niversity of C alifornia: Lawrence B erkeley N ational Laboratory, A ugust 23, 20 0 2. A vailab le at http://repositories.cdlib .org/lbnl/LBN L-51453 M attinson, B ill, R oss D eP aoloa, and D ariush A rasteh. “W hat Should I D o A bout M y W indows?” Home E nergy M agazine (July/A ugust 20 0 2): 24-31. www.homeenergy.com/19 -4.html M yers, John H. “The R epair of Historic W ooden W indows” P reservation B rief Series # 9 . T he N ational P ark Service, www.cr.nps.gov/hps/tps/b riefs/b rief0 9 .htm N ational P ark Service. “The Secretary of the Interior’s S tandards for R ehab ilitation” www.nps.gov/history/hps/tps/tax/rhb /stand.htm N ew E ngland W indow R estoration A lliance www.windowrestorationne.org N ew Y ork Landmarks C onservancy. R epairing O ld and Historic W indows: A M anual for A rchitects and Homeowners. W ashington, D .C .: The P reservation P ress, 19 92. R ypkema, D onovan D . “E conomics, Sustainab ility, and Historic P reservation..” Forum Journal 20 , N o. 2 (20 0 6 ): 27-38 .

R eferences This list is a p lace to start—it is not intended to be comp rehensive, nor does the inclusion of a business or organization serve as an endorsement. A merican P recision M useum. W indows on P reservation: restoring windows at the A merican P recision M useum, ed. John C . Leeke. W indsor, V T : A merican P recision M useum, 20 0 5. A vailab le at www.lulu .com. C amb ridge (M A ) Historical C ommission. “W indow G uide.” A vailab le at: www.camb ridgema.gov/Historic/windowguide.html G arvin, James. A B u ilding History of N orthern N ew E ngland. Hanover, N H: U niversity P ress of N ew E ngland, 20 0 2. Hadley, James. “The Home of the F uture?” A rchitectureB oston 10 , no. 2 (M arch/A pril 20 0 7): 44-47. www.architects.org/documents/pub lications/ab /marapr20 0 7/HomeO fTheFuture.pdf Historic Homeworks www.historichomeworks.com James, B rad, A ndrew Shapiro, S teve F landers, and D r. D avid Hemenway.

A d d itio nal Help

Sedovic, W alter and Jill H. G otthelf. “W hat R eplacement W indows C an’t R eplace: The R eal C ost of R emoving Historic W indows.” A P T B ulletin, Journal of P reservation Technology 36 , no. 4 (20 0 5): 25-29 . www.apti.org/pub lications/P ast-B ulletin-A rticles/Sedovic-36 -4.pdf Shapiro, A ndrew and B rad James. “C reating W indows of E nergy-Saving O pportunity.” Home E nergy M agazine O nline (September/O ctober 19 9 7). www.homeenergy.org/archive/hem.dis.anl.gov/eehem/97/9 70 9 0 8 .html Shapiro, A ndrew and B rad James. “R etain or R etire? A F ield S tudy of the E nergy Impacts of W indow R ehab C hoices.” In W indow R ehab ilitation G u ide for Historic B u ildings, edited b y C harles F isher III, D eborah Slaton, and R eb ecca Shiffer. W ashington, D .C .: Historic P reservation Education Foundation, 19 9 7. S ullivan, James. “P reserving windows to the past. History-minded vinyl critics say wood remains the b est.” B oston G lobe, 30 July 20 0 6 . [C ited July 31, 20 0 6 .] www.boston.com/news/local/articles/20 0 6 /0 7/30 /preserving_windows_to_the_past?mode+P F 7/31/20 0 6 .

page 4 Historic W ood W indows

6 mil plastic taped to the floor.

• E ating a nutritious diet rich in iron and calcium will reduce the amount of lead ab sorb ed b y your b ody if any does happen to b e ingested.

• For more tips on how to work lead-safe, see “Lead P aint Safety: A F ield G u ide for P ainting, Home M aintenance, and R enovation W ork” availab le at www.hud.gov/offices/lead/training/LB Pguide.pdf and the N ational P ark Service B rief # 37, “A ppropriate M ethods for R educing Lead-P aint Hazards in Historic Housing” at www.nps.gov/history/hps/T P S/b riefs/b rief37.htm.

• John Leeke’s web site www.historichomeworks.com also has practical tips on lead- safer work practices.

Lead continued

W ith nearly half of greenhouse gas emissions attrib uted to the con-struction and operation of b u ild-

ings, older and historic b u ildings are cen-tral to our efforts to address climate change. The N ational T rust for Historic N ational T rust for Historic N ational T rust for Historic N ational T rust for Historic P reservation’s S ustainab ility InitiativeP reservation’s S ustainab ility InitiativeP reservation’s S ustainab ility InitiativeP reservation’s S ustainab ility Initiative promotes the reuse of existing b u ildings, reinvestment in existing communities, and green retrofit of older and historic b u ildings to help lower carbon emissions. For more information visit www.preservationnation.org. A dditional help may be availab le from your S tate Historic P reservation O ffice S tate Historic P reservation O ffice S tate Historic P reservation O ffice S tate Historic P reservation O ffice (SHPO ). F ind your SHP O at www.ncshpo.org/. P rivate statewide and statewide and statewide and statewide and local preservation groups local preservation groups local preservation groups local preservation groups serve as the network centers and representatives of local preservation activities within their states. The nine R egional and F ield O f-R egional and F ield O f-R egional and F ield O f-R egional and F ield O f-fices of the N ational T rust for Historic fices of the N ational T rust for Historic fices of the N ational T rust for Historic fices of the N ational T rust for Historic P reservation P reservation P reservation P reservation (N THP ) b ring the programs and services of the N THP to preservation-ists within their regions. F ind your nearest N THP R egional O ffice and state and local preservation organizations at www.preservationnation.org/about-us/partners/statewide-local-partners/contacts.html