While you wont recover the cost of replacement windows from the resulting
energy savings, there are other good reasons to replace old windows: If
they are ugly or deteriorating; if they are hard to wash; or if you want
to minimize your homes impact on the environment. You might also want
to install a new window where there was no window before.
The kind of windows you buy will determine the appearance, amount of light
admitted, comfort and energy savings you achieve, and how long they will
Salespersons may provide data on energy savings, but check their claims
using the tools described in this article. You wont be able to get verifiable
data about durability, but you can learn quite a bit about window construction
by talking to different salespersons and reading manufacturers literature.
Also, compare warranties.
There are, unfortunately, a lot of unhappy window customers. As our Ratings Tables reveal, some companies were rated inferior by 30 percent or
more of their surveyed customers. But there are also some very highly rated
Get several price quotes. Price differences are big. For one very specific
replacement job, we received price quotes from area companies that ranged
from $2,100 to $8,256.
U-factors, E-coatings, Argon, Kryptonwere not talking about computer
chips or Lex Luthors latest weapons against Superman but rather windows.
Modern windows are technological marvels compared to the old window/storm
window combinations. They are easy to clean: no need to teeter on high
ladders; simply tilt them in or remove them and wash them inside your house.
And modern windows provide such good insulation that the window area feels
about as warm as the rest of the house.
Although window sellers may make extravagant claims about how much new
windows will reduce your energy bills, even new windows that replace old,
very drafty ones wont pay for themselves in energy savings.
But you still may value new windows for other reasons. Replacing drafty
windows that admit drafts on cold nights will let you maintain a more constant,
comfortable temperature and humidity level. And many consumers want to
replace old windows with new, energy-efficient ones to minimize the environmental
impact of their homes.
In addition, you might want to replace old windows that have become unsightly
or difficult to open and close.
The benefits for homeowners have created opportunities for businesses,
which some have exploited with high-pressure sales tactics, exaggerated
and confusing energy claims, and substandard installations.
This article will help you explore your window choices and find a high-quality,
reliable window installer.
A good way to learn about window options is to visit installers showrooms.
Let salespersons describe window features and the different installation
techniques. Visit several showrooms and listen to pitches from more than
one salesperson. Pick up copies of manufacturers catalogs and look through
them when you get home. But dont agree to buy anything on these exploratory
If you are adding or enlarging windows, or doing new construction, you
can benefit from creative ideas in magazines and books and on the Web.
There are many features to consider when selecting windows and the company
that installs them. You will have more to think about, of course, if you
are adding windows or doing new construction than if you are simply replacing
Youll want windows appropriate for the architecture of your house and
your neighborhood. If you live in a historic district, or if your neighborhood
is governed by a homeowners association, find out what is allowed. Preservation
officials or homeowners association rules might ban vinyl windows, for
instance, or specify certain types of window muntins (grids). Ignore these
rules at the peril of having to tear out what you install.
Assuming you arent constrained by neighborhood requirements, youll have
to decide among various types of windows and construction materials.
The most common styles are
Double- and single-hung. Double- and single-hung units look the same, but
on single-hungs only the bottom sash moves. These windows can be cracked
for ventilation and locked in that position with window pins for security.
Tilt-in models are made to be easy to clean on both sides. The marginal
downside is that only half the window area can be open at any time, while
other styles open fully for greater ventilation.
Casement. These outward-swinging windows open fully for ventilation, and
the view isnt obstructed midway by the frames of two sashes. The weak
link is often the cranking hardware, particularly on large units. Because
casement windows also provide too-slow escape routes in the event of fire,
they shouldnt be installed in bedrooms.
Awning and hopper. Awning-style windows swing out at the bottom; hoppers
swing in at the top. Both types of rectangular units (which look like casements
turned on their sides) can be inset at the top of foundation walls to provide
light and ventilation to basements.
Figure 1Types of Windows
All styles are available in different materials, including wood, vinyl,
fiberglass, and, to a lesser extent these days, aluminum. You may base
your choice on appearance, cost, energy efficiency, maintenance, or a combination
of factors, but the most significant differences in quality among windows
are not materials but in how well they are constructed. A cheaply made
wood frame wont hold up as well as a top-quality vinyl or fiberglass frame,
and vice versa. Aluminum is no longer a popular option because it is a
poor insulator, requiring disconnects (called thermal breaks) between
the inside and outside frame surfaces, and may still be subject to condensation
in cold climateseven when the new double glazing prevents it on the glass.
Although there is a very wide price range for each type, vinyl is on average
the least expensive, wood is mid-range, exterior-clad wood is more expensive,
and fiberglass tops the list. A quick rundown of other pros and cons
VinylThe first generations of vinyl windows had problems with expansion
and contraction during temperature swings. Modern formulations have greatly
reduced that problem, although most manufacturers stick to light colors
and no longer offer dark brown frames because they absorb too much heat
from the suns rays. Frames with welded corners are the sturdiest and most
WoodThis traditional choice is a good natural insulator that can be milled
to provide classic architectural detailingeven styles that comply with
historic districts and neighborhood association restrictions. Many come
factory primed, ready for a finish coat in any color. That versatility
is also the main drawback: the need to scrape and repaint every few years.
Having vinyl cladding on all exterior parts of wood windows increases the
price and may limit your ability to change color schemes over time, but
it can eliminate the need for regular repainting.
FiberglassThis grainy synthetic is considered the most durable and strongest
type, making it a good choice for large panes of glass and assemblies of
several windows. It can be extruded into slimmer profiles than vinyl, making
it a good choice for frame-plus-sash replacements. It can be painted to
suit and is available with wood veneer facings on the interior side.
In addition to choice of the material for windows, youll need to decide
on other visible details. You will find windows with thicker or thinner
frames, more or less substantial muntins, and various types of hardware.
If you are replacing old windows, you need to choose one of three basic
types of installation:
If your frames and trim are in good shape and you mainly want to get more
energy-efficient window glass, consider a sash pack, the least expensive
option. In a typical installation, old sash and tracks are removed, and
jamb liners are installed against the sides of the window frame. They seal
and secure the new sash.
Major manufacturers may carry over 100 stock sizes, fabricate custom sizes,
and offer many colors, cladding, tilt-in hardware, divided-light grills,
and other features. Some companies market sash pack installation as a do-it-yourself
Frame and Sash
This common, more expensive replacement option consists of a fully framed
sash unit that slips into the existing window frame after the old sashes
and tracks are removed. In this case, again, the existing frame and trim
are left in place, so they must be sound; framed replacements cant compensate
for major leak damage.
The key to this option is the amount of space between the old and new frames.
A good match will produce a close fit, with no two-by-fours added to pack
out and significantly downsize the opening. Glass area may be reduced by
an inch or so, but not by several inches. Small gaps between the old and
new frames are fine; they can be insulated and existing trim built up with
narrow strips that blend into the overall facade. Installers should tuck
in loose-fill insulation or spray in low-expanding foam. (Standard foam
has enough pressure to bow the jambs.) On the other hand, if the fit leaves
large gaps, they typically require wide boards or aluminum panels to bridge
the openings; the result looks out of scale and doesnt fit in with the
This start-from-scratch option is the most expensive approach. The old
unit is pulled out, any damaged framing repaired or replaced, and then
a new window installed as if it were new construction. This is the only
option if the framing needs to be significantly altered. It also avoids
the reduction in glass area produced by the frame-and-sash approach.
If your old windows are stock sizes (most are), you shouldnt have to spend
extra for custom construction. Window manufacturers catalogs often list
at least 75 stock sizes just for double-hungs. For the rough opening (the
distance between framing members that allows for shimming space), typical
widths start at 24 inches and increase at four-inch intervals up to 48
inches. Typical heights start at 36 inches and range up to 72 inches.
By choosing the right windows, you can conserve energy. That saves you
money, saves world resources, and reduces your contribution to pollution.
In addition, preventing heat from escaping your home will make your home
more comfortable by eliminating cold areas around windows. Modern windows
are constructed to reduce your homes heat loss, enhance its heat gain
from the sun on cold days, and suppress its heat gain on hot days.
Heat transfers in three ways:
Conduction, the movement of heat through solid material like glass or aluminum,
the way heat reaches your hand through a drinking glass when you pour hot
tea into it.
Convection/air infiltration, the movement of heated air and other gas (or
liquid), the way hot air rises out of an oven when the door opens.
Radiation, the movement of heat without conduction or convection, the way
warmth reaches your face as you sit by a sunny window even on a cold day.
Modern windows are typically constructed using two or three panes of glass,
with air or an inert gas such as argon or krypton filling the space between
panes. The air or gas is an insulator, more resistant to the passage of
heat than solid glass. In many windows, one or more panes are glazed with
a thin, transparent film of metal that reduces the panes ability to radiate
heat; this is called a low-E coating. In high-quality windows, the materials
of the frame itself are poor heat conductors. The spacer material that
separates the panes of glass around the edges is another issue. Aluminum,
a common spacer material, is highly conductive, transferring heat from
pane to pane; rigid foams and other less conductive materials replace aluminum
in some windows.
Several factors measure the energy conservation performance of windows.
The U-factor, which measures the ease with which heat passes through the
window, is sometimes calculated for the glass area only. That is not very
useful; you should get information on the U-factor for the entire window
You want windows with a low U-factor. A single pane of glass in an aluminum
frame might have a U-factor of about 1.3; some high-tech windows have U-factors
as low as 0.1.
When the outside temperature is cold, heat passes out of your home through
closed windows in various ways, all of which contribute to the U-factor.
For example, with a double-pane window heat might be absorbed and conducted
through the inner glass, absorbed by the gas that fills the space between
the panes, circulated to the outer pane by movement of the gas, absorbed
and conducted through the outer pane, and absorbed and carried away by
the air that moves along the outside of the window. Simultaneously, heat
might be absorbed by the glass and radiated to the outside. Heat might
also be absorbed by the inner glass pane, conducted to the outer pane by
the spacing material that separates the two panes around the edges, and
then radiated to the outside by the outer pane. In addition, heat might
be absorbed by the window frame and conducted directly through it to the
outside, where it radiates away or is absorbed by the outside air and moved
away by convection. The U-factor measures the ease with which all these
and other heat-transfer processes occur.
The Solar Heat Gain Coefficient (SHGC) expresses the fraction of the suns
radiation that is admitted through a window, taking into account both radiation
directly transmitted and radiation absorbed by the glass or frame and then
re-radiated inward. A high SHGC number is desirable in cold weather for
windows that receive a lot of direct sun exposure. The heat from solar
radiation a home takes in through a south-facing window may be great enough
to more than offset heat loss through the windowmaking the window better
than a well-insulated wall from an energy conservation standpoint. On the
other hand, a high SHGC number in windows that receive a lot of direct
sun exposure is undesirable in hot weather; the heat from the solar radiation
raises indoor temperatures, forcing air-conditioning systems to work harder.
The ideal solution is to have a high SHGC on south-facing windows, which
get direct exposure to the sun when the sun is low in the sky in the winter,
and then protect these windows in the summer with a roof overhang that
obstructs sunlight when the sun is high in the sky or with fully leafed-out
In general, as U-factor goes down (when more effective low-E coatings are
added to the glass), so does the SHGC measurement. For a south-facing window
you may decide to sacrifice some ability to prevent heat loss in favor
of a window with high solar heat gain potential. A window with a single
clear pane of glass with no special low-E coating, might have an SHGC rating
of about 0.70; a double-glazed window with low-E coating on both panes
might have an SHGC of about 0.35, meaning it transmits about half as much
solar heat as the single clear pane.
Air leakage, which is reported in cubic feet per minute per square foot
of window (cfm/sq ft), is a measure of the movement of air (convection)
between the inside and outside of a building through cracks in and around
the window frame. Look for windows that have an air-leakage rating of 0.3
The performance of windows on the U-factor and SHGC measures should appear
on a label developed by the National Fenestration Rating Council (NFRC);
a sample label appears in Figure 2. Dont buy a window that lacks this
label. Window manufacturers arent required to test their windows for,
or display on the label, scores on air leakage. Testing and reporting on
this measure is voluntary.
Figure 2Sample Label
Computer programs can help you estimate the energy cost consequences of
different ratings on these performance measures. Some stores will have
one of these programs to help you estimate the differences in energy costs
that will result from selecting windows with different ratingsand also
from adding new windows. You can also download for free a program called
RESFEN from the Lawrence Berkeley National Laboratory website at http://windows.lbl.gov.
Figure 3 illustrates the energy-savings payback you might expect from installing
better windows, which wont offset the cost of the windows at todays energy
prices. Some features produce more energy savings than others, with the
biggest savings generated by going from single- to double-pane glass.
Figure 3The Energy-Savings Payback from Better Windows
When deciding whether to invest in new windows, in addition to thinking
about energy savings consider
How much you value the increased comfort and improved appearance the windows
How much the window improvements are likely to increase your homes resale
How many years you expect to live in your house
How much you could make (after taxes) if you instead put the money that
windows would cost into a secure investment (such as a long-term bank CD)
In terms of windows with additional energy-saving elements, consider not
only the extra costs but also other issues. For example, the extra energy
savings yielded by triple glass compared to double glass might require
you to accept lower light transmittance, greater visual distortion, heavier
and harder-to-move sashes, increased risk of breakdown of seals and the
resulting condensation between panes (because there are two sets of seals
rather than one), and less attractive grids (because grids placed between
panes must generally fit into a smaller space in the triple-glazed windows).
For more information on window-related energy savings and many other aspects
of window purchases, check the Efficient Windows Collaborative website
You wouldnt have much interest in windows you couldnt see through and
that didnt admit light into your home. But not all windows are equal in
this regard. Visible transmittance (VT), a measure of the amount of visible
light that passes through a window, is affected by the windows glazing
material (glass or plastic), number of layers of panes, and any coatings
applied to the panes. VT ranges from more than 90 percent for clear glass
to less than 10 percent for windows with highly reflective coatings on
tinted glass. NFRC labels report windows VT ratings. You may have to sacrifice
some visible light that would come through a window to achieve an acceptable
level of energy efficiency. This means that what you see outdoors will
not look as bright as it otherwise would. The diminished brightness may
not bother youmight even please youon sunny days, but could be undesirable
Depending on construction, windows can last for decadesor rot and fail
within a few years. Guarantees for the better-sealed window units run for
20 years or more and dont prorate reductions in the covered value as time
You will have to judge for yourself the claims salespersons make about
durabilityno independent testing data on future durability of currently
manufactured windows exists. By talking to various installers, you can
get opinions on durability from companies that sell multiple brands, but
this will provide a rough gauge at most.
Major causes of window failure are weak corner joints in vinyl and wood-frame
windows, and moisture (especially from condensation in wood windows). Ask
for information relating to these hazards. In general, vinyl sashes that
are welded rather than screwed together are stronger. To avoid moisture
accumulation in wood window frames and sashes, buy windows with drainage
holes and spaces for air circulation.
With vinyl windows there is no required maintenance. Similarly, aluminum-covered
areas of wooden windows require no maintenance. Exposed wood surfaces require
painting, but the better manufacturers apply a thorough undercoating in
Just as you need to be careful about selecting the right windows, you also
need to be careful selecting an installer. Weve received a disturbing
number of complaints from consumers regarding window installation work.
Even more alarming is that a large percentage of the complaints were about
incredibly sloppy work.
The ratings of local window installers on our Ratings Tables can help
you avoid many of these problems. We surveyed area consumers (primarily
CHECKBOOK and Consumer Reports subscribers) for their ratings of window
installation outfits they had used. Our Ratings Tables show the results
of our survey for the companies that received 10 or more ratings. The table
reports the percent of each companys surveyed customers who rated it superior
(as opposed to inferior or adequate) for our survey questions doing
work properly, starting and completing work promptly, letting you know
cost early, advice on service options and costs, and overall performance.
Our Ratings Tables also report the percent of surveyed customers who
rated each company adequate or superior (as opposed to inferior)
for overall performance. (For more information on our survey and other
research methods, click here.)
In addition to ratings from customers, for firms that were evaluated in
our last full, published article, our Ratings Tables show counts of
complaints we gathered from the Consumer Protection Division of the Washington
Office of the Attorney General for a recent two-year period, and complaint
rates relative to the volume of work companies do. For more information
on reported complaint counts and rates, click here.
Cost can vary substantially depending on which windows you select and who
Table 1 indicates the price variation between installation companies when
we gave them exactly the same job specifications and let them decide which
brand of windows to use. You can see that the highest priced companys
quote was often twice as high as the lowest quote.
You cant get the same brands of windows from all companies, but even among
companies offering the same brand, company-to-company differences of $50
to $100 per window are common.
Table 1 shows how surveyed companies compared on price when our shoppers
got quotes for specified jobs. Our shoppers called the companies that were
evaluated in our last full, published article and, without revealing their
affiliation with CHECKBOOK, requested prices for three different jobs.
The price comparison scores shown on our Ratings Tables (further described
here) show how each companys
prices compared to the average price for all companies that quoted on the
same jobs. We adjusted the price comparison scores so that the average
for all the companies is $100. If a companys score is $110, for example,
this means that the companys prices were, on average, 10 percent higher
than the average prices we found for the same jobs.
Table 1Price Variation for the Same Specifications
|Five double-hung replacement windows, 34 inches by 63.5 inches, insulated vinyl, fully fusion welded, double glazing, low-E coating, argon or krypton between panes||$1,750||$2,945||$5,150|
|Eight double-hung replacement windows, 36 inches by 48 inches, insulated vinyl, cheapest assembly option, double glazing, cheapest air or gas fill,
|Six double-hung replacement windows, 36 inches by 72 inches, insulated vinyl, fully fusion welded, double glazing, grids of six panes over six panes
for each window, argon fill, low-E coating||$2,100||$4,301||$8,256|
To get a good price we recommend the following steps
Have several installers come to your home, measure your windows, recommend
a replacement method, recommend a brand and model of window, explain the
reasons for their recommendations, and quote prices.
Discuss these recommendations and ask about lower priced alternatives.
If substantially lower prices would be available for less energy-efficient
windows, ask the companies to estimate the actual energy savings the more
expensive windows will produce. If you have no confidence in the scientific
basis for these estimates, download the Lawrence Berkeley National Laboratory
computer program mentioned above and ask for the National Fenestration
Rating Council rating information for the recommended windows so you can
make your own calculations.
Based on the information collected, decide on your final specifications.
Call the companies that already provided estimates and others to get their
prices for these final specifications. Get a final quote from each company
If you are not confident that the quality of the windows themselves is
comparable from company to company when the companies simply quote on specifications,
have the companies quote on a specific brand and model; several companies
are likely to quote on some of the same brands and models.
If you are remodeling and will be putting windows into roughed-in openings,
consider having the contractor doing the other construction work purchase
and install your windows, rather than dealing with a specialized window
installation outfit. Window installation companies are primarily geared
to installing replacement frames rather than new construction jobs.
Check whether government programs or your utility company offers rebates
or low-interest loans for installing energy-efficient windows. An excellent
resource for incentives for all types of energy-efficiency solutions is
www.dsireusa.org, which maintains an up-to-date database of whats
currently available nationwide.
Whichever window company you choose, make sure you have a tight contract.
Details on the Product and the Installation Procedure
What brand and model of window will be used in each opening? Will flashing
be installed? Will it be painted? Will it match the existing trim? Will
the windows meet Energy Star standards and qualify for the federal tax
credit? Will there be an Energy Star label? Exactly how large will each
opening be when prepared for the window, and how large will each window
bethe glass and the opening? This last point is especially important because
vagueness here means you risk having the company supply windows that are
smaller than they should beconvenient for the company because the windows
can easily be worked into place, but undesirable for you because the result
might be packing out of the space before the new window is installed, less
glass than you expected, and an ugly window.
Contractors should carry two types of insurancegeneral liability and workers
compensationand be willing to show you a certificate that confirms the
coverage. The first type insures against damages when a contractor drops
a window; the second covers injuries to the worker it fell on. Homeowners
policies may cover those incidents, too, but the contractors insurance
should kick in first.
You should be able to pay all, or at least half, the contract price after
the work is complete. The more you leave to the end, the more leverage
youll have to make sure the work is done satisfactorily.
The starting date should be firm so you can prepare for the job. A completion
date is less important because most projects can be started within a week
and take less than a day to complete. But its wise to add a phrase that
the work will be continuous, and a note about who will be onsite supervising
To provide some recourse if the job proves to be obviously substandard,
contracts should contain a phrase to the effect that the contractor will
complete the project in a workmanlike and professional manner.
Because window replacement projects generate a lot of construction debris,
carting it away (and paying disposal fees) should be part of the contract.