If your windows are ancient and aren’t doing a passable job of keeping heat inside your home in winter (or keeping it out in warm weather), maybe it is time to consider having new, energy saving windows put in. But new windows, especially good quality energy efficient ones, can be prohibitively expensive. This means that it can take a long time for them to pay for themselves in energy savings. For the amount of cash you would pay to replace the windows in a single big room, you can achieve almost the same energy savings with some basic weather stripping and by using energy efficient window coverings to eliminate heat transfer between your home and the out of doors.

Let’s first review how windows keep the cold out in winter, and the hot out in summer. Windows reduce heat transfer in three ways: convection, conduction, and radiation.

Windows stop or reduce convection airflow between a room and the exterior, blocking heat from passing through the window along with the airflow. A leaky window, or one with cracks in the glass or broken putty, allows air through these openings, so heat gets out in winter, and heat sneaks in during hot weather.

Even the thinnest sheet of glass has some insulating properties, but if the glass is double-glazed and the space between the panes is an inert gas such as argon, the panes provide extra insulating value, which reduces heat transfer through conduction. Conduction is the type of heat transfer that causes the metal handle of a pot to heat up when you boil water in the pot; so you can imagine that a metal window frame, if not properly built, can conduct a lot of heat. Although you can’t readily add extra glass panes to a window, there are other techniques to create extra still air spaces between the window glass and the room, which will increase insulation and reduce conduction transfers.

Radiation, the third type of heat transfer, usually happens when sunlight in the infrared spectrum travels through windows, heating the air inside, or when infrared radiation inside the room radiates out through the glass. Home energy auditors can actually take infrared photos of a house to illustrate where heat losses are most significant, and windows are often among the greatest sources of heat escaping from houses in winter.

How does knowing about heat transfer through convection, conduction, and radiation help you cut energy losses through your windows?

The first issue to tackle is convection. If your windows have broken panes, get them repaired. If you still have the old wood-framed windows with putty holding the glass in, check the pane for any peeling or missing putty. It’s fairly straightforward to pry cracked putty out with a putty knife and put a fresh layer on in its place. If the wood of the window itself is rotten, or if the glass is hard to get out for replacing, you may not be able to avoid getting new windows, but if you can cut the minor air leaks, you’ll have accomplished a lot towards minimizing energy losses and should feel some relief in your heating and cooling bills.

You might be surprised to know how much heat can travel out of a house in winter through the wood trim around a window. Just wait for a really cold day, put all the exhaust fans on in your house( kitchen range vent, bathroom exhaust fans, etc.), and run your fingers along the edges of window and exterior door trim on the inside of rooms. Anywhere you feel cold air coming in, you have a draft that should be sealed. It probably doesn’t hurt to run a thin bead of clear or white caulking around window and door frames to cut this convection heat transfer.

The final thing to try to minimize convection heat losses is to use tape-on or Zip-Loc type window kits to close off any windows that are very drafty, or windows that really should be replaced but that can’t be replaced because of your budget (or because you are renting the place). These window insulation kits are a good way to rapidly cut your heating losses in winter: the kits normally come with several sheets of 3 by 5 foot clear plastic, and a roll of double sided tape. (If you have many windows to cover you should purchase a 48″ roll of the plastic and get the tape separately as you’ll pay far less than buy buying several kits.) You measure and cut plastic rectangles slightly bigger than the window, run the tape around the window frame, remove the protective tape from the double sided tape, and then place the cut plastic over the window, sealing along the tape line. Blow dry the window plastic for five minutes, and it shrinks to form a tight, flat extra pane of ‘glass’ that is practically unnoticeable. This plastic can hold its flat shape for weeks, although you may find it needs an occasional short blow dryer blast to pull up the odd wrinkle in the plastic.

The next problem you’ll want to tackle is conduction – heat being drawn through the solid materials of the window. In terms of energy saving window coverings, your goal here isn’t really to stop this conduction – you can’t usually change the materials the window is made of – but to add barrier layers between the window and the room to slow that conduction down. The plastic window insulation kits stop convection heat loss by eliminating drafts into the room, but they also eliminate conduction, by providing a layer of still air between the room and the window. A curtain can accomplish a similar task: when closed, the curtain traps a small amount of air between the curtain and the window, so that on a cold day the air behind the curtain naturally gets cold but the room itself stays cozy.

When you put curtains on a window to reduce conduction heat transfer, you need to consider convection currents within the living area. Hot air rises, and cold air falls, so if you install curtains you should ensure that the air currents are blocked, preferably at both the top and bottom of the curtain or blind. Otherwise, in cold weather, the cold window will cool the air between the window and the window covering, and that colder air will fall down onto the floor, drawing warm air from above the window covering down in front of the window in a continuous cycle. In summer, the flow runs backwards, with the air between the curtain and the window warming from sunlight, flowing up out the top opening, and drawing cool room air up towards the glass where it gets heated.

You can stop these air flows by having the window covering flush with the wall at the top and bottom, or by having the bottom touch the floor and by closing in the curtain rod area at the top.

If you have cloth blinds that cover the window frame, you can use Velcro tabs along the sides of the blinds that you then press into Velcro tape along the window frame; this completely seals the air space between the window and the blind, providing an excellent insulation barrier. Cloth blinds as well as curtains can use a similar technique but with magnetic tape in the fabric, and metal along the framing, so that the window covering sticks to the walls on either side of and below the opening.

Another method you can try to add an insulation barrier to conduction through the window is to buy cellular blinds, which are made in a honeycomb or cellular cross section, or other blinds that incorporate a hollow space within the blind (for example, air-foil shaped blinds). Cellular blinds when fully retracted take up almost no space and the cells are empty; when extended, they can add insulating value from R-2 (for single-cell blinds) to R-5 (for double-cell).

Window blinds can help address the third type of heat transfer, radiation, by preventing heat from radiating across the window pane (into the house from sunshine in summer, and towards the outside from the radiant heat inside in winter). The most effective blinds use light, reflective colors on the outside, so that sunlight is more or less completely reflected away from the room. Good blinds can reflect enough solar energy away from the window to reduce heat transfer by up to 45%, but they do very little to the R-value of the window, so have little effect in winter.

Roller shades, which have a spring mechanism and can be pulled up or down (we used to call these blinds when I was young) are a great barrier against radiation, and also provide good insulation to reduce convection air flows around the window that lead to conduction losses through the pane or frame. Roller shades, because they are placed so close to the glass, are better at reducing convection currents, especially if their sides and bottom are attached to the window frame (for example, by using side tracks). Unsecured shades can cut heat exchange by as much as 28%, while secured-edge shades cut it up to 45%. Shades that can be reversed, with one side dark and the other light, are ideal, because the light side can reflect the heat where you want it (outside in summer, inside during winter).

Awnings and overhangs are a good way to cut direct light from entering a room and heating it up in summer. Because the solar angle is lower in the winter, these window coverings only block the sunlight you don’t want, letting the lower-angled winter sun warm your home.

Storm windows – which are found on many older homes – can be up to 50% more energy efficient than single-pane windows, provided the storms are sealed against drafts. So if you have old wood-framed storms sitting around in your basement or garage, you should use them each fall and take them down once winter has passed. If you have aluminum framed storms you can typically leave them up all year long; just don’t forget to close the glass during the winter.

Windows make up such a small percentage of the surface area of a home, yet they are among the biggest potential sources of energy waste in a house being heated or air conditioned. So it’s important to do anything you can to limit heat exchange through convection, conduction, and radiation. Just remember to set aside a portion of the money you save on lowered utility bills, so you can replace any worn-out, leaky windows with new, energy efficient ones when the time comes.

Window Terminology
Keeper:

The hook-shaped piece of hardware that it is mounted on the inside sash stile of a casement window in which the sash lock engages.
Knocked-down:

Not assembled. Parts for a window frame pre-manu?factured for assembly later on a job site.
Label:

A projecting molding by the sides and over the top of an opening.
Label stop:

Ornamental projection on each end of a label, sill, or sill course. Often takes the shape of a gargoyle or other decorative carving.
Labeled window:

Windows bearing fire-rating labels of Underwriters? Laboratories (UL).
Laminated glass:

Similar to the construction of car windshields, this technique sandwiches a piece of transparent film or plastic between two panes of glass. Typically used for safety reasons because of its resistance to shattering. Also reduce noise transmission to the interior.
Lancet window:

Tall, narrow window with a pointed-arch top, often with leaded diamond shaped lights; characteristic of Gothic architecture.
Lattice window (also lozenge):

Window with glazing bars set diagonally.
Lead light (also lead glazing; stained glass): Window with small panes of glass set in grooved rods of cast lead or came. The glass may be clear, colored, or stained.
Lift:

A handle or grip installed on the bottom sash rail of a double-hung window to assist in the raising or lowering of the sash.
Light (also lite):

A window; a pane of glass within a window. Double-hung windows are designated by the number of lights in the upper and lower sash, as in 6-over-6.
Lintel:

Horizontal member (wood, steel, or stone) over a window opening to support the weight of the wall above. A header.
Loop window (also Balistraria):

A long and narrow vertical opening, usually widening inward, cut in a medieval wall, parapet, or fortification for use by archers. Modifications appear in Roman?esque Revival architecture.
Low-E Glass:

A term used to refer to glass which has low-emissiv?ity due to a film or metallic coating on the surface of the glass. Usually constructed of dual, sealed panes of coated glass filled with pure inert gas to block ultraviolet heat, for cooling purposes, while reflecting room heat back into the room for heating purposes.
LVL:

Laminated Veneer Lumber ? A combination of many pieces of veneered lumber glued together to give added structural capabilities. Often used in window or door frames.
Masonry Opening:

The space in a masonry wall left open for the window or door.
Meeting rail (also lock rail):

One of the two horizontal members of a double-hung sash which come together. A check rail.
Meeting stile:

The vertical member in a pair of stiles, as in abutting casement windows.
Mold stone (also jamb stone):

A stone that serves as a window jamb.
Mortise:

A slot or rectangular cavity cut into a piece of wood to receive another part.
Mortise and tenon:

A strong wood joint made by fitting together a mortise in one board and a matching projecting member (tenon) in the other.
Mullion:

A vertical member (usually wood or metal) to structurally join two window or door units.
Muntin:

Vertical or horizontal bars used to separate glass in a sash into multiple lights. Often called a grille.
Nailing Fin:

A vinyl or aluminum extension attached to the frame of a window or door which creates a positive seal be?tween the window and the framed wall. Acts as an additional barrier against air and water leakage. Screws or nails are fastened through the fin to hold the unit in the opening.
NFRC label:

NFRC stands for the National Fenestration Rat?ings Council. This non-profit trade group sets energy standards for windows – the NFRC label shows everything you need to know about the window you?re

considering.
North-light roof:

Sawtooth roof with north-facing clerestory windows.
Ogee curve (also ogee molding):

Reverse flex curve commonly found in window moldings and trim pieces.
Operable window:

Window which can be opened for ventilation.
Operator:

A metal arm and gear attached to a window which al?lows for easy operation.
Palladian window:

A large, arch-top window flanked by smaller windows on each side.
Panel:

Usually refers to the glazed panel or panels in a door frame.
Parting slip:

A thin wood strip separating the sash weights in the weight box of each jamb of old double-hung windows.
Parting stop:

A vertical strip on each jamb that separates the sash of a double-hung window.
Picture window:

Large fixed windows.
Pivot window units:

Window units in which the sash hardware is located near the midpoint of the stile or rail to permit sash rotation.
Prime sash:

Balanced or moving sash of a window unit.
Prime window:

Window with single or multiple glazing. A storm sash may be installed.
Projected window:

Awning type window that swings either inwards or outwards at the top or the bottom. The window usually may be cleaned from the inside.
Quarrel:

A diamond- or square-shaped glass piece set diagonally. A medieval term for small panes of glass set diagonally in Gothic windows.
Queen Anne window:

A window with small glass windows or lights arranged in various forms, usually only on the upper sash. Appeared l870s.
Rail:

Horizontal member of a window sash or door panel.
Reglet:

Plastic or wood molding put in a concrete or masonry opening for a uniform groove for a spline-type gasket to hold window glass.
Reversible extension blind stop:

An extension blind stop that is rabbetted to receive l/2 or 25/32-in. sheathing.
Rough Opening:

A framed opening in which the unit will be installed.
R-Value:

The measurement of resistance to heat transfer in a material. The higher the R-Value, the greater the insulation value.
Sash:

Framework of stiles and rails in which the glass of a window or door is set.
Saddle bar:

Light steel bar placed horizontally across a window to stiffen leaded glazing.
Saddle bead:

Glazing bead for securing two panes.
Sash lock:

A lock applied to the window to pull the sash tightly against the frame (casement) or to pull the check rails together (double-hung) in order to seal the sash from weather and for security.
Single-hung window:

Window similar to double-hung window, except the top sash is stationary.
Seat board:

A flat board cut to fit the contour of a bow or bay window and installed between the sill and the wall surface, providing a seat or a shelf space for plants, etc.
Shading coefficient:

Decimal value which is the solar gain of a window, divided by the solar gain for a clear single-glass

window of the same size. The shading coefficient of clear, double-glazing is about 0.85 to 0.9.
Side light: A fixed, often narrow glass window next to a door opening or window opening.
Sill: Horizontal member at the bottom of the window frame.
Simulated divided lights: A method in constructing windows or doors in which muntins are fixed to the inside and outside of the insulated glass panel to simulate the look of a true divided light. Modern Divided Light? in EAGLE terminology.
Single glazing: Use of single panes of glass in a window sash or door panel. Not as efficient as double glazing.
Single-hung window: Window similar to double-hung window, except the top sash is stationary.
Slide-by window: Windows which slide horizontally.
Smartwindow: Generic term that refers to windows with switchable coatings to control solar gain.
Solid frame: Window frame made from a single piece of lumber.
Sound-insulating glass (also sound-resistive glass): Double glass fixed on resilient mountings and separated so as to reduce sound transmission.
Splayed window: Window unit set at an angle in a wall.
Stacked windows: Combined grouping of awning, casement, or non-operative windows to form a large glazed unit.
Stile: Vertical member of a window sash or door panel.
Stile Lug or Horn: One of two extensions of the sash stiles to support the upper sash of a double-hung window.
Storm clip: Device attached to the muntin of a metal sash to stop the pane from moving outwards.
Stool: An interior trim on a window which extends the sill and acts as a narrow shelf. Often seen on double-hung window.
Stop: A wood trim member nailed to a window frame to hold, position or separate window parts.
Tandem lock: A locking system which secures the window at two locking points by the operation of one lever.
Tempered glass: Special heat-treated, high-strength safety glass which shatters into pebble-sized particles and not in slivers.
Tenon: A rectangular projection cut out of a piece of wood for insertion into a mortise.
Thermal break: A thermal insulating barrier between two thermally conductive materials.
Transom joint: Horizontal member separating a door from a window panel above the door, or separating one window above another.
Transom: Small window located above a door or another window.
Top hung-in window: An awning window pivoted at the top and with the bottom swinging-in.
Transom (also transom bar):

Horizontal member separating a door from a window panel above the door, or separating one window above another.
Triple glazing:

Three panes of glass with two air spaces between, com?monly consisting of an insulating glass with a separate storm sash. Also available in an insulating window in a single frame.
Triple window:

Generally refers to any tripartite group of windows with square heads. Found on Colonial Revival houses. Units suggest Palladian windows but are less expensive to construct.
U-Value:

Measurement of heat transfer through a given mate?rial. The lower the U-Value, the better the insulation value.
Venetian window:

Same as Palladian window.
Vertical sliding window:

One or more sash that move in a vertical direction.
View sash:

Picture window with the lights divided by muntins.
Venting unit:

A window or door that operates or opens for ventilation.
Wash cut:

Beveled cut in a stone sill to divert water.
Water drip:

Molding sometimes used on exterior surfaces of an in-swinging casement sash to prevent water from being driven over the sill.
Weather-stripping:

A strip of resilient material applied to the perimeter of the sash and/or frame of a window or door to minimize the potential for water and air infiltration.
Weep cut (also drip cut):

Groove in the underside of a horizontal board or masonry unit which projects beyond the wall service below to prevent water from moving back toward the wall surface.
Yoke:

Head window jamb in a box window frame.
Yorkshire light:

Window with one or more fixed sash and a horizontally moving sash.
Windload:

The force exerted on a surface by moving air.

I already have my computers set up a certain way and don’t want anything to change – as far as the display goes. All my shortcut icons are set up and arranged in a very efficient way for myself so I don’t have to search for certain files/folders. Will upgrading to Windows 7 screw this up?