What is a Low-E Window?
E stands for Emmisivty and it plays a vital role in keeping your inside of the house more energy efficient. Low-E, or low-emissivity, glass was developed by the Engineers to minimize the amount of infrared and ultraviolet light that comes through your glass, without minimizing the amount of light that enters your home. Low-E glass windows have a very thin coating that is transparent and it also reflects heat. This coating is thinner than human hair! This Low-E coatings keep the temperature in your home consistent by reflecting the interior temperatures back inside.
According to the Glass Education Center, there are four factors used to measure the effectiveness of glass with Low-E coatings:
1-Solar Heat Gain Coefficient (SHGC): This is the fraction of incident solar radiation that is admitted through the window. This can be either directly transmitted and absorbed or radiated inward.
2- U-Value: This is the rating that is given to a window based on how much resistance to heat flow it allows.
3- Visible Light Transmittance (VLT): The measure of how much visible light passes through the glass.
4- Light to Solar Gain: The ratio between the window’s visible light transmittance and its Solar Gain Coefficient rating.
Light coming from Sun consists of three types of lights , Ultraviolet (UV) light, visible light and infrared (IR) light all occupy different parts of the solar spectrum – the differences between the three are determined by their wavelengths.Low-E coatings have been developed to minimize the amount of ultraviolet and infrared light that can pass through glass without compromising the amount of visible light that is transmitted hence the rise of the temperature in the space is minimized effectively without compromising natural lighting intensity. In simple words low E keeps the good part and remove the bad part.
FIVE BENEFITS OF ENERGY EFFICIENT WINDOWS
1-Reducing your Carbon foot print-Save 1,000 - 6,200 lbs. of CO2/year when replacing single-pane windows, which is equivalent to 50 - 300 gallons of gasoline.
2-Lowering Energy Costs Helps keep your home warmer in the winter and cooler in the summer with Low-E double-pane insulating glass with argon.
3-Increasing your home comfort by eliminating draft , reduce condensation and noise pollution
4-Boosting your home value- Replacing your windows with new energyefficient windows can return more than 72% of the project cost upon resale.
5-Low-E insulating glass helps protect furniture, curtains and carpeting from fading in the sun, and can block 69% - 95% of harmful UV rays that cause interior fading
5 factors IMPACTING YOUR WINDOW’S ENERGY EFFICIENCY
1-Glass Multiple panes of glass offer more protection between the weather and your home. Look for double- or triple-pane glass.
2-Installation Even the best windows and doors are only as good as their installation. Proper installation is critical to maximize your energy efficiency.
3-Placement You can increase your window’s energy efficiency by selecting specific Low-E insulating glass options for different areas of your home based on sun exposure and accessibility.
4-Region Your home’s geographic location and climate help determine what kind of windows you choose and what glass options can enhance your energy efficiency
5-Frame construction Your choice of frame material influences your window’s overall energy efficiency — frame selections include wood, fiberglass, vinyl or aluminum
GET A FREE QUOTE FROM WINDOW REPLACEMENT CONTRACTOR IN YOUR AREA
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1-Reputation
2- Glass Options
3- Window Frame Options
4-Window Types
5- Installation Details
6-Warranty and Service
7- Price.
The most important piece of advice to consumers is to
compare windows by comparing the NFRC labels!!!
The National Fenestration Rating Council (NFRC) energy
performance label can help you determine how well a product
will perform the functions of helping to cool your building in the
summer, warm your building in the winter, keep out the wind,
and resist condensation. By using the information contained on
the label, builders and consumers can reliably compare one
product with another, and make informed decisions about the
windows, doors, and skylights they buy.
Energy codes in most states, require
NFRC certification of windows
U-Factor
U-factor measures how well a product prevents heat from
escaping. The rate of heat loss is indicated in terms of the U-
factor (U-value) of a window assembly. U-factor ratings generally
fall between 1.20 and .20. The insulating value is indicated by
the R-value which is the inverse of the U-value. The lower the Uvalue, the greater a window’s resistance to heat flow and the
better its insulating value.
Solar Heat Gain Coefficient
Solar Heat Gain Coefficient (SHGC) measures how well a
product blocks heat caused by sunlight. The SHGC is the
fraction of incident solar radiation admitted through a window
and subsequently released inward. SHGC is expressed as a
number between 0 and 1. The lower a window’s solar heat gain
coefficient, the less solar heat it transmits.
Visible Transmittance
Visible Transmittance (VT) measures how much light comes
through a product. The visible transmittance is an optical
properly that indicates the amount of visible light transmitted.
VT is expressed as a number between 0 and 1. The higher the
VT, the more light is transmitted.
Air Leakage
Air Leakage (AL) measures how much air will enter a room
through the product. AL rates typically fall in a range between
0.06 and 0.3. The lower the AL, the better a product is at
keeping air as well as dust out. AL is an optional rating, so
many manufacturers choose not to display it on label. The label
itself only displays one decimal point so a window that has a
0.06 rating will display as 0.0. Glass-Rites Energy Quest
windows have a 0.06 to >0.01 AL rating depending on the
operation of the window
One of the important decisions you’ll be making is
determining the best kind of window frame for your home.
Each frame type has its own advantages and disadvantages. There are three types of window frames available in the market.
1-Vinyl Frames
Vinyl frames are
more efficient than thermally broken aluminum,
and in many cases, even more efficient than wood or
fiberglass.Here are some advantages:
1-Because vinyl is the same color throughout, scratches
are virtually unnoticeable.
2-Good quality vinyl windows are welded together not
held together with screws.
3-Because screws tend to pull out of vinyl, good quality
vinyl windows will have metal reinforcements in the
parts of the windows where hardware (such as a lock)
is screwed in.
4-Vinyl windows are generally available in two colors , white or beige.
2-Aluminum Frames
Good quality aluminum windows have a thermal barrier that
prevents the frame from conducting heat or cold. However, even
with the thermal barrier, these windows are not as efficient as a
vinyl or wood window.
3-Wood Frames
Good quality wood windows will use treated wood that
is resistant to water saturation, insects, and deterioration.
Interior finishes on wood windows can be time consuming
and expensive to apply.
The window should be certified by the National
Fenestration Rating Council.
2) Airspace between the panes of glass of at least ½ inch.
3) Metal or vinyl clad exterior to reduce maintenance and
eliminate painting.
4) High quality hardware and locks.
5) Uses good quality wood that won’t warp or twist.
6) Good quality roller systems on sliding windows.
7) Double locks on all windows over 30 inches.
There are as many different configurations of windows as
you can imagine. Here we’ll go over the most common
1) Fixed; non-operable picture window
2) Single-Hung; a window where the
bottom sash slides up.
3) Double-Hung; a window where the
bottom sash slides up and the top
sash slides down.
4) Horizontal slider; a window that
slides open to the side.
5) Picture slider; a window that has
three sections: a fixed center panel,
and two end vents that slide open to
the middle.
6) Casement; a window that cranks
open and is hinged on the side.
7) Awning; a window that cranks open and is hinged on top.
Unless you really know a lot about a
product or service, it’s hard to determine exactly when you are
getting a fair price.
A price that’s too cheap means corners are going to be cut
and you will pay the price later. A price that’s too high means
you’re being taken for a ride. What you really want is a quality
product and a fair price!
Here are some things to look for:
1- Does the company have “repeat” business? In other
words, do customers buy from them time after time?2- Has the company been in business for at least ten years?
3-Do their consultants help you make a good decision or do
you feel you’re being high-pressured into buying?
