Energy Savings and Efficiency Ratings
"The new windows look great and
I can already feel the difference"
When you get your quote from us
by email you'll see that it includes one of several energy efficient
packages. It's easiest to explain the options after you have
the quote and price list so you can see what is involved. If you don't have your
quote and price list yet you can
request one here.
The price list we'll send along with your quote will
also list some of the other common choices. There are actually over 100
options, but we typically don't send all of that info at once as it can get a
little heavy. We're trying to make this simple, not more complicated.
We know some people want all the details and some
folks just want us to make a recommendation or two. No matter which camp
you fall into we'll be happy to help out. If you have more questions and
can't find the answers here just let us know.
Summer Solar Heat
In the summer, heat from the sun passes through your windows causing your
air conditioner to run more often and your bills to increase. Solar
heat gain coefficient (or SHGC) is a number that represents the fraction of
solar heat transmitted through a window. The lower a window's solar
heat gain coefficient the less solar heat it transmits. Climates that
rely heavily on air conditioning will benefit from a product that has a
It's important to remember that we also like the
heat from the sun in the winter. Here in the Knoxville area we have
both hot summers and chilly winters. We
need windows that will work great all year.
As shown here, our windows with our Energy Star
package a low emissivity (or low-e) glass option and argon gas fill will
outperform a standard clear unit by as much as 49% in the summer months.
If your quote includes the Energy Star package the SHGC rating for a double hung window with no grids will be 0.30.
Energy Star requires 0.40 or lower so we're already ahead of the game. Remember, lower is better, so this option will keep most of the heat from
the sun out in the summer and still allow some heat to pass through in the
If you wanted an improvement in terms of solar
heat gain you could pick the Radiant Barrier package. That will lower
the SHGC to 0.21, a substantial improvement for only a few bucks. Adding grids
to the Radiant Barrier glass will lower it to 0.19. If the sun beats
down on one side of the house or if you just want extra protection from the
sun this can be a great option.
We have other packages with SHGC ratings as low as
0.17 so let us know if you're looking for anything else.
Remember, if you're not into all of this
ratings info feel free to skip it and just ask us if you have any questions.
We love making things easy.
Improving A Window's Winter Performance
In the winter a more efficient window will not let the heat generated by the
furnace escape. The U-Factor (or U value) represents the rate of heat
flow through a window. The lower a U-Factor the greater the window's
resistance to heat flow, and the better its insulating value. When the
space between the panes of glass is filled with an inert gas (typically
argon or krypton) the U-Factor is dramatically reduced.
As shown here, our windows with our Energy Star
package including a low emissivity (or low-e) glass option and
argon gas fill will out perform a standard clear unit by as much as 51% in
the winter months.
To meet the Energy Star standards in terms of
U-Factor in Knoxville we'll need to have a U-Factor of 0.30 or lower. A
double hung with the Energy Star package will have a U-Factor of 0.29 so
we'll be good there.
If you wanted a wintertime upgrade you could pick
one of several upgraded spacer options or the triple pane package. The
spacer is the part that goes between the 2 (or 3) pieces of glass to make
the unit more efficient. If you wanted to pick the SustainaView
package on the price list you'd get an improvement in the U-Factor and the
condensation resistance rating would also go up substantially.
The triple pane package includes an extra piece of
glass and an extra sealed chamber filled with argon gas. It's an
effective upgrade at a very reasonable cost.
We even have packages with U-Factors as low as
0.18 so it really just depends on what you want for your home.
All of this translates into substantial savings in utility bills and a
significant reduction in carbon emissions.
Remember, if you think this all sounds neat, but
you have other things to worry about that's just fine with us. If you
like learning about ratings and options we have even more info here.
A Window's Air Infiltration
The next factor to consider is the air
infiltration rating. If you've ever felt drafty windows you know that
air infiltration can make a HUGE difference in the comfort of your home.
Many older window models out there will have air infiltration rates as high
as 0.15 or even 0.30. The fact is those were decent numbers 10 or 15
years ago, but things are much better now.
Here you can see how much air can get into your
home when you have windows with a higher air infiltration rate. There
are still companies out there offering windows like this.
The double hung windows we typically recommend
will have air infiltration rates of 0.04. The casement windows we
offer will have ratings of 0.01. Some other styles will be a little
different so feel free to ask us if you have any questions. Every
product we offer comes with a very tight seal which means your home will be
more comfortable than ever before.
If you haven't received your free quote by email
yet just swing over to this page to get that.
Once you have your quote the rest of this will make a little more sense.
Many of the other large window companies do not have
windows with the same options. All vinyl replacement windows are not the