What is Solar Heat Gain Coefficient (SHGC)?

So you're shopping for new vinyl windows, and you're trying to figure out what all the window ratings mean.  In your research, you come across something called SHGC.  Below is a guide to solar heat gain coefficient, to help you better understand this particular window rating.

So, what is the Solar Heat Gain Coefficient?

Technically speaking the solar heat gain coefficient (SHGC) is the fraction of solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward.  Since it is a percentage of total solar radiation, it is expressed as a number between 0 and 1.

Is the SHGC the same thing as Visual Transmittance (VT)?

Although they may seem to be measuring the same thing, they are not.  Solar radiation comes in a wide spectrum that includes ultraviolet, infrared, and visible light (among others).  These parts are defined by their particular wavelengths.

The solar heat gain coefficient measures the entire spectrum of energy, not just visible light.  Visual transmittance, on the other had, is only a measurement of the visible light that passes through a window.  And visible light only makes up a small fraction of the entire solar energy spectrum.

Does window tinting help with SHGC ratings?

Yes, but not nearly as efficiently as low-E.  Low-E is designed to let in as much visible light as possible, while attempting to reflect as much of the rest of the light spectrum as possible.

Window tinting only aims at lowering the visible light penetration.  So it lets in less visible light, but lets in much more of the solar radiation (from other wavelengths) than low-e.

So what SHGC rating should I look for in a replacement window?

The answer to this question depends on what region you live in.  There are different climate zones defined by Energy Star.  You can click here to find out which zone you live in.


Windows Plus is here to help answer any of your questions.  Visit Windows Plus of Cincinnati or Windows Plus of Dayton to get more information.

Tips for Replacement Window Shopping

I wanted to cover a few key things everyone should be aware of BEFORE they contact their local window company for an estimate.  So I broke down three different things everyone should know when they're window shopping.  Take a look below, and let me know what you think!

1. Learn the Replacement Window Vocabulary.  Study up on the terms you might hear when your friendly window salesman comes to your home.  Do you know the difference between a sill and a sill return?  Or the difference between a hopper and an awning window?  Do you really want a bay window, or are you considering a bow or garden window?  Studying up on key terms will make any window presentation less overwhelming.
2. Learn the Replacement Window Science.  No, I'm not saying you need to become a window expert.  But studying up on structural and energy ratings for windows will really help you make an informed decision when comparing windows.  You can check out the window ratings guide from Windows Plus, which breaks down the most important window ratings, how to read them, and explains exactly what each rating measures.
3. Check out Company Reviews BEFORE you Call!  You should be able to find reviews from any window company you're seriously considering.  There are multiple websites you should check out, so don't look at just one.  Angie's List, BBB, Google reviews, Yelp, etc., should be a great place to start.  Just remember:  if you can't find any reviews about the window company, chances are they haven't been around long enough.  So maybe move on to the next, more reputable company.  A company that has NO reviews may be just as bad (or worse!) than a company with a few BAD reviews.

Preparation is the key here.  Taking a bit of time to learn about windows BEFORE you shop will keep your window shopping from feeling overwhelming.  And an informed shopper is a smart shopper!

For more information, check out Windows Plus of Cincinnati or Windows Plus of Dayton anytime.  We'd be glad to help!

It Ain't Just About the Glass

When most people think about replacing their windows, there's one thing that people tend to focus on most with their new replacement windows:  the glass.  But there's  more to energy ratings than the glass panes (and what's between them)... the rest of the window!

EnergyStar uses the U-Factor as an assessment of energy efficiency of a window.  It's one of the most important ratings of any window.  But they don't use center-of-glass U-factors and R-values.  The reason is that center-of-glass values only measure the efficiency of the glass--not of the entire window as a whole.  A standard U-factor (or R-value) measures the energy efficiency of the entire replacement window.

The frame of the window (and the sashes) can make or break the efficiency of a vinyl window.  And there are ways to make a vinyl window stand out from the competition.  One of the most effective ways is to insulate the dead air space between the vinyl.  Not all window companies offer this, so it's important to make sure you're asking about it when shopping for your windows.

Of course, you can learn more about what makes up an energy efficient window by visiting one of our websites:

Windows Plus of Cincinnati
Windows Plus of Dayton

Thanks for reading!
Mike G.
The Window & Door Guy

ProVia Entry Doors - The Best of the Best

When it comes to residential entry doors, nothing beats ProVia.  ProVia builds doors the professional way.  They've developed a competitive position by catering to customers' desires to have a high degree of customization, together with outstanding quality.

ProVia offers four lines of entry doors:

• Embarq
• Signet
• Heritage
• Legacy

The first three door lines are a fiberglass shelled door.  The last one, the Legacy, is a steel door.  Most of their Signet, Heritage, and Legacy doors are Energy Star certified.  All of their Embarq doors are Energy Star certified.

In addition to a structural and hardware warranty, ProVia also includes a warrant on the finish of their doors.  Finishes on the Heritage and Legacy doors come with an additional 7-year finish warranty.  For the Embarq and Signet lines, a 10-year finish warranty is included.  

There are four pillars that make up ProVia doors:  beauty, security, durability, and energy efficiency.  Together, these four qualities make ProVia the obvious choice for your home.

Of course, if you're in the Cincinnati area, contact me at Windows Plus anytime for more information!

Thanks again,

The Window & Door Guy

Pocket Sill vs. Sloped Sill Windows

No matter what replacement window you purchase for your home, those windows have a few jobs to do.  One of those things all windows must do well is keeping the rain out of your house!  All decent windows succeed in keeping your interior dry, but not all windows do it the same way.

When the rain hits the window, whether it be the glass pane, framing, sash rails, etc., there needs to be a way for the rain to leave it.  Much like gutters are used for removing water from your roof, the sash systems removes the water from your windows.

The pocket sill is one of the most common window systems.  The technology has existed since the beginning of vinyl windows.  The concept of the pocket will works like this:

1. Rain water hits the window and falls to the sill.
2. The water drains into the vinyl chambers (pockets) in the sill.
3. The water drains out of the closed pocket sill via weep holes, typically in the front of the window.

The sloped sill window system predates pocket sills.  If you have wood windows, chances are you have sloped sills.  However, this is NOT a common sill for replacement vinyl windows, because it is more expensive to manufacture.  

Here's how the sloped sill works in a vinyl window:

1. Rain water hits the window and falls to the sill.
2. Water drains out of the weep holes on the bottom of the sloped sill.

As you can see, the sloped sill is a simpler system.

So which is better, the pocket sill or the sloped sill?  Well, there's less things that can go wrong with a sloped sill:

• No standing water
• No clogged weep holes
• No bug infestations

Given the option, go with a sloped sill.  It's a cleaner look too.  Here's a picture of a pocket sill (left) vs. a sloped sill (right):

As I said, if you have an option to pick the sloped sill, you should go with that.  And if you're looking for windows in Cincinnati, make sure to check us out!

Mike

The Window & Door Guy

Low-E and Your Replacement Windows

When you're doing your research on replacement windows, you will come across a whole lot of crazy terminology.  One of those terms is something called "low-e".  Let's take a look at what this means.

Low-e stands for "low emissivity".  Emissivity is a measure of the effectiveness in emitting radiant energy.  You can also think of it as the inverse (i.e. opposite) of reflectivity.  If something has low emissivity, it means it emits more radiant energy.  This would mean that it reflects more radiant heat.

In most modern replacement windows, low-e coatings are applied directly to one (or more) of the panes of glass.  On double and triple pane windows, the coatings are applied to the inner side of the glass.  In the summer, this helps keep the radiant energy outside of your house.  In the winter, this helps keep the radiant energy inside your home.

 Most new windows come with "soft coat" low-e.  This is a newer technology compared to the older "hard coat" low-e coatings.  On double pane windows, there is usually just one coat of low-e in the window.  On triple pane windows, there may be one or two coats, depending on the quality of the window.

Most people in the US live in an area where they need low-e glass.  So when doing your research, make sure to consider this vital criteria.  And as always, if you're considering replacement windows in Cincinnati, make sure to give us a call directly.  We'd be glad to answer any questions.

All the best!
Mike G.
The Window & Door Guy

How to Understand Window Ratings

So you're shopping for replacement windows, and you keep hearing all different types of numbers and figures being thrown around about them.  From energy efficiency to strength ratings, these things can get overwhelming.  

So what I've put together is a straight-forward guide to window ratings.  What they are, what they mean, and how to read them (is a lower U-factor better, or a higher one?).  

So here are the most important window ratings:

U-Factor

• The lower the U-factor, the better.
• The lower the U-factor, the greater a window's resistance to heat flow and the better its insulating value. It is a number between 0 and 1.
• Industry standard windows usually have a U-factor of 0.30 or lower.

Design Pressure (DP)

• The higher the DP, the better.
• The design pressure measures the strength and resiliency or a window, specifically how much pressure it can withstand without suffering breakage or damage.
• The higher the number, the stronger the window, the less air infiltration, and the longer it will perform to specifications.

Air Infiltration

• The lower the number, the better.
• A measure of air leakage per minute around a window, which is expressed as cubic feet per minute, or CFM. The lower the CFM, the better its air tightness.
• Industry standard is 0.30 CFM or lower.
• One CFM equals 7.5 gallons of air per minute leakage.

Water Penetration

• The higher the number, the better.
• Measures the ability to withstand water pressure in pounds per square foot, or PSF.
• Industry standard is 4.0 PSF or better.

R-Value

• The higher the number, the better.
• The R-value is simply the inverse of the U-factor. Meaning the R-value = 1/U-factor.
• As in the U-factor (above), this measures heat conductivity.

Solar Heat Gain Coefficient (SHGC)

• The lower the number, the better.
• The fraction of solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward.
• Expressed as a number between 0 and 1.
• The lower the SHGC, the less solar heat it transmits.

Visible Transmittance (VT)

• The lower the number, the more light the window blocks.
• It is the fraction of light transmittance through the window, measured between 0 and 1.
• Personal preference and circumstances my determine the desirable VT for you.

Condensation Resistance

• The higher the number, the better.
• Measures how well the product resists the formation of condensation.
• Expressed as a number between 1 and 100.

I hope this helps.  If you have any questions, please feel free to leave a comment below.  And as always, if you're interested in talking to the best replacement window company in Cincinnati, you can reach out to me directly by giving Windows Plus a call.  

Thanks for reading!

Mike G.

The Window & Door Guy