What is the R-Value of a Window?

older window with plants decor

It’s intimidating and annoying when you need to replace your windows and all of your research keeps bringing up technical jargon like R-values, U-values, and SHGCs, whatever those are. What do these things tell you, as the homeowner? Why should you care about them? I’ll tell you exactly why you should be interested in them.

The R-value of a window measures the thermal resistance of its material (the glass). It measures how effectively barriers, such as windows, resist heat flow, therefore keeping warm air from passing through it. R-values are not the only unit of measurement important for rating a window’s thermal efficiency. U-values are also important. 

To better understand the usefulness of the R-factor and its relationship with U-factors, read below.

What is the R-Factor of Windows?

The R-factor, or R-value, of barriers, such as windows, doors, insulation, walls, etc., measures the resistance of the barrier to the flow of heat. It’s how well a window resists heat flow. In other words, how well a window insulates. So, the way R-values work is, the higher the R-value, the more resistant the barrier is to heat flow, and therefore the better insulator it is for the home.

We call these units of measurement R-values because we’re measuring the glass’ resistance to heat. Why do R-values matter? Because they measure the effectiveness of the glass’s resistance to heat conductivity, these values tell contractors which windows are the most energy-efficient and will therefore save homeowners as much money in heating and cooling as possible. As a homeowner, you can imagine that is pretty useful information for you too as you start to watch the electric and gas bill amounts decrease bit by bit.

What is the Difference Between Window R and U Values?

Whenever you find glass or barrier performance charts, in addition to seeing the R-values, you’ll likely find U-values. U-values, or U-factors, refer to the whole window’s ability to insulate, not just the glass, like the R-value measures. After all, when a window is made, air can often sneak its way in or out through the grid, the track that the window slides on, and/or the edges of the frame. The U-value measures the efficiency of all of the materials used for the window, the frame, and the glass that was used. 

Along with the R and U-values, manufacturers will include something called the Solar Heat Gain Coefficient (SHGC). Glass windows are usually double-paned. While the R and U-values measure how well the interior pane in the windows keeps heat and cold inside the home, the SHGC measures how well the exterior pane keeps outdoor heat and cold out. 

All of these units tell a manufacturer and a contractor the thermal efficiency of the glass so that they can find the best windows for your home and budget. 

What is the Best R-Value for Windows?

R-values will normally lie somewhere between the range of 0.9 and 3.0, and like I was telling you earlier, the higher the R-value is, the more effective the window is, so you want as high an R-value as you can get. R-values can certainly reach higher levels, even as high as 8.065, but this is rare. It’s also important to remember that when one value is high, another is sacrificed. It’s just the balance of things.

What is the Best U-Value for Windows?

Unlike R-values, desired U-factors will vary based on geographical location. The Department of Energy’s  “Energy STAR” joint program with the Environmental Protection Agency divides the United States into four climate zones:

  • Northern Climate Zone
  • North Central Climate Zone
  • South Central Climate Zone
  • And Southern Climate Zone

Each quadrant will naturally desire different levels of transmittance in their windows. While Maine, in the northern climate, would want less transmittance in order to keep as much light and heat from the sun inside as possible, Texas would want more transmittance so that as the sun sends heat through the windows, it can be sent out almost as quickly and keep the air conditioning from working too hard. 

U-values will usually fall between the range of 0.20 and 1.20, where the lower the U-value is, the better because a lower U-factor means there is a lower thermal transmittance, where the warm or cool air comes through the window from the outside to the inside and creating a shift in the temperature difference. When the U-factor is low, that means there is less and less heat escaping. 

How to Calculate R and U-Values

As a homeowner, you won’t have to do these calculations when you’re replacing your old windows, because the values will be on the window labels for you. However, if you would like to calculate your own windows’ efficiency I’ll let you know how you can calculate both the R-value and U-value of a window. 

Normally, U-values are calculated by measuring the heat flow per unit area, time, and degrees F difference. In other words, U = [Btu/(ft²•°F•hr)]. Meanwhile, R-values are calculated inversely, with [(ft²•°F•hr)/Btu]. Want to know a secret? Once you’ve calculated one value, like U, R would be 1/U, and vice versa. 

There’s also a convenient calculator available here.

As you calculate these values, you might end up with a less-than-desired result. There are four factors that will influence what R and U values you get:

  1. The number of glass layers the windows have
  2. The space between each layer of glass
  3. What glaze was used
  4. How well and how tightly the windows were fitted 

What Windows Have Great R-Values?

Now that you know what values to look out for the next time you look for windows, where are you going to get your windows from? For my part, I recommend taking a look at Amerimax Windows.

Besides including stunning finishes like rain, glue chip, and satin etched, just to name a few but their glass and grid options include an argon gas option and super spacer option that will increase thermal efficiency, regardless of which one you choose. 

When argon gas is added to windows in between the glass layers in production, the gas will help insulate the house further by acting as a moving, thin barrier that minimizes heat transfer from the inside to the outside. 

Naturally, windows that are going to have high R-values and low U-values like you want will be labeled as Low-E windows. Low Emissivity glass is coated with layers of metallic oxide. This way, natural light comes in through the windows but the UV rays and infrared are deflected. In doing so, the metallic coats will act like a reflective mirror with heat and light waves of specific wavelengths and frequencies to come in and out, keeping the house warm during the winter but cool during the summer.

Conclusion

As you can see, replacement windows with good R and U-factors and SHGCs are a worthwhile investment to consider. From my experience as the owner of a professional home-improvement company, Amerimax Windows have consistently had some of the best thermally efficient windows, which is why I like to use them so much. Are you interested in switching out your tired windows to experience the difference? If you’re located in the Northern Colorado or Southern Wyoming areas, feel free to give us a call today at (970) 663-2868 or visit the window services page and fill out the contact form to make an appointment to discuss the finer details of your replacement window home improvement project.

What Is the Difference Between a Deck, Patio, Porch, Covered Roof, and Sunroom?

picture of a huge deck and cover built in Loveland, CO

When it comes to home improvements and additions, it helps to know the difference between some of the different options before you start hiring contractors to begin working on your property. You may want to add things that will increase the value of your property while giving you more space to do some of your favorite things, such as grilling, sunbathing, or simply relaxing outdoors.

Whether you want a deck, patio, porch, or something else added to your home, it helps to know the difference between these options before you officially pay to have anything done. So, what is the difference?

A deck is a wood framed platform that is commonly attached directly to your home. A patio is usually a cement slab in the backyard right up against the house. A porch is most commonly a covered deck with screens for walls. A Covered Roof (or sometimes referred to as a hard cover) is a shade covering for a deck or concrete patio and is commonly made from the same roofing materials as the house. And lastly, a sunroom is similar to a porch except made from as much glass as possible.

pic of a wood deck built in Loveland featuring built in seating and lighting

What Is a Deck?

A deck is a structure composed of wood that does not have a roof attached to it. As a homeowner, you can get a deck installed on any specific area of your home. Some people like to have a deck in their backyard, while others prefer having a deck that is off to the side of the property. It all depends on the location of your home and the amount of space you have available to get this type of addition constructed.

Decks come in all different sizes and shapes. Before getting a deck installed, you would need to have measurements taken to determine how much space you have available to work with in the first place. You may want a large deck to have plenty of room for a grill and chairs that you will have out for guests to sit on when they visit you. In addition to getting a deck that is the perfect size for your personal space, you will also need to decide on the shape, style, and color of the deck.

You can have a deck built with different types of materials. While wood is the most common goto for decking, decks made from wood-plastic composite have become extremely popular. No matter what you plan on choosing, you will need to decide on the species of wood that you would like used based on its longevity and general appearance. You want something that is going to look good and last a long time while not requiring nearly as much maintenance as some other options.

What Is a Patio?

Many people often confuse a patio with a deck or porch, but these are three entirely different things. While the patio is an outdoor area like a porch and deck, it is typically a paved area that is outside of the home and not attached to it. When constructing patios for clients, it is common for contractors to use concrete, bricks, and even assorted stones that were selected by the clients.

The purpose of having a patio is to have an outdoor area where you can sit, eat, and relax. Many people with patios like to host parties and gatherings with their loved ones where they are preparing food and serving it outdoors. Once there is the patio, homeowners may invest in items for those patios, including outdoor furniture, that they can leave outside and use whenever they want to sit outdoors.

Not all patios look the same, and some are much bigger than others. It does depend on the space available to the homeowner. One thing that most patios have in common is that they are found in the back of the home and may even be situated near a deck.

What Is a Porch?

The porch is an open structure that has breathable walls, but protection above it. Because there is a cover or roof above the porch, you can comfortably sit outside in any weather without worrying about dealing with the rain, sun, snow, and other elements. The porch is often added to the front of the home. There are several reasons that homeowners choose to get a front porch installed if they do not already have one. It gives them a safe and comfortable place to sit out while enjoying the weather and chatting with their neighbors.

There are different types of materials used to create sturdy and reliable porches for those who would like them. Some of the most commonly selected porch materials include plastic, PVC, wood, aluminum, and solid stone. The materials, colors, and overall style picked for the porch will vary from one home to the next and will typically depend on the personal preference of the homeowners.

You can choose from various porch options. For example, you may want an open-air porch that does not have walls, or you may prefer having a porch with screened walls. These are some of the things you will need to think about before you get this type of addition to your home.

covered deck shingled roof stone pillars all covering a hot tub

What Is a Covered Roof?

A covered roof often goes along with a patio. While patios are usually out in the open and provide a space for dining and relaxing with friends, some people choose to invest in a covered roof that gets installed directly over the patio. Having a covered roof comes in handy for potential rainstorms and other weather elements that could get in the way of an outdoor event. The closed roof also provides additional protection from the sun when sitting outside for extended periods.

Before getting a covered roof installed over the patio, professionals must first take measurements. It is necessary to make sure that the roof will provide the maximum amount of coverage for the patio. If you are thinking about getting a covered roof, you must also decide how much coverage you want. Some people like to have a portion of the patio covered while leaving a separate part open because that allows them to soak in the sun if they would like to do so.

What Is a Sunroom?

The sunroom is a sheltered room that is attached to the home. It is an added room to the house that has more windows than the average room, allowing plenty of natural sunlight to soak through. Property owners often like adding assorted plants to their sunrooms because that is the perfect room to get plants to thrive because of the added sunlight. Those who want to enjoy the benefits of the sun without sitting directly outside where they would end up dealing with insects may enjoy having a sunroom available to them.

Sunrooms are often smaller than the average size of a living room or bedroom, but they still offer an adequate amount of space. While the location of a sunroom may vary from one home to the next, it is common for homeowners to have a sunroom attached to the back of the house. There is a common misconception that a sunroom and back porch are the same thing, but this is false. These two home features are different from one another.

It is quite common for people to confuse decks, patios, porches, covered roofs, and sunrooms. Many people believe these home additions are all the same, but that is the furthest thing from the truth. Each addition has something unique to offer. If you are thinking about adding something extra to your home, you should make a list of your wants and needs and then decide which of these different options are the best for you.

Once you decide which additions to add to your home, you can start choosing materials, styles, and colors. You can go over these details with a professional contractor by giving us a call today at 970-663-2868 or visit the contact page to send us a message. Also, if you want more info please check out our DECK and PATIO COVER services pages.

timber frame sun-room with amazing mountain views built by TNT Home Improvements