How Much Does Double Glazing Cost?

If you live in a planting zone that has four distinct seasons and gets cold during the winter months, you probably know all about the importance of weatherproofing your windows. Double glazing can work to keep more or your home’s heat inside, and this is why many people wonder about the average double glazing cost. They also help to reduce carbon pollution, cut down on outside noise interference, and lower your heating and cooling bills all year-round. 

If you’d like to know which factors play into your double glazing cost and what the average range is, this is for you. We’re going to outline everything you need to know about picking out and installing the best energy-efficient windows on the market. You can install them yourself to try and save on your total double glazing cost, but we recommend that you have a professional come and do it for you since this is a more high-end project. Let’s dive in. 

Defining Double Glazing

First off, what is double glazing and how does it work? Traditionally, most people had single-glazed windows installed in their home, and these windows had a single pane of glass. These traditional windows were very popular up until a few years ago, but they’re terrible for energy-efficiency. A good portion of the heat from inside your home could escape from these windows to the outside, and the cold air can seep in during the winter months. 

This is why many people justify the double glazing cost and invest in these types of windows when they remodel, build an extension, or replace their current windows. These types of windows come with two panes of glass and a small space between them. The gap between the two panes of glass usually has trapped air, but some can have argon gas. Argon gas keeps the windows even more energy-efficient, but it’ll add to your double glazing costs too. 

Additionally, you can also get triple glazing on your windows, but this is more rare due to the high cost. Triple-glazed windows have more layers of glass, and the more layers there are, the less heat loss you’ll experience. 

1 Installing New Windows
Double glazing allows you to insulate your home better because the air or gas pocket between the two panes of glass prevents heat from escaping. Some can also reflect heat away from your home to make it even more energy-efficient.
Wallboard goes up around windows by moccasinlanding / CC BY-NC-ND 2.0

Rating Double Glazed Windows

Each window has a rating attached to it, and you can use these ratings to determine how efficient your potential windows will be when you get them installed. The rating will impact your double glazing costs, and there are several great options available. The most common ratings include: 

Air Leakage

This is a very self-explanatory metric that measures that amount of air that can pass through your window. Knowing this will help you justify your double glazing costs. The lower the number is, the more airtight your window will be. If you live somewhere that is very windy, get a window that has a lower visible transmittance rating on it. 

Condensation Resistance 

This metric will tell you how much moisture can and will build up on your window’s surface. This scale starts a 1 and goes up to 100. The lower your rating is, the more condensation can build up. This can lead to more ongoing maintenance and window damage.  So, if your local area gets a lot of moisture, rain, or it has a lot of humidity, get a higher condensation rating. Although this can drive up your double glazing cost, it’s well worth it to prevent damage to your windows. 

Design Pressure

This is an interesting metric that will tell you how much pressure your window can take before it breaks. The higher this rating is, the stronger your window will be. If you live in an area that frequently sees heavy amounts of snowfall, storms, or winds, it’s a good idea to get a higher design pressure rating. The typical metrics range from 30 to 50. 

SHGC (Solar Heat Gain Coefficient)

The SHGC is the rating that measures how much solar radiation and heat can pass through the windows into your home’s interior. The lower this number is, the lower amount of radiation that will make it through. This measurement can start at 0 and go to 1. Again, if your home has a good deal of direct sunlight, you’ll want to get a lower SHGC rating to make the most out of them. 

U-Factor or U-Value

This metric will measure the rate of heat transfer. U-Factor or U-Value is responsible for telling you how much heat your window will lose or gain with a particular glass rating. The U-Value can start at .25 and go up to 1.25. The lower your U-Value is, the more energy-efficient the windows will be. If your windows have a lot of direct sunlight and you want to justify the double glazing costs, try to find lower u values. 

Visible Transmittance

If you want to know how much light is allowed to pass through your windows, look for the visible transmittance rating. It has a scale of 0 to 1. The closer you are to 0 with this rating, the less light that will pass through your windows. Depending on the amount of sunlight your home gets and where you live, your specific range could vary, depending on your preferences. 

So, if you’d like to let more natural light stream through your windows and into your home, you’ll want to pick windows with a higher visible transmittance. If you want to keep your home slightly cooler and darker during the hot summer months, get a lower visible transmittance. 

Certification Labels

Another critical factor in your double glazing cost is the certification labels. You’ll see these labels when you start to shop for your windows, so it’s a good idea to see why they’re so important. The following labels are the ones to watch for: 

American Architectural Manufacturers Association (AAMA)

The AAMA certification requires that the window goes through three tests. These tests include air leakage, structural strength, and water leakage. The windows that go through testing for thermal performance only get a Silver Certification label on them. Windows that go through tests for water, air, and structural, and thermal performance will get a gold label. Always go for the gold label because the benefits that come with it can help to offset your double glazing costs. 

Energy Star

This qualification comes based on the SHGC and U-Factor ratings. The certification doesn’t measure anything itself, but it uses the NFRC’s window thermal test to help create zones. These zones pertain to different areas of the country, and it’ll recommend a tailored SHGC and U-Factor value for the windows based on where they fall in the zones. 

National Accreditation and Management Institute (NAMI) Structural Certification

This is an independent company that works to certify windows after an inspection. It gives the windows energy performance ratings that come based on values like the SHGC and U-Factor. This certification label will let you know the standard that they tested the window to, and this can help you understand the double glazing cost. The label should outline the grade or performance level, the manufacturing facility, and the model or series name of the window. 

National Fenestration Rating Council (NFRC)

THis council works to help people compare window performance levels using various ratings. These ratings include the Solar Heat Gain Coefficient, U-Factor, Visible Transmittance, Air Leakage, and Condensation Resistance. The labels test standards for this certification include the NFCR 100, 200, 300, 400, and 500

2 Window Certification and Ratings
Each window you look at should clearly display any certifications or ratings. Comparing these ratings can help you narrow your choices down and pick the one that best suits your environment.
Oops we broke a window installing it by Giles Douglas / CC BY 2.0

Materials That Impact Your Double Glazing Costs

One of the first things you’ll notice when you’re trying to set a budget for your double glazing cost is that you have a host of materials to choose from, and some are very expensive when you compare them to others. These types of windows can feature many materials, including: 

  • Aluminum or Steel – These materials are very popular because they’re durable, will withstand a lot of wear and tear, and water doesn’t bother them because they don’t rust. You can also recycle them when you swap your windows out. 
  • Composite – Composite frames are another popular choice that feature an inner timber frame that has plastic or aluminum on the outside. They’re low-maintenance, and they’ll withstand a variety of environments without breaking down. 
  • uPVC – These are plastic-based frames that can help lower your double glazing costs, but they’re also more prone to damage. They don’t need a lot of maintenance, and you can even recycle most of them when you change them. 
  • Wood – Many people like the look of wood frames, but they have a much higher maintenance need to them. They’re prone to damage, swelling, and warping with a lot of exposure to humidity, fluctuating temperatures, or moisture.

When you look at the glass, some of the highest ratings will come from low-emissivity glass. This glass comes coated with a special material that allows light in from the outside, but it reflects heat back to to help keep your room cool. It has a higher double glazing cost due to this ability. 

As for the small gap between the glass panes, it can have a huge impact on how well your windows perform. Ideally, you’ll always go for slightly smaller gaps than large ones, but there are a few different options to consider when you shop. 

Sealed windows also come with spaces between the panes. This is a small strip made from polymer or metal, and it has a drying agent on it. This reduces the amount of moisture that can get trapped between the sheets of glass when it snows, rains, or gets humid. 

Double Glazing Cost Checklist for Pricing and Installation 

There are a few things you can do to lock down the best double glazing costs, and there are things you have to consider that will make your project budget fluctuate. They include but are not limited to: 

  • Expect for your double glazing costs to fluctuate from company to company. Every company has different overheads and operating expenses when they create these windows, and this impacts the total prices. 
  • Get three to five estimates before you choose one contractor for your windows. Most of the time, they’ll be happy to give you free estimates for your double glazing cost, and they’ll tailor it to your unique situation. 
  • Ideally, you’ll get your prices in the late fall or early winter months. This is when a lot of contractors offer aggressive price discounts to get rid of their stock as the season winds down. 
  • Whatever estimate the contractors give you, budget up to 15% more for your final double glazing costs. Difficult patterns, configurations, valleys, hips, curbs, dormers, and ventilation can all cause your prices to go up. Your roof’s complexity can also factor in. 
Basic per WindowMid-Range per WindowHigh-End per Window
Material Prices$120 to $150$180 to $260$280 to $340
Labor Costs$150 to $170$190 to $220$240 to $270
Total$270 to $320$370 to $480$520 to $610
Cost Per Square Foot$2.50$3.40$4.70

Cost Factors for Double-Glazed Windows

Your double glazing costs can be as low as $150 for a uPVC window and up to over $1,000 for a wooden frame. This is why it pays to shop around and get multiple quotes, and your total double glazing costs will depend on several items, like: 

  • How many windows you want to replace at once 
  • How many openers the windows have 
  • Window size 
  • Material choice 
  • Any special glazing processes like tinting 
  • Whether or not you can recycle your old windows. Some companies offer discounts.

Benefits of Installing Double Glazed Windows

These types of windows come with a host of benefits included that can help you justify your upfront double glazing cost, especially if you’re building a whole new extension and want to upgrade all of your windows in one go. 

  • Your home will stay cooler in the hot summer months if you have energy-efficient double glazed windows installed. The air or gas trapped between the two panes of glass block the outside heat, and this allows your HVAC system to work more efficiently. 
  • These windows can help protect your home from the elements by protecting your window frames. Normally, when the moist air meets a cold surface, it forms condensation. This can cause pools of water to form, and it can damage your window frame or cause damp problems. Double glazing prevents this from happening in the first place. 
  • If you live near a busy road or in the city close to your neighbors, these windows have sound deadening qualities. They can minimize medium and high-frequency noises, and this can make your home quieter overall. 
  • They work well as part of your energy efficiency strategy. If you have loft insulation, cavity wall insulation, and an energy-efficient heating system in place, they can reduce the amount of energy you need to heat your home. In turn, this can reduce your carbon footprint. 
  • It can boost your home’s curb appeal and value, so you can make back some of your original double glazing costs if you decide to sell the house. How much it goes up depends on your location and how hot the market is. 

Drawbacks of Installing Double Glazed Windows

Even though these windows have a huge range of benefits associated with installing them, there are a few drawbacks you should be aware of. Knowing them will give you a better understanding of these types of windows and whether or not they’re right for you. The biggest drawbacks are: 

  • Difficult to Fix – It’s not easy to fix these windows if they break. If the seal isn’t completely airtight, condensation can form between the panes of glass. You can’t pull them apart to fix it. The only option you have available is to replace the whole window. 
  • Price – Your double glazing cost will be much higher than a single glaze. However, these windows do tend to pay for themselves over time because you lower your home energy bills. 
  • Dated Looks – Unless you choose to go with more expensive wooden frames, a few more modern double glazing styles can look out of place when you put them on more traditional, older homes. 

Yearly Savings Potential for Double-Glazed Windows

Depending on the rating your window has, you could be in for some significant savings. The table below can give you a rough idea of your savings potential, and this can help offset your original double glazing costs. 

RatingBungalowDetachedFlatMid TerraceSemi Detached
High$55.00$105 to $110$35.00$55.00$75.00
Average$50.00 to $55.00$100 to $105$30.00 to $35.00$50.00 to $55.00$70.00 to $75.00
Poor$50.00 to $55.00$70.00$30.00$50.00 to $55.00$70.00

Choosing the Correct Double Glazed Windows

When you first start searching for your double glazed windows, you’ll realize very quickly that there are a plethora of choices available. This short section will introduce you to the most popular types of windows to help you make an informed decision: 

Bay 

Bay windows typically feature three or four windows in a very distinct curved design. These windows are usually much larger, and they allow a lot of natural light to stream in. You can choose from a wide range of finishes and materials, but the installation process, shape, and size can drive up your double glazing costs very quickly. 

Casement

Better known as an egress window, this type of window attaches to the frame using one or more hinges. They can open to the side, or you can get them hinged at the bottom or top so they turn and tilt. This makes them more child and pet friendly, and more secure at the same time. They usually open inward, and this makes them easier to clean. They use casement stays to keep them open, and these are small metal bars that close using a scissor motion. You can get them made from aluminum, timber, or uPVC. 

Sash

A sash window is the traditional windows you have in your home that you open and close by lifting the frame up and down. A single sash hung window comes with a single moving pane with a static one. If you have a double hung sash window, you can move both panes. One pane will move up while the other one moves down. 

3 Double Glaze Window Types
Getting in touch with a local contractor can help you pick out the best type of double glazed window for your situation. Some will suit your area better than others, and it’s important to get the correct ones since this can be an expensive project.
Storm window by Charlie Vinz / CC BY-NC-ND 2.0

Installation Considerations

Before you install your windows, you want to contact your local planning office and ask about permits. Most of the time, you’ll need them to perform significant renovations or upgrades to your home. If you go with a professional installer, ask if they take care of the permits for you or if you have to do this yourself. You should give yourself at least 7 to 10 days for the paperwork to go through, and don’t forget to add your cost of the permits to your double glazing costs. 

How to Tell if Your Double Glazed Windows Need Replacing

Everything will fall apart sooner or later. However, your windows should last around 20 years before you have to worry about replacing them and adding to your double glazing costs. There are a few ways you can tell if it’s time to replace them, including: 

  • Water is starting to leak through the frame
  • You notice more noise from the outside world getting inside
  • Condensation is building up between the two glass panes
  • The glass broke or it has cracks or chips
  • You can feel a draft leaking in around your window
  • The window is harder to close, open, or lock
  • The frame is very soft to the touch or falling apart

Alternatives to Using Double Glazing to Insulate Your Home

If you can’t afford the double glazing costs right now or you’re not ready to take on such a large project, there are a few alternatives open to you. They include: 

  • Install secondary glazing over your current windows in the form of another pane of glass. If you measure and fit it correctly, it’s almost as effective as a true double-glazed window. 
  • You can draft-proof existing windows to seal out air and moisture. To do this, you’ll run compression strips or silicone gel around the frame. 
  • There are acrylic, polycarbonate, or plastic window insulation available. They have everything from sheets that cling to your windows and stick to the frame to acrylic panes that use a magnetic strip to stick to the window frame. These are more of a short-term fix though. 
  • Curtains can do an excellent job of blocking out drafts and keep heat in the room, especially if you get insulated blackout ones. However, they will block the light too, so they’re not a good idea if you want natural light. 
  • Hollow blinds are another option you have available. They fit into place with a sealed frame and a set of sealed shutters. They can lock the heat in and cut drafts. 

Where You Can Find Double Glazing Installers Near You

If you buy double glazed windows from a company, they’ll usually come out and install them for you, and they usually include the double glazing cost for installation in the final quote. If not, you can easily find an independent contractor or a smaller local company to come out and perform the installation. If you’re not sure where to look, you can start here: 

Bottom Line

Your double glazing cost will depend on a broad range of factors, and it’s very easy for it to fluctuate and go up quickly. We encourage you to take a good look at this guide and start contacting local companies. If you do all of your windows at once, many will offer you a nice discount since it’s fewer trips to coordinate for their staff. Get your double glazing cost estimates, get the job done, and watch the windows pay for themselves in savings year after year. 

Double Glazing Cost 1 Double Glazing Cost 2

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