How to compare Vinyl Sliding Glass Patio doors & Replacement Windows For Homes.


Some vinyl sliding doors and double pane replacement windows will last for decades with no maintenance other may cost hundreds of dollars in repairs.
After installing doors and windows in local homes for over 30 years, DP Door is uniquely qualified to help you compare various brands of patio doors and windows for your house.
Window manufactures all seem to claim they have the best windows and patio doors. Some promote their windows with great advertising but fall short when you ask them for service. Since our reputation depends on the quality of what we install we look past the advertised claims.
At DP Door we have tried many brands and seen them a decade or two later. We learned what to look for in quality and will share that with you. The 5 steps below should help you to compare different replacement window and sliding glass patio door brands.

installing a reto fit window
Brent of DP Door Co. Rancho Cucamonga installing a retrofit windows in a house. His right hand is on the Milgard z-bar exterior trim.

The z-bar is the exterior trim that makes the replacement window or sliding glass patio door a true retrofit. It is about 20% of the cost of the door or window. Cheaply made doors and windows will have a flimsy exterior trim.
Bootleg doors and windows will not have a true z-bar but just a stick on vinyl exterior trim. (they use interior trim on the exterior)

All z bars are about the same width, it is the thickness that varies between manufactures.

A good z bar is at least 1/4" thick. Anything less is just single ply with no honey comb structure inside.

A single ply will bend giving an unpleasant ripple effect.

milgard window latch Milgard's Smart Touch lock

is perhaps the nicest locking system available.

This is a Single Hung Milgard window, a horizontal slide would look the same if you turned the picture sideways.

Residential Window Latch: Doors and windows in your home need to be safe but the lock can still look good. The new built in locks are very nice but the cam locks may be a little more resistant to unwanted intruders.
Of course sliding the window and feeling how smooth it slides and locks is something no article can describe. Most vinyl windows will slide 10 times better then your old aluminum windows so even a cheep one may be a surprise at first. After the initial shock compare brands and you will feel and even hear the difference between high quality replacement windows and the mediocre ones.
milgard sculptured grid between glass close upSculptured grid in dual pane window.
Dual Pane Window Grids; In wood windows they were called mullions. They are for looks not structure. Most are between the glass so there is no cleaning to worry about.
Milgard sculptured grid in picture windowEven if you don't want grids looking at the quality of the girds will help show you the manufactures attention to detail.

When comparing quality look at the joints were the girds intersect. There should be no more then a smooth consistent hairline space at the joints.

Look at the stock that the grid is made of. The material is made from a sheet of aluminum that is rolled into a bar shape. There is a seam along the length. The seam should be barley noticeable.


Window Warranties:



Anlin Windows has a double lifetime warranty. This means the Anlin doors and windows warranty is transferable to the next owner. Anlin's warranty is to the original purchaser as long as they occupy that residence plus they do it again to the next owner.

Anlin is know for doing things a little better than the other companies. As with most higher quality products they do cost more but you do get what you pay for and then some. There are technical things about Anlin Windows that would bore many people, but if you need better insulation, less dust coming in, better resistance to air and water infiltration, glass that is easier to clean, screens that don't bend (with optional heavy duty screen frame) and a double lifetime warranty that even covers the screens, and homeowners accidental glass breakage , then you would be surprised they only cost a little more.

Besides Anlin's Double Lifetime warranty it is also good to hear they cover homeowners accidental glass breakage of not just stock or normal glass like others do, but also the special and decorative glass (not laminated glass.) Having decorative glass in a bathroom is so much nicer then the old sand paper looking glass. It is an upgrade like having nice cabinets or fixtures. Decorative glass is not cheap so it is nice that Anlin includes it in their warranty even though others don’t.

Anlin is the only major window company with a 5star rating. I turst Yelp the most of all online review companies. The reson is they have the tougest algariytms to fool. Many reviews that you see online are not true and there are people that for a fee will improve a businsess ratings. Yelp does not work that way, they can be trusted.




milgard warranty

Milgard Windows has proven to us that they do stand behind their product. We have never had a qualified claim turned down and their customer service is one of the best of any company we deal with.

compare anderson window warrantyAnderson warranty is good on parts not so good on labor to replace the parts.

jeld wen warrantyJeld-wen is a good window but the warranty only covers labor for 2 years. Labor is the most expensive part of a repair.

milgard low e glass


The glass is the most important part of the window.

It is why we have windows in our homes.

In the past the problem was that clear glass does not block heat from the sun. The old tints helped some but not a lot. 

Now there is low e glass.

Low-e is is amazing. It is a major break through in energy efficiency. low e is far and away superior to tints.

As unfair as it may seem the big guys get first dibs on the latest technologies. So Low-e from Anderson and Milgard is one to two years ahead of other brands.

The name of the low-e is called a lot of different names; Milgard is SunCoat, Anderson is High-Performance Glass.

The most popular is low e2 & low e3.

low e2 is very good,

low e3 is stronger for harsh direct sun light.

It is best to use Low e3 in most cases.

Low e 2 is used if the window is shaded.

We rarely use clear glass (no low e).

The amount of fading on furniture and floors alone makes it invaluable.


Low-e Glass is made from Cardinal Glass and PPG not the window manufactures.

Some overzealous sales people;e will claim that their glass is better then one of top companies; the fact is the top companies get the best glass the first year it comes out ( Milgard & Anderson) then the others eventually a allowed to buy it.

milgard windows tuscany spacerSpacer Bars;

The space between two pieces of glass is maintained by a spacer bar. These vary from manufacture to manufacture. There are many arguments on which type of spacer is best. The spacer bar is very important since a failure would cause the window to fog up and the glass would have to be replaced.

The number one problem with dual pane windows for homes is a failure of the spacer bar.

A failure will cause moisture to collect inside the window. This will stain the window.

Cheap windows have a high percentage of failure. Even the best windows have occasional problems.

The spacer material has some affect on the energy efficiency. It is a small amount of the overall energy efficiency but if the window has to meet a specific energy rating it can help.

Aluminum spacer, it is durable and holds the seal very well.

Stainless steel is similar to the aluminum spacer but slightly more energy efficient. Stainless steel cost more then aluminum.

Super Spacer, (has different catchy names) is a soft material that transfers almost no heat or cold.

There is a much greater chance of the super spacer to become extremely distorted if it is exposed to high temperatures.


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Contractors License #1006847. Copyright; all rights reserved, DP Door 2015 ~2021 . Some information has not be updated; Always check the manufacture’s web sites for up to date information.