Window experts discuss energy efficiency

We spoke with three highly rated companies to find out why homeowners should make their windows more energy efficient and how they can do it.

Allan Ross: It's very difficult to make old windows more efficient. In order for windows to meet today's energy efficiency standards, it requires insulated glass packages with coatings that can only be provided with new windows. We offer a full line of windows that incorporate different levels of energy efficiencies as well as aesthetics.

Rhonda Steffes: A lot of times, we see people put plastic over their windows. It's a temporary fix. You could try caulking your windows if you see cracks in them. It won't do a whole lot for you, but it's something you could try temporarily. In the last 15 years, there have been a lot of advancements in energy-efficient windows. Low-E coatings have really helped. Low-E stands for low emissivity, which means lowering the heat flow through the window.

Michael Cavanna: Beauty, comfort, functionality and energy savings are just some of the advantages for replacing your old windows. Single-paned or older double-paned windows don't provide the energy-efficient benefits [that newer windows do]. We manufacture double-paned windows that use Low-E 366 glass, which includes three layers of silver and is specially formulated to provide more protection against the sun's heat.

What makes windows efficient?

Ross: There are four factors - the glass, the [Low-E] coatings on the glass, the dead air space, and the gas used [to fill that space]. Argon or krypton gases are both efficient.

Steffes: On our windows, we have 11 layers of coatings on the glass. Some windows use less than that, so their windows are not as energy efficient. In northern climates like ours, you want to look for windows with a low U-factor, which measures the heat escaping through the window. A U-factor value of 0.30 or lower is good. They also measure the solar heat gain coefficient, which is the amount of solar heat admitted through the window. Typically, a number below 0.30 is good.

Cavanna: Our glass also has a dual seal with an all-foam spacer [which keep the panes the correct distance apart]. It compensates for natural expansion and contraction but will always return to its original shape. That's something metal and plastic spacers can't do.

Steffes: The argon or krypton gas is odorless and nontoxic, and heavier and denser than room air, so the insulated windows don't allow the heat and cold molecules to transfer back and forth through the window. It's like invisible insulation.

Cavanna: We use vinyl window frames, which can be welded at the corners rather than being mechanically fastened or glued - which could mean potential corner separation when the house is settling or if there's an earthquake. They also have a low profile to maximize aesthetic appeal.

What's the cost?

Steffes: Our average job runs about $6,800. Of course, some people do two windows and some do 20. Purchasing and installing energy-efficient windows can cost between $400 and $800 per window.

Ross: There are obviously a lot of factors and features that can affect pricing, but you're looking at $500 to $1,500 per window for ones that meet the government's standards for the federal energy tax credit.

What certifications do your products have?

Ross: All of our windows are Energy Star rated, and they all meet or exceed the Energy Star requirements. Windows that meet the more stringent Federal Energy Tax Credit will allow a tax credit as well as provide energy savings that, over a period of time, will completely pay for the windows. Also, your home will get an updated look that gives you great curb appeal and increases your home's value.

Steffes: Our windows are certified by Energy Star and the American Architectural Manufacturers Association.

Cavanna: Our windows are Energy Star and American Architectural Manufacturers Association rated, and the energy they save certainly helps maximize a green-friendly environment.


Look up what the DOE has to say about window replacement. They say it has the worst return on investment for any type of weatherization to your home. They will not allow it at all in our state for the DOE sponsored weatherization program unless the window is unserviceable. I just finished the course and I am a window replacement contractor. I was shocked but it is true.

$1500/window is, in a word, absolutely absurd. Go to your local building supply, check out the windows there. the old ones come out easily, and the new ones insert just as easily. do a little research - markup on windows is usurious. jay

Another way to make windows more energy efficient is having window film installed. Window film keeps out 99% UV rays (UVA & UVB) and can keep out anywhere from 40% to 65% of the heat. It costs a considerable amount less than installing new windows. Film comes in a wide variety of shades & color tones. There are even films that are almost clear yet keep out incredible amounts of heat. Installing window film is also eligible for the Federal Tax Credit.

I live on the coast in Northern California -- about 20 yards from the beach -- we have high winds and lots of fog and mist. On an ocean facing window, which is better, double pane or single?

j. johnson. I think what you are overlooking is that there are a myriad of tests that these windows go through. and while low e storms may help the shgc, there are many other factors. aama is the best testing facility in the country. they test replacement windows for load, for air infiltration and a host of other things. so in its simplest terms, the window is only as good as its weakest link. if i want to make a case that storms with low-e are just as good for a fraction of the cost, and ignore u factor, air infiltration, and load numbers, then i probably can make a case. berkley can bend info any way they want, but in the end its only as good as the weakest link. storms do not do the job as well. plain and simple.

Nowadays, you need to pay attention to the whole envelope of the house--windows, doors, insulation, etc. Replacement windows can be a good place to start, but is not the answer for everyone. There is no doubt that lots of energy (heat and cold) is lost through inefficient glass--that's why windows and doors are a good place to start when trying to improve the energy efficiency of an existing home. We find that dealing with a local contractor for installation, not a window company that does its own installed sales, is a great way to get a straight-forward opinion on what works best for you--use someone who is not trying to sell the product they are installing, but has access to lots of options.

I would like to see this article contain information on old wood windows and the value, both financially and aesthetically, of retaining and restoring/repairing them to their original functionality. When combined with weatherstripping and good storm windows, old wood windows can perform as well as double pane replacement windows.

No one has said one thing about Solar Screens. What about them? I heard they are so cheap, and block actually 80% and 90% of BTU's. The ones I've seen even on old homes, instantly makes the home look newer. There sure are A Lot of companies claiming to do them. What are the Pros and Cons? Every single thing on here listed has both Pros and Cons. Apparently the Pros are enough for plenty of people out there. Thanks for all Help/Responses

Is there a rated window contractor in the 44235 area.

Looking for windows replacement. Zip code is 92841

I want to replace 10 windows and 1 big slider

I perform HERS Reports, Home Inspections and Energy Audits. Our staff is knowledgeable in assisting home owners locate loan officers who will help them through the qualification process of EEM's and EEL's guaranteed under the Stimulus Grant.

i had new windows put in and i notice that cold air is coming in through the tracks that the window goes up n down , they were top of the line windows, can u give me any information please

looking for replacement windows -Wichita Falls 76308

I both agree and disagree with Chris Betts - while caulking is in many cases a great idea, replacing (or starting out with) dual-pane, low-e glass windows with an argon gas fill WILL save on heating/cooling costs and we've seen it first hand. There's a good reason the top-of-the-line EPA building in North Carolina chose these windows! Look it up and see for yourself.

I am totally against unnecessary replacement of vintage wood windows. This report is a disappointment. I won't renew my Angie's List membership.

In my auditing practice, I find that window replacement has a very long payback period compared to other, less expensive improvements like reducing air infiltration, insulating, installing setback thermostats, and several others.

The post by Jonah on 6/28/09 is complete nonsense with regard to the tax credit available. The tax credit for qualifying energy property is 30% of the first $5000 of expenditures or a maximun of $1500 in the years 2009 and 2010 combined. Current law does not allow the credit to offset alternative minimum tax in 2010 but this could change. Check with your tax accountant.

With the consideration of out of pocket costs there is a far greater insulation benefit and dollar cost savings if you forego the window replacement cost and put that same money to work adding insulation, caulking and weather sealing have a energy audit done and install window film on all the homes windows. The benefits will be quite rewarding and some of this you could do yourself and save money.

As a certified home energy auditor, I agree that replacing your windows is one of the least effective means of reducing home energy cost. Identifying air leaks and caulking is more beneficial and a whole lot cheaper. Also, if you do choose to replace your windows you should also consider the issue of sound proof quality of the window. Once the windows are in it is too late to complain. In my opinion, many of the folks who sell windows do not really understand their product at all and pretty much tell you give the same old industry mantra. Be smart and know your product.

even though windows have improved. window film can still be applied on them. it will help to reduce heat and uv rays. Just try it.

I am a remodeling contractor and must say that the prices for replacement windows mentioned in some of these posts are ridiculous. I install energy star vinyl replacement windows that qualify for the energy tax credit for a price of $230 to $300 per window Labor and material. And yes, they do make a big difference in heating and cooling costs according to my customers, so there has to be a good return on investment unless you pay what some others have posted. I work in northeast Ohio...cold winters.

Regarding Kevin Stubbs comment on 11/18/2009 above, the data does not support your rebuttal. I just read the study quoted by John on 10/28/2009 and it supports other research which concluded that indeed, "Prime/low-E storm window combinations performed very similarly to the replacement window." I have done my homework. Jeff Johnson, B.S. Mechanical Engineering and owner of a house with storm windows built circa 1895

looking for window replacement in zip code 85256 area

Regarding Susanna's comment from 6/17/2009. You are dead wrong about wood windows with storm windows being as good as the new energy efficient windows. You have not done your homework. I have been in the window business for 19 years and I have toured several different glass and window manufacturing plants. The new insulated glass is SUPERIOR in several ways. Kevin Stubbs: president "Successful Investments Home Remodeling" South Carolina

Storm windows are a good option for those who do not wish to replace existing windows. The Lawrence Berkeley National Labs has a very interesting report comparing storm windows, both interior and exterior, to replacement windows. To quote from the first paragraph:"Prime/low-E storm window combinations performed very similarly to the replacement window." You can find the report at

Our policy is to explain to our customers full benefits of replacing old windows with new LOW E Energy efficient windows. Replacing windows with LOW E energy efficient windows improves the comfort level, lower energy cost/month, lower carbon foot print, higher resale value and much improved aesthetic value. Also, changing these windows allows them to earn upto $1,500 IRS tax credit. Based on 33% tax bracket, it helps shave off $4,500 from taxable income. In other words FED is helping you pay $4,500 towards the purchase of these windows.

Using low-e coated windows can greatly make your old window energy efficient and at a low cost.

I have leaded-glass windows circa 1930's. The old wooden storms are eroding and no longer provide much, if any protection. Any suggestions to improve efficiency without losing architectural design? Jaime

I have leaded-glass windows circa 1930's. The old wooden storms are eroding and no longer provide much, if any protection. Any suggestions to improve efficiency without losing architectural design?

What some of you have not mentioned is that you can achieve much more than energy savings with replacing your windows. How about impact windows for storm and security protection. If the glass does not break then you and your family are safe. That my friends is priceless. Film cannot provide that guarantee. A side note think about the look of new windows and how they provide a more modern look to an older home. The money you spend on new windows have always been a great source of return for your home.

Mim McNulty, Thank you for responding. As to whether a single or double pane window would be best for your location, we'd recommend that you consult a qualified professional. At, there are hundreds of window specialists in listed in Northern California. Best of all, you can see how other homeowners have rated their experiences with them.

I don't disagree that you can achieve some great performance benefits with new windows if your budget allows. However, if your windows are structurally sound, you can improve the performance greatly with the addition of window film for a fraction of the cost of replacement. Low-E window films are available to produce year-round savings with an installed cost per window averaging less than $90. We are a three time Angie's List SSA winner with hundreds of satisfied clients. Window film may not be the answer for everyone but it should not be overlooked, especially since most of our products qualify for the same tax credits as windows.

There is way to much to cover about windows to include in this small blog. I would not listen to anyone who has an opinion based on their own experiences. Look at who the U.S. department of energy recommends, or the Crime Prevention council. Not all windows are made the same - it's a fact. Look you can buy cheaper products everywhere, that's true with everything. When I do a project I would like to only have to do it once, especially when it is expensive. Lifetime warranties are sometimes only 3-5 years in most states. Check your state law on lifetime warranties. Lifetime only means the lifetime of the product, (which is determined by the manufacturer) not your lifetime.

Can wooden windows, 20 years old be covered with very good storm windows for a comparable result?

Window Films! Very affordable way to make an impact on your energy bill! If you have direct sunlight hitting your windows, then films work great. The major manufacturers of window films give a lifetime warranty with their products.

Most of these people are trying to sell you windows. What they are not telling us, or don't want us to know, is that you save more energy by air sealing and dense pack insulating than you ever can with new windows. And usually at a lower cost.

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