Hey Guys,

Im looking at buying energy efficient windows for my home. I hear they can considerably reduce heating loss in winter while keeping the place cool in Summer. Does anyone know rounghly how much they cost and are they worth the investment?

Looking here - https://priceexperts.co.uk/window-prices/energy-efficient/ - there’s a rough estimate. Does anyone have any experience cost versus benefit?


Tags: efficient, energy

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Windows are a long term investment and do not expect energy savings alone to justify replacing them.  In most homes, your limited dollars for investing in energy saving measures would not go to windows unless you had addressed other systems first -- air sealing, insulation, reducing plug load, etc. However if you are planning to replace windows anyway for aesthetic reasons or resale, definitely do your homework so you buy the more efficient models. You may be in a situation where replacing your storm windows would make sense. Here is a good basic place to start looking at options. https://www.energy.gov/energysaver/energy-saver

If you're looking for energy gains and your windows are old, here's my general approach: 

1) if they are old metal-frame windows, then replacing is probably a good idea as the metal brings a lot of outside temperature in (thermal bridging). Otherwise (as Barbara said) it's replacing mostly makes sense if you're looking for other purposes. 

2) But there's lots you can do to improve the efficiency of your existing windows. Start by making sure you don't have drafts coming in around the window - and air seal if you do. If it's real bad, you may want to remove trim and use (window-specific) spray-foam around the window. Second, look at ways to create an additional, well-sealed barrier. Typically this means some kind of storm window to create another barrier against the cold. Lots of different approaches can be done here with lots of different impacts, and can be done on the exterior or interior, ranging from $10 / window to $200 / window. Just make sure you can live with the aesthetics and that the seal around it is good so it creates another air barrier and creates an insulating layer with the air between the window and the storm. 

Caveat #1: All of this said, lots of specific factors can create different recommendations depending on your weather, goals, local climate, existing windows, etc. 

Caveat #2: This is my general approach for just generally improving efficiency. If you're looking for a deep retrofit (ala Zero Energy or Zero Energy Ready), then it may be a different story. 

Let's talk incremental cost.  You could buy double pane windows. Standard size about $10 - 15 per SF, Custom $25 - 30. EnergyStar Standard size $25 to 30, EnergyStar Custom $35 to 40. 

Ultra Premium (Triple pane, fiberglass frame, $40 to $60 per SF.   I am a fan of minimum effective dose methodology.  All of these are more expensive and less effective than R13 wall. 

So what is a window. Source of light, views, ventilation. What do good windows improve? Less cooling through tinting and thermal conductivity. Less heating by infiltration reduction and thermal conductivity. Less noise transmission. Possibly better operation, intrusion resistance, etc. 

Don't look for the energy savings to pay for the window project. Look for the best energy per dollar benefit.  Typically once you pass EnergyStar, the costs climb faster than the savings.  I have a sermon that I give on super insulating which also translates to ultra efficient windows. This improvement lowers the balance point of the building (temperature where the building changes from heating to cooling). This causes the building to require more cooling.  The good news is the additional cooling is the cheapest cooling, like when it is 55 deg outside.

If you look at the R factor of the window and compare it to old school single pain glass windows you will definitely see that energy efficient windows will save you money.  If you have old school tech windows then chances are you live in an old house that will benefit from new window installation by another means which is to say, installing new windows can rid the home of drafts.  Some sealing of the home can be accomplished during window installation since the installers will be looking for things that can cause drafts and will want to seal those matters in order to complete the job properly.  Technology as provided us with Lo E glass which blocks the transmission of infra red energy through the window and hence helps to keep or reflect the heat back into the house instead of it traveling through the window.  This improvement comes to us along with the double insulated glass construction that has a air space trapped between the two pains of glass to act as an insulator.  If you have large windows in your house, which are not very energy efficient then you have allot of energy loss.  Given enough of them.  Hence you might want to look more closely at your windows and what the market has to offer.

The range for energy-efficient window pricing is wide, but Energy Star-qualified windows start around $100 for a 35-inch-by-72-inch, single-hung window and can go up to 10 times that. With labor, you're looking at about $270 to $400+ per window.

In certain climates, energy efficient windows are certainly worth investing.  It depends on what you want to do with your home.  Vinyl windows do well on the coasts but are a short-term solution for harsher climates like Colorado and New Mexico.  Fiberglass windows are a long-term solution anywhere if you plan on staying in your home forever.  Wood windows are good for cold climates and historical home renovations but may require maintenance.  It all depends on what you want to put in your home for value and comfort. If you sell your home people always ding you on the windows and doors if they are falling apart, so replacing them before the sale may help also.

Hi Tom, lots of great replies on this already, which I agree with. I wanted  to express that software can come in handy for these types of situations. The software I work on has an optimization function that can model out thousands of combinations of different insulation, air sealing, and windows upgrades, and tell you payback info. We also recently added the ability to load weather data from non-U.S. locations. You'd have to modify the default cost data on the different improvements to align with local prices. It would be fun to work with you on this. Let me know if you want to explore. 

This was from a new window install that had fiberglass insulation stuffed around it before the trim was re-installed. Made me so sad, as the gentleman had cancer and was preparing the home for his wife when he passed! 

As far as ROI, my calculations put a good DP window at around 16 yrs! There are a lot of energy improvements with shorter ROI with much smaller upfront cost!

All great questions but are we to now require an ROI for jetted hot tubs and interior flooring? Of course not. We buy these items because they make us comfortable.

Comfort is defined by three primary components; air movement, humidity and radiant surface temperature. Properly installed windows affect all three factors.

I have always counseled our clients to replace the one window nearest to where they spend the majority of their time with a high thermal quality product before deciding to go cheap. Quality windows are a long lasting building modification that offers improved occupant comfort and reduced maintenance over many decades. They afford a higher interior relative humidity (CRF) in cold climates and cooler interior surface temperatures in hot and humid climates, where AC is king. We consider reduced maintenance and energy savings to be a side benefit.

Things to look for in high quality windows requires a bit of research. New replacement windows should ideally have:
Pultruded fiberglass frames
Frame and sash should contain rigid foam insulation in all available spaces
Insulated edge spacers separating glass panels
Two surfaces coated with Low e film
Gas filled interpane cavities (Argon or Krypton)
Double gasketing at all sealing surfaces
Casement design with good quality hardware

Leaving any one of these attributes out may negatively impact the comfort, maintenance and energy efficiency of the building. We have worked in northern latitudes over forty years (Alaska & Yukon) Shipping costs are high and so should be product quality. After all, it costs the same to ship junk, does it not? What is the ROI? ... this may not be the most important question to ask.

We have never sold windows. We sell good sound principles of building science. Ask your clients, do they want 50 years of comfortable savings or 40 years of uncomfortable, high maintenance, energy waste? Not convinced? Try installing one near your favorite place to relax before committing to products not providing the benefits considered here.

To add to your research, here's an article about storm windows: https://indowwindows.com/resources/storm-windows-guide/.

The company I work for manufactures interior storm windows that require no construction. They're custom made for your window so just press into place. They provide the energy efficiency and insulation of double pane windows, but cost less and are easy to remove and reinstall. Because they are custom built for your window, they create a well-seal barrier.

I've only been working here a few months, but I've seen/felt it work. We use them in the office (I sit next to big windows and live in a place with lots of cold and rain). I've also read tons of genuine customer comments. It's a quality company where the employees really believe in the product. Some even have Indow inserts in their home! 

I know I'm biased, but it does work and it's a good option to know about.

We purchased Indow window inserts (interior storm windows) for our house built in 1860. The increase in comfort is significant. The dining room used to be freezing cold and now is comfortable.

To really know how much you are going to save it is important to know the current condition of the windows you have.  It will be much more worth your investment to hire a window replacement company, if your windows are more than 10 years old, have some defects and you notice things drastic temperature fluctuations in certain rooms.  Our window replacement company in Denver prides itself in being energy professionals FIRST and if you can find a company that will give you genuine advice and numbers, you should be in good hands.


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