What window? Where in the South eastern area? Low-E could mean low-E on surface 2 or 2 layers of silver that make up the low-E coating. You could have “Low-E 2” applied to surface 3 as well .

We are selecting a vendor as the "required vendor" for all installations on our property. There are two buildings with windows in the living rooms, the bedrooms off the balconies, french doors, etc. This is in Atlanta, GA, and the property is surrounded by a lot trees. We are making an architectural requirement decision and trying to gather as much information prior to making that call.

What toddinmn is saying is we need more info on the glass packages proposed other than just Low E2 vs 3.

This is all I know about the windows: The window product is: Infinity Ultrex Fiberglass Advantage from Marvin Windows with fiberglass frames and sashes.

Do your homeowners complain about how HOT their units get? If you have a significant amount of owners who feel it is hard to keep the units cool (ie. their air conditioning costs are SUPER HIGH) then go with the better/higher grade window.

The cost savings for the cooling conditions is worth considering. The down side = plants don't grow indoors.

Here's what the website says about the DIFFERENCE between the two:

Energy Star Window & Door Replacement | Infinity from Marvin (infinitywindows.com)

Low E2

Low U-Factor
Medium solar heat gain

Low E2 offers year-round performance in moderate climates. It will help retain heat in your home during the winter and keep heat out during the summer. Low E2 has two layers of metallic coating. It also blocks 84% of the sun's UV rays to reduce fading.

Low E3

Lower U-Factor
Lower solar heat gain

Low E3 rejects solar heat while letting light in, resulting in increased performance in climates with intense sun exposure. Low E3 has three layers of metallic coating. It also blocks up to 95% of the sun's damaging UV rays.

And to be clear, Atlanta GA is NOT considered 'moderate' climate. It is HOT. That means it is considered extreme (heat) climate.

Check with your homeowners. Do a basic questionnaire for your homeowners. Ask WHO has issues with HEAT. Ask who places more importance on HEAT REDUCTION than on material costs. And then ask if $80/unit is worth it to the owners if they get BETTER heat reduction.

I bet you will find the answers to your questionnaire will help drive your decision for your community. It's democracy at its best.

Thank you for your feedback. It is $80 per window. Are you referring to window when you say, "unit"?

Yes. Unit = window.

Another related question: Is it possible to acquire this same product on my own and negotiate maybe lower labor costs with another vendor? For example, we are telling our community they must use this vendor. Question: Is it possible that another window installer could procure the identical windows, in all dimensions and specifications, form the manufacturer? And, if so, is it possible that the labor costs could be different than what has been quoted? I am just trying to make sure we are able to answer all of the questions and determine if this particular window installer has exclusivity over this product.

You will have to call the manufacturer. It is possible they have other licensed vendors in the area...or it is possible this vendor has exclusive rights to the location.

Remember: Cheap labour works out to be more expensive in the end. Do your homework about local LABOUR costs for window installation (other people using other labels) and then check to see if your vendor has quoted something in the same range. So long as they are in the range then you can be assured you are paying "Industry Norm" for installation/labour costs.

Thanks much! Not really looking for "cheap labor". Looking for quality labor, while making sure that we are exploring ALL options for our owners. I have worked with a lot of vendors and have found that costs doesn't always equate to "quality". So, I want to make sure that we are doing our "due diligence".

LoE glass helps keep homes warm in the winter as well -- it helps reflect heat indoors. so it's not just about the sun. in the long run, LoE3 could be a better value for heating and cooling bills year round. And it will do a better job preventing fading on their furniture, etc. But unless it gets really hot in the summer where you are, you might be fine with LoE2. The higher the "E", greener the glass looks and some people don't like that.

Note that some cities offer rebates or tax credits for things like this, so that's worth looking into.

The other question that has been asked is can plants grow in the presence of Lo E3 glass? I have read mixed reviews: "yes....might be good for the plants" AND "no...might have problems".

that might be a better question to ask the gardening boards. some of the people over there never check the interior decorator side. or take it to reddit. for example: https://www.reddit.com/r/HomeImprovement/comments/hjqgrp/thoughts_on_loe_window_coatings/

or post your question to https://www.reddit.com/r/houseplants/ 

The UV rating (or block) is a good indication of what you are getting into. The UV is what allows plants to photosynthesize = growth. If you block more than 50% you start losing plants. Once you get above 75% you get into the 'death of plants' range.

Both of your options are well above the 75% blockage. The Lo E2 = 85% UV block. The Lo E3 = 95% UV block.

Ask the vendor about the viability of having indoor plants with their UV block above 50%. They will have the best answers.

Your vendor Will probably give a blank stare.