[Equest-users] Low-E Window Film

[MattDubrovich at Eaton.com]

Low-e films reflect heat back into the space based on their emissivity
so you can expect heating savings even with a lower SHGC.  

 

I'd expect Window5 to include the correct emissivity and for that to be
passed through the glass definition to eQuest.  Is the film on the
correct surface in Window5?  If you were entering your glass in eQuest
using the simplified method you would have to change the emissivity
manually.   

 

Though this is from the manufacture, it's still an interesting read:
http://www.enerlogicfilm.com/pdf/EnerLogic-White-Paper.pdf

 

 

Matt Dubrovich 



 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Daniel
Knapp
Sent: Friday, May 27, 2011 9:23 AM
To: McArdle, Mike
Cc: equest-users at lists.onebuilding.org; Dan Raphael
Subject: Re: [Equest-users] Low-E Window Film

 

On 2011-05-27, at 11:05 AM, McArdle, Mike wrote:





Dan, Do You mean  decreasing the heat  load  ( not increasing )  

 

If the solar heat gain is reduced in winter, less heat from the sun will
enter the windows and the heating load will be increased. 





 

 

Thank you,  Sincerely,

 

Michael J. McArdle , P.E.

Buildings Engineer II, Project Manager

State of Vermont,

Buildings and General Services (BGS)

2 Governor Aiken Avenue

Montpelier, Vt. 05633

 

Office: 802-828-5650;  cell: 802-272-4828

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Daniel
Knapp
Sent: Friday, May 27, 2011 11:01 AM
To: Raphael, Dan
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Low-E Window Film

 

How does the film affect the U-value and the SHGC for the window?  It
sounds like the film is reducing the solar heat gain coefficient, and
increasing the heating load.  You should also keep in mind that outdoor
air loads can dominate the heating load in winter and that envelope
effects can be minimal depending on the climate and type of building.
You may want to look into the loads reports in the SIM file to see what
effects the film has on the building cooling and heating loads.

 

Cheers,

Dan

 

-
Daniel Knapp, PhD, LEED(r) AP O+M
danielk at arborus.ca

Arborus Consulting
Energy Strategies for the Built Environment
www.arborus.ca <http://www.arborus.ca/> 
76 Chamberlain Avenue 
Ottawa, ON, K1S 1V9 
Phone: (613) 234-7178 ext. 113
Fax: (613) 234-0740






 

On 2011-05-27, at 10:42 AM, Raphael, Dan wrote:






Has anybody successfully modeled window film installation using eQuest?
Specifically, I am trying to model the Vista EnerLogic low-e film (since
it is eligible for tax incentives).  I've used Optics5/Window5 to
construct the glass type using the EnerLogic applied film (NFRC ID#
2545) and imported that into eQuest.  When I test this retrofit in a
sample building, the savings are not what I expect (~65 yr. payback,
assuming $7 installed cost).  I would expect to see a payback somewhere
around 10-15 years.  What bothers me is that in the model, the heating
load increases, which would be expected for a typical window film, but
this film claims to have savings in all seasons due to the ability to
trap heat in the building.  If anybody has had any success in modeling
these window films and could provide me with step-by-step instructions
or any guidance, it'd be greatly appreciated.

 

Thanks!

 

Dan Raphael

Building Performance Analyst

Integrated Design Solutions

Architecture, Engineering, Interiors & Technology

1441 W. Long Lake, Suite 200

Troy, Michigan 48098

tel:   248.823.2171

fax: 248.823.2200

www.ids-troy.com <http://www.ids-troy.com/> 

 

<image001.png> <http://www.energystar.gov/> 

 

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