×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Heat Gain from Lighting

Heat Gain from Lighting

Heat Gain from Lighting

(OP)
I am doing a cooling load calculation on a small office building <2000 sqrft.  It is a pre-engineered steel building, r-19 roll insulation at the roof deck and r-19 batts on top of the lay-in ceiling.  

When calculating the heat gain from the lay-in light fixtures should I use a multiplier to decrease the heat gain as a result of some of the heat being transmitted to the 'attic space'?

best regards,
Darrell

RE: Heat Gain from Lighting

I find the difference is minimal, and generally do not account for it, becasue if some section is not properly insulated, you can easily lose any credit, and have an increased infiltration load.

knowledge is power

RE: Heat Gain from Lighting

The only thing to confirm is that, if you put insulation over the luminaires, make sure the luminaires are rated for that application. Insulation will prevent them from dissipating heat from the back.

RE: Heat Gain from Lighting

It looks like you will lose much heat to the attic. It sounds like that ceiling is not sealed and much air ex-filtrates and infiltrates somewhere else. I assume you inquire about cooling calcs. For heating you shouldn't account for the heat gain from lighting.

don't put insulation on the lights unless they are IC rated. Also, the ballast will die sooner being warmer.

If my assumption of your leaky building is true, the heat gain from lights is your smallest problem and you need to assume more infiltration.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources