Attic temperature

[David A. Andersen]

A. Enter the attic or unfinished spaces that are not readily accessible or where entry could cause damage or pose a safety hazard to the inspector in his or her opinion.

Attic heat will kill you dead now or later!
You'll be gone before the Real Estate Agents gets off the phone and realizes you've been gone a while!

[Russel Ray]

Originally Posted by mcyr

If it's hotter than 80°F, Ms Margarita and Dr Cuervo head to the beach, not an attic!

If that is the case, you must not be inspecting the roof and/or the attic's too often. ha. ha.

Marcel

It does seem like Ms Margarita and Dr Cuervo are always at the beach, doesn't it. I shall have to put them on a time clock, I guess, to see if they're carrying their weight around the office here.

[Gregory Allen]

I just learned of a Realtor I knew just died of heat exhaustion.His elderly clients asked him to empty their attic of items and he got overheated.He came down out of the attic, got some water,went out on the porch , sat down and died.This happened last week in Wilmington , NC.His obit is here:
http://www.wilmingtonstar.com/apps/p...4025/-1/news11

We all need to be aware of the dangers we face everyday.
Safety First.

[gporter]

130 in the attic I was in today.

[Bruce A. King]

Some houses here have 2 water heaters and two hvac units in the attic.
I try to inspect those in the am but for afternoon inspections it is really hard. I have to do it in stages on real hot days and drink lots of water early in the day.

Most builders are only using soffit and ridge venting. The ridge venting is sometimes marginal due to length of the vents and lack of proper opening in the sheathing. Sometimes the ridge venting is blocked with felt paper or sheathing. Sometimes the soffit venting is partially blocked with insulation too.

[James M. Troth]

I have been using 30 degrees higher than the outside air as my rule of thumb. Are most of you measuring the air temp or rafter/truss?

[ebadofsky]

Originally Posted by jtroth

I have been using 30 degrees higher than the outside air as my rule of thumb. Are most of you measuring the air temp or rafter/truss?

Most of our inspectors measure air temp:

- 25-35 degree difference - acceptable
- 36-44 degree difference - marginal/monitor
- 45+ degree difference - ventilation needs improvement

You may want to check with your local code enforcement official for verification in Ohio. Hope this helps...

[William Warner]

I asked this question some time back and received the same amount of varying answers.
Many of the answers steered me back to the formula of 1 sq ft vent per 300 sq ft attic space with vapor barrier - per 150 sq ft w/o vapor barrier (of which I already knew). Regardless of code requirements, you can have this ratio of vent to attic space and still not have adequate ventilation for various reasons (mostly substandard building practices).
After much research, I have arrived at an answer to my question of "what the temperature differential between attic air and ambient (outside) air should be to indicate adequate ventilation."

Here is the rule of thumb I have implemented:

1. Attics should be very drafty areas during all seasons
2. Summer attic temps should be within 10 to 15 degrees of outside temps.
3. Winter attic temps should be same as outdoor but there is some lenience here.

Anything outside of these is an indication of inadequate ventilation whether it be poorly placed vents, blocked vents, not enough vents, no vents, etc.

Essentially, an ideal and properly working roof/attic ventilation system should provide the above parameters. Any thing else is not working properly or as intended.

This is my humble and researched opinion. Your mileage may vary.

[Marcel R. Cyr]

Has anyone come across this product yet and know how it's performance factor is. Seems interesting and somewhat an ingredient to lower attic temperatures in the South.

http://www.gp.com/build/product.aspx...rchy#question1

Marcel
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[Bruce A. King]

Not sure what those panels cost but I think it is one of those products that may not make much difference. Attic ventilation is needed which in turn will lower the temperature. That product could make someone think ventilation does not matter.

Some people from up north use that in the south and do other strange things like build deep walls to install R25 insulation on a brick house. Then they turn around and build on a crawlspace and allow floor insulation to be compressed in place which drops the R value considerably. Much of the cooling loss is through the floor in the south. If you want an energy efficient house in a cooling climate, build on a slab or put more floor insulation in, don't worry about the walls unless you are using vinyl siding. Also use R38 in the attic and install powered attic ventilators.

[Russel Ray]

I found those panels in a house a couple of months ago. I asked the seller about it and he claimed that the attic fan doesn't come on as much since he installed them, and that his utility bills have decreased. I told my Client to get the receipts for the work and inquire about any warranty on the panels, and to get copies of utility bills if the seller were willing to provide them. Everyone worked together and it did appear that the utility bills dropped by about 10% beginning at the time the panels had been installed.

[Marcel R. Cyr]

Thanks for the input RRay;
Never seen the product before and was curious.

Thanks;

Marcel

[dchew]

Radiant barrier do work especially in dry hot climates like central California and Arizona. The aluminum metal film absorbs the heat energy from the sun. A property of aluminum is that it has terrible emisivity properties which means that it can radiate the stored energy energy outward into the attic areas. That means it's much cooler in the attic and the house stays cooler.

In California, we have energy regulations commonly known as "Title 24". If you use radiant barriers in the attic area, you get extra credits for it in the energy analysis which you can trade off for more glass area.

If you're in the attic and see radiant barrier sheathing, it also suppose to be on the side walls of the attic too. Lots of time, it's not there. Not a biggie, but something to note in the report.

[Marcel R. Cyr]

Dwight;

Thanks for the information, I guessed that it had to be of some use somewheres and the logic behind the system only seemed to make sense. Reflect heat, attic stays cooler or not much hotter than the ambient temperature.

Thanks

Marcel

[Dan Bowers, CMI]

In 38 years of inspecting, building, and HVAC work I've never measured the attic temp unless out of curiosity as to how hot it is so I could tell everybody I was in a 145 degree attic today. Never met anybody in my area that did so OR talked about it if they did????