I have a couple questions for the experts on radiant barriers.

1. Are they worth the expense in reducing utility bills in a hot
climate?

2. Is there a preference between the paint and a physical barrier
stapled to the rafters.

It seems that using a physical barrier on the rafters would block
air flow.

Suggestions please. Thanks in advance.

Bob-tx

On Mar 30, 6:19*am, "Bob" wrote:
I have a couple questions for the experts on radiant barriers.

1. Are they worth the expense in reducing utility bills in a hot
climate?

I've never seen hard, actual data that proves they are, but the
consensus does appear to be that they work and are worth the cost.
The material is maybe $100-200 for a typical attic, which you should
recover relatively quickly if you use AC in an area that gets
reasonably hot.



2. Is there a preference between the paint and a physical barrier
stapled to the rafters.

I've only seen either the stapled type or else the similar type that
is already applied to sheathing. Never knew paint type existed. If
you have 2 people, IMO, it's going to be a lot easier, cleaner, faster
to staple.



It seems that using a physical barrier on the rafters would block
air flow.

You leave an open area of a foot or so at the bottom and the top.
This leaves plenty of space for air to enter at the bottom and exit at
the top, preferably through a ridge vent. If you don't have a ridge
vent, then I would think it could impact air flow through a gable
vent, etc.




Suggestions please. *Thanks in advance.

Bob-tx

Bob wrote:

I have a couple questions for the experts on radiant barriers.

1. Are they worth the expense in reducing utility bills in a hot
climate?


yes

2. Is there a preference between the paint and a physical barrier
stapled to the rafters.

It seems that using a physical barrier on the rafters would block
air flow.


probably, but you don't cover 100%, especially at the top and bottom, so
air will still circulate

Suggestions please. Thanks in advance.

Bob-tx




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Joseph Meehan wrote:



wrote in message
...

On Mar 30, 6:19 am, "Bob" wrote:

I have a couple questions for the experts on radiant barriers.

1. Are they worth the expense in reducing utility bills in a hot
climate?


I've never seen hard, actual data that proves they are, but the
consensus does appear to be that they work and are worth the cost.
The material is maybe $100-200 for a typical attic, which you should
recover relatively quickly if you use AC in an area that gets
reasonably hot.



2. Is there a preference between the paint and a physical barrier
stapled to the rafters.


I've only seen either the stapled type or else the similar type that
is already applied to sheathing. Never knew paint type existed. If
you have 2 people, IMO, it's going to be a lot easier, cleaner, faster
to staple.



It seems that using a physical barrier on the rafters would block
air flow.


You leave an open area of a foot or so at the bottom and the top.
This leaves plenty of space for air to enter at the bottom and exit at
the top, preferably through a ridge vent. If you don't have a ridge
vent, then I would think it could impact air flow through a gable
vent, etc.




Suggestions please. Thanks in advance.

Bob-tx




I agree with trader and suspect that the physical barriers would work
better since they would create a separate air space as well and that
would increase the insulation. Remember you want to keep the shinny
side clean.


You want to keep one side that adjoins free air clean. I don't think
it really matters whether it's the shiny side or not.

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On 2008-03-30, CJT wrote:

You want to keep one side that adjoins free air clean. I don't think
it really matters whether it's the shiny side or not.

Yes, it need to be the shiny side. A radiant barrier is a shiny
surface with an air gap next to it (so there is no conduction). If
the shiny surface gets dusty, then you no longer have a radiant
barrier.

Cheers, Wayne