Leeh wrote:

I am purchasing a new house (2400 sq ft, 4 bed rooms) in San Diego.
The builder asked me if I want the inside walls insulated just like
the outside. They mentioned two benefits: noise reduction and better
insulation(windows in one room could open). The cost is $1250.
I like a quite house and this seems like a good option to have. But I
don't want to waste money if the benefit is minimum. Any suggstions?

It's a standard feature in the higher end homes around here on what they call
"sound walls". Those are walls with water pipes or between bedrooms. Also
between floors near the bedrooms.

I wasn't real impressed as the insulation they use on sound walls is R-11 -
hardly worth the effort. I did pay for blown damp cellolose on the sound walls
though. That's dense enough to really work.

--
"Tell me what I should do, Annie."
"Stay. Here. Forever." - Life On Mars