CJT wrote:
CJT wrote:

louie wrote:

Adding 6" of cellulose to the attic will help tremendously, so long as
the soffit vents are kept open with some baffles. You'll add an
average R value of 3.5 per inch of the cellulose so you'll increase
your attic insulation from R-19 to R-40.



Which is what, about 3% difference in heat loss?


Oh, and that's the heat loss through the attic, which is only a
fraction of the whole-house heat loss.

As you can probably tell, I'm skeptical.



Other things you can do is move around your house with an incense stick
looking for drafts. Seal up as many drafts and leaks as you can.
There are professional services that will install a temporary blower
into a doorway and will actually pull air from the house, creating a
slight vacuum. Then they will actually test how much negative pressure
is created and how much air volume is moving through the fan and from
that determine how "leaky" your house is. They usually go around with
a smoke pencil looking for leaks while this is happening too.


I think it will be more than a 3% saving. Say the temp difference from
inside to outside is 50 degrees. The heat flow with R19 insulation is
50/19 = 2.6 in some arbitrary units like BTUs per fornight. With R34
the loss flow will be 50/34 = 1.8 in the same units. So in some amount
of time the heat lost will be (2.6-1.8)/2.6 = 0.31 or 31 per cent less.