Currently reading Tauton’s “Graphic Guide to Frame Construction” – great book BTW. I am looking at beefing up the insulation in my 1940’s stucco home in Sacramento. The Tauton book frequently recommends installing the vapor barrier on the “warm” side of the wall, in a cool climate.
My question – is Sacramento a warm or cool climate? Compared to Alexandria, VA. Sacramento is warm. Compared to Los Angeles, Sacramento is cool (for the most part). Our average summer high is 90-100 degrees Fahrenheit, requiring a fair amount of air conditioning. In the Winter it probably gets not much lower than 20 degrees at night – not too cool, but low enough to cause condensation on the remaining single-pane windows. Is Sacramento warm or cool?
Replies
My guess is hot/dry.
http://www.buildingscienceconsulting.com/designsthatwork/hygro-thermal.htm
http://www.buildingscienceconsulting.com/designsthatwork/hotdry/default.htm
Polk around that site, lots of good info.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Looks like it is hot-dry. Thanks for the link. So much reading - so little time. But doing the research first sure beats doing the work twice!.
Great site. I don't know if it is my browser, but for some reasons a bunch of ?the? text ?seems? to have ?question marks all over the place.
Fascinating stuff, however.
101310.4 in reply to 101310.3
Great site. I don't know if it is my browser, but for some reasons a bunch of ?the? text ?seems? to have ?question marks all over the place.
Fascinating stuff, however.?that's just ? the ? beer goggles :-)????
Sacramento has 1237 cooling degree-days (base 65º) and 2419 heating degree-days (base 65º).
Don't have Alexandria, but Richmond, Va is 1348 cooling/3865 heating.
A degree-day accrues for every degree the average outside temperature is above or below the target temperature for a 24 hour period.
PAHS Designer/Builder- Bury it!
I am SUCH a dolt!What does:A degree-day accrues for every degree the average outside temperature is above or below the target temperature for a 24 hour period.mean, then? In other words, what is the meaning of the the avg outside temp being above/below the target temp?
If you measure the average outside temperature for each 24-hour day during the heating season and calculate the delta-T or difference between that and the indoor setpoint temperature (standard is 65°), and add each day's delta-T for the entire season, you'll get the total DD for your locale.
Or, you just look it up or call any fuel supplier in your area.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong get you squared away?
I've found it surprisingly common that folks talk about their climate and have no idea how untemperate it really is. Heating and cooling degree-days are the common denominator.
Around here, many would say cooling's as important as heating. But the cooling degree-days are only 27% of heating. Even if I haven't had an opportunity to test drive my new-to-me toboggan. <G>PAHS Designer/Builder- Bury it!
VaTom,Yep that helped. Seems like the vast majority of books on this subject are written from an East Coast perspective - with sidebars regarding mixed or "cooling-required" environments. Anyway, the light-bulb is beginning to turn on.- - Greg
Goes well beyond East Coast.
Had a conversation with the Spokane house designer, who coined "annualized geo solar", a take-off from PAHS (passive annual heat storage), who opined about his very hot summers. >90º common. When I pointed out that he had only 398 cooling degree-days, he shut up.
The house he was bragging on grossly under-performed mine, when climate corrected. Otherwise, it was great.
Perspective is good.
Comparing my performance to a Vermont house awhile back, they were thrilled with only 4x my modest heat need. But it was in a climate with only twice the heating degree-days here. Not that my house is all that efficient...
You get the gist.
BTW, I was surprised to learn there are parts of Texas with zero heating degree-days, only cooling degree-days. Lots of 'em.PAHS Designer/Builder- Bury it!
I know you guys are not big fans of fiberglass insulation in a wall - but the exterior wall is only 8 feet wide - so I am leaning towards fiberglass batts vs compressed cellulose. Would a Kraft Paper faced fiberglass batt act as a vapor barrier? IE - the batt facing I should avoid is aluminum faced?
both the foil & the kraft are pretty good vapor retarders
it's the edge leaks that defeat itMike Smith Rhode Island : Design / Build / Repair / Restore
You're in a mixed heating/cooling climate, so you should not install a vapor barrier anywhere in the wall system. Make the walls as air-tight as possible and allow them to breathe (water vapor) in both directions if possible.
Solar & Super-Insulated Healthy Homes
No barrier anywhere - makes it easy, doesn't it?
I found my biggest air leak yesterday - don't forget to close the chimney flue. Duh. You can tell that I grew up in a much warmer climate.