I know your question is not directed toward me, however I figured you would not mind if other people chimed in :)

Without knowing your location, that affects higher r recommendations. However assuming it is mild, then air sealing should be your #1 (in any climate).
"caulk to code"...I am not exactly sure what he means. However what SHOULD be caulked chances are is too late. Ideally for better air sealing, caulking sill plates, head plates, exterior sheathing to studs, etc are just a few of the places. Exterior penetrations (outlets, plumbing, hvac) should be caulked and sealed. Think like air and water. Any place it can get it, it will. Caulking is super cheap and will be the cheapest possible energy enhancer you can do in your house.
What are you using to get to r-19? batts? Look into blown products such as cellulose or fiberglass. It will give you a better insulation value and help to seal up your house better than batts will. It is usually priced right between foam and batts, usually closer to batt price.
Same with the roof. Assuming you do not have unusable attic space, blow cellulose into your attic instead of foaming. Foam, even open cell, is one of the most expensive ways to insulate your house and rarely hitting a ROI. Caulk and cellulose/blown fiberglass will achieve nearly the same thing (will not have as high of a perm rating as closed cell however, nor have the structural advantages).

Finally, for the windows, you can easily do that yourself, however most insulators include that in their package. There are really 2 kinds of foams off the shelf for DIY window sealing. Standard expanding foams and low expansion expanding foams. You want to use the low expanding one to keep stress off of the window frames.

R-13 walls and foamed windows and doors by insulation contractor. I too was worried about messing up windows and their cost was very reasonable ($200 I think). They had a $500 caulking package which my builder talked me out of. Caulk to code sounds like a joke - code allows huge air leaks.

I did do some areas with caulk myself. I foamed with cans my 2nd store ceiling (ie attic) which was eye opening. What you find is huge holes particulatly around bath fans but all electrical penetrations had significant leaks (smoke detectors, lights etc). I'm convinced this made a huge difference. I was also caulking around OSB used in the knee walls and various wall areas. But none of these holes were anything big and then the whole area was getting covered with drywall, base and crown to give a further barrier to air movement. So some of this seemed like overkill but the attic was definitely not overkill.

I know lezarc hates batts. But in the South, I'm just not sure there is much of an issue. The primary focus is air infiltration and while there are better barriers than batts, nothing beats foam and caulk in the right places. I think r-19 batts is fine for your area and 99% of the effort should be on air infiltration (and 90% of that into the attic).

After that - shade trees on the west facing windows.

Thanks to both of you for chiming in! We do have old growth woods in the back and a tiny back yard - facing due west. Because we are 3 stories back there (walk out basement) we likely won't be able to plant anything tall enough to make a huge difference there anyway. Basement is covered by a raised stone terrace, but family room that runs across the back of the house has 3 sets of french doors.

I too thought caulk to code sounded like a joke. . . and yes, we were planning on batts (mild climate but 6" exterior studs). We had priced out r-21 but David has me convinced that the upcharge is not worth it from a payback standpoint.

Thanks again!

And as far as too late, not sure what you mean. We haven't even started framing yet (next step is waterproofing the basement after the walls cure some more) so we should be able to do everything at this point. . . .

its not really that I hate batts per say, but like many things in construction, they have to be installed PERFECTLY to come close to achieving their claimed performance values. Even with pro installations, and easy rule of thumb is batts will perform just over half of their advertised values. R-19 will really perform closer to r-10-12 clear wall values due to voids around outlets, over compacted installs, and various other install issues. Blown products are marginally more expensive (sometimes not if the insulator prefers blowing instead of batts, some do) and your performance values will be much closer to the advertised values. Cellulose in a 2x6 wall will be just under r-21, performing around r-18. Plus its a greener product, is a much better air buffer and sound buffer due to its densities. Blown fiberglass will get you a higher r (around 23, performing around 19).
Many people think northern climates you need high r to keep cold air out. While that is true, one thing remains the same no matter what climate you are in. Insulation also keeps conditioned air IN.
Like mentioned, air sealing first, and then focus on keeping that conditioned air in.
but then again, being in my colder climate I am used to going more crazy over the wall makeup and construction methods. Sometimes I have to tell myself something under r-30 is just fine for other places! :)

lzerarc and david, I really enjoy your posts. We are still in the design phase so I am collecting information for all things construction. This post is saved as, "Think like air and water-Caulk". lol
Nan

talk to your builder about caulking sill plates to the floor sheathing. Sheathing to the face of studs. Every connection between 2 hard elements such as wood to wood, wood to concrete, etc should ideally have some sort of flexible sealant applied between them. THe house settles, expands, contracts...gaps and joints open up over time. Doing the simple fast task of caulking between items at this stage just keeps it tighter and sealed longer then surface caulking (for example caulking a crack of 2 objects instead of a bead between the objects which is best since you are not started).
good luck on your build, and nice to hear you are really putting this to thought. just realize, EVERY builder I have ever talked to for my projects always objects to details and specs because they do not understand, see the point, or do not share the same values for efficiency. I am not sayings yours will, but just be prepared for them to attempt to talk you out of it. If not, then IMO you have yourself a good contractor!

I'm all in favor of foaming around windows and doors. But it has to be the low-expanding stuff (which also cures kind of soft as opposed to hard like the regular poly foam). The flashing (as noted by energy rater in the other post) is the key thing to get right beforehand.

Assuming you'll have lots of windows and doors, it probably makes sense to have the builder do it. My guess is that it'd take 1/2 to a day to DIY. If you do the whole thing yourself, I'd recommend getting a gun instead of just cans. Much less waste because easier to control.

I picked my Great Stuff gun at Kentec in Lilburn. I keep meaning to re-stock on foam b/c I have some more places to seal up (old house- never done).

Thanks! I talked to the builder about my concerns about air infiltration and he said when they frame they caulk sill plates to the floor, along with some other caulking stuff I didn't understand (but I remember you mentioned that)and use low compression foam around windows, doors and all protrusions. That sounded like a good start.

As far as caulking the sheathing to the frame, do you mean run a bead of caulk on the exterior of the stud before applying and nailing the OSB?

I also asked him about the Huber Zip system sheathing and he said he had never used it, but had been "watching" it. I noticed on their website that there is a 900.00 rebate for first time builders who use this product. This may bring it closer in line to standard OSB and house wrap. Any thoughts on this if it is cost competitive? Is it worth more than OSB and caulk (my concern of course is that how do you know they have caulked and where they have caulked?) Is it a "proven" system (in other words, can I be confident that it will work and won't fail, disintegrate, etc. (new building products concern me!)?

My builder is fine with batts in the walls in this climate if we focus on air infiltration. He did say that foaming the rafters can be beneficial and it has the proported benefit of perhaps lengthening the life of your HVAC stored in the attic. It is a 7,000 adder for us though and we talked about payback times and David's decision in a similar climate along with the fact that it may not be beneficial to extend the life too much (ours are over 18 years old now) given the rapid changes in efficiency, etc. We have come down on the side of no foamed rafters . . . and since it is time to design the roof vents, etc. that is a done deal!

about your osb and caulking question, yes, that is exactly what I mean. Some builders like to go one step further and use liquid nail too. This enhances the connection and rigid frame of the walls. However even I think it is pushing the line of overkill.
ZIP is a great product. Prices around here have been about just under 2x the price of osb per sheet, plus tape. However with that price you can also eliminate the air infiltration barrier (tyvek) and the labor involved with the osb. After those discounts, it prices pretty close. Your builder can also qualify for discounts on first time users as well. It installs just like osb, and they simple tape the seams with a roller Hubber provides that works great. It is a waterproof and air proof system. Tyvek is never installed correctly (with staples) and has thousands of tiny holes in it because of that. Hubber sheathing gets your house air and water tight as soon as its installed and taped. I do not know your house size, however in the whole scheme of things, it should work out to be a small add, but well worth it IMO. You can also use it for the roof as well and eliminate roofing felts.

This may be a dumb question, but at what "air-tight" point do you have to worry about some type of fresh-air ventilation system? (I'm not sure I have used the correct terminology.)

any of the above mentioned sealing would require an ERV or HRV. I am of the opinion that most (if not all) new homes should have them anyway. It really aids in better indoor air quality. Anytime you use SIPs or ICF, they are required. The use of exterior foams sheathings, ZIP sheathing, etc, you should have one. Any time you use spray foams you should have one. Code minimum 1/2" osb on wood studs with batts does not really need one, however, like I said, the 2k add (typical) is well worth it for indoor air quality.

Thanks for all the input! david_cary, curious if you used radiant barrier in the attic. I know you talked about it before. I think we are using the same energy star company.

you don't know if you require a mechanical fresh air unless air changes per hour are determined.
this is usually done with a blower door test & mathimatical equation to determnd ach.

ashrae 62.2 ventilation standard
determines how much air to be added.
doesn't have to be erv, but can be
barometric damper.
we use the barometric damper
filter back grill located under porch or
patio (clean air before entering system)
duct to return side of system, with barometric
damper. clean the air, control amount of air
and dehumidify before entering the house.
much less cost than erv, and better performance
in my experience.

best of luck.

I used a radiant barrier. Very cheap. Probably doesn't do a lot if you don't have ductwork in the attic. An ORNL study showed a very small improvement with good attic insulation.

I think if it is cheap and you have an airhandler and/or duct work in the attic, it is a no brainer. If your ductwork is not in the attic, it might be more cost effective to upgrade the attic insulation. The radiant barrier does keep the attic a bit cooler if you store things up there.

If you are using the same rater, it should be noted that they really overestimated some things. They had $1350 for heat and it is close to $500 (obviously some of that was improvements but that is way off). The cooling was about right at $500. That despite higher seer, better air sealing and a radiant barrier (but I have to admit we sleep at 65 degrees....)

How do you find an energy rater? We definitely want a blower door test done. Do they make recommendations as well?

Builder suggestion. I inquired about energy star designation and he sent them the plans. That designation cost about $800 which included blower door test and an audit with recs. The designation also gave 5% off electric and NG for life (2 seperate companies).

The discount is small but it makes the $800 paid for in about 10 years. I spent another $500 upgrading particular things that they require (foam around windows) and that probably pays back even faster. I do think it would be a resale advantage if that ever comes up.

I would give Southface a call about doing your blower door test (at least- they do a lot more). They can either do it or point you toward a contractor who can.

Here is a link that might be useful: Southface Energy Institute (residential services)

another source for energy raters:

http://www.resnet.us/directory/raters