I am trying to decide what is best for insulating my new home. Looking back after doing research on this I wish I would have went with 2x6 walls. So in my scenario what would be my best but cost efficient way of insulating my new home. I am doing a sealed crawl space. The info below is the pricing I received on insulation.


It is a one story home with 9' ceilings. Tyvek house wrap is on (should I tape this?) Plywood sheeting and 2x4 studs. Electrical,hvac, and plumbing are all roughed in.


So I have been thinking about cellulose in attic and stud cavities. If I went this route I would try and air seal in some way. I took the ecoseal coarse so I can obtain the products. But again ecoseal may not be the most cost effecient way to air seal?


The other option would be to foam the stud cavities and cellulose in the attic. From my research I am pretty sure I dont want to foam the attic. Especially since I do not have ductwork in the attic and ridgevent is already in. I am welcome to all thoughts and suggestions? Lots of great info on this site and glad I came across it!



Walls Option 1
Install approximately 3 ½” to 4” of Icynene open cell foam in the exterior walls of the wood framed walls.
Cost - $3025
Walls Option 2
Install 3 ½” of cellulose in the exterior walls.
Cost - $1250

Caulk and foam air sealing package
Cost - $275

Attic Option 1
Install R50 Blown Attic Insulation
Cost - $1935
Attic Option 2
Install 6” of open cell foam over the sheetrock
Cost - $5000

Crawlspace
Install 10 mil poly on the ground in the crawlspace of the home, seal the seams, install approximately 1 ½” of closed cell foam on the interior of the foundation walls and the band joists, and install a hygrothermometer with a remote sensor that displays the humidity and temperature in the crawlspace as well as the home. You will need to install 2 supply vents in the crawlspace.
Cost - $3715

Please consult the “True Cost of Energy Efficiency” on our website. Keep in mind that at today’s interest rate on a 30 year mortgage, an additional $1000 in costs for foam only costs approximately $3.75 per month. An additional $10,000 spent on foam adds approximately $37.75 to your monthly mortgage. It saves you much more in energy costs for the life of the home including a smaller HVAC system and increased comfort.

I tried to space this out in short paragraphs but it didnt work when I posted it...

Which internet browser are you using.  Look at Navigating long threads in Suggestions/Feedback within this forum.

I am using safari. It shows all the spacing then I hit submit and it disappears

Quick Questions
What is the zip code?
Are the windows installed already?

Cheers,
Eric

Zip code is 35773 basically Huntsville AL

The windows are holding me up. They should be in middle of July. They are Loewen SDL(simulated divided light)
Thank you all for the comments

I would think the best bang for the buck would be external rigid foam. This greatly reduces the heat transfer through the wall studs, making the wall insulation perform much better.That, with cellulose and air sealing will give you decent performance. The heat coming through the studs is a big hit on R-factor with a thermal break. Someone here will come along with advice about what thickness the exterior foam should be.Blown cellulose in the attic as well, after doing a good job of sealing all of the penetrations. How big is the house? The price for blown-in sounds high. I paid 80 cents per square foot for R-50 here in SC, but quotes were all over the place.

Yes external foam would of been great if I would of planned ahead. The problem is my windows and doors are all for 2x4 walls. Also all my brick ties are already nailed up.

My square footage is right at 2800. All single level with 9' ceilings. It's looking like my unit will be a rheem 3 ton variable speed unit. Hvac guy says it's a communication system.

Here are a few exterior pics. Pics are there but they are not loading after hitting submit... Sorry

Another

Yes, tape the Tyvek, and seal the sheathing- there is no such thing as too much air-barrier redundancy.

If there is no way to add exterior continuous insulation, is there room add some on the interior? At 1.5-2" unfaced type-II EPS is still sufficiently vapor open that the assembly can dry toward the interior in summer, but not so vapor open as to create a wintertime moisture problem at the sheathing as long as you use only modestly vapor retardent interior finishes (standard latex is fine.) With 2" of EPS on the interior you would be almost doubling the wall performance over a 2x4 16" o.c. studwall w/o.c. foam or 2.5-3.5lb cellulose.

There is no real advantage to open cell foam over cellulose other than the air-sealing in this stackup. No matter what the density, there will be less than an R1 "whole-wall" performance difference between cellulose or o.c. foam after factoring in the thermal bridging of the framing. Since you took the course on how to do a good job with caulk type sealants, the much cheaper cellulose option is the way to go. Cellulose is also more protective of the structural wood, since it "shares" the seasonal moisture loads with the studs & sheathing, and can adsorb/release quite a bit of moisture without damage or loss of function.

The attic is pretty much a no-brainer- make it air tight and go with (code-legal) R50 cellulose rather than (sub-code) R20 open cell foam. Don't even THINK about punching a dozen recessed lights into that air-barrier though.

The 1.5" closed cell foam + ground vapor retarder in the crawlspace is about right.

Dana thank you for all the details. I will definitely tape the tyvek. I spoke with the eco seal distributor today and should pick that up sometime next week.

Is there specific caulk recommended for air sealing also? I have seen some recommend silicone where others say acoustical.

I really dont think I have room to add EPS on the interior. I guess the biggest issue would be my plumbing on my toilets. I am sure there is a way to add it and move the electrical boxes and it would be a matter of trimming the windows out on the inside. Maybe my best bet is just to air seal the best way possible and use cellulose? I will measure the toilets and see how much room I have and I know they also make toilets for smaller spaces but it would limit my options.

Are there any threads with pics or videos showing application of foam to the inside and how to attach the plugs?
Thanks again and Happy 4th of July

Using interior EPS on most but not all of the house is much better than not at all.

Be sure to have a blower door test done.

Can someone direct me to the details on the interior foam? Tried the search function but no luck so far. Also is EPS or polyiso recommended for interior?

I really wish I had installed a layer of rigid foam on my house. If you can do it since it is a lot easier than trying to retrofit later.

I am currently insulating an additions with a hybrid closed cell, 1inch, and open cell 5 inch combination. I put a while topic up detailing the project and it seems to have disappeared...
If you get frustrated at all with the pricing of foam in your area and start looking at DIY options, hit me up and I can tell you what I have learned and what is probably a good idea to avoid.

Also, after it is all said and done I am considering roofing foam in my crawl space over the moisture barrier. This is mainly because the ground mostly stays in the 60s and a little bit more robust liner would be nice as well as a little thermal insulation on those really cold nights. But mostly the ability to roll around in there on a creaper if I need to get to anything.

Would love to here more about the diy?
Also what exactly do you mean about the roofing foam verses the vapor barrier in crawl space?