Getting house built, need advice for insulation

[Tiamat]

ATOT, this is my first home and I wanted to get the insulation right the first time so I don't have any regrets. This house will be in Virginia, around Quantico area. $15k option is hard to swallow. I'm hoping I don't need to spray foam the entire exterior... but I'm willing to hear opinions.

Thanks!


House is 3800 sqft.

I have the following options:

1. Spray foam for exterior walls & ceiling (R38) – $14,910

2. R15 Batt for exterior walls from attic to band board & spray foam in attic in addition to standard attic insulation (R41) – $6,200

3. Spray foam for attic only – $5,460

4. R15 Batt walls only with R38 attic (no spray foam) – $1,500

 

[Jadow]

yeah it will take a lot of years to make up the added up front cost of the 15k option.

VA isn't like living in northern MN or southern FL either, I'd do option 4. You can always spray foam in the attic later if you want.

 

[MikeyIs4Dcats]

http://www.ornl.gov/~roofs/Zip/ZipHome.html

whats the R value of the spray foam?

 

[Tiamat]

http://www.ornl.gov/~roofs/Zip/ZipHome.html

whats the R value of the spray foam?

I believe it is R38 Spray foam.

 

[Modelworks]

I would go with option 2. Va gets cold but no need to prepare for the perfect storm

 

[sdifox]

so option 2 gives you overall R41? and cheaper than option 1?

 

[Tiamat]

so option 2 gives you overall R41? and cheaper than option 1?

Option 1 and 2 give substantially the same overall R41. So, right now Option 2 is very high on my opinion list. It seems to be price/performance leader.

However, I was uncertain if even Option 2 is overkill for Virginia. I lived in Boston for 7 years and upstate NY for 18 years prior, so for those regions, I could see getting the maximum insulation...

 

[MikeyIs4Dcats]

http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table


One advatage of the spray foam is it will seal the envelope of your home much better, eliminating drafts which are the biggest cause of wasted energy.

 

[sdifox]

Option 1 and 2 give substantially the same overall R41. So, right now Option 2 is very high on my opinion list. It seems to be price/performance leader.

However, I was uncertain if even Option 2 is overkill for Virginia. I lived in Boston for 7 years and upstate NY for 18 years prior, so for those regions, I could see getting the maximum insulation...

insulation helps in the summer too.

 

[EagleKeeper]

Lived in Fredricksburg for 3 years and cross the river for another two.

The R38 would be an overkill.

We would get 2-3 times at the most per winter when it became real cold - near zero.

I think that it will take 10-15 years to save the extra $30-50 per cold snap.

Plant a few shade tress and evergreens to help with the cooling issues for the summer.
Plus in 5-10 years, the shade trees can support a tree house and tire swing. Perfect size for a son!

 

[sdifox]

Lived in Fredricksburg for 3 years and cross the river for another two.

The R38 would be an overkill.

We would get 2-3 times at the most per winter when it became real cold - near zero.

I think that it will take 10-15 years to save the extra $30-50 per cold snap.

Plant a few shade tress and evergreens to help with the cooling issues for the summer.
Plus in 5-10 years, the shade trees can support a tree house and tire swing. Perfect size for a son!

tree roots will get to your house though.

 

[Tiamat]

Thanks for the comments folks! I'll be reading this as long as their are comments added. I have to make a final decision this monday.

 

[sdifox]

op what is the R value the government website tells you to get?

 

[lupi]

but, even though virginia is going to be a good bit midler winterwise, he does have a good sized interior and the extra insulation throughout could help there.

 

[Scarpozzi]

You lose the most heat out of the ceiling. Second to that is air leaks around doors/windows....third is walls....last is floor.

If you have a leak in your ceiling (air leak), it can cause a chimney effect that will essentially suck cold air in the house as the warm air exits.

If you don't have the cash for the whole job, spray insulate the ceiling and use R15 in the walls. Option 2 makes the most sense. Just make sure you have house wrap on your exterior walls as an air/moisture barrier between the walls and siding...whatever you go with.

 

[Tiamat]

You lose the most heat out of the ceiling. Second to that is air leaks around doors/windows....third is walls....last is floor.

If you have a leak in your ceiling (air leak), it can cause a chimney effect that will essentially suck cold air in the house as the warm air exits.

If you don't have the cash for the whole job, spray insulate the ceiling and use R15 in the walls. Option 2 makes the most sense. Just make sure you have house wrap on your exterior walls as an air/moisture barrier between the walls and siding...whatever you go with.

House comes with "Dow® Weathermate* Plus energy efficient housewrap"

 

[Tiamat]

op what is the R value the government website tells you to get?

R38-R60 for Attic

 

[Squisher]

You lose the most heat out of the ceiling. Second to that is air leaks around doors/windows....third is walls....last is floor.

If you have a leak in your ceiling (air leak), it can cause a chimney effect that will essentially suck cold air in the house as the warm air exits.

If you don't have the cash for the whole job, spray insulate the ceiling and use R15 in the walls. Option 2 makes the most sense. Just make sure you have house wrap on your exterior walls as an air/moisture barrier between the walls and siding...whatever you go with.

I agree with what you're saying, but I wonder whether the bulk of energy costs in Virginia are for heating or cooling? If it is 40/60 heating to cooling then he'd want to put emphasis on the walls, windows, and floors and less on the attic as MikeyIs4Dcats link might show along with return on investment for each.

 

[sdifox]

R38-R60 for Attic

no mention of walls?

 

[Tiamat]

Using the ORNL.gov site and the simplified R-value calculator:

Attic: R49
Wall Cavity: R15

 

[sdifox]

Using the ORNL.gov site and the simplified R-value calculator:

Attic: R49
Wall Cavity: R15

option 2 it is :biggrin:

 

[Tiamat]

option 2 it is :biggrin:

How would i get the attic from R41 to R49? With that spray stuff, can you even add more insulation?

 

[sdifox]

How would i get the attic from R41 to R49? With that spray stuff, can you even add more insulation?

better foam or thicker foam.

 

[Tiamat]

better foam or thicker foam.

Ah, thanks! I guess that will be another 5000$ project some other time, but not before my home theater gets done...

 

[MagnusTheBrewer]

Did you check the cost on rigid foam insulation, cellulose or, recycled jeans?