First I have to say - Wow! What an awesome forum this is.

We are building a new house on our acreage.  We had planned stick built over an ICF basement, but are now considering ICF all the way.  The house has a lot of windows to enjoy the views and doors leading to the porches.  (There are 7 doors on the 1400 sq ft first floor.)

Our primary reasons for considering ICF are longevity and reduced energy requirements.

The first estimate we've had for going all ICF came in at over 20% higher than stick - we'll be looking for others!

But, in your opinions, do many openings significantly reduce the benefits of ICF?  Any other advice/tips?

Thanks!

Doors and especially windows are inefficient. The insulation of an ICF is a constant, so the benefits of the ICFs remain the same, it is the benefits of the openings that decrease.

There is other benefits to ICFs such as strength and mold resistance.

If your doors and windows are concentrated in one wall, then consider using SIPS for this wall in lieu of ICFs. Your cost savings will be significant and energy efficiency will be near the same. We do this all the time with walkout basements, and above grade walls, also.

Any buiding technique will be compromosied by window openings whether icf, stick or sips.
However you will have better return efficiency with any superior building product.
Icf can accomodate any number of openings required if this is your concern.
Cheers!

Shelly,
I'm almost finished building my ICF house. I just looked at the heating/cooling load calculation sheets my HVAC nephew generated for me. I have 11" ICF walls (6" concrete, 5" foam) and Andersen 400 casement windows. Here's the bad news regarding windows vs wall.

For heating the heat loss per square foot of window is about 8 times as much as for the wall, i.e. every square foot of window looses as much heat as 8 square feet of wall.

For cooling it's worse. Every square foot of window adds about 40 times as much heat as does a square foot of wall, heat that has to be removed by the air conditioner.

For doors it's about 5 and 11 times.

 These numbers are a composite of all the windows, which of course face all four directions. However, nearly all are on the north or east side or are well shaded in summer.

Have a competent HVAC person do a Manual J heating/cooling load calculation based on your plans. That way you'll have a reliable number to chew on for your specific situation.

In short, windows and doors add tremendously to the heating and cooling requirements for any house. In fact, for my house, which has a modest amount of window area, the windows are about the same percentage of the total heating load as is all the wall area. You can see some pictures of my house in this thread. http://www.greenbuildingtalk.com/Forums/tabid/53/view/topic/forumid/4/postid/44303/Default.aspx. That'll give a you a good idea of the window to wall ratio for my house.

dmaceld
Your statement about loss and gain is based on your location, and can be misleading. However, I do agree that windows and fully glazed doors have to be accounted for.

shelly
Once again we have results posted without being in context. You say 20" differential, BUT, this 20% is meaningless until you compare what you get with ICFs versus a stick framed wall that is in the same completed stage, meaning insulated, of course I assume the exterior sheathing is in your number, but you need exterior tyvek on the frame wall, you need the interior sealing of ALL cracks and penetrations, and you need Usually a VB on the interior. Then you are copmparing apples and apples. Please review your numbers and then make your decisions on a level field.

As to windows and doors, if you are going to go the route of ICFs, look also into some of the triple-glazed high R windows and doors as the next step. Remember, you then need to review hvac calcs again to see what your return will be!

True. I was thinking I said her situation would be different, but looking back I see I didn't make it clear. What I really wanted to emphasize though, is there is a vast difference in heat loss/gain between windows and walls.

Thank you all very much. The 20% (actually about 23%) higher number is from the builder who would do the stick frame. That number is for the completed house. So, the two numbers are as close to apples to apples as we can get. He went back to all his subs for updated bids on everything. He did up the insulation in the attic for the ICF bid. (I forgot to ask him to what as I was stunned by the dollar figure and he was listing off all the reasons it was so high.)

I don't see us giving up the windows. I know the longevity of the structure will still be there if we use ICF with the current plan. I guess I was wondering if we'd see the value of the increased insulation of the ICF with so many windows and doors - either in comfort or in energy use.

Thanks again and would love to hear any more thoughts...

glass is your enemy.........

tall windows and door may not be needed to still maintain a good view.....with proper shading, high efficient, smaller windows placed at proper locations will yield a more efficient house without losing your view

mac

I agree, I think to many homeowners like the idea of a lot of windows, then don't use them, need them once the house is built.

I think the comments about cutting down on windows is crazy. The benefits of building with ICF's and SIPs is so you CAN design with more windows. An all glass house is what I think most people would love to build, but reality is we need the solid walls for energy efficiency.

Windows are the weakest part of the wall system, but you only lose 40% of your heat through the walls. It's the ceiling and roof systems where you really need to use SIPs or solid foam insulation to block the 60% of your heat from pouring out through your roof.

I say build with high energy framing systems and open up that beautiful view.

Jim you old die hard.  Its nice to see you are still around, send me your phone, I will be in NY soon, and up through rhode Island, and would like to get the chance to say hi again.

Its been a while.

Mark Ross

I was thinking the same about your recent postings!

I'll send you a PM