Hello, let me start out by saying that I’m new to the forum. I am currently in the planning stages of a ground-up build. In reviewing all current building techniques, I’m sold on green options. After reviewing several options (ICF, SIP’s and stick built with sparyfoam), I personally would like to go with the ICF construction. In my area (Minneapolis, MN) we get extreme cold and heat and I just feel that ICF is probably the most energy efficient way to go. Upon speaking to a GC in the area and discussing my budget and project with him (I wanted to do ICF and add a geothermal system) he indicated that doing both would severely impact the budget leaving not a whole lot left for finish work and the other items that go along with building a house. He suggested doing a partial ICF home. He clarified and advised that it would be a less expensive way to go, to have an ICF basement (below ground) with stick built above ground (2 stories above ground) with sprayfoam insulation. He acknowledged that the stick build wouldn’t provide the exact same test results that an total ICF home would (r-value, envelope, etc.) but that with the use of a geothermal system, it may off-set the noticeable difference. I’m new to the ICF concept, so I would like to get some feedback about doing a partial ICF build. Any thoughts or comments are welcome.

In my opinion doing an Icf foundation, sip main floor and raised heel trusses is your biggest bang for your buck.
If you want to go to Icf on the main level get prices before you make that decision.

this is almost exactly what we're doing. The only thing in question is whether we will use trusses or SIPs for the roof - still waiting to get some pricing..

Sips will be more expensive for the roof system then raised heel trusses. This is due to the product itself, interior bearing considerations, taller interior partitions and under framing in areas where you want to drop the ceilings.
Sips will give you a better look and feel in most cases but will also cost more.

I have heard mixed things about SIP’s. I will never take away their insulation properties, but one things that was a concern of mine, is living in a climate where there are such significant weather changes, rot, mildew and mold are things to consider and attempting to replace a SIP if it is ever damaged is very difficult.

Now I fully understand that there are steps to be taken to avoid moister of any sort from getting into your SIP, however should any moister get in there, it is very difficult to treat. This is the only reason for veering away from SIP’s for walls. Anyone have any thoughts?

I do like the idea of raised heel trusses for the roof though – they seem to be very energy efficient and I would enjoy the cost savings as well.

My project is as follows:

Dimensions: (roughly) 68 feet wide x 38 feet deep

2 Story (above ground) with full walk-out basement (total of 3 stories)

4 Bedrooms (2nd floor), 3 ½ baths above ground (3/4 bath in basement)

I would like to put a geothermal system in and if the budget allows, a wind turbine. The reason that I’m leaning towards the geothermal system, is because here in Minnesota – it gets pretty darn cold in the winter!! The cost to keep the house at say….70 degrees would be far less monthly with a geothermal system than a traditional. I’m looking at a positive pressure system also. I plan on dying in this house, so the long term pay off of the system isn’t a factor (the average time for a geothermal system to pay for itself here in MN is about 7-10 years).

Your stick built home will be the cheapest but not the most energy efficient. At this point we are talking the walls only due to the fact the roof in an Icf home and a stick home can be the same. Depending on your spacing of studs your stick home sprayed with foam will have a great R value but it will not be consistent and will have short energy circuits at each stud and plate line. You can minimize this with 1" foam on the exterior of the studs. My self I would go Icf foundation with sip walls and roof depending on your design.

while I commend you for building with energy savings in mind, it is MY OPINION that you are not making the wisest choice overall. Geo is great, I won't deny that, but for your build, you would be much better served to build totally icf and forget the geo. With icf (and sips in certain regions) you are PREVENTING energy usage in the first place. Geo is just using energy wisely and I feel there is a difference. ICF/sips and geo are nice but serious overkill with no forseeable payback regarding the geo. You can get a properly sized high seer hvac system for half of geo but if your home is super insulated like with an all icf home (or even all sips) you won't need to use it much to begin with. You will be better served to go all icf and reduce your tonage on a high seer hvac, or even a ductless minisplit if your floor plan is open. Your plan is like buying a porsche, getting the navigation package and heated steering wheel, and then putting the crappiest tires you can find on it. In other words, whats the point?

IF THIS WERE MY HOUSE (which I know it isn't this is just feedback to help with your decision), all icf, spray foam the underside of the roof decking and use a high seer or ductless mini split hvac system. I would caulk and seal every flippin hole in that roofand service penetrations twice. Seal every window and exterior door like you are posessed. THEN, look at wind/solar, etc. Prevent energy useage first, then reduce it second. It's exciting to build a home and It's nice to know that even if you do do a hybrid type house, it's gonna be WAY better than a stick built. Technology today is awesome. :) Good luck!

That's what I have, a Daikin 3 ton air to air heat pump. I know this will sound like heresy, especially in these forums, but I'm almost wishing I would have gone with plain ol' ordinary gas heat. I got my power bill the other day and it hurts. Total is $272. I'm all electric with pellet stove back up. I did not use the pellet stove at all. The bill covers 11/20 - 12/21, 32 days. We had a real cold spell. Here's how things break down.

3238 Kwh
~ 1380 HDD (a lot for one month I think)
Heat pump COP between 2.5 and 3.0 according to factory engineering data
45% of power going into heat pump (my best guesstimate)
55% of power for all other uses, including shower water down the drain
2000 sq ft living area inside the walls

My best guess is power input into the house was about 125 Btus/HDD/1000 sq ft.
I estimate the total heat load of the house was about 200 Btus/HDD/1000 sq ft. I'm assuming about 90% of the other power used degenerated into heat that was contained within the house. This is not taking into consideration at all solar heating, which is significant on sunny afternoons.

Right now, natural gas is pretty cheap. At a COP of 3 for the heat pump the cost of electricity isn't a whole lot less per Btu than is NG. I heard a news comment the other day that NG supplies in this country may prove to be quite plentiful for decades to come. Makes me wonder if all electric is really the best route.

Right now the top tier rate for power on my bill is about $0.087/Kwh. NG is about $0.77/therm. One of the disparities between electric and gas rates is electric charge goes up as consumption goes up but gas goes down. Doesn't seem fair!

How do my heat load numbers look to you guys?

Here is my humble opinion:
I think rykertest is very accurate when he said " Prevent energy useage first, then reduce it second." Why spend the extra money on something that will need to be serviced often and then eventually replaced when you could put it in a very efficient house that will outlast you twice? I have a propane furnace for a 2600 square foot house that will burn less than $500 a year. It could be less, but when I built, I didn't know about all of the other energy savers.

"Prevent energy usage first, then reduce it second" is the correct approach. Call some of the qualified ICF suppliers in the state and find out the facts.

We should all take cold showers??? Brrrrrr!

Shouldn't we really say, "Prevent energy loss first, reduce energy usage second?"

Shall we now argue about which fly is bigger on the cowpie, or how to pick up a turd on the clean end? lol (I can't take credit for those I read them somewhere)

I would echo what PDk said. With raised heel trusses you can put in a lot of cellulose insulation which is the best of the cheap insulations. If you stick build you could also put purlins running horizontally on the outside of framing and then spray foam the inside. That way your thermal break is minimized. Sheet foam on the outside is cheaper and more effective though. Dow makes a sheathing/foam combo that is interesting - STYROFOAM SIS.

There are a lot of choices these days.

I would insulated first then see what sort of heating system you can afford. Also, if you lower your energy requirements, you could spend money on energy generation like wind or solar. It would be better to one day generate more than you use.