Hi all
First off, let me say I have been creeping around in the background for sometime now, reading a lot of info.  I am a young architect in Iowa, dealing mainly with commercial application.  However I have about 6-8 years of residential construction experience, including working on a crew for a couple years, remodeling my current home, my parents home, various other homes, and building large addition on my parents home.

I have done a lot of searched and read a lot of different postings.  I have really yet to get some clear cut answers or make decisions on what I would like to do.  Here is the run down:

I am designing a new home, in the prairie style.  I basically have 2 schemes we want to get more final.  Of those 2, I have 2 more of the same design, just slightly different to sit on either a flat site or a walk out basement site. 

One scheme is a 2 story with about a 1200 sqft footprint (living, kitchen, dining, etc on main floor, master and 3 bedrooms upstairs, full basement with guest bedroom and tv/game room).

Second scheme is about 1900 sqft footprint single story with full basement.  This would really need a sloping site to work best, otherwise a lot of grading and retaining walls.

I plan to do most of the construction myself, however probably paying someone to do some of the items that will take me more time (such as setting trusses, shingling, possibly framing up the exterior, and plumbing).

Obviously I am green conscious, and wish to incorporate some of that into it as budget allows.  I do however understand that some of my options are not necessarily a green build.

Here are my build type considerations: 

1. Stick frame 2x6 with 1-1/2" rigid on the exterior, either batt or spray foam on the interior
2. SIPS construction
3.  ICF construction

Keeping in my our location, Iowa, we have extreme heat degree differences ranging from 30 below to 105 during the summer with long heating and cooling seasons and high humidity....basically a crappy place to live .  To boot, we have high wind storms and tornadoes.  I have designed several storm shelters for schools and other projects, all of which used precast panels to withstand 200mph winds and 100 mph 2x4 penetrations.  While the obvious choice is an ICF house, I also realize I could save money on stick framing or SIPS as I could construct it myself.

So really here are my first series of questions. 
For MATERIALS cost, how do SIPS and 2x6 construction compare?  Obviously the 2x6 would have the added cost of spray foam (or possibly r-19 batt) and the rigid on the exterior.  Not to mention longer build time.  The SIPS could possibly also reduce my HVAC requirements.  But looking at calculations, not by much if any compared to the stick build. 
Also, I have found SIPS cost roughly 5% more than stick framing, but does this compare to labor included in stick framing which mine would not have?  I also assume it includes labor in the SIPS construction too, which could be a wash?  Any thoughts on this?

Now with ICF, I really do not know where this will come into play.  I have read ICF can cost 5-10% more than stick framing, however I assume the stick framing also includes the labor, which mine would not have.  So I am looking at possibly 15-20% more for an ICF?  I also assume those numbers deal with the material percentage and not the total house construction? 

And finally, I am interested in installed a geothermal system, most likely using vertical wells.  Soils here are good, so we can go 100-200' easily.  I did a project where we got soils report saying up to 400' would work, but we made the fields 300' deep.  Assuming I can go 200', this would make me have about 3-4 wells.  Here the well price is roughly 2k each.  Talking with our mech. engineering consultants, they estimate a complete system costing around 25k, and if I also add well heated radiant floors int he basement and well heated hot water, around 30-33k total. 

My question with this is, if using a SIPS or ICF house, will the payback on geo really be worth it?  Obviously with a highly efficient house, great systems will take even longer to pay back.  I would think my added monthly mortgage and interest will more than double my energy savings.  However if I saved slightly and went with the 2x6 frame house, then geo would have a higher payback.....but only because the house construction is not as tight. 

It really looks like a tradeoff in up front costs.  However I am starting to think the numbers are pointing too SIPS/ICF with a high efficiency furnace and AC with an exterior air exchanger.  Then again, I realize the 2x6 framing will be close to the SIPS system, especially with spray foam, and the peace of mind with a Geo system knowing my costs will/should forever stay low.

So with ALL of that looooong, drawn out jumble, I am sure I lost most of you.  Please, chime in with your ideas and thoughts, as well as possible prices you have ran across.  I am in the beginning stages of planning this thing out over the next few months to a year, but hope to break ground around then. 

I suspect that for 25K in better design, air-sealing, windows, & insulation you could go all double-studwall PassiveHouse on this, skip the geo heating system. (High efficiency heating systems are for low efficiency buiding envelopes, IMHO. Bang for buck you get a lot more out of $25K in cellulose & double-stud framing than in geo. Even if you heated with electric baseboard or something your energy use would be lower in a superinsulated house.)

You'd still need to run a dehumidifer in summer when outdoor dew points are over 60F, but if you control the solar gain by design you won't roast in a superinsulated house insulated with higher-thermal mass goods like cellulose, and a very modest mini-split could keep up with the cooling load.

Batts basically suck- don't go there if that's your primary insulation-sprayed/blown fiberglass or cellulose are far far superior. SPF is very expensive, but useful for getting a near-perfect air seal. Cellulose is cheap, and dry-blowing using rented equipment doesn't take a rocket-science degree- it's an easy DIY if you plan the framing right. If you can get R60 clear wall R values, R40 rigid foam on the the foundation & maybe R25 under the slab, with R75+ attic, you'll be most of the way toward a Passive House. Minimizing glazed area and sizing/placing the glazing carefully for solar gain/rejection with appropriate overhangs can get you there.

I suggest that you get some modeling software that will allow you to look at operational costs of all the different options. HEED might work for you.

It's a fair question - "why are people selecting moderate insulation + geo or conventional" over super insulation"?

Geo would be a long term investment obviously.  The idea of geo is more so alternate energy means as well as reduced energy consumption.  Ideally if money weren't an option, both a tight home and geo would be the way to go, powered from solar panels of course.  Geo just "feels right", especially in my profession.  We make a lot of money from designing geo systems into client's buildings.  But then again, money really talks too.  I can have one of our engineers run a life cycle cost and energy cost analysis on a couple options. 

I am not sure how I feel about SIPS.  It seems there are some good pros, but the cons are more so what I am concerned with.  Changes in the build, wiring, etc, are all possible issues. 

I think I need to explore ICF more too, and see what DIY factors it can have.  I talked with a guy in our office who has constructed his basement and a small addition with ICFs himself.  I have worked on 2 projects in the last 2 years that have been destroyed by tornadoes and we did the rebuild for them.  That is definitely a piece of mind, and my insurance would cut in half I am told. 

I did not mention it in my first post, however passive solar design is definitely something I will work into it.  The plan is the backside would be southfacing utilizing large windows and possibly poured and stamped/stained concrete floors at least in the basement as my mass collection source.  With the prairie style we are after, killing the summer sun angles will not be hard.

Intersesting read, I have had many of the same questions in my mind and continuously read the new posts throughout the forum everyday looking for answers!

John

I am with Dana on this one.
The key to a good New building from an energy perspective is reducing demand. IF you get demand low enough then nothing else matters too much. This requires a systematic approach to energy conservation and requires a lot of thought.
 My approach was to take the low cost steps to building an efficient house and leave the exotic ones for people with big budgets.

The biggest bang for the buck is usually upgraded building envelope. Better attention to air sealing, better and more insulation, reduction of thermal bridging.
 In a heating and cooling climate like New England or Iowa good passive solar design is probably the next most important thing. This can provide a very large fraction of the total energy necessary to heat the house. Couple with proper overhangs, this should not add to the summer cooling load.
 Next comes natural daylighting design and using efficient electrical lighting and appliances. According to the local power company the Average CT home consumes 805 KWH per month. This number can be lowered dramatically. My house averages 210 kwh/month. It is not magic just looking for efficient ways of doing things.
 
Next in line is active solar thermal technology’s . Solar air heaters, solar domestic hot water heaters are effective ways to heat stuff that are moderately expensive, but have demonstrable paybacks 

After that would be uber efficient heating systems. In this category would be geothermal, high efficiency gas boilers, very efficient newer AC systems, masonry heaters.
 
Last is onsite generation of power by photovoltaic systems.
 
Look at this picture carefully and you see two houses
 House 1 Smaller, simple shape, icf foundation, tight building envelope, passive solar design, solar air heater, solar DHW, Wood stove, summer shading of east and west windows.
House 2 in the background. Much larger (2.5 X size), conventional foundation, double hung low solar gain windows, poor overhangs so summer heat gain a problem, conventional lighting and appliances, conventional fiberglass insulation, 5.5 kwh solar photovoltaic system and 4 ton 2 stage geothermal system with 4, 400 ft vertical wells.

Both houses have low energy bills, but the costs to get there were radicaly different.

Posted By lzerarc on 15 Jul 2010 02:43 PM
Geo would be a long term investment obviously.  The idea of geo is more so alternate energy means as well as reduced energy consumption.  Ideally if money weren't an option, both a tight home and geo would be the way to go, powered from solar panels of course.  Geo just "feels right", especially in my profession.  We make a lot of money from designing geo systems into client's buildings.  But then again, money really talks too.  I can have one of our engineers run a life cycle cost and energy cost analysis on a couple options. 

I am not sure how I feel about SIPS.  It seems there are some good pros, but the cons are more so what I am concerned with.  Changes in the build, wiring, etc, are all possible issues. 

I think I need to explore ICF more too, and see what DIY factors it can have.  I talked with a guy in our office who has constructed his basement and a small addition with ICFs himself.  I have worked on 2 projects in the last 2 years that have been destroyed by tornadoes and we did the rebuild for them.  That is definitely a piece of mind, and my insurance would cut in half I am told. 

I did not mention it in my first post, however passive solar design is definitely something I will work into it.  The plan is the backside would be southfacing utilizing large windows and possibly poured and stamped/stained concrete floors at least in the basement as my mass collection source.  With the prairie style we are after, killing the summer sun angles will not be hard.

If you're looking at DIY labor on a stick build on a superinsulated double-studwall or Larsen truss with blown cellulose (DIY or contracted-out) vs contracted-out geo starts looking dramatically LESS attractive.  Seriously- if you design to meet the PassiveHouse standard your "heating season" can be reduced to a few weeks where you might be cycling on modest amounts of supplemental heat, and your "cooling season" will be about humidity control when outdoor dew points are high. Most of the cost-adder of a Larsen Truss or double studwall is framing labor- the material cost for doubling or tripling the insulation is quite modest.

Read up on High-R wall construction.  Make sure there excellent thermal breaks on structural elements to avoid short-circuiting the high-R assemblies with framing timber, etc. Use high performance windows, placed for optimal seasonal solar gain/rejection, and simulate performance for you site & climate. (The PassiveHouse tools can be useful in that regard, even if you're not going all the way to true PassiveHouse performance.)

In most of the US heating-dominated US going geo needs a COP of 3 or better to just break even with a cheap condensing gas furnace. Well designed systems can break 4.0 on average- if you're lucky (or live in an exceptionally low electricity cost area) you'll cut it down to half the cost of heating with a condensing gas appliance. But for $25K additional cost (even all-contracted) you should be able to super-insulate a 2500' home sufficiently for an 80%+ reduction in heating & cooling requirements, at which point the efficiency of the mechanical systems meeting those loads becomes inconsequential.  With a lot of DIY labor on the framing end, a very high-R double-studwall or Larsen Truss design would come in far under the $25K in additional cost you're talking about for a geo system. 

This isn't pie in the sky- houses meeting Passive House standards have been built without breaking the bank in many areas as-cold or colder than yours. But you DO have to design for it.  High-performance building envelopes are a far better long term investment for residential construction than high-efficiency heating systems as expensive as geo.

the more I read and research, I am starting to find the same thing.  In college I studied under an architect that has built his long career around passive solar design.  Very few of his designs used geo, although a couple did.  He focused on mass and winter collection for his basis of design.
I am getting some quotes on ICF construction, sent off inquires this morning.  I watched about 2 hours of videos last night...does not look like it would be too hard for someone with construction experience to pick up.  Just a lot of thinking a head and details with electrical, window, etc and all items that need to pass through the walls to block out for (or connect to). 
I can model the house up in Revit and run some load simulation for wood and ICF construction, then see what sort of HVAC would be required, hoping a size reduction and reduce some of the size of the units.  ICF really seems like the way to go, I think I will dismiss SIPS at least for now.

The same questions as the OP but I can spend a lot more then I should! I have to consider market/resale value and not over build or over price myself out of the market in the area that I will be infilling in! I have to keep costs down! Probably going to go ICF foundation, walk out basement, with a basement radiant floor (solar hot water).
The lot is NOT conducive to solar gain through windows, then a super insulated first floor bungalow, 2000 sq/ft.

I've read a lot of statements that have been bothering me lately and I do see a little light at the end of the tunnel. Hopefully i will come to some conclusion in the next year and decide on which way I will build my retirement home!

Very informative, thanks!


John

John,
How can a house that can utilize solar thermal hot water systems not work for Passive solar? I can only see this for an urban house on a very small lot next to another house or obstruction.

On a 1 story house, the rooftop panels are only going to be 5-10 ft higher than the windows. It might be worth your while to reexamine your location. Get a solar pathfinder and a 12 ft stepladder and you can quickly find out what the solar potential of the site is, and orient a house accordingly.
 
Active solar hot water systems for space heating are usually fairly costly. Spending the money for better insulation is (usually) more cost effective.
 If roof mounting solar is your only viable option, look at solar air heaters. These are far cheaper then water systems and work similarly to passive solar. Couple this with a small solar DHW system and you have a viable system at a reasonable cost.

Cheers
Eric

Thanks for the comments Eric, I do have to look at solar air heaters as I know very little about them.

I do live in a custom, passive solar, super insulated home (stick built) PWF, Solar DHW (preheater) that I designed and had built in 1987. It's on a 2 acre estate lot in the country. My wife has been after me to move back into the city and I have agreed, were downsizing. The biggest problem that I had was the garage, we had to purchase a lot and build custom again as I need room for my hobby, cars, which meant a large garage. All of the tract homes being built just do not provide for my needs! The only serviced lot that I could find and afford is a south facing to the street lot, that's where the garage will go. luckily the back of the lot is much lower and will enable a walkout! I have not looked into costs yet as the deal for the lot does not close until the end of September.

So far a flat roof with a roof terrace and a clear sight to the sun, ergo solar hot water, large home made collectors. Dana1 had posted a web site in Arizona I think, with a large homemade system but at them moment I can't find the link?

Can you use solar air heaters for space heating in January in Ottawa ON, I don't know it's something I never thought about , links?

Cheers
John

PS yes there are houses on both sides of a 52 foot by 150 deep lot, a house there now which will be demolished when the deal closes!

JohnnyH,

How about running your driveway to the rear of the house and put the garage back there or construct it in the basement? Then you can use the south facing front for some passive solar.
richm

Posted By richm on 17 Jul 2010 10:15 PM
JohnnyH,

How about running your driveway to the rear of the house and put the garage back there or construct it in the basement? Then you can use the south facing front for some passive solar.
richm

Not possible, so a walk out basement will be in the plans! The winters we have here I don't relish a drive way sloping down. THere are a lot of them but again I don't feel it's appropriate for the weather we have here!

John

I would agree. Iowa winters are not as bad as ON no doubt, but we still get up to 10'+ of snow, ice and pretty bad situations for any sloped paved areas. At Least 90% of our state is flat and boring .
We have 2 sits we really like. As mentioned they are a flatter one and then a sloping one. Unfortunately neither have good south solar gain options at all. The access street runs north to south, so it would have to be turned 90 degrees on the sit...odd look. If we got a corner lot this would not be that big of a deal. However then our large, open backside would be over looking someone else's backyard...not a good privacy design. The best we could do would chose the flat site, which does not really help it that much to begin with, and orient it south of east, getting minimal gains, but still something. Besides when I told her to maximize the solar gains, we would do about an 8" basement slab that is stained and stamped...she didnt like that idea so much....
However we really like these sites because of the mature trees (something RARE in our area...most are farm fields converted to housing developments) and a small lake less then a block away.
With a lot more research, we are leaning toward ICF all the way. I will be getting some estimates soon, and go from there.

"With a lot more research, we are leaning toward ICF all the way. I will be getting some estimates soon, and go from there."

Do you have house plans done already?

John

Not quite.  I am still working on some designs.  But enough to get rough linear feet/heights and corner estimates.  Talking with a contractor, he said for rough estimating purposes, the deduct for the concrete not used for window and door openings is basically offset by bucks and labor for the openings...so not worry about them just yet.

Johny,
I installed http://www.yoursolarhome.com/solarsheat.com/solarsheat/1500.html on my house on a wall mount
I am using a 2 panel system powered by a separate PV panel. It works very well and it can be roof mounted easily. A lot easier to install then a hot water system. IT works quite well on sunny days even when it is quite cold. the units are manufactured in Ontario. I first saw one on a house in montreal.

Cheers,
Eric

Thanks Eric, bookmarked! "http://www.yoursolarhome.com/solarsheat.com/solarsheat/1500.html "

John

Great thread all. But what about the insulation? What distinguishes "superinsulated" from just normal insulation?