What you're missing s that framing is only a small portion of the overall construction. Doing all of the other things like rough plumbing and electrical will be higher in cost with SIPS, and must be planned out to the nth detail. It's not like a stick framed house where if you forget you want a light there, or add a laundry sink there it's an easy fix. That two weeks you saved will be added back in the rest of the stages. Especially if you are like so many around here and don't have a fully designed house from an a actual professional architect. The more loosey goosey you are about the design, the less sense SIPS makes.

Instead of Superior Walls for the basement and ICFs for the main floor, why not just do precast concrete panels from the ground to the roof?

ditto what bronco said about the labor. That is extremely high for framing. 3-4k for ALL of the materials/labor to build ALL interior walls???? It's gonna be 'much' more than that. Have you looked into ICF? You might want to go to this web site, They also have a Sips forum.

greenbuildingtalk.com

You might use this to get more quotes on the SIPS in your area.

http://www.sips.org/

sips for roofline too?
that would be my choice.

does the builder & crew have experience
with sips builds?

that to me would be the most important
area to focus on.

best of luck...fwiw...I'd build sips if I were
building new!

If you do go with SIPS, why not have them install them(all ext walls and roof) and then be an O/B? The framing cost labor alone that they quoted you is 2x of what it 'should' cost. They just marked it up by that much. It should actually be a good bit less than that since they are not doing any outside walls and roof.

A reasonably tight home in Alabama with good attention to solar gain will cost very little to a/c.

I'm always amazed at a/c costs or perception. Just a reasonably tight house (ie not SIPS) will have its a/c load completely dominated by solar gain. So many people have old systems with old houses with horrible windows that have high bills.

An example based on my house.
Solar gain 60%
Internal gains 10%
Infiltration 10%
Wall/roof gain 20%

Great insulation/sealing is only affecting 30%. People seem to think they will cut their bills by 50% which is nearly impossible. A SIPS house might cut 15% from my a/c bills vs standard stick.

Now - getting ducts out of the attic space would save about 15%. Not nearly as sexy. Going from Seer 13 to Seer 16 would save about 15%.

I live in NC so a little cooler. My a/c bill for 4000 sqft (+finished basement for 5500 total) is perhaps $400 a year. I have 40 fairly large double hung windows. Majority of windows are East/West. Zero south.

Makes me think your house is 1/2 the size but climate a little warmer. So lets say equal cost. SIPS saves perhaps $60 a year.

You could save far more of that by focusing on solar gains. BTW my framing cost was 1/2 yours. I know wood is up but that seems ridiculous.

While I totally appreciate building green, don't pretend there is a reasonable payback.

The focus should be were the money is - solar gain for a/c. If you ever got below freezing, then you can start worrying about SIPS. Maybe you do but since you are worried about a/c, I'm guessing even No Alabama doesn't get cold.

I live in NC so a little cooler. My a/c bill for 4000 sqft (+finished basement for 5500 total) is perhaps $400 a year.

I'm curious, how do you calculate your a/c bill? I'm wondering how you separate the electricity needed for a/c from the rest of the electricity used.

You've got a couple of months of time in the South where you aren't using heating or cooling. So, I'd imagine that David is calculating from those months. Of course, we've got a couple of weeks of using both the heat and the AC in the same day as well. So a lot depends on the location the OP is building. If it's in the Birmingham hills,or someplace modulated by a marine influence like Mobile, I can't imagine ever getting any payback for this construction method. 2x6 would be not a lot of extra costs over standard 2x4, and be much easier to see the results from.

I am not familiar with SIP other than what I just read on the internet (I think it looks like a neat idea), but I am familiar with AL temperatures and the last two winters have been cold. I live in SE AL almost in FL and we have already had at least 4 nights below freezing and more are coming this week. It's not MN cold, but it is still cold.

If SIP ends up being too expensive, you could look into 2x4 construction with spray in insulation in walls and roof and 1 to 1.5 inch foam sheathing on all exterior walls and roof as well with a conditioned attic. My reading has lead me to believe that this method could be more efficient than 2x6 walls because you get all the insulation but eliminate the thermal bridging from the wood, and I think it ends up being cheaper. I have no experience to back this up, just been researching on the internet to build my own place.

While David's example is useful, one shouldn't use other people's energy modeling results for making decisions about their own new build. Hire a 3rd party to do your own energy modeling. I agree with his main point that the sun, and how it impacts both the heating and cooling should be accounted for. If one does avoid west windows, like they should, it completely changes the percentages and individual cooling and heating costs can vary greatly.

Comparing regular stick framing to SIPS is tough. IMO if you are going to make a stick frame perform at the same level of energy performance of SIPS, you will probably end up at about the same costs once you include the insulative sheathing and other air sealing exercises to get the stick framing there and its mainly in the labor. If you can get a good price on SIPs with an experienced crew it can be a fine way to go and not necessarily more expensive than traditional. While we see a slight upcharge from our electrician, plumbing should not be effected, it should be out of exterior walls anyway.

For walls, the Huber zip + R is a product worth looking into for the south where we still have low levels of insulative sheathing code minimums.

N. AL is in climate zone 3 but would prefer to see folks there build to the climate zone 4 minimums AT LEAST. Iam pretty familiar with some of the plateaus of N alabama and they get as cold as lower elevations in north TN/NC.

Climate zone 3 in 2012 IECC minimums calls for cavity R20 (2x6) but you will probably get better performance with the alternative R13+5 (2x4 + ~1" of insulative sheathing). R49 roof is the upgrade you would need to achieve zone 4 energy performance minimums.

A regular 2x6 wall is not going to perform as well as a 2x4 with R5 insulative sheathing in both energy and long term durability performance. SIPS become cost competitive with stick framing when we include this insulative sheathing as a best or better practice.

Thanks all.

I received another quote for SIPs that was nearly 20k less which makes SIPs construction less than stick from what I can gather. Other quotes are coming soon and I'll update this as I go along.

Yea - mine was certainly just an example.

Typically my zero HVAC months are $50 and July/Aug/Sept are $130 so $240 for those 3 months. June is probably $80 or so. So $270 and then rounded seriously upward for $400. We do a/c some in Apr and Oct but less than $10.

I have a whole house energy monitor (egauge) also and I can look back and see when the a/c ran and how much it used.

SIPS are not used often around here so I can't speak to them. Certainly 2x4 with an inch of rigid foam is pretty good for the SE (in general). But that 1 inch of foam is all about the winter and is unlikely to reduce your a/c tonnage.

Do you have NG? I would suspect heat pumps which makes sense.

Just like the energy modeling can vary drastically from home to home, energy costs in identical homes can vary widely from occupant to occupant.

Its true that increased insulation benefits colder climates more but that doesnt mean warmer climates dont benefit from the increased performance of insulative sheathing. Without insulative sheathing, ~25% of typical stick framed wall area is practically un-insulated.

A hot summer day at 92 with a 68 degree thermostat setting has the same Delta T as a relatively cool 44 degree day. That's just the air temperature. Add in some direct solar gain to the wall and the delta T on that side of the home can climb dramatically.

I also tend to think that adding insulative sheating will result in tighter blower door tests which have benefits beyond HVAC costs. Of course, we are only talking about the solid wall areas here which are relatively easy to insulate and make airtight. One needs to address the entire building envelope for measurable effects.

We are building in Colorado. We used ICF in the basement and SIPS for the upper floors. We spent approximately $49k for material and labor in SIPS. They were shipped from PA and the company was Murus SIP. Our home is not complete yet, but so far so good. We also incorporated other energy savers, such as good site positioning as to solar gains in the windows, we personally used triple paned windows as it made since at our location, foam insulation, wrapping of the house. I posted pictures of our SIPS at this link http://ths.gardenweb.com/forums/load/build/msg0819330125186.html

Brian - 68 degrees? With a reasonably tight home and the resultant low humidity, that would be uncomfortably cold for most people. Does manual J use that interior temp as design point - no. Go with 76 and then you are talking a comparable LOW temp of 52 with average diurnal variation, a high of 72. Most people would call that perfect and wouldn't even need fiberglass in the walls.

Now that being said, we set our stat at 65 at night in our bedroom. But then the outside temp is 70 - close enough to zero delta T. .

Now every house and every climate is different but examples are still instructive. The energy cost for a/c for our walls was like $50 a year with seer 13 a/c and $.11 a kwh. Even if foam cut that in half (and it is probably more like 30%), you are chasing $25 a year.

Now I have solar panels and a TOU rate so the actual wall cost is near zero. I never pay peak in the summer so I pay $.05 and I have Seer 16. So my walls are closer to $20 and foam would honestly save $6.

Insulate for the winter. Looking into the future, solar is making a/c cheaper (and lower pollution) every year. Winter is much harder. 10 years down the line, electricity on a sunny summer day is the cheapest place to get electricity.

BTW - I did recommend foam sheathing to the OP somewhere above. My argument is that it is for the winter.

68 doesnt seem unreasonable to me when you mention you keep some of yours at 65. I know of another individual who keeps it in this range with the windows open for "fresh air". 76? Maybe for some but not the majority which could be true for 68 too though. The Tstat setting is one of the many factors that account for drastic differences from house to house. Absolutely agree with your main points and think your individual specific details are instructive.

I dont agree however that those in warmer climates shouldnt consider upgrading their thermal performance with sips or insulative sheathing based on your questionable examples. While colder climates tend to benefit more, summer weather in warm climates is not insignificant. According to this data from Weatherspark, Huntsville AL has temperatures between 85-100 degrees 26% of the time. This quibble mostly surrounds air temps. Walls that receive direct sunshine, will see even greater thermal and comfort benefits.

Perhaps the biggest advantage though is much harder to quantify. SIPS or framing that includes insulative sheathing are likely to do better on their blower door tests which is a measure of home quality that goes beyond individual energy costs and payback guesstimates.

I think most projects are better off when they build to international code minimum at least. Most of AL is in building climate zone 3 and the 2012 IECC requires 2x6 framing to achieve R20 cavity insulation. Compare this cost increase to doing the alternative 2x4+ R5 insulative sheathing as it will probably result in a more durable, efficient home with a fast, simple payback. I would much prefer to see people building better than the cheapest performance allowed by law.

This post was edited by BrianKnight on Sat, Dec 13, 14 at 15:48