Written by: Bryan Osborn, AIA LEED GA AKA: THEGREENOZ
This is my cat Gomez (Yes, he has a brother named Fester). At about 30 pounds, Gomez is attempting to break the record for the longest tabby cat in the world. I have raised him since he could fit in a tea cup and, despite his intimidating size, he’s a big softie. However he is still a cat, if you are holding him and you hear four chainsaws starting up it’s best to drop him and RUN! But what does this have to do with SIPs, Structural Insulated Panels? – COMFORT. The immeasurable effect of SIPs.
How do you measure comfort? You can google “comfort Index” and get a range of indexes from consumer spending to theories on temperature + humidity = comfort. You could use probes and probing questions but the fact is you will get a wide range of opinions about what is comfortable. We can take a tip from the occupants of a SIP structure and that includes pets. If it’s comfortable that’s where you will want to be. If it is too hot or too cold outside they are inside, and if the hydronic heat is on in our concrete floors that is where you will find them. Lazing around the floor in a boneless state.
Due to building our home with SIPs I can run the hydronic heater/in-line (Baxi Luna 310) for one hour and I can get about a 24 hour heat cycle depending on outside temperatures. Extended below freezing temps without solar gain (aka: cloudy) I might have to fire it up a shorter second time within 24 hrs. My wife usually stops these experiments after 24 hours. She likes it warm while I’m seeing how long I can go and still be comfortable. She tolerates me. In 2010 we used approximately 500 gal of propane for both heating and all of our hot water needs. Using 2010 propane pricing under $3/gal that translates into about $105 a month for all our heating and hot water needs. But those days are over with energy prices climbing. All the more reason to build with SIPs.
I do need to quantify that I did design the house with a modest amount of passive solar features. Mainly most of the glass is south facing and has adequate solar shading plus stained concrete floors. Nothing elaborate, I could have done much more, but it makes a big contribution especially on sunny days. Being simple, logical, and attending to orientation and the envelope from the beginning pays big dividends without causing much added expense, if any, to the project. I am not an advocate of going hog-wild on solar features and expensive equipment if you cannot recoup the expense in a few years. That in itself is not a good use of materials and should be thought through. Due to creating a tight envelope by building with SIPs you have decreased the demands. Now you can downsize the heating and air conditioning units saving initial equipment expenses and on-going costs every single day thereafter.
That gets back to comfort. In Premier’s Master Brochure for 2011, there is a good illustration that’s black & white, or should I say, green & fire orange. Repeat after me: Green is good. Green is good. Fire Orange is bad.
These UV Thermal images illustrate the effective insulating qualities using SIPs which decrease thermal bridging, convective looping, and greatly increase airtightness. That is what provides comfort and what current energy codes are trying to steer us towards. I don’t want to bog down the blog so to speak, so take a look at Premier’s Master Brochure which is a great explanation of what green challenges we face and how SIPs can be a solution to meet those challenges.
I have designed, built, and lived with SIPs for many years now and I am more of a fan than ever. I have worked with typical framing, advanced framing, traditional adobe, ICFs, metal studs, and researched more exotic building methods. I keep coming back to SIPs. You can run the numbers back and forth but when you price full wall & roof assemblies including the actual realized benefits, like initial expense, long term savings, no venting, and much more, SIPs consistently come out ahead. Plus SIPs are simple, straightforward, and work with traditional framing methods.
Don’t assume SIPs are mainly for residential projects. The majority of the projects we produce are commercial. BTW I am here to help you assimilate SIPs into your project from concept to completion and available to address your questions. I am just a click away. TheGreenOz