Energy efficiency can be a very controversial topic to discuss. I know it has been here on The Building Code Forum and at ICC hearings, along with some legislative sessions at the state levels. I would like everyone who is willing to watch this video to do so with an open mind. I am very opinionated on this subject and remember when I lived in an older home in the north 20 years ago, and every December through March, I could guarantee my monthly heating bill would exceed $600 and be as low as $70 during the summer. Please watch and let us know what you think.
Well. So let me reflect on the video. Several points (like others) I agree with.
First off, from participating in this forum for nigh on four years, I’ve come to realize that the scattered, Balkanized code structure in the United States is a critical issue. The regional fiefdoms unwilling to accept something nationalized is a huge roadblock to reasonable standards.
Not having national-level standards is an impediment to the industry. How can a window manufacturer grow scale when it must meet six different requirements to serve eight different states? Sure, the manufacturer could build to the highest of those six standards, but now that means a less-costly, but less-efficient window will be cost-incentivized.
I’d also argue that politics is a major factor. Let’s be blunt: Big Oil controls a lot of the U.S. political landscape, and the proliferation of for-profit, private energy companies creates capitalistic pressure *against* energy efficiency measures. (Witness the blowback when some states subject to wildfires wanted to ban vinyl siding ... siding your house with vinyl is equal to wrapping your house with barbeque lighter.... )
There’s another hidden observation: the North American zeal for oversized single-family homes. I’ve seen several mansions built whose total footprint was so large that the building almost landed in the high-end commercial codes (ie: flirting with more than 6,000 ft2, for a single-family dwelling). By comparison, I live in a 500-square-foot cabin. The new house is 1,100 square feet.
Additionally, there is perilously little understanding of building science in the design community and building community. I had a conversation with a client this week – the client has been building homes for 40 years. The client did not understand that if they didn’t place foamed insulation between a slab-on-grade floor and a load-bearing frost wall, or on the outside of said frost wall that they would be creating an R-somewhere-near-1 thermal break. Our inspectors fight building envelope requirements on a regular basis.
We also have this unholy fascination with staggeringly large volumes of windows. The PassiveHouse standard is to have a ratio of window to floor area of 1:10, that is, 10 per cent. I meet that in the new house I’m building – it has all of its windows on non-north faces save for a teeny bathroom window on a northwest face. It meets the 10 per cent threshold. It is not dark: two 7x4 goth-arch windows allow for plenty of light. The soffit overhangs 3’, which limits solar gain in summer.
I didn’t truly realize how over-windowed designs were until NBC 2015 introduced seismic bracing requirements for about 30 per cent of our region. Those bracing requirements limit openings to 75 per cent of a wall (in general). I had several plans in the queue when the new rules came to play that wouldn’t have met those requirements, and several builds since that didn’t …. Think about that for a second. If you have, say, a house with southeast and southwest walls, overlooking the ocean and want to have half of those walls be windows, you're going to lose a crapton of heat - or gain it. Our area requires R17 walls.
Windows are pathetic insulators. The Code requirement for houses sets the thermal transmittance at what amounts to R3.5…. how the heck are you heating/cooling a 4,000 square foot home when half of the walls have an average R-value of about 10? That’s about the same as one of those cheap-ass, blow-away-in-a-storm mobile homes with the pencil-thin walls…