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Best Practices

Simple Forms Are Key to High-Performance Homes

Peter and Ann expand on their shared belief that keeping things simple is always the best approach

Photo courtesy of Creative Commons - DollyHaul

If you want to build a high-performance home on a limited budget, and you want to do it right the first time, your best bet is to keep it simple. This month, using some real-world examples, we’re going to show you exactly why this cliché is so pertinent to home building.

I don’t think things get much simpler than Mr. Potato Head. Sure, it’s a toy, but just like houses there are simple toys and complicated toys. When a child decides to play with Mr. Potato Head, the activity is straightforward, they start with his simple form and stick shit on it.

What does this have to do with building? Let’s look at this example, from Rob Myer’s project posted on GBA:

That is a very different from this:

There is a nice over-roof to get great R-value in this cathedral roof timber frame, but the through-beams moving from inside to outside the building are big thermal bridges, as well as conduits for both moisture and air movement due to the difficulty in air sealing in those locations.

This timber frame and roof deck are gorgeous but, again, huge thermal bridges and potential air leaks are likely as the decking and framing move from inside to out.

Thermal bridging inside-out beams can be a hygrothermal nightmare in modern buildings too.

If you theatrically fog a timber-frame structure, including any of the above, and pressurize it with a blower door, this is what you’ll see:

The strategy applies to remodeling too.

Of course, Mr. Potato Head, as a building, might look something like this:

The metal-roof building “addition” may make perfect sense from a building performance perspective, but pretty much only mechanical engineers would call this a beautiful building.

So, it’s not just about keeping…

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One Comment

  1. Doug McEvers | | #1

    Configuration does matter in terms of energy efficiency. In looking at gas usage for 2 of my building customers both with an 80% furnace, my observation. They are similar in square footage and are mostly original in insulation and air sealing.

    House 1 is a multi-level with a tuck under double garage, 60% vaulted ceilings and a walkout facing north. There is a heated 4 season room (5 exterior surfaces) on the north side and a laundry room that juts out along side the garage with 3 exterior walls. Gas usage for heating before ceiling insulation upgrade was 5.5 Btu's per square foot per heating degree day.

    House 2 is a rectangular 2 story with lower level walkout facing west. Just 4 corners with each floor stacked on the rectangular foundation. Gas usage for 2019-2020 heating season was 3.63 BTU/sf/hdd.

    A rough comparison but both homes are of similar vintage but vary greatly in square feet of exterior wall. This is assuming a similar ACH50 for both homes, example 1 has been tested, example 2 has not yet been tested. A comprehensive vaulted ceiling and attic insulation with air sealing has been done on House 1, current Btu/sf/hdd about 4. Still not as efficient as the 2 story.

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