Passive House Design: Live like Goldilocks, Minus the Bears

Designing by trial and error can be exhausting. Take it from Goldilocks. She was so tired after all the rigmarole of finding “just right”, she actually fell asleep in a bear’s house. LEAP Architecture takes the guess-work out of Passive House Design with our (Bear-Proof) Design Process. Our intelligent site design consists of four main steps, each with the aim to maximize human comfort, energy efficiency, and real cost savings.

Passive House Design Process

Site Analysis
Doors and Windows
Insulation
Air Sealing

This week, we focus on the in’s and out’s of site analysis. We circumvent all the wandering through the woods, sleeping on hard beds, and eating loads of porridge. We nail just-right the first time around. Did we mention it also provides a great payback?

Proper Planning Prevents Piss Poor Performance

That old military adage couldn’t be more appropriate here. Maybe we’ll make it the company tagline. But seriously, upfront site planning for your building makes so much sense. And, it doesn’t cost anything extra! The builders don’t care if your front door faces north or south, but when the arctic air blows in, you will. It pays to orient the building to capture more sun-heat in the winter and stay cool in the summer. Here’s how we figure it out.

The Down and Dirty of Passive House Design

We measure, map out and consider all of the following:

Sun paths—Measure and diagram the arc throughout the year, location of shadows
Wind patterns—Measure and map the micro and macro climates
Vegetation— Survey what, where, tall/short, do they break wind? (hehe, break wind)
Topography—Hills? Valleys? (Caves of hibernating bears?)
Roads—The approach. You would like to access your building, wouldn’t you?
Views—Gaze on lavender fields doing dishes (move to France, but you get the idea)
Notoriety or Privacy?—To be seen or not to be seen, that is one of many questions.
Acoustics— Want to hear the babbling brook, but not the highway?

We combine your personal preferences with the climate data to optimize the placement of your structure.

Geometry: Be There or Be Square—if You’re a House

Building geometry is defined by how large your structure is going to be, or it’s volume. Smaller structures, like houses, are more efficient with a square footprint and minimum surface area. If you are not a house, be rectangular. High surface area buildings are much better for offices and larger structures.

To help understand surface area, picture a cube vs. a long rectangle. They can both have the same volume, but the cube is more compact, where the rectangle is long and skinny. The actual surface exposed to the outside environment for the cube is smaller, requiring fewer square feet of insulation. Smaller structures tend to be externally loaded, which means the outside environment has the largest influence on its energy efficiency. Minimizing the area for that interaction to take place helps to dampen the effects.

A higher surface area to volume ratio is desirable for larger structures, as they tend to be internally loaded—meaning inside activities have the greatest influence on the inside environment. Picture a skyscraper—the sheer number of people occupying the building, machinery running and other inside activities have a much greater impact than the outside environment. A rectangular structure is preferred (vertical or horizontal), not only for the higher surface area, but to also help maximize natural light penetration into the space. Ample natural lighting can significantly reduce electricity usage.

Quick Summary of Building Geometry:

Smaller structures:

Maximize building volume; minimize surface area
Square floor plan preferred
Tend to be externally loaded structures- outside activity effect environment

Larger structures:

Higher surface area than volume is desired
Rectangular floor plan is optimal
Better for natural light penetration
Internally loaded structure -inside activity effects environment

Orientation – Get your Walls on Straight

All that previous work of mapping the sun and wind and rain and…well, that gets put to work. Houses for example, will predominately have windows and doors located on south and east facing walls. This helps reduce blasts of arctic wind infiltrating your domicile, as cold wind tends to blow from the north in the north east. Eric Davenport, our very own Avatar, also considers things like banking wind currents off hills to create more ventilation in your house. If this isn’t some air-bender shit, I don’t know what is.

For larger structures, orienting the short end of the rectangle to face west will prevent that terrible afternoon glare on your computer screen and eyeballs. Maybe you’ve experienced this unfortunate office situation, or another. When the long side of the building faces west —the afternoon sun heats 1/2 of the building, jacking that side up to 90 deg—and those people get hot. People on the dark side freeze because the air conditioning kicked on and now their space is 50 deg. Intelligent site design gets the temperature in your office building just right, keeping the bears happy and solving all your HR issues. Well, at least the fight over the thermostat.

[box type=”bio”] LEAP Architecture Makes Environments JUST RIGHT!