Craftsmen of Homes

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Roanoke & Smith Mountain Lake, Virginia

Passive House

Passive House Design - Passive House Build

When asked what defines a 'Passive House', we aim for non-technical answers to provide a clear starting point.

Passive House is a voluntary certification program, encouraging the creation of low-energy and high-comfort buildings.

 Passive House builders focus first on these priorities:

  • owner comfort
  • health-promoting indoor environment
  • durable enclosures
  • energy conservation

Owner Comfort in Passive Houses

Comfort may seem subjective, but simply think of uncomfortable buildings you've encountered. Variations in temperature, leakage of air from outside, and poor forced-air movement have caused discomfort in most homes and buildings.

Even, consistent temperature comfort clearly is key. This is accomplished by keen attention given to floor, wall, and ceiling composition. Materials are thoughtfully chosen, as are methods of assembling them. Building components you interact with daily, such as windows and doors, are critical elements to success as well. Comfortable ambient temperature in a living space is usually a good indicator of a well-designed, well-built home. For a Passive Home - for any low-energy/ high comfort home, really - this is essential.

Limiting air leakage is another key. Unintended movement of air through floors, walls, and ceilings causes a host of undesired results: discomfort, wasted energy, unhealthy air quality, and increased risk of building decay. An airtight building enclosure system is critical for a Passive House.

Uncomfortable air movement associated with forced-air heating and cooling systems is both a problem, and symptom of a larger concern. Traditional homes and buildings leak energy much like a strainer "leaks" water. ON/ OFF Cycling of furnaces and air conditioners, and the forcing of that heated or cooled air through the building, can 'wash' the occupants in mixtures of hot / warm / cold air streams, as that conditioned air with energy passes by and leaks outside. Passive Houses are very tight, and very well insulated, dramatically reducing heating and cooling needs. The heating and cooling needs that remain are addressed with much smaller mechanical equipment, with air circulation accomplished through gentle, continuous ventilation.

Indoor Environmental Quality in Passive Houses

Alongside greater comfort, Passive House owners remark on how much they enjoy fresh air. This, of course, points to a key concept: 

  • continuous, controlled, whole-house fresh-air-exchange ventilation is highly desirable
  • "average" houses which suck our breathing-air from basements or crawlspaces and wall cavities, mixing it with off-gassed chemicals, pests and decay - not so desirable
  • Yes, you can notice the difference

We'll wager fresh air promotes health and well-being inside your home. Step outside, enjoy fresh air, and envision what a Passive House would be like.

Durability and Passive Houses

Though the concept and the planning of durability may seem unremarkable, what good is any building that isn't durable? The founding principle of every building - be it 'Green', 'Sustainable', or 'Passive House' - should be what is durable, and enduring.

We are often asked, almost as a natural assumption, if Low-Energy homes like Passive House are more durable.  The answer is "No, not necessarily."  Does that seem counter-intuitive to you?

Plan for Durability or Reap the Rot - Adventures in Good Green Building - Timber Ridge Craftsmen Inc.A 'Low-Energy' building is, by definition, an enclosure where the flow of heat (inside to out, or outside to in) has been dramatically slowed.  This means there is far, far less heat energy to dry parts of the enclosure that may get wetted by poor detailing - such as flashing of walls, installation of windows or doors, sealing of penetrations, or holding water-wicking cement materials (cement lap siding, or cement mortar or veneer 'stone') against sheathings. So long as the enclosure's ability to dry exceeds the ability to wet, durability is built in.  Otherwise, you get a "rot sandwich". 

A Low-Energy building is far LESS forgiving of bad design, bad planning, and bad detailing - hallmarks of popular "get it done FAST, damn the consequences" thinking prevalent over the past few decades.  Unfortunately, a great many designers and builders haven't been adequately trained or prepared to think, or build, in terms of durability. You would think that is Good Building 101, and it is.  But most missed that class in school.  Designers thought that was someone else's job, no need to attend (avoid knowledge & liability).  Builders thought the 'Good Building' title was Plan for Durability or Reap the Rot - Adventures in Good Green Building - Timber Ridge Craftsmen Inc.teaching something they grew up knowing, no need to attend (mistaken assumption).  And owners haven't known what details to look for anyway - they trusted the dream-team of Awesome Architect and Best Builder to take care of them.  After all, their advertisements said "Of course we exceed your expectations - every day", so what could go wrong ?

Durability isn't sexy, but it is fundamental to any building.  Especially a Low-Energy building.

Energy Conservation

Naturally a key goal of Low-Energy building programs like Passive House, is dramatic reduction of energy use.  The heating and cooling costs of a Passive House are much, much, smaller than a typical 'code' built home.  And that is THE point, for many.

Less well known, but also important, are strategies for controlling other energy costs building owners see. Heating water uses much more energy than owners first realize.  It is common in a Low-Energy house, for example, for hot-water heating to consume more energy, than heating and cooling the entire house does. Strategies to control that cost, then, obviously become important considerations.  It is also common in a Low-Energy house for energy costs of operating appliances and using "plug loads" - think of everything you turn on or plug in - to exceed space heating and cooling costs.  While that may sound daunting, informed strategies for dealing with those challenges are easy to create and implement.  Knowledge is power (savings).

 


 

Timber Ridge Craftsmen, Inc.

One of Virginia's finest home builders, located at Smith Mountain Lake. We are in the heart of the Blue Ridge Mountains, just outside of Roanoke and Lynchburg.