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ERV or HRV

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Balanced ventilation systems use either an energy-recovery ventilator (ERV) or heat-recovery ventilator (HRV), typical in Passivhaus construction. While both enable the simultaneous stream of fresh air in, stale air out, and recovery of some heat from the warmer stream in passing each other, the ERV also transfers moisture to the drier air stream with minimal mixing between the two streams. An ERV can transfer 40-60% of the humidity in the outgoing stale air stream to the incoming fresh air stream helping to maintain a more consistent relative humidity level indoors. In higher humidity climate zones, indoor humidity can be effectively controlled using a dehumidifier, as a stand-alone unit. In the long-running debate between which of the two types of units makes a better choice for passive house construction, ERV or HRV, energy efficiency is still a primary criteria to assess different units on the market. Following are some of the more highly cited makes available online: ...
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Cladding Alternative v.1

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This is Part 1 in a series of posts considering cladding alternatives to more commonly used materials such as brick veneer, wood clapboard, shingle or vinyl. First up are wood siding and cladding products. Wood shingles are typically made from cedar, a naturally decay resistant, light softwood with low density and shrinkage values as well as good thermal insulation properties. Wood clapboard and siding is made from softwood species (conifers) such as pine, spruce, redwood, Douglas fir or cedar. If your wood siding is made from North American softwoods, there is a greater chance of it coming from well-managed forests than hardwoods, which are likely to be harvested from far away, tropical and unregulated markets. If you bother to check labels on your clothing and food purchases, then it's not a large step to check the origin of your building goods - it's rather interesting to know. The availability of wood products certified under sustainable programs such as FSC ( For...
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Heating with wood pellets

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  Ever thought about heating systems that use wood pellets?  This fuel type is known as solid fuel / biomass, a renewable fuel source that is currently manufactured in most regions of North America, making wood pellets a locally supplied product.  Wood pellets are typically made from the waste byproducts of wood product manufacturing, including compacted sawdust and sawmill wastes, as well as from leftover material of the logging industry.   Although wood pellets resemble a recycled wood pet litter available in American supermarkets and pet stores, the type used for wood fuel in the US market is manufactured to achieve less than 10% moisture content.  The criteria of this standard was originally developed by the Pellet Fuels Institute , which has now engaged the American Lumber Standard Committee  to serve as the accreditation body for the PFI Standards Program.
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Wall switches go wireless

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Well, this was an eye-opener I recently found. Can you imagine wireless wall switches? And why would you want these in your project?  Minimizing air-leaks in the building envelope is a priority to maintain air-tightness.   Every time a control or outlet is installed on an exterior wall, the envelope is compromised introducing the potential for leakage around the wall plate. Enter the battery-free wireless light switch, which is just one application made possible by a wireless, energy harvesting technology known as EnOcean. EnOcean technology emerged in 2001 from EnOcean GmbH , a spin-off enterprise of Siemens AG from Germany whose technologies are used in building automation, industrial automation and the automotive industry.  In 2007, MK Electric was the first UK manufacturer to use EnOcean for wireless switches.  Here in the US, a number of companies have adopted EnOcean to offer wireless switching products on the market that are widely available. Wireles...
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Blower door tests

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What's a blower door anyway? When building a superinsulated and very air-tight building, blower door testing is conducted to measure air-tightness.  A calibrated fan in conjunction with a pressure testing device depressurizes the the building revealing the level of air infiltration. A standard system known as Minneapolis Blower Door from the Energy Conservatory uses an adjustable door frame with nylon sheeting within which the fan and pressure gauge are mounted.  Manufacturers of similar systems include Infiltec and Retrotec . Further combined with a smoke pencil or fog machine, the blower door test provides visual evidence of air leakage paths.
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Insulation tools for comparison

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With a wide array of insulation types on the market with some more sustainable than others, tools for comparison should be consulted.  Where and when to use certain types of insulation requires careful analysis for each project.  Economic, energy and environmental considerations have prompted increasing availability of alternate options.  Here, we offer a few excellent resources.
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Insulating with wool?

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Photo by Rainer Ebert Super insulated, air-tight buildings rely on high-quality types of insulation and lots of it.  Accommodating upwards of 12 inches in your wall assembly becomes a financial decision as well as a detail adjustment (i.e. double-stud walls).  Easily available, often sustainable products are made with cellulose (recycled paper), cotton (recycled jeans), spray-foam and fiberglass. An uncommon type of insulation in the US is wool, but awareness is growing of its benefits.  If you are a fan of wool socks, then you know that wool breathes! 
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