Can you do a HERS Rating on an apartment in a 30-story building? Not now, but maybe in 2019!

ANSI/RESNET/ICC 301-2014 is the Standard for the Calculation and Labeling of the Energy Performance of Low-Rise Residential Buildings using an Energy Rating Index. It is the basis of the most common Energy Rating Index, RESNET’s HERS Index, which is utilized by utilities and building programs like LEED© and ENERGY STAR®, which require a consistent index to evaluate performance.

ANSI RESNET ICC 301-2014 imageOn March 2, 2018, RESNET released a draft of the 2019 version of ANSI/RESNET/ICC 301, where the most significant change will be the expansion of its scope to include Dwelling Units and Sleeping Units in ANY height building, whether that building is defined by IECC as “Residential” or “Commercial”. Other changes will include those developed by the RESNET Multifamily Sub-Committee, to better address shared systems like HVAC, hot water, solar PV, and laundry, and other scenarios specific to multifamily buildings that have largely been unaddressed until now.  The 1st preliminary draft standard of the 2019 version (dubbed PDS-01) includes these important improvements, along with all addenda to Standard ANSI/RESNET/ICC 301-2014 that were approved prior to March 2.

How Does the Revision Process Work?

The ANSI/RESNET/ICC Standards 301 (and 380) are under “continuous maintenance”. What does this mean? As revisions are needed to improve the standards, they are accomplished via “addenda”. Each addenda has to go through a “public comment” period to ensure that all stakeholders get to provide their opinions or objections to the proposed change before it becomes part of the standard. Rather than re-publishing a new edition of the standard each time a revision is approved, these standards are instead updated every 3 to 5 years to integrate any approved addenda into the body of the standard (instead of as separate addenda), along with any other necessary revisions into a new edition. This is similar to other standards like IECC, ASHRAE 62.2, or ASHRAE 90.1, which typically release a new version every 3 years. Read more

Montgomery County Green Building Requirements

IGCC Logo

Montgomery County, Maryland recently passed new green building requirements, including adoption of the 2012 International Green Construction Code.  Montgomery County was one of the first jurisdictions in the country to enact a green building law in late 2007. Now, county officials have repealed the original law and replaced it with Executive Regulation 21-15 that will likely reduce requirements for many new buildings.

New Requirements

There are some pretty big changes brought about by the new law, which took effect on December 27, 2017 and includes a six month grace period for projects already under design. New projects permitted after June 27, 2018 will need to comply with the following:

  • Projects 5,000 gross square feet and larger must comply, lowered from 10,000 gsf.
  • Buildings must meet the 2012 International Green Construction Code (IgCC), replacing the requirement that buildings must meet LEED Certified criteria.
  • Residential projects under five stories must use ICC-700/NGBS at the Silver Energy Performance Level.
  • R-2 and R-4 portions of Mixed-Use buildings may comply with ICC-700/NGBS and the non-residential portion shall comply with the IgCC or the entire building may comply with IgCC or ASHRAE 189.1
  • R-1, non-residential and R-1/Mixed-Use projects may select IgCC, ASHRAE 189.1 or LEED Silver with eight points or more under the Whole Building Energy Simulation path.
  • All buildings using the IgCC compliance pathway must achieve a Zero Energy Performance Index (zEPI) score of 50 or lower.

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Ventilation Idyll

Residential ventilation is really a tricky topic. But if you’re looking for a practical, cost-effective, holistic solution, go somewhere else. This post offers none.

Hopefully I can dig into practical solutions in future posts, but I think it’s important to be clear about why we ventilate and what an “ideal” ventilation system might look like in a new, efficient home. My ideal system is similar for both single-family or multi-family (though practical issues can be very, very different).

Purpose of ventilation: Remove contaminants that can compromise health, comfort, productivity, durability, etc. I’m sure there are more rigorous definitions out there, but this will work for now. There are other ways to lower contaminant levels:

Shangri La

Shangri-La image via Olga Antonenko

  • Emitting fewer contaminants from materials and activities is obviously good. Do this.
  • Actively filtering, adsorbing, or otherwise removing contaminants from indoor air can also be good. There’s talk about doing more of this, but I’m tabling it for this discussion. This may be something to keep an eye on down the road.

For most new residential buildings, mechanical ventilation is still be the primary means to remove contaminants. Or at least it’s the primary method that designers/developers need to plan for now.

If building a new, efficient home in Shangri-La, my ideal ventilation systems would look like this: Read more

Wishing You a Sustainable-ish Holiday Season

Whether you’re a Clark Griswold or an Ebenezer Scrooge, it’s that time of year again: the holiday season is upon us.

dog holiday

A less-than-enthusiastic participant of a holiday photo shoot.

Even those of us who try to live a greener, more eco-conscious lifestyle have a tendency to abandon ship and surrender to the flow of unabashed consumerism and waste in the name of “just getting it done.” It’s hard to put added pressure on ourselves to be mindful of our environmental impact when there are gifts to be purchased, cards to be sent, stockings to be hung, and photos of dogs in Santa hats to be taken.

But you don’t need to do it all to have an impact.

Find one or two ways to improve your holiday traditions by making them greener. Perhaps pick the ones that justify you doing less work in the name of the environment (Reusable bags instead of gift wrap? Yes please). Think of it as a gift to Mother Earth or humanity, or as a way to further annoy that aunt who just can’t understand why on earth you would want use cloth diapers. Sigh.

Here are some ideas, tips, and tricks to help you be just a little more sustainable this holiday season:

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When the Rubber Meets the Road

 

As the Passive House standard continues to make waves across New York City and the U.S., an entirely new design process has evolved to respond to the challenges of higher insulation levels, balanced mechanical ventilation, and perhaps the most difficult hurdle – an air tightness level that most would think is impossible. For the recently certified Cornell Tech building on Roosevelt Island, the tallest Passive House in the world, a several year-long coordinated effort was required to achieve such a feat. So what is the requirement, how is it measured, and what are the strategies and considerations required to achieve it?

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