Projection Alarm Clocks

3 Comments

1. Kevin Dickson, MSME
   Posted October 27, 2010 at 1:45 pm | Permalink

   If a LEED rating isn't a guarantee, it's worthless to a consumer. Sorry for repeating this post from greenbuildingadvisor:

   In building code terms, LEED is far too prescriptive and not performance oriented enough. Throw in “too complex for real customers” and too expensive, and what you have is nearly worthless.

   Here's a solution I've been mulling:

   1. Let the building departments adopt the 2009 energy code as they wish. Then STOP any energy code changes forever. The technology is still changing too fast to attempt to follow it with prescriptive code “improvements”. Another reason for freezing the code is to prevent those pesky unintended consequences that aren't even discovered for 20 years. (see Solar Driven Moisture in Brick Veneer at BuildingScience.com)

   2. Then let builders build as they see fit. Good ones will keep improving the sustainability of their product. (If you care enough to be reading this blog, you're probably one of the good ones)

   3. Here's where we replace prescriptive with performance: You can't get any sort of LEEP (Leadership in Energy Efficiency Performance) rating PRIOR to building anything. To get a LEEP rating, the home must have a simple Web-based monitoring device installed for at least one year. The cost of this should only be $1000-$3000, it only needs a handful of measurements, some of which are already there, like kwh consumption, water consumption, gas consumption. Add two indoor temperature readings, hot water tank inlet and outlet, outdoor temperature north side of house and south side of house, major appliance electricity consumption, etc.
   This data can then be used to “normalize” the performance results. The square footage of the house is left out of the normalization calculations.

   4. The LEEP rating is in dollars, just like a yellow EPA EnergyGuide label for appliances. A true net zero energy house gets a LEEP rating of $0/yr. If you put on excess PV panels, and the utility pays you for your excess production, then your LEEP rating can be calculated to equal what the utility pays you for the year, and is negative, say -$200/yr.

   A 1000 sq. ft. home built to 2009 code minimum might get a rating of $800/yr. A 2000 sq. ft. home built to 2009 code minimum should perform a little better per sq. ft. than the 1000sq.ft. home, so it might get a rating of $1400/yr.

   This performance rating will always guide the builder in the right direction.

   5. The other non-energy efficiency related metrics can have their own rating, such as LEEPdurability, and LEEPwater. A near-zero maintenance house might have a LEEPdurability rating of $30 per year, while a house that needs painting and new light bulbs often would be rated at $300/yr. Again, the LEEPwater rating is in $/yr. Oh yeah, don't forget LEEPembodiedenergy. That could be in kwh or $.

   The ratings are thus understandable, simple, standardized, and allow the builder his own solutions rather than any prescribed by LEED.

   Eventually these ratings will be meaningful to buyers, and that's when the builders learn they must generate good ratings. That's what I like, market forces in play instead of federal policy!

   Since this is so similar to the appliance rating program, the LEED officials must have studied the method, but I can't figure out why they rejected it.

   Instead we got a mess that some people hate enough to sue for $100 million.

2. egregg14
   Posted November 11, 2010 at 2:25 am | Permalink

   Solve each of those equations for A so…

   A = 21 – 21e^(-k) and A = 30 – 21e^(-2k)

   Now set the right hand side of each equation equal to each other…

   21 – 21e^(-k) = 30 – 21e^(-2k)

   now you can solve for k, then just plug k into one of the above equations to get A (the outside temp)

3. Don Mason
   Posted June 14, 2011 at 4:22 pm | Permalink

   @Timo