John C. Semmelhack
  • Charlottesville, VA
  • United States
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John C. Semmelhack replied to George Kopf's discussion How does efficiency factor into a grid parity world?
"Graham, The U.S. is catching up to Germany very quickly on solar installs. As of the end of 2013, the Germany-to-U.S. cumulative installed solar capacity ratio was about 2.6 to 1. At the end of 2014, it will be closer to 2 to 1. The U.S. will likely…"
Oct 23
John C. Semmelhack replied to Jack Baikoff's discussion Measuring fresh air intake ducted to a return and no way of measuring from outside.
"HVAC contractor (ideally) drills the 1" hole, then tapes over afterward.  I invested about $250 for 4", 5", 6", 7" and 8" versions of the device. "
Jan 24, 2013
John C. Semmelhack replied to Jack Baikoff's discussion Measuring fresh air intake ducted to a return and no way of measuring from outside.
"By the way...not sure what climate you're in, but someone should probably should insulate that fresh air duct!"
Jan 24, 2013
John C. Semmelhack replied to Jack Baikoff's discussion Measuring fresh air intake ducted to a return and no way of measuring from outside.
"There are in-duct measurement techniques that are accurate enough for this purpose. Here's what I use - http://www.kele.com/flow/fxp-series.aspx It's essentially an "averaging" pitot tube to take care of the likely…"
Jan 24, 2013
John C. Semmelhack replied to Jack Baikoff's discussion Measuring fresh air intake ducted to a return and no way of measuring from outside.
"Why are you wondering how much airflow occurs at this intake?   1) Required for Energy Star 3.0 certification 2) Code compliance 3) Ensure there's enough airflow to help ensure healthy indoor air quality 4) Ensure there's not too…"
Jan 24, 2013
John C. Semmelhack replied to Curt Kinder's discussion AirGenerate Heat Pump Water Heaters - any experience?
"Dan,  Good to hear you're evaluating the reduced airflow form the CAR's. I'm interested to see the results.  Regarding the discharge airflow - comfort issues are relatively easy to mitigate with location, placement and…"
Nov 20, 2012
John C. Semmelhack replied to Curt Kinder's discussion AirGenerate Heat Pump Water Heaters - any experience?
"Dan,  Have you measured the drop in efficiency/capacity caused by reducing the airflow?  Why are you recommending exhausting the discharge outside of the house?  John "
Nov 16, 2012
John C. Semmelhack commented on Roch Naleway's blog post Borrowing from solar thermal system - Why not use two tank systems with heat pump water heaters?
"Are you kidding me? That's the worst thing I've heard all month. Cutting the airflow across the heat exchanger of a heat pump system by 50-60% will significantly reduce capacity and efficiency. I'm glad I'm not a rate-payer in…"
Sep 13, 2012
John C. Semmelhack commented on Roch Naleway's blog post Borrowing from solar thermal system - Why not use two tank systems with heat pump water heaters?
"The ATI-50 and ATI-66 have a 6" diameter discharge collar on the top of the unit that can be ducted in the case of installations in small spaces. In the particular scenario I've been discussing, the discharge is ducted about 15' over…"
Sep 13, 2012
John C. Semmelhack commented on Roch Naleway's blog post Borrowing from solar thermal system - Why not use two tank systems with heat pump water heaters?
"The ATI-66 for the seven-person household is in conditioned space (hallway closet between kitchen and living room), so the ambient temperature is pretty consistent. I'm sure HPWH's have a harder time keeping up with demand in colder months…"
Sep 13, 2012
John C. Semmelhack commented on Roch Naleway's blog post Borrowing from solar thermal system - Why not use two tank systems with heat pump water heaters?
"It seems like a better solution would be a larger tank for the HPWH in these situations, such as the Steibel Eltron or the AirTap ATI-66. Certainly, both of these are more expensive than the 50-gallon models from GE, Rheem etc., but they also have…"
Sep 13, 2012
John C. Semmelhack replied to Pam Worner's discussion DHPs in MF projects
"Yes, this can be done and is done.   Many of the ductless heat pump manufacturers have these types of units available. The most well-known is 'City-Multi" from Mitsubishi. The ratio of indoor units to outdoor units depends on the…"
Nov 10, 2011
John C. Semmelhack is now a member of Home Energy Pros
Oct 11, 2011

Profile Information

Company
Think Little
Professional Certification
Certified Passive House Consultant, HERS Rater, EarthCraft Virginia Technical Advisor, BPI Building Analyst
Website URL
http://www.think-little.com
Blog URL
http://www.think-little.com

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At 1:19pm on October 11, 2011, Diane Chojnowski said…

Hi John,

Welcome to Home Energy Pros! Feel free to join the conversation in the Forum and Groups. And share your energy efficiency photos, videos and upcoming events. If you're blogging about home performance, this is the place for you!

Don't forget to upload your profile photo. And add your location on our Member Map!


Thanks!
Diane, HEP Moderator

 
 
 

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