David Butler
  • Male
  • Huachuca City, AZ
  • United States
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David Butler's Discussions

How would you insulate this roof?

Started this discussion. Last reply by David Butler 23 hours ago. 2 Replies

I have a client who needs your help. In the early 80's, he and his wife built a beautiful off-grid home on a small island near Fort Myers, FL. It currently serves as a convenient getaway, but as they…Continue

 

David Butler's Page

Latest Activity

David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"theoretically, let's say you perfectly isolate the HPWH from a heat source. The HPWH's will eventually cool the air to the point that mold will grow. Here's the math: 30x30x8 = 7200 ft3 x 0.075 lbs/ft3 = 540 lbs of air 540 lbs x 0.24…"
22 hours ago
David Butler replied to David Butler's discussion How would you insulate this roof?
"Interesting idea. Commercial roof on a slope! Typical density for roofing spray foam is 2.5 to 3.0 lbs/ft3, depending on expected foot traffic, with R-value of about 6.5 per inch. On 'flat' roofs, the mix is normally set for a slower…"
23 hours ago
Sean Lintow Sr replied to David Butler's discussion How would you insulate this roof?
"You might consider a commercial grade roof foam spray (higher density than normal CC Foam) with a coating over that - if they want metal over that, that's fine as there are some special clips & rails they can use but the clips need to be…"
yesterday
David Butler posted a discussion

How would you insulate this roof?

I have a client who needs your help. In the early 80's, he and his wife built a beautiful off-grid home on a small island near Fort Myers, FL. It currently serves as a convenient getaway, but as they approach retirement, they want to install a limited amount of air conditioning in the form of a couple of small, high-SEER ductless mini-splits. The aging 12V PV system is quite small -- the refrigerator is propane powered, and there's no well (fresh water supplied by rainwater collection). So…See More
Sunday
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"Regarding Sanden... US distribution is fairly new so I imagine they make it easy to set up an account, or would sell direct. The plumber would have to be on board, though. The current model is good to -15F, and the forthcoming Gen3 is good to -20F…"
Saturday
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"Yes, now that I've taken time to make sure I understand the physics, I'm in full agreement. Consider that with an air-air heat pump or A/C, the heat rejected by the condenser is roughly the same as the heat absorbed by the evaporator. A…"
Saturday
David Butler replied to Sean Lintow Sr's discussion Water Saver or Gimmick? in the group Best Practices (Residential)
"Since others reactivated this thread, I'll chime in. In recent years I been including DHW distribution in my design review conferences. As others noted, each house is different, requiring its own solution. The device Sean mentioned in the OP…"
Friday
David Butler joined Sean Lintow Sr's group
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Best Practices (Residential)

Best Building, Retrofitting, or even Auditing Practices - what are they, what should change, what needs to find it's way to the dust bin of history?See More
Friday
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"It' irrelevant whether the basement is intentionally heated now. My point is that if you install 3 HPWH's down there, it makes no sense to NOT intentionally heat it. The heat pumps must get their heat from somewhere. Without a heat source…"
Friday
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"Hi Brad, as you know, a heat pump's capacity and COP depend largely on ambient temperature. But in situations like this where heat pump operation will have an out-sized impact on ambient, you essentially create a feedback loop. Unfortunately,…"
Thursday
David Butler replied to Classic Residential, Inc.'s discussion Learning Thermostat
"I'm with you on this one PJ (for once!). All else being equal (or equally bad), setback has the potential to save more than downsizing source equipment, although if the AC is grossly oversized, say, 200% or more, who knows. It's true that…"
Jan 15, 2012
David Butler replied to Classic Residential, Inc.'s discussion Learning Thermostat
"review of Nest @ new york times: http://nyti.ms/sX66eZ"
Nov 30, 2011
David Butler replied to Classic Residential, Inc.'s discussion Learning Thermostat
"Ted, by saying that homes that benefit from setback are somehow broken, you're making a huge generalization, and one that flies in the face of physics and common sense. You wrote: I ask how much and they say "a lot". I can't…"
Oct 29, 2011
David Butler is now a member of Home Energy Pros Forum
Oct 28, 2011

Profile Information

Company
Optimal Building Systems
Role in Home Performance Marketplace
Building energy modeler, Researcher (Lab. academia. etc.), Other
Professional Certification
Other
Website URL
http://optimalbuilding.com
LinkedIn Profile
https://www.linkedin.com/in/davidbutler52/

Comment Wall (1 comment)

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At 9:43am on November 1, 2011, Diane Chojnowski said…

Hi David,

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 add your location on our Member Map!


Thanks!
Diane, HEP Moderator

 
 
 

Forum Discussions

Too many Heat Pump Water Heaters in a basement?

Started by Brad Cook in General Forum. Last reply by David Butler 22 hours ago. 9 Replies

How would you insulate this roof?

Started by David Butler in General Forum. Last reply by David Butler 23 hours ago. 2 Replies

Dirty solar panels

Started by Evan Mills in General Forum. Last reply by Stacie Bagnasco yesterday. 1 Reply

Fixing a water heater?

Started by John Shillito in Best Practices. Last reply by Eric Kjelshus on Friday. 21 Replies

Latest Activity

Profile IconSarah Burger, Troy Spindler, Mike Berg and 3 more joined Home Energy Pros Forum
2 hours ago
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"theoretically, let's say you perfectly isolate the HPWH from a heat source. The HPWH's…"
22 hours ago
David Butler replied to David Butler's discussion How would you insulate this roof?
"Interesting idea. Commercial roof on a slope! Typical density for roofing spray foam is 2.5 to 3.0…"
23 hours ago
Summer Redman added a discussion to the group Job Board
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Hiring 2 Training Specialists in Champaign-Urbana, Illinois

The Applied Research Institute (ARI) at the University of Illinois at Urbana-Champaign is seeking…See More
yesterday
Summer Redman joined Diane Chojnowski's group
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Job Board

This group is for posting jobs related to all aspects of the home performance industry including…See More
yesterday
Profile IconJeff Farlow, John Hatfield, Crystal McLain and 5 more joined Home Energy Pros Forum
yesterday
Stacie Bagnasco replied to Evan Mills's discussion Dirty solar panels
"This is a great idea. I clicked on your discussion because it made me remember that I forgot to get…"
yesterday
Kirsten Richnavsky posted an event
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rCloud - The Future of Testing at Your Office or Home

October 18, 2017 from 2pm to 3pm
Integrating rCloud as an essential part of your RESNET QA process.Retrotec’s rCloud app is here,…See More
yesterday

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