Replies

1. GBA Editor
   Martin Holladay | Sep 15, 2013 05:43am | #1

   John,
   Clearly, you have chosen to build a large house. If you are interested in making this design more energy-efficient, I have a few observations.

   You might want to address some design issues:

   1. I notice that this house has 4 chimneys and at least 6 flues. Is there any way to consolidate the flues so there are fewer thermal bridges in the house?

   2. I notice that there are two exterior brick chimneys. Such chimneys draw poorly and represent a big thermal bridge. Can the chimneys be located near the center of the house instead of on the exterior of the house?

   3. I notice that these northwest windows are very large. These windows will lose a lot of heat during the winter, and may cause overheating during the summer. You might consider making them smaller.

   4. I notice that the roof is chopped up, with many competing roofing planes and many valleys. This is the type of roof that leads to insulation problems and air-barrier problems. Is the air barrier carefully shown on the plans? Will the builder be able easily to maintain air-barrier integrity in all the locations where there may be kneewalls and dormers? You might consider a simpler roof design.

   This house appears to have many issues that are more important than the choice between double glazing and triple glazing. If you are willing to spend an additional $20,000 in energy upgrades, my guess is that there are places where the money could be better spent to achieve more savings per dollar invested.

2. 
   user-2310254 | Sep 15, 2013 08:57am | #2

   John:

   You might also want to engage an environmental engineer. I did and found his input very helpful in making efficient use of my budget. I was considering some choices that really sounded "green" but after analysis did not represent good value.

   Martin also makes a good point about optimizing a structure through design, but I know that sometimes personal aesthetics wins out.

3. 
   jguzz | Sep 15, 2013 09:24am | #3

   Martin,
   Thank you very much for your prompt response. While I definitely appreciate your suggestions, I find myself troubled by your judgment as your answer seems very precocious. Your assumption that I do care about energy efficiency is correct since I am taking the time to do my due diligence by reading websites such as this one. While I appreciate that you feel I am well off enough to build a house such as this one, I ask that you please be cautious about making assumptions about a person by the amount of money they may or may not make. Enough about that subject however, because I believe your intentions were good natured, so lets address your other concerns:

   I apologize for the picture, this was one I was just quickly able to grab off of the internet. We have made some changes to the plans. .
   The plans for this house do call for it being an energy star certified home.

   1 & 2. The two smaller chimneys in the back are not connected to the house at all - they are only connected to the patio (fire pit and grill) and should not affect the thermal envelope. The 2 chimneys on the roof are for gas fireplaces that are fully enclosed and acting more like faux chimneys- just coverings for the vents.

   3. We do enjoy the appearance of the large windows in the back (our personal preference) and for this reason I was trying to educate myself as much as possible to provide the best outcome relating to energy efficiency for this specific situation.

   4. I'm not sure what the architect had in mind when he/she developed this house in regards to the roof, but we showed these plans to CGP contractor and he did not seem to think there would be a problem with the air barrier.

   Martin, I definitely agree that there are many areas to concentrate in when considering making a home energy efficient. However, I am definitely not an expert or professional such as yourself and therefore was trying to concentrate on one area at a time. For this reason, I was concentrating on the windows and trying to get answers to my previously asked questions regarding LoE coatings, double or triple glazing, and whether these should be different for the different sides of the house. I very much respect your opinion after reading many of your responses on the internet and hoping for some of your sound advice.

   Thank you again for your consideration,
   John

4. 
   jguzz | Sep 15, 2013 10:30am | #4

   Martin,
   Please disregard the first paragraph of my response post, It seems as though your initial response has been edited. Thank you for that. I very much do appreciate your input and knew your intentions were pure despite the initial overtone of the message.

   Steven,
   You hit the nail on the head! I am definitely more interested in the components/"guts" of the house while my wife has more of the aesthetics as her concern. I am trying to find a balance to keep both of us happy (happy wife, happy life :) I think an environmental engineer would be a great idea - I have read about energy audits to see which decisions make monitary sense. Do you have any suggestions as the best way to go about finding one (websites etc)?

   Thank you Gentlemen!

5. 
   jguzz | Sep 15, 2013 01:56pm | #5

   Martin, this is a 3800 sq foot home with a walk out basement if that helps with your analysis at all. Again, I do really appreciate your expert opinion.
   Thanks!

6. GBA Editor
   Martin Holladay | Sep 16, 2013 06:01am | #6

   John,
   I'm sorry we got off on the wrong foot, before I edited my first answer.

   I don't want to jump to conclusions, but at first glance, there are many features of your proposed house that are clues that this design has not been optimized for energy efficiency.

   To answer your first question directly: triple-glazed windows will save energy compared to double-glazed windows. However, I doubt whether upgrading your windows is the best place to spend $20,000, if that is the amount that you are willing to invest in upgrading the performance of your house.

   Do your construction documents include airtightness requirements backed up by a blower-door test? Do the documents hold the contractor responsible for meeting those airtightness goals?

   What R-values have been selected for the walls and ceilings? Are these R-values the same as minimum code requirements, or do your construction documents call for above-code levels of insulation?

   What type of fuel and what type of equipment will you be using to heat and cool your house?

   Are you and other members of your family willing to consider major design changes, including a reduction in the area devoted to windows?