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Custom high-performance certified green homes? Been there, done that.
如果您已经建造了一个体面的自定义房屋，该自定义房屋已在Energy Star认证附近，将其绿色应该很容易做到，并且每平方英尺不到1美元。在大多数社区中，建造一个经过全国认证的定制绿色房屋的真正不再是新的基础，除非它是设计出奇特的翡翠或白金级零能源的房屋。简而言之，在整合绿色设计细节，产品，材料和施工方法方面，住房的定制市场就像许多行业的定制细分市场一样，最终将成为主流。
Now, logically, these practices should be trickling down to semicustom and high-end production homes for the middle class, right? And as they become more widespread and costs drop, the final frontier will be starter homes, workforce housing and government-subsidized housing, correct? Well, my experience shows that the middle market is being left behind as low-income housing jumps to the front of the race to build nationally certified green homes.
In the last year alone, we have priced out 200 LEED-certified Section 8 townhouses that came in at less than $70 per square foot, including a gross profit of approximately 12%. We are currently working on the pricing of 95 single-family homes considered LEED/NGBS-certified workforce housing, and they are coming in very close to the same cost and gross profit return. How is this possible?
The home-size adjuster in each program is what makes it possible. In essence, there is a sliding scale that compensates for the effect of home size on resource consumption. All else being equal, a larger home consumes more materials and energy than a smaller home over its life cycle, so both programs adjust their awards threshold points in each category based on the size of the home. Thus, smaller-than-average homes require fewer points to reach a given award threshold than larger-than-average homes.
The average home sizes for the LEED program are 1900 square feet with three bedrooms, 2600 square feet with four bedrooms, and 2850 square feet with five bedrooms. The NGBS also applies bonus points to the scoring for smaller-than-average homes. The bottom line is that the ratio of a small home to a large number of bedrooms has a much easier time reaching any given point threshold in either program than does the ratio of a large home to a small number of bedrooms.
And that’s the key to how we are making green affordable in the workforce housing and/or low-income market. These houses are smaller and they have lots of bedrooms. That makes them a lot easier to certify. A 1700-sq.-ft. townhouse with four bedrooms gets a 10-point credit and only needs 35 points to be certified. At that point, it becomes a footrace to the least expensive way to get those points. But does that make it greener? That’s the topic of my next blog!
9 Comments
Michael
LEED代表什么？
Response to Roy
罗伊，
LEED = Leadership in Energy and Environmental Design.
Read more here:
利兹为房屋
What's LEED? What's NGBS?
谢谢马丁！就像NAHB（国家房屋建筑商协会）的NGB（国家绿色建筑标准）一样。
Depending on whether it is a LEED project or a NGBS project it may be the renovation or new construction of a home, commercial building, school, warehouse, neighborhood, hospital etc... to name a few of the many building types. For mor einformation on the NGBS go tohttp://www.nahbgreen.org
家庭规模罚款
Michael- I agree; shrinking home size helps certification efforts, however, LEED is really the only program where it substantially matters. NGBS penalizes larger homes at about 10% of what LEED for Homes does. The points are about the same, but the scale is much, much different between the two programs. In fact, NGBS has no scale for number of bedrooms, and the below grade portion of any building is not included, so finished basements get a free pass in SF calculations. I think LEED definitely has the right approach here.
Article missing the point
迈克尔，感谢您的文章。我认为您缺少如今正在绿色建造负担得起的住房的一些关键原因。1）实际上，所有50个州现在都在其主要生产计划中针对补贴租赁住房的主要生产计划都有绿色建筑要求，如果不是LEED认证要求；2）经济适用房有许多资金来源，可用于中等收入住房的住房生产；3）许多市政当局要求获得当地州或联邦资金（负担得起）的项目以满足LEED或其他绿色标准；4）许多负担得起的开发商是非营利组织，他们看到其任务的一部分是为弱势人口提供可持续，健康的住房，而弱势人口历来将其收入的30％仅用于公用事业，并且一直生活在经常受到环境污染的地点的不健康住房中。
中等收入住房（对于获得该地区中位数收入的80-120％的家庭），上述胡萝卜或棍子很少，将开发商推向绿色实践。为了使这个庞大的中层部门更可持续地建造，我们将需要更多的激励措施以及在所有房屋范围内更好地建造房屋的授权以及授权：长期逾期。
Finding the Missing Points
博客杰伊（Jay）的好补充。您提出的所有要点都是目标，当然正在为负担得起的住房带来领先于中间市场的绿色，我感谢您将其添加到讨论中。也就是说，我相信这不是因为您提到的理由实际上没有获得认证的房屋规模调节器，因为所需的额外积分会太大的预算，因此获得了绿色认证。我认为您的四个原因使项目进入起跑线，但是房屋尺寸的Adjsuter使他们能够起飞！
我想要得到高的h end custom green builder to think outside the box they are working in and see what other market segments are going green. With the affordable market segment as strong as it is I think they need to see if they cannot leverage their green expertise to win some of these projects. I have found our middle income market flat this year and am looking at the affordable segment in the year ahead for any growth. If other green builders do not realize the home size adjuster makes it easier (and less expensive) to get the home certified they may not look twice at the opportunity they present.
Green Building, is there really a cost benefit?
OK, this is going to sound somewhat controversial but I've been in the process of designing a new home to be built in northern VT. Martin Holladay and others have been very helpful in giving me advice.
I had previously thought I would build a passive solar house with triple pane windows and polyiso SIP R-40 walls and R-50 roof over a timber frame. That was until I recently downloaded REM/Design and started plugging in numbers.
The windows I've been most closely looking at are from Inline because unlike most American manufacturers they offer windows which appear to balance the U and SHGC to maximize passive heat gain. I also looked at Thermotecs but the price/performance ratio is better for those from Inline as best I can tell. For my house design it looks like triple panes will run around $5000 more than double panes. At current energy prices REM/Design calculates the savings for this at $170/yr. That's a 30 year payback.
对于具有相同类型的Windows I类型的建筑物，我将EPS SIP（R-26墙，R-33屋顶）的加热成本与Polyiso（R-40墙，R-50屋顶）进行了比较。由于设计尚未完成，所以我从我为这些选项中获得的每个SF价格报价摘要，并使用与REM/设计相同的尺寸手动计算该区域。尽我所能，这之间的成本差异约为10,000美元。REM/设计显示每年节省$ 226/年的供暖成本。回报率超过40年。
Combining these and comparing a home with double pane windows and EPS SIPs to the triple pane windows and Polyiso SIPs shows a 37+ year payback.
Now this assumes fuel costs don't go up. But it also assumes I don't do anything with the cost savings. I checked the 20 year history of propane prices in New England and they appear to have an average annual increase of 5% for that time frame. So I applied assumptions of 5% and 10% average annual price increases for the next 20 years and then took the total additional heating costs under those scenarios and back calculated what yield I would have to get on the $15,000 I would save going with a less well insulated building.
For the 5% average annual fuel price increase I would need to earn a 3.5% return on the $15,000 to keep up. For the 10% average annual fuel price increase I would need to earn a 5% return on the $15,000 to keep up. Both of these are lower than the 20 year average returns of stocks. The lower one is better than the 20 year average yield on bonds.
那么，我对数学，疯狂或严重误导了吗？
或is there really a good deal of diminishing returns in trying to build to a higher level of efficiency?
我的感觉是后者，因为否则我会认为，更多的人会建立我最初正在考虑的更高标准的类型，我猜我可能不会比其他所有人都聪明...
这是什么共识？
Response to Jay Hersh
Jay,
尽管我还没有仔细检查您的数学，但您引用的回报期与正确的声音。
您已经击中了指甲：直到燃油价格大幅上涨 - 与您所谈论的年度价格上涨的5％或10％的价格不同 - 许多超级疑虑措施都没有经济意义。
The people who are building superinsulated houses today are NOT interested in saving money. Their reasons for investing in a superinsulated house vary, but here are a few:
- 有些人担心未来的能源危机将使化石燃料难以获得或过于昂贵。
- 有些人想为未来的经济崩溃做准备。
- Some people want to reduce their carbon footprint to be good environmental stewards.
- Some people are willing to pay thousands of dollars for improved comfort. (Trust me -- those triple-glazed windows are nice. When it's -20°F outside, you can sit right next to one and not feel cold.)
Others -- perhaps like you -- may wonder whether Americans are investing too much in their houses, and wonder whether all this foam and all these fancy windows are a good use of the world's resources. Good questions!
Thanks for the sanity check
Thanks for the sanity check Martin. It's good to hear I haven't forgotten all my basic engineering skills and totally munged the math.
We may indeed end up falling into the category of those who spend the extra $ but I thought it was a good idea to at least make sure I understood the cost benefit trade-offs we were making if we go that route. We're definitely going to price out both approaches for the final plan so we really have a good grip on the price premium but we may end up deciding to put that $ elsewhere.
I haven't posted it yet, but I also did a cost comparison based on three different heating system approaches stemming from our discussions in your article about heating a tight, well insulated home (//m.etiketa4.com/blogs/dept/musings/heating-tight-tight-well-ussuald-house-house?page=1#comment-21281）。有点长。我会在该主题中发布它（因为这里是不在主题的），因为有些人可能对我学到的知识感兴趣。
thanks
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