My Ideal Energy Efficiency Building Standard

pinterestcontact

ED – Mark has written a lengthy piece on energy standard reform that we insisted he chop into bite-sized parts for this blog. This is the first installment and provides a basic overview of his “dream standard”. Future posts will go on to provide some critique of existing standards and a fleshing out of details . . . we assume.

It’s very easy to find faults with existing standards or certifications because they all purport to define the ideal in a given space, but to be broadly accepted they are forced to make various concessions and end up as an odd mixture of both the ideal and current practices. The good ones retain their core focus and over time make improvements to slowly get closer to that original ideal, lifting the industry with them along the way. The bad ones lose their initial focus and become jumbled monsters that are a burden on all participants while also being ineffective at accomplishing their original goal.

This series of posts will detail my ideal energy efficiency building standard without regard to any established interests. My overall goal is to reduce the amount of energy that we all require to live happy, fruitful and comfortable lives so my ideal standard gives the highest praise for buildings that allow someone to live comfortably on the lowest amount of energy (as the pictures below show, that definition of comfort may vary significantly).

It is good to keep in mind that this form of energy standard has two main purposes. One is to provide an estimate of the likely energy consumption of the building based on typical occupancy. This number can then be used by a number of groups including regulatory agencies enforcing an energy efficiency code, real estate agents selling a house and builders to fine tune the efficiency of their designs and give them something that they can use to compare to other builders for bragging rights. The second purpose is to allow potential occupants the ability to estimate what their total energy consumption would be at each of the homes that they consider. This is where the rubber hits the road as they say. Though these two groups will use slightly different inputs, they can both use the same energy modeling tool or standard.

Without further ado, here are the main tenets of my ideal energy efficiency standard:

1. It’s rating would be displayed in the form of one number that translates to the amount of energy that each occupant requires over a year to operate the house, to perform their daily commute and to account for their portion of the home’s embodied energy (depreciated over its lifetime).
2. It would have an air-change requirement, but it would be based on natural air changes instead of air changes when the building is pressurized at 50 Pascal.
3. It would be a prescriptive standard but every few years it would require owners to publish their actual energy usage data (and monitor the building’s temperature and humidity).

In my view this is the only truthful way of rating a building with regards to energy consumption. Also, it can easily be adopted by taking any existing energy modeling tool and adding an embodied energy calculation and a way for prospective owners to estimate their commuting energy consumption.

I think that I’ve said enough to get the discussion mill turning, so I will end here for now. I will use subsequent blog posts to delve into the details of each of the tenets, why I think they’re important and how they differ from current energy efficiency building standards.

There are a few aspects that are more difficult to assess but should perhaps receive some attention. Should water consumption be one of the core tenets? Would an embodied energy calculation sufficiently emphasize the importance of sourcing building materially locally, using recycled content and avoiding construction waste? Should the ideal standard specify air quality measures or is it just common sense that things that cause cancer should be avoided? Should it specify a Cradle to Cradle framework where all buildings need to be able to be disassembled at the end of their lifetime and entirely reused (recycled instead of down cycled)?

Or, should we abandon the idea altogether because it will prevent people who live in a certified Passivhaus but commute 100 miles every day via helicopter or those who have 3 people living in a mansion featuring a HERS 0 because of a football field sized solar PV array from being able to brag to their friends that they are “green”?

Please let me know in the comments below and stay tuned for part two where I will delve into the first tenet, the idea of comparing energy use per person vs. established practice of energy use per square foot and explain why commuting energy and embodied energy are so important.

14 Comments

  1. Sam says:

    My concept would have ASHRAE-style mandatory requirements but would boil down to two numbers. The first would be embodied energy per square foot. This would include transportation, installation and waste, everything that can be reasonably attributed to the construction process. It would, rightfully, give a large advantage to renovation over new construction. The second number would be energy use intensity (again, per square foot, including all utility inputs). Most of the components of systems like LEED that aren’t addressed by these two numbers should probably be part of a different system/program (like transportation proximity) that works farther upstream of architects and contractors.

  2. Sam – I disagree on a few counts. The only thing that is important with regards to energy is the total energy used by all humans. The square footage of our buildings doesn’t matter (besides their embodied energy). If you have 2 one-bedroom houses with the same energy use per square foot and one is 10,000 SF and one is 1,000 SF the larger one will use 10x the energy, how can you debate that?

    Also, in the process of editing I think I cut out a key point. The idea is to not create and market a new standard with the associated infrastructure etc. but to give a simple way for conscious builders and consumers to quantify the total energy impact of a given building.

    Someone would still have to take a building through the standard Passivhaus process (or LEED or Energy Star etc.) with the focus on energy use per square foot (because it is an important metric in much of the Passivhaus research and associated building science calculations). Then separately, on their own, spend 10 seconds to convert that final third-party verified number to energy use per person and spend 30 minutes estimating the embodied energy. Then a prospective tenant can spend 10 minutes calculating how far the building is from their work, school etc. Then voila, we have one number showing the total amount of energy that person will consume as a result of living in that building, which was our initial goal.

  3. Sam says:

    I guess we are working on different goals. I want to compare the as-designed and as-built performance of multiple buildings and make sure that a high-performing but all-new structure has to account for all the new resources that were extracted in it’s construction. I know a 10,000sf single family residence is absurd to both of us, but that is still a value judgement for each prospective owner/renter to make. The only way I know of to compare the performance of two buildings in the same area is on a square foot basis. Is there another way to normalize that information? The trade-off in size and consumption is a lot easier to do from a square-foot number and is something most consumers of houses are already used to. I also think most people have much less of a handle on how to compare commute times and modes. Also, most U.S. cities are so thoroughly multi-nodal, with poorly integrated public transit, that they are rightfully leary of making a significant larger investment based on one location having a shorter commute for one of the wage-earners. That situation can and does reverse itself very quickly.

  4. Vijay says:

    Mark,

    Great start to what looks to be a very promising and inspiring blog. I enjoyed your perspective on determining a happy medium between comfortable living and minimal energy consumption. In tenet #1 of your Ideal Energy Efficiency Standard, it seems like you are missing a key point when deriving that number. Would it not be important to take into consideration the amount of energy you can leverage through local, natural resources (sun, wind, shade, dirt, etc)?I think by factoring this into your calculation, this will encourage real estate developers, agents, and dwellers to focus on not just what they will be consuming, but what they are saving and recycling. In turn, this will help drive decision on not just the building structure, but also the location based on local and natural resources.

    Just a thought from some one with very little knowledge of this space. Looking forward to your next article.

  5. Sam – you made a few more points that I disagree with. I wanted to reserve the in-depth discussion for after I write the post that details all of this but I just can’t leave these comments without a quick rebuttal to prevent any confusion.
    1. Energy use per person – If your goal is to reduce total energy consumption then the Achilles heal of energy use per square foot is that there is a relatively limitless amount of square footage that we can build. Said differently, if population didn’t change and we had 4x the square footage of buildings and all buildings were 2x more efficient they they are now, would this be good? Per person makes more sense because we build buildings for people. Finally, I don’t know where you got the idea from that I would somehow prevent you from being able to compare buildings energy consumption on a per square foot basis. I am just saying that I will view and talk about my buildings energy consumption on a per person basis going forward.
    2. Embodied energy – it’s important but it’s dwarfed by operational energy and commuting energy. Ill show in future posts that you will save a significant amount of total energy if you abandon a typical existing house in the burbs for a brand new energy efficient house in a city next to a subway or good bus line.
    3. Commuting – I was saving this for my next post but you make it sound too complex. I grew up in your typical suburban setting in California. The closest convenience store was 2 miles away, grocery store 4 miles, most friends 5-10 miles and the main work hubs 15 and 30 miles respectively. As a result I spent the same energy driving to and from my house as I did on heating and everything else I did in the house (no cooling needed). I now live in West Philly within 4 blocks of the trolley that takes me to work, my favorite cafe, brewery, park and some fantastic restaurants. At times I’ve gone 4 weeks without using a car. My commuting energy is 1/10th of my houses total energy. Easy math. Ill elaborate in further posts and include a handy excel sheet also.

  6. jim wild says:

    Great thoughts Mark,

    The per person rating is important, but in reality how do you deal with 5 bed houses that have 2 occupants? Do those two occupants be come 2.5 times greater energy users. Sam’s per sqft rating will easily calculate into a whole building rating, does your idea do the same?

    As you reach passivhuas surely embodied energy become significant enough to justify inclusion at some point? Especially if using PVs to generate electricity. Commuting and travel habits are so varied (especially this part of the world) that they could be really low total energy values. I look forward to the future posts about this.
    Jim.

  7. Thanks for your comments Jim, while I think energy use per occupant is the honest way to rate buildings, and they way that progressive builders should think about their buildings and compare notes, and the way that progressive buyers should think of their energy consumption, I completely agree that it’s a sloppy metric and not a valid basis for a practicable standard. I guarantee that if it became part of a national standard at least one builder would put in an extra “bedroom” where it was not needed just to make the house appear better, which is completely contrary to the point.

    You would certainly be able to get a whole building rating from it though. You would have three values: the total buildings energy use, the total buildings square footage and the estimated number of occupants, you could mix and match those values anyway that you want to compare various buildings by energy use per square foot, energy use per occupant or even occupants per square foot. Or you could leave those metrics out and just compare total energy use.

    With regards to Passivhaus and embodied energy I wholeheartedly agree with your comment. In a similar vein the people that created the Passivhaus standard only learned how important thermal bridging was because in their first project they used all the energy efficient building techniques that were known at the time and were able to cut the buildings heating energy demand by 60% or so. The problem was that based on their model the energy demand should have been cut by 80%. The difference was that they had not modeled thermal bridging. Homes had used so much energy that thermal bridging had not been important but by dropping the demand so significantly from baseline other factors do become important. Embodied energy is a similar case.

    Finally with regards to commuting energy use, I believe that you would be surprised how important it is, check out this post and stay tuned for my next one coming soon:
    http://www.100khouse.com/2010/10/29/energy-consumption-home-vs-transportation/

  8. Thanks Vijay. All of these components are extremely important but for the most part they are already included in good energy modeling tools such as the Passive House Planning Package (PHPP). These tools account for the fact that an energy efficient house successfully will harvest heat from the sun and soil in the winter and in the summer it will block the heat from the sun and harvest the coolth from the soil.

    Wind is not captured in these energy modeling tools because it is very difficult to model but good homebuilders do account for it’s effect on our comfort. If it is hot out and we increase wind speed by either allowing good cross-ventilation in the house when all windows are open or have fans strategically located, then we can make people feel comfortable with a minimal amount of energy consumption, or none at all. It’s kind of fun to take a look at a psychrometric chart to see at what intersection of temperature, humidity and wind speed most people feel comfortable, and to understand what is going on in the body that makes us feel comfortable at those different levels.

  9. Mark,

    You’re looking for food for thought, so here’s a link to my thoughts below.

    Note, I don’t think a good standard can be prescriptive while the technology is changing so fast. Next year’s zero energy cost home will be quite different from the a 2008 zero energy cost home.

    Also, keep unrelated standards and ratings separate, i.e., a home has several ratings: yearly energy consumption, embodied energy, location energy, durability, water consumption, etc.

    http://greenbuildingindenver.blogspot.com/2010/10/leed-for-homes-rating-system.html

  10. Goran says:

    Keep it simple. The are parts of the standard that have a lot of subjective value judgements built into them: about material sourcing, recycling, ideal living space per person. A good energy efficiency standard would be one that makes sense to broadest possible range range of potential home purchasers. “Money” was pretty much invented to provide a universal value metric for different things, and that might be the safest thing to stick to: actual operating costs and lifetime cost for the owner. Sure, there might be a “per person” energy cost component, for things like laundry, hot water, dishwasher. Include that number, and let people plug in how many occupants they want. Same thing goes commuting.

    Having complete cost numbers will give people the tools they need to decide they want to live in a smaller house, or live closer to commuting hubs, etc., without making value judgements for them about how many people they should have in the house. It will allow them look at the purchase price of a home, and decide whether paying more for it up front makes sense over whatever term they expect to own the house for.

  11. Goran says:

    Mark, please allow a correction: “my” ideal energy efficiency building standard would have the tweaks above. Yours is fine the way it is. Thanks for the article.

  12. mike eliason says:

    looking forward to part 2.
    some thoughts i have:
    1. energy usage per person is a difficult metric – as families change over time, building occupancies change over time, new owners may have smaller families in an existing house. this is why kBTU/ft2a is the common metric, and not kBTU/person. while i see the merits of a per person number, i just don’t see a way of pulling it off.

    2. i’m really looking forward to the next post… for the most part, i don’t feel embodied energy should be looked at unless you’re already planning on bringing the operational energy down considerably. this is one of my bigger issues with LEED – people spend a significant amount of time selecting lower embodied energy products but completely miss the ball on the energy points – the least utilized points in the LEED program. the result is that a building has maybe 15- 20% lower embodied energy – but this is dwarfed over time by operational energy.

    3. also for the next post – if discussing commuting energy – can we talk about source energy for housing? i don’t think recent articles on the topic have been looking at the whole picture, focusing on site energy demand muddies the picture.

  13. Buildingwell says:

    Mark, you make some great points and point to the potential of a better efficiency building standard. In relation to your questions at the end of the post, I would certainly agree that water consumption should be incorporated into this standard (hence my reference to “efficiency building standard” than “energy efficiency building standard”). Many regions are struggling with water resource issues. Our buildings and the sites we maintain can certainly stand to be far more water efficient and therefore a any building standard should certainly incorporate this resource. Looking forward to the follow-up pieces. http://www.buildingwell.org/Water+Conservation

  14. Nicefiller says:

    Very good blog! Do you have any hints for aspiring writers? I’m planning to start my own blog soon but I’m a little lost on everything. Would you advise starting with a free platform like WordPress or go for a paid option? There are so many options out there that I’m completely overwhelmed .. Any recommendations? Thanks a lot!
    Nicefiller http://www.nicefiller.com

Leave a Comment