New Mexico Green Builders Create Water Efficiency Rating System
Energy usually gets top billing in the green building community. It has a huge impact on the environment. We sometimes pay a significant amount for it (although most of us don’t pay enough to motivate serious change, but that’s another story). We can do energy modeling and home energy ratings. Plus, it’s just really interesting! But water deserves a lot of attention, too, and green builders in New Mexico are innovating a way to move water to the fore.
Energy usually gets top billing in the green building community. It has a huge impact on the environment. We sometimes pay a significant amount for it (although most of us don’t pay enough to motivate serious change, but that’s another story). We can do energy modeling and home energy ratings. Plus, it’s just really interesting! But water deserves a lot of attention, too, and green builders in New Mexico are innovating a way to move water to the fore.
Meet the WERS
If you’ve been reading this blog for any length of time, you’ve no doubt heard of a HERS rating. It stands for Home Energy Rating System, and it includes calculations that produce a HERS Index, a number whose main reference point is 100. The lower the number, the more energy efficient the home. A HERS Index of zero would be a net zero energy home.
Likewise, the WERS stands for Water Efficiency Rating Score1 and has a 0 to 100 scale, with lower numbers being better. Created by the Green Builder Coalition in cooperation with Build Green New Mexico (BGNM), Santa Fe Area Home Builders Association (SFAHBA), and members of the City of Santa Fe Water Conservation Committee (SFWCC), the WERS is a software-based program that tells you how efficiently your home uses water.
You may be wondering why they felt the need to create this when the US EPA already has a water efficiency program, WaterSense. There’s a big difference between the two, though. WaterSense is actually two things. First, it’s a label for products like toilets and faucets, similar to the ENERGY STAR label for things like computers and refrigerators. Second, it’s a program for new homes. (Check out program details at the WaterSense website.)
So, the WaterSense new homes program is based on a checklist. WERS is a rating system, similar to HERS.
Calculating a WERS
The New Mexico folks have done a lot of work to put this rating system together, and it’s in the pilot stage now. The inputs and calculations are done in a spreadsheet (see screenshot below), and it’s not that difficult to use. In fact, it’s easier than doing a home energy rating because you have a lot fewer inputs.
In the screenshot above, which is one of several tabs in the WERS spreadsheet, you can see the inputs needed for the calculation. For toilets, faucets, and other indoor water appliances and fixtures, you enter the water consumption rate. The spreadsheet then calculates the water savings for each one compared to the industry baseline and prescriptive path requirements for water efficiency programs.
The “Minimum Prescriptive Indoor WERS” box at the bottom left shows the WERS for a home with the same inputs as you see in the “Program Minimum Prescriptive Path Units” column. In the example above, that would be 85.4. The box to the right of that shows the WERS for the home as rated, using the numbers in the “Proposed or Actual Units” column.
Currently the WERS includes only indoor water use, but it can be reduced by reusing greywater or rainwater. There is a checklist, however, for outdoor water use, and the plan is eventually to incorporate it into the WERS, too.
But doesn’t a HERS rating include water?
The short answer is no. Not like the WERS anyway. Yes, a HERS rating includes hot water, but it’s only the energy use associated with it. And it doesn’t include anything about water use in toilets, faucets, and other water fixtures. The HERS rating is just about energy.
Once the new ANSI standard HERS protocols go into effect, the HERS rating will be better about hot water use. According to hot water efficiency guru Gary Klein, the thinking behind modeling hot water in a HERS rating now has shifted to put water efficiency and time efficiency (how fast does it get to the fixture?) first and the energy impact second.
But it’s not a WERS.
Scaling water efficiency
One of the best things about the WERS is the 0 to 100 scale. As with the HERS Index, it gives builders, home buyers, and anyone else who’s interested a way to compare houses. Kim Shanahan is Executive Officer of the Santa Fe Area Home Builders Association and one of the people responsible for making WERS a reality. “The zero to 100 scale of the WERS program plays right into the competitive nature of builders and the marketplace,” he said.2
The fledging program in New Mexico is off to a great start. There’s a lot of interest in it there, and they’re also having discussions with the EPA and others about taking it national. I think you’ll be hearing more and more about WERS in the coming years.
Related Articles
How to Install a Branched-Drain Greywater System in a Green Home
Won’t That Stink? — Living in a Green Home with a Composting Toilet
Everything You Ever Wanted to Know about the HERS Index
Footnotes
1. There’s one thing I wish they had done differently, though. WERS stands for Water Efficiency Rating Score. (At least that’s what it is in most places I’ve seen it defined.) What that means is that it’s going to become the next Grrrrrrrrrr-inducing term like ATM, PIN, and ECM because everyone is going to want to say WERS score the way they say ATM machine, PIN number, and ECM motor. I’m feeling it already. Grrrrrrrrrr!
2. Yes, “he.” Kim is a perfectly respectable man’s name. Which reminds me: In case you haven’t heard, I’ve started a new movement to get parents to reclaim names that were traditionally boys’ names but which have since been co-opted by girls. Come on, parents! Don’t be afraid to name those boys Allison or Kim or Kelly or Mary Ann. Well…maybe not Mary Ann, but did you know that John Wayne’s original name was Marion Robert Morrison?
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I think utilities are making
I think utilities are making it way too complicated. If they REALLY want to get people to cut back on use then reduce the amount of fixed monthly fees and increase the cost put unit of water. "Fees" are $40+ of our "water bill", the actual water is $2 per 1,000 gallons.
Roger that on water rates,
Roger that on water rates, Bob. <br /> <br />Here in drought plagued Northern Nevada (not that we are unique with that malady), our water bill is approaching $60/month with only $3 being water usage. Our household of two retired folks is in the bottom consumption tier, leaving us with no <economic> reason to further reduce our use. <br /> <br />Fortunately, our water authority has recognized the shortcoming of this antiquated system, and is gradually changing the billing structure by adding additional blocks at lower usage levels (while protecting customers on limited incomes) and flipping the conventional structure of declining unit costs for higher usage. <br /> <br />Unfortunately, looking for any respite from fixed costs of water are unlikely as deeper wells, more treatment requirements and replacement of aged infrastructure all necessitate increasing costs in those sectors as well. <br /> <br />It would appear the only way to get most folks attention is to reach into their wallets. <br /> <br />All the best and thanks for another excellent article, Allison.</economic>
I think utilities are making
I think utilities are making it way too complicated. If they REALLY want to get people to cut back on use then reduce the amount of fixed monthly fees and increase the cost put unit of water. “Fees” are $40+ of our “water bill”, the actual water is $2 per 1,000 gallons.
I first wanted to thank
I first wanted to thank Allison for writing about the WERS program. We appreciate the objective viewpoint on it. <br /> <br />I smiled at your 1st footnote. I had a lengthy conversation about the naming & wording. And I agree that there are some interesting acronyms in the English lexicon. (They don’t make me react quite like you, sir, but as a serious baseball fan I acknowledge the awkwardness of RBIs.) <br /> <br />Therefore, I have gone to using the following vernacular: When speaking about the program itself, I use "the WERS program". When speaking about the specific score, I would say a home achieved "a WERS of XX". That way, if the latter is spelled out, it is grammatically correct. <br /> <br />Thanks again, and maybe I’ll see you in southern CA next week.
Proper rate design is much
Proper rate design is much more complicated than you might imagine: <br />1) Utilities that heavily weight the volumetric charges with minimal monthly fees find themselves in dire financial crisis when water use is reduced during droughts. Water utilities have huge financial burden for maintaining and building the infrastructure – those costs occur monthly no matter if the customers use one gallon or a million gallons per day. <br /> <br />2) Water utilities are regulated; they cannot reap huge profits just for the sake of reducing water use. Water pricing at its cost to pump, treat and deliver – not at its value. <br /> <br />If the answer to a widespread problem seems easy to you; you probably do not truly understand the problem. Your water utlity has some very smart people trying to solve these complex problems.
Roger that on water rates,
reason to further reduce our use.
Roger that on water rates, Bob.
Here in drought plagued Northern Nevada (not that we are unique with that malady), our water bill is approaching $60/month with only $3 being water usage. Our household of two retired folks is in the bottom consumption tier, leaving us with no
Fortunately, our water authority has recognized the shortcoming of this antiquated system, and is gradually changing the billing structure by adding additional blocks at lower usage levels (while protecting customers on limited incomes) and flipping the conventional structure of declining unit costs for higher usage.
Unfortunately, looking for any respite from fixed costs of water are unlikely as deeper wells, more treatment requirements and replacement of aged infrastructure all necessitate increasing costs in those sectors as well.
It would appear the only way to get most folks attention is to reach into their wallets.
All the best and thanks for another excellent article, Allison.
Allison, thanks for the
Allison, thanks for the information and the insight. One thing I personally think the WERS system would need is some way to assess landscape watering needs and use, which is such a big part of water use. I hope that aspect is given attention as the system is refined. Maybe the landscape and plantings can be given a rating so a reasonable amount of accuracy can be determined.
I first wanted to thank
I first wanted to thank Allison for writing about the WERS program. We appreciate the objective viewpoint on it.
I smiled at your 1st footnote. I had a lengthy conversation about the naming & wording. And I agree that there are some interesting acronyms in the English lexicon. (They don’t make me react quite like you, sir, but as a serious baseball fan I acknowledge the awkwardness of RBIs.)
Therefore, I have gone to using the following vernacular: When speaking about the program itself, I use “the WERS program”. When speaking about the specific score, I would say a home achieved “a WERS of XX”. That way, if the latter is spelled out, it is grammatically correct.
Thanks again, and maybe I’ll see you in southern CA next week.
The one that drives me crazy
The one that drives me crazy nuts is HOT WATER HEATER used when it should be just WATER HEATER. HOT WATER HEATER is redundant. COLD WATER HEATER would at least make sense, since you do heat cold/colder water rarely if ever do you heat hot water.
That one drives me crazy, too
That one drives me crazy, too, Joel. Glad I’m not alone!
Proper rate design is much
Proper rate design is much more complicated than you might imagine:
1) Utilities that heavily weight the volumetric charges with minimal monthly fees find themselves in dire financial crisis when water use is reduced during droughts. Water utilities have huge financial burden for maintaining and building the infrastructure – those costs occur monthly no matter if the customers use one gallon or a million gallons per day.
2) Water utilities are regulated; they cannot reap huge profits just for the sake of reducing water use. Water pricing at its cost to pump, treat and deliver – not at its value.
If the answer to a widespread problem seems easy to you; you probably do not truly understand the problem. Your water utlity has some very smart people trying to solve these complex problems.
Allison, thanks for the
Allison, thanks for the information and the insight. One thing I personally think the WERS system would need is some way to assess landscape watering needs and use, which is such a big part of water use. I hope that aspect is given attention as the system is refined. Maybe the landscape and plantings can be given a rating so a reasonable amount of accuracy can be determined.
I do not know about plants or
I do not know about plants or nurseries in your area, however in the north east most plants come with a label stating whether the plant like dry , damp or wet locations and whether it likes sun part sun or little sun. I am sorry that this not the exact wording but I am sure you get my drift. I also assume that you are talking about how much a plant uses per year. This would be nice but near impossible since the amount of water needed changes as the plant grows and changes again when it is fully mature and again as it start to near the end of its life
Doug – You are absolutely
Doug – You are absolutely right; there are big gains in efficiency when looking at outdoor water use. It is the next step for us, and we’ve already been working our way through that as we develop the next version of the WERS program. It’s not an easy task, though. I’m finding that politics often pose a greater challenge than the technical aspects of it all. <br /> <br />Thanks for the feedback! We appreciate it.
@Thomas, of course you’re
@Thomas, of course you’re correct regarding utility rate structures. The same thing is beginning to happen withe electricity… high fixed charges and lower kWh charges to protect recovery of sunk distribution costs as energy efficiency and PV is cutting into their revenues. <br /> <br />One simple solution (although not so simple politically) would be to impose conservation taxes to consumption that would fund efficiency incentives and R&D; (or gov’t subsidies for large scale groundwater retention projects, desalination plants, etc).
Doug – You are absolutely
Doug – You are absolutely right; there are big gains in efficiency when looking at outdoor water use. It is the next step for us, and we’ve already been working our way through that as we develop the next version of the WERS program. It’s not an easy task, though. I’m finding that politics often pose a greater challenge than the technical aspects of it all.
Thanks for the feedback! We appreciate it.
@Thomas, of course you’re
@Thomas, of course you’re correct regarding utility rate structures. The same thing is beginning to happen withe electricity… high fixed charges and lower kWh charges to protect recovery of sunk distribution costs as energy efficiency and PV is cutting into their revenues.
One simple solution (although not so simple politically) would be to impose conservation taxes to consumption that would fund efficiency incentives and R&D; (or gov’t subsidies for large scale groundwater retention projects, desalination plants, etc).
Doug brings up a great point.
Doug brings up a great point. Landscape watering is a major contributor. The Western states face critical water situations. Kudos to New Mexico for working to bring conservation front and center.
Doug brings up a great point.
Doug brings up a great point. Landscape watering is a major contributor. The Western states face critical water situations. Kudos to New Mexico for working to bring conservation front and center.
The one that drives me crazy
The one that drives me crazy nuts is HOT WATER HEATER used when it should be just WATER HEATER. HOT WATER HEATER is redundant. COLD WATER HEATER would at least make sense, since you do heat cold/colder water rarely if ever do you heat hot water.
That one drives me crazy, too
That one drives me crazy, too, Joel. Glad I’m not alone!
I do not know about plants or
I do not know about plants or nurseries in your area, however in the north east most plants come with a label stating whether the plant like dry , damp or wet locations and whether it likes sun part sun or little sun. I am sorry that this not the exact wording but I am sure you get my drift. I also assume that you are talking about how much a plant uses per year. This would be nice but near impossible since the amount of water needed changes as the plant grows and changes again when it is fully mature and again as it start to near the end of its life