July 2017

Buildings that Conserve Resources


Katherine Mortimer


Designing water and energy conservation into buildings, sometimes called “green” building, is not only good for reducing the amount of water and energy resources used; it also provides more comfortable indoor environments and saves money. 


Heating and Cooling

Heat and cold from the outside get into a building in three ways: first by convection, where hot or cold air directly enters the building through cracks and openings; second by conduction, where the building materials transmit the temperature differential by getting cold or hot themselves and transmitting that outdoor temperature into the building. Insulation is intended to slow that process down. The third way is by electromagnetic radiation, which commonly enters a building as light and heat waves that come through windows. There are different approaches to addressing each.


By sealing building materials where they connect to each other, buildings aren’t as drafty, reducing convective temperature transfer. Unconditioned outside air, either hot or cold, has limited access to enter into the building. By adding insulation, conduction is reduced. Insulation is made of materials that naturally don’t transmit heat through them as well. Thermal bridges form where insulation is interrupted by building materials. These can be reduced by adding rigid or other contiguous insulation to span those bridges. Curtains, shades or shade cloth can reduce radiation heat transfer. 


Some of these strategies are built directly into the building, while curtains and shades typically require some human intervention to open and close, though there are high-tech versions with sensors and automatic controls. These things are part of the building envelope, and once the investment in them is made, they continue to perform for the life of the building.


Improving a building’s envelope reduces the heating and cooling demand of the building, but in most climates some heating and/or cooling is still needed. The next step is to select equipment that is sized correctly for the load and that has a high efficiency rating. Water- and space-heating equipment efficiency is expressed in percentages where 100 percent would mean that 100 percent of the energy used by the equipment is transferred into the water or air. Typical efficiencies are around 80 percent, but higher efficiencies, well into the 90-percentiles, are available. Other efficiency measures are used for electric equipment. High-efficiency equipment does cost more, but it saves on utility bills, so its life-cycle cost can be a good investment. Air-conditioning equipment efficiency is expressed in SEER (seasonal energy efficiency ratio) and is the measures of the equipment’s cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. A higher SEER rating means greater energy efficiency. SEERs currently range from about 14 to as high as 25. 


Solar thermal panels use the sun to heat liquid which passes through loops behind a glass cover that heats the liquid. The liquid is pumped into a building to pre-heat hot water and/or pass through pipes in a floor to heat up its mass for space heating. This basic technology has not changed much over the decades, though modern controllers can increase the efficient use of these systems. In places with lots of sunny days, especially during the winter when heating is needed, these can be part of a plan to reduce energy needed to be purchased to heat a building. Passive solar design is a low-tech strategy where well-placed windows with mass (concrete or adobe) inside the building and in the path of the sun through windows warms the materials, which re-radiates the heat collected back into the space at night. Interior window covers that keep the heat from escaping again at night are helpful. Overhangs sized to block high summer sun but let in low winter sun help to avoid overheating in the summer. 


Electrical Demand of Equipment and Lighting

As with heating and cooling equipment, other appliances can be selected for their efficiency rating to reduce electricity demands. EnergyGuide labels help consumers understand how much money they would save the average household. That usage may not match yours, especially if it is a commercial rather than residential use. However, knowing how your use differs from a typical household can help you decide how much efficiency is worth buying up front. If you will use the equipment more than the average, your savings per year will similarly be higher.


Lighting uses more energy than many people realize. New light bulbs, such as compact fluorescents and light-emitting diodes (LEDs), can reduce the electrical demand of lighting substantially. You can also take advantage of natural lighting by designing window locations to take advantage of this free resource. 


Phantom electrical loads come from the energy used by electronic equipment that work with remote controls (computers, TVs, etc.) use energy continually, “waiting” to receive a signal from the remote control. While it’s a small amount of energy, it can add up. A simple way to eliminate phantom loads is to plug those items into a power strip than you then turn off when not in use.


By doing what you can to reduce your load, you can then consider purchasing or installing renewable energy.  New Mexico has one of the highest potentials for solar energy, and, with the cost of photovoltaic panels coming down, installations pay for themselves quickly. An additional benefit is that, if you generate all your own electricity, you are not subject to electric-rate increases, and your system’s payback is quicker with each increase. Federal tax incentives continue to aid in making that payback even shorter.


Saving Water Saves Energy and Visa-Versa

There are clear reasons to conserve water in the arid Southwest with our history of droughts that are projected to be even longer and more severe with climate change. However, there are reasons to conserve water in other regions too due to a strong link that exists between water and energy. Water is typically the largest electric bill of a municipality that has a water system. Energy is needed to extract the water, clean it to drinking standards, and move it through pipes into buildings for use. Energy is also needed to move the wastewater to a treatment plan and treat it. On the flip side, both coal and nuclear-energy plants use large amounts of water in their processes. The net result is that you conserve water when you conserve energy and you conserve energy when you conserve water.


Conserving water indoors has become quite familiar to people in the Southwest. Low-flow faucets, showerheads and toilets have become ubiquitous, and their costs now match those of their higher-use brethren. Clotheswashers and dishwashers have similarly become much more water-conserving with recent advances. However, water-conserving landscapes still evoke images of dusty, barren wastelands with a cactus here and there. This reputation is unwarranted. Drought-resistant plants can create attractive landscapes. Additionally, by taking advantage of the water that falls on roofs, either by directing it to planted areas or by keeping it in rain barrels or cisterns for use during the days following a rain, it is possible to create more lush landscapes that include vegetable gardens and fruit trees. Greywater (water from showers, washing machines and bathroom sinks) can also be directed under the surface to planting areas. More elaborate systems can be used to clean captured rainwater to be used to flush toilets and wash clothes. 


The challenge with water use in the landscape its to reduce evaporation so as much water as possible can be harnessed for beneficial plant use. Using efficient irrigation systems that use either moisture sensors or are linked to weather reports or both can be employed to fine-tune the application of water in the landscape to maximize the benefits of water. Plants in turn provide their own benefits by providing shade, building the soil, providing habitat, supporting pollinators and even food for human consumption. The challenge here in the Southwest is to realize those benefits while using water as efficiently as possible.



Katherine Mortimer is the Sustainable Land Use supervisor for the City of Santa Fe. She facilitated the development of green codes for new residents, residential additions and remodels, and the recent update to a performance code the city hopes to use as a model for multi-family and commercial buildings. kemortimer@santafenm.gov






New Mexico’s Construction Industry Improves

 New Mexico’s construction industry, along with leisure and hospitality, has been among the state’s fastest-growing industries. According to the U.S. Bureau of Labor Statistics, there were 46,000 construction jobs in New Mexico in March 2017. While not comparable to pre-recession numbers, there were enough new jobs to qualify as sixth best in the nation, according to the U.S. Bureau of Labor Statistics. The industry added 3,200 jobs over 12 months since May 2016, up 7.4 percent, according to the New Mexico Department of Workforce Solutions. Construction-related gross receipts taxes are up as a result, helping cities’ bottom lines.


Residential transactions, including multifamily residences, increased 3.5 percent from April 2016 to April 2017, according to the Realtors Association of New Mexico. Most were in Bernalillo County.


While homebuilding has been lagging in New Mexico, in Santa Fe both higher-end single-family homes and more affordable projects such as those facilitated by Homewise and the Santa Fe Housing Trust have increased.


Homewise has received $5 million in federal New Markets Tax Credit funding to construct 20 energy-efficient homes and provide affordable financing to qualified low-income homebuyers in the “severely distressed census tract” Siler Road/Agua Fría area, which has started to become an innovative epicenter of commercial activity. U.S. Bank, the project’s investor, will receive a federal income-tax credit and Homewise will get a low interest rate for its capital investment.


Apartment Affordability in New Mexico

 According to a report from an affordable housing advocacy group, the Washington, D.C.-based National Low Income Housing Coalition, using U.S. Census data, in 10 New Mexico counties, residents have to earn an average of $38,825 a year to afford a modest two-bedroom apartment and utilities. That means that at the statewide minimum wage of $7.50 an hour, residents need to work 84 hours a week to afford that apartment. In Santa Fe County, according to the report, a household needs to earn about twice that amount. Santa Fe is the most expensive place in the state for rent.


Home-Based Work and Co-Working Spaces Becoming More Common

New Mexico has had the highest unemployment in the nation for some time, but in May, at 6.6 percent, the state was surpassed by Alaska’s 6.7 percent. Colorado had the lowest rate in the nation, 2.3 percent.


Reflecting a national trend, the New Mexico Department of Workforce Solutions reports that 4.7 percent of New Mexico’s workforce is home-based. New Mexico ranked 18th in the country for home-based workers from 2011 to 2015 in the U.S. Census American Community Survey.


This may be a promising development for the state’s economic future. New Mexico is largely a rural state, and a remote workforce is one way for companies to recruit skilled workers who may not want to relocate. Telecommuting, however, requires a stable Internet connection, which is not available everywhere.


This form of work also reduces companies’ needs for office space and has led to “co-working” spaces, where startups, freelancers and small companies pay to co-locate and share equipment.


Entrepreneurial hubs FatPipeABQ, the Santa Fe Business Incubator and Project Y Cowork Los Alamos have formed an informal partnership called the New Mexico Coworking Collaboration. Members of those organizations can work at any of those locations. Collaboration and networking are encouraged. FatPipe’s directory lists about 30 coworking spaces, incubators and accelerators around New Mexico. FatPipe will be opening new locations in Las Cruces, Santa Fe and Taos.


Some city governments and larger companies are also offering coworking spaces in underused, converted facilities.




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