Some Cool Thoughts

Roby Rutherford Nunn

Ruby Rutherford-Nunn, my husband’s grandmother, grew up in north Texas.  She was the very first campus sweetheart at SMU.  She and Mr. Nunn lived in New York after they were married, where he was a part of the Nunn Bush Shoe Company.  When it came time to retire, Mr. Nunn asked her if she would be willing to move to Austin.  Her answer was, “Only if we have air conditioning.”  

We all know that, in Austin, hot weather comes early and stays late.  And in summer months, humidity hovers around 80%.  The humidity holds heat in the atmosphere and prevents temperature drops in the evening.  We need our AC. 

I have heard that the greatest user of electricity in Austin is our own city utility.  They use energy to pump water to serve homes and businesses.  So, in a round about way, we can help to reduce Austin’s electric energy use by reducing our need for water.   Another reason for converting to native plants. 

One of the most important elements in green building for Austin’s climate is making AC systems more efficient.  For example, it is more efficient to install the smallest system possible for the area served.  A larger system is more expensive to buy and uses more electricity by turning on and off more frequently.  In recent years the City of Austin has encouraged contractors to install no more than one ton of cooling capacity per 600 square feet.  

An oversized system will cool too quickly, leaving the room humid and clammy.  A smaller AC system runs long enough to reach the desired temperature, and, at the same time, clear the air of humidity.  A lower humidity means that people can be more comfortable at a higher temperature, so less cooling is required.  The downside is that a smaller system may have trouble cooling the house below 80 degrees on days when the outside temperature is over 100 degrees.  In my opinion, that is a minor inconvenience.  On our last building project, on

Brownwood Drive, Jim was proud that the AC contractor said it was a very energy efficient design, and he could recommend a 3.5 ton system.  This was one ton per 729 square feet.  This house had 18 windows and 12 glass doors.  However, the orientation, overhangs, and Low E glass protected against heat gain. Heating and air conditioning account for about 40% of our energy needs.  Improvements in this area can have a big impact on our overall energy use.  New requirements relating to  sizing AC systems, prevention of air leakage, and better insulation have just been mandated by the City of Austin.   

 

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Energy Audit and the Seller Disclosure

I recently wrote a guest editorial regarding the City of Austin’s initiative to improve the energy efficiency of existing homes.  A good friend, Bill Moore, whose opinion I respect, sent me an email, and I would like to quote it here:

 

“I did read the article. I thought it was very well done.   I don’t totally agree with your conclusion. Just as the health of the citizenry depends on the septic systems being periodically evaluated and rebuilt at a sales transfer there should be a mandate of some sort at some time to force the improvement of the performance of the existing housing stock. The use of fossil fuels to heat and cool houses to maintain the constant temperature that everyone expects is a far worse threat to the very survival of humanity. If all use of fossil fuels stopped today the worldwide temperature would rise another 50 years before leveling off. The consequences of inaction are catastrophic. There are massive amounts of information out there to support the claims of the climate scientists. And every year another huge chunk of the ice shelf melts that they were convinced would last another 100 years. We are already 30 years too late. We pay more now and sweat more now, or we swim to Central Park and plant Sonora cactus in Austin.”

 

Bill is one of Austin’s original green builders, and has been on the cutting edge of green construction techniques for a long time.  I believe we are slowly moving in the direction that Bill would like to see Austin move as a community.  Gas prices are causing people to re-think their needs and lifestyle.  And, the city is taking steps to move Austin in a green direction.  A task force recently submitted their report on ways to improve the energy efficiency of existing homes. 

 

Regarding single family homes, one proposal is this:  The seller of a house must have an energy audit done, and must add the audit report to their seller’s disclosure.  The seller’s disclosure is an informational form that is required by law to be provided by the seller to the buyer of their home.  

 

If this proposal is made into law, an energy checkup will be required on homes of a certain age that are being sold.  This will make the buyer more aware of how a house performs, energy wise, and what could be done to improve it.  Any audit recommendations would be negotiated between the buyer and seller.  The buyer may ask that the seller make repairs or upgrades; or the buyer may make them himself after closing; or the buyer may choose not to make them. 

 

Bill brought up septic systems, and this might be considered a parallel issue.  It is typical for the buyer to get a septic system evaluation during the contract inspection period.  If repairs are recommended, they are negotiated between buyer and seller.  Sometimes the seller will have the septic checked before marketing the home, in order to avoid surprises later.  Regardless of who orders or pays for the septic inspection, any recommended repairs are negotiated between buyer and seller.  There is no law that I am aware of that requires upgrades to a septic system in connection with the sale of a home. 

 

I think that most people want to save money on utilities and live in a healthier environment.  We need to find ways to do this.  And, more that ever, we need people like Bill to help us get there.

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Austin Real Estate Market – Back to the Future

The serious decline in housing sales in many parts of the country is well documented. This downturn was preceded by several years of rising home prices in many areas. In some cases, prices rose beyond levels that were supported by local salaries, and were clearly not sustainable. The driving force that fueled the rise in home prices was the availability of low interest money. Easy availability of home purchase money, plus historically low interest rates, allowed the demand side of the market to build.

When buyers could expect 15% appreciation and get 6% interest rates, who would not be motivated to buy? Of course, high demand always drives up prices. And, high demand always drives up the supply of homes, as builders increase inventory in response to demand.

The flow of money for mortgages came from new and unregulated sources. In the not too distant past, government regulated entities, such as Fannie Mae, were the main buyers of mortgages from lenders. More recently, Wall Street investors entered the market for buying real estate loans. Alternative loans, interest-only loans, 100% loans, creative ARM’s, no-documentation, and other high risk products became commonplace. Some of these loans began with a low interest rate that the borrower barely qualified for, and then switched to a higher rate after a short time. In many cases, the borrowers did not understand the risk that they were taking.

For most of my experience in real estate, buyers usually put 5% – 20% down, with 28% of their income allowed for mortgage payment, and their income was fully documented. When we began to see 100% financing on contracts, we were a little concerned by the shortage of personal investment, or skin in the game, as they say. The underlying expectation was that the market value of the home would increase quickly, and the buyers would be covered, if they needed to sell. Home ownership became speculative.

Sub-prime, alternative, no-doc, and other high risk loans are not limited to low income or poor credit buyers, and are not always predatory. Often, very sophisticated borrowers chose to keep their cash and leverage the purchase. In all price ranges, the easy availability of low interest money fueled the demand for home ownership, as well as investment in rental property. Inevitably, the demand for homes led to price increases, and elevated inventories, as builders produced more homes. Then the cycle was broken.

What caused the break? Foreclosures. Investors realized that mortgage backed securities contained more risk than expected, and stopped buying them. Suddenly, lenders did not have this market for selling loans. Without the flow of funds for easy mortgages, demand for homes slowed down. Prices began to fall in many parts of the country, and oversupply conditions prevailed. This has created challenging conditions for many homebuilders.

Of course, there is variation in how markets will survive this. Some will fare better than others. To be sure, in Austin we are experiencing the effects of the reduction in demand for homes, but it is not devastating. Why?

First, the Austin market did not experience double digit appreciation during the past few years. The graph showing the relationship between new listings and sales reveals that during the years from 2001 to 2004, the market in Austin was somewhat soft. This was just after the Dot.com bust, in which high tech areas suffered a downturn. The median price of homes only rose by about 3.5% per year. You can see that inventory was high relative to sales, and that kept appreciation at modest levels.

From 2004 to 2007 the Austin market heated up, and we began to see strong demand coupled with low inventory, especially in the central areas. The median price of homes grew about 6.5% per year. Over the nine years shown on the graph, appreciation has been steady, but reasonable. Builders were able to meet much of the growing market, keeping supply in balance with demand. We avoided a boom. Home prices did not rise excessively, and now are not falling precipitously. And, in Austin, home prices are in line with local salaries.

Second, the real estate market always reflects the job market. In the Austin metro, approximately 20,000 new jobs were added during the past year. Unemployment is about 3.5%, a level that some would consider full employment. Retail outlets are opening at a fast clip – an indication of widespread employment. New companies are moving here and Austin companies are expanding. Jobs bring in people, and people buy homes. Even in good job markets, it is possible for homebuilders to swamp the market. However, this has not happened.

In Austin we are not immune to the effects of the “new” tighter restrictions for obtaining loans. For the next year, we will see a more balanced market than we had in 2006 and 2007. Sellers will have to consider the fundamentals to attract a buyer. They will need competitive pricing, excellent presentation, and top level marketing. Buyers will have to have a down payment, good credit, and proper income for their loan.

So, for the next few years, it’s back to the future for Austin real estate.

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Green Building – Solar Issues

Glass creates connection to outdoors.

Large glass areas can connect us to the natural world, but they have to be used responsibly. We have tried to develop a style that uses large windows and glass doors for maximum impact, but with a minimum of increased utility costs.

Large, wood doors with glass panels can be used as both operable doors and fixed panels to form a wall of glass. This gives a sense of openness, but keeps the glass area to a minimum. By comparison, the floor to ceiling glass curtain walls seen in high rise buildings and contemporary homes use significantly more glass. The wood doors also give a warmer, more craftsman look.

Similarly, large wood windows can be grouped and located to give a maximum impact connection to the outdoors. So long as these windows are carefully shaded and properly oriented, they can be used without seriously damaging the energy performance of the house.

Also, they can reduce energy consumption by providing good ventilation. In central Texas open windows are not practical most of the time, due to the heat and humidity. But, they can reduce the length of the season when air conditioning is required. Fortunately, we don’t have very cold winters, so heating concerns are less of an issue.

The Taylor Road house faces southwest. The front side is protected from the west sun by trees, porch roof, and it has fewer windows. The rear opens to the view side – the northeast. Glass on the view side is crucial to the appeal and impact of the house. However, the morning sun can make the interior uncomfortable and costly to cool. We will need to mitigate this. Deep overhangs, propped awnings over windows, and Low-E glass will be used. The lower floor is not a concern, because of trees and porches, but we have some concerns about solar penetration on the second floor, where tree cover is not available. If this were the west side, we would have a big problem. However, the morning sun does not have as much of an impact as the afternoon sun.

The give and take between connecting to the outdoors and shielding against harsh Texas heat has been at the heart of the design process. This is where some difficult compromises have to be made.

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Austin’s Green Goddess

Mary and Norm at

We had not seen a dear friend of ours in a long time, so we decided to give Mary McLeod a call and invite her over for dinner. Mary is a director of the Austin Residential Green Building program. She was one of the original creators of the program. It was interesting to hear about how much it has grown since the early 1990’s. There is tremendous interest in green building from contractors, suppliers, builders, and the general public. Mary said they are swamped with educational workshops, case studies and rating evaluations of individual projects. Many builders want to achieve the 5 star rating given by her department.

We have long been interested in passive energy design for energy saving and comfortable living. Back in the energy crunch of 1978, we drove a tiny Honda, and installed a Norwegian Jotul wood burning stove in our family room. I am not sure why busy people in a hot climate needed a Jotul stove. But, at the time it seemed like the right thing to do.

We showed Mary our plan for the house on Taylor Road, and got her feedback. One of the things we discussed was the placement of the HVAC units and the ductwork. Most homes put the air handler and most of the ductwork in the attic.

Of course, in Austin our attic spaces get very hot during the summer. As the air is carried through the ducts in the superheated attic, it loses refrigeration. Although the duct work is insulated, that is not enough to protect it against heat transfer. And, ducts have many joint connections that can come loose and leak air. Duct leakage can account for up to 30% of the cost of air conditioning.

The trade off is the loss of space in the house for other things. We are really tight on space in this house. It will be hard to give up several closets to house AC units. And, we would need to build boxes to hide interior ducts, or perhaps leave them exposed.

The placement of the interior AC units inside the conditioned space is a key component of the top level 5-Star energy rating. Mary brought us a copy of the rating form used to evaluate the level of greenness of a project. Although we do not have a need for an official rating, I thought it would be interesting to understand the point system and sort of self assess where we stand.

We are fortunate to have the best Green Building Program in the US right here in Austin. It would be unfortunate to build without studying what they have to offer.

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Austin Green Rating System

The Austin Green Building Program is considered one of the top programs of its kind in the US. Its focus is to guide our community toward more energy efficient, safer, and environmentally responsible construction. They have developed a list of features that contribute to a greener building. Each feature is worth a certain number of points. Here are the basic ratings:

1 STAR: 40–59 points

2 STAR: 60–84 points

3 STAR: 85-114 points (including 2.07; 3.02 or 3.03; 5.08 or 5.09 or 5.10 or 5.11)

4 STAR: 115-149 points (including all 3-Star requirements plus 7.14, 7.15, 7.17, and 8.01–8.03)

5 STAR: 150 or more points (including all 4-Star requirements plus 2.08 and 2.09)

I thought it would be interesting to grade our building project using their checklist. I must admit that I found it a bit daunting just to get the information off the website. Then, you must understand the requirements. Then, you have to make the construction decisions. Then, for some items, you have to deal with inspectors to prove that you have done it. It is no small deal to get a 5-Star rating!

But, putting aside the 5-Star rating thing, we are interested in building a house that relates to the natural world, requires less energy and less water to function, and uses materials that are safe and as economical as possible. I believe that these are the fundamental goals behind building green. So, I want to explore the rating system and use it to assess our building project. Perhaps my investigations will be useful for others.

So, getting started: Here are the basic requirements to qualify as a green home. They don’t contribute any points toward a star rating. Think of them as “green lite.”

1. Home design allows a minimum 500 square feet of living space per ton of cooling as calculated by a correct Manual J, based on actual site orientation, plans and specifications

2. Cooling equipment specified and installed matches sizing as determined by correct Manual J calculations

3. Cooling equipment minimum efficiency: 14.0 SEER for split systems

4. Duct leakage no greater than 10% as verified by a direct duct-pressure test, performed by approved 3rd party.

5. Pleated media filter(s) installed in heating and cooling system(s)

6. No un-vented gas logs, fireplaces, or heaters installed

7. Air barriers installed on attic-side of knee wall insulation and interior side of tubs, showers, and fireplaces located on exterior walls

8. Fluorescent lights (compact or tube) installed in a minimum of 5 light fixtures

9. Ceiling fans: minimum of 2 installed

10. Low-VOC (volatile organic compound) interior wall and ceiling paint: maximum VOC level of 150 grams per liter

11. Minimum of 2 toilets selected from current Austin Water Conservation Program Rebate list

12. Current City of Austin International Residential Codes, and International Energy Conservation Codes must be met, regardless of project location (including prohibition of electric water heaters).

As I said, these minimum standards do not give you a star rating. This looks like a list we can handle. We will be green lite for now. I will be taking a look at the star rating requirements in later blogs. Stay tuned.

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The Original Austin Green Builder

Bill Moore, Austin

Over the years we have worked with Bill Moore many times on building projects. He has the deep knowledge that comes from 30 years experience in remodeling and building new homes. Bill has been a great personal and building friend. When Jim is stumped about a problem, the first thing he wants to do is take Bill out to lunch and talk it over. He always comes home feeling a lot better about it. The truth of the matter is, Bill knows just about everything.

And, Bill is really into green building. He was on the orginal advisory board for the creation of the Austin Green Building Program. He was awarded the first “5-Star Remodel” given in Austin for a project on Reagan Terrace in Travis Heights. And he was selected as the general contractor for the “This Old House” project filmed in the Hyde Park neighborhood of Austin. This home also received a 5-Star Green rating.

Bill tends to be on the cutting edge – trying out new materials and techniques. He is working now on an interesting project in Dripping Springs using something called Perform Wall panels. They are made from recycled foam products. The blocks are 85% foam and 15% concrete. They are stacked up, creating forms for poured concrete. When the concrete is poured, the forms stay in place. They are a permanent part of the structure, adding insulation and sound proofing. Stucco is then applied over it. The stucco does not need expansion joints because it is not applied over wood framing. The final structure is very strong and wind resistant. It relies on recycled materials and concrete instead of harvested trees for structure.

Bill has done straw bale, rammed earth, AAC block, light gage steel framing, and SIPS construction. As I said, he is one of the people out there trying new things, and forging a path for others to follow. On Nov. 7 he will be a panelist at the U.S. Green Building Council’s “Green Build Conference” in Chicago. (More on that later.)

So if you have a question about anything to do with green building, just ask me to ask Bill. He’s our go-to guy.

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Austin Green Building – Site Selection

A Country Setting

The Austin Green Building Program has developed a list of features that contribute to a green building. Each feature is worth a certain number of points, shown on the left. This is a look at the section on “Choosing a Site.”

5 - Green by Design workshop attended by homeowner +/or design staff +/or builder staff

4 - Lot size is less than 5,750 sq. ft.

4 – Street, electricity, water and wastewater have been in place for a minimum of 25 years

2 - Public transit stop is within a 1/4 mile radius

2 – Grocery store is within a 1/2 mile radius

2 - Public hike and bike trail, green belt, or park is within a 1/2 mile radius

In reviewing the list of site selection items, I can see that the goal is to get people to focus on central areas. However, development in Austin has long been suburban in nature. Retail and commercial are not blended with residential. Very few people live within an easy half mile walk to a grocery store. Crossing a four lane highway does not qualify as an easy walk. For better or worse, we are a car culture here in Austin. Zoning laws have long prevented grocery stores and other businesses from locating next door to homes.

This is now being reconsidered. The new development downtown is a good example of people living, working and shopping on the same street. The new Mueller neighborhood overturns many of the long established rules of neighborhood planning, and makes mixed use a reality in Austin.

With regard to our lot on Taylor Road, it looks like we’re dead in the water on this section. Our cliff-side lot is out in the county, in an area where a septic system and well are needed. The only item for which we could qualify is the first one – attending a workshop. The next workshop is in February, 2008.

We plan to attend.

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Below is the explanatory info about these items from the Green Building sourcebook:

SECTION 1: SITE SELECTION

1.01 AEGB Green by Design workshop attended by homeowner +/or designer staff +/or builder staff
When people have a good understanding of what green building is all about before planning or purchasing a lot or new home or remodeling an existing one, they make smarter choices and get better results—greater comfort and convenience, lower utility bills, better durability and less maintenance, better health, higher resale value, and reduced environmental impact.

At the Green by Design workshop, attendees learn that a good home is the result of teamwork among all the people responsible for designing, building and operating it. They learn that a good home must be designed for the conditions it will “live” in, both the macro-conditions of its region and the micro-conditions of its site. They learn that a house is a system – its site, materials and products, methods of construction, mechanical systems, and occupant behavior all interact together for success or failure. The goal of the workshop is to show people how to design, construct, and operate better homes that will provide the most long-term benefits to the owners, their neighborhood, and their community.

Although not meant to be an in-depth technical seminar, it nevertheless offers building professionals a helpful overview as well, and lets them know what homeowners are learning about green building.

1.02 – Lot size is less than 5,750 sq. ft.

A small lot may pose design problems and constraints but it can also encourage one to design and construct a space-efficient, or not-so-big, home. (See 2.03 below.) Building on a small lot also increases density, thereby decreasing the need for sprawling new development and supporting infrastructure.

Increased density typically reduces automobile use and resulting pollution, since jobs, mass-transit, “life support” businesses, and recreational facilities are more likely to be located close by. Moreover, the cost of development infrastructure increases as lot size increases. (See 1.02 below.) Depending on zoning ordinances, there are several neighborhoods in the City of Austin that allow lot sizes between 3,600 and 5,750 sq. ft.

1.03 – Street, electricity, water, wastewater have been in place for a minimum of 25 years
As developable land in central urban areas becomes more scarce and costly and may require clean-up, developers usually purchase land surrounding existing development. Consequently, infrastructure is being extended to support development that is further and further from existing sewer facilities, water supplies, roads,

and electricity. In situations where state and local governments provide these services, this growth can ultimately cost taxpayers more money than the residential development provided to the city or town in return for its investment.

Several factors regarding a development’s form are relevant. When other variables are held constant, the cost of extending infrastructure increases as the distance to established service centers increases. Lots become more widely dispersed. Lot size increases.

Building in areas where the infrastructure for development–streets, electricity, water and wastewater– have been in place for at least 20 years reduces environmental damage caused by urban sprawl. Homes using existing infrastructure place less demand on city services, which are paid for by all taxpayers and utility ratepayers. Because existing developments are usually closer to shopping and job centers, building in these neighborhoods also minimizes impacts by reducing automobile miles traveled each day.

1.04 – Public transit stop is within a ¼ mile radius
1.05 – Grocery store is within a ½ mile radius
1.06 – Public hike and bike trail, green belt, or park is within a ½ mile radius

Building homes within close proximity to public transit stops, retail establishments such as a corner grocery store, and green belts or parks gives homeowners an easy opportunity to travel short distances without needing to drive their personal car. Using public transit eliminates pollution caused by automobiles and eliminates the stress of driving. In some cases, it may eliminate the need for the homebuyer to have a second automobile. After a day of working or commuting in rush-hour traffic, many people would consider it a great convenience to be able to walk to the market instead of getting back into their automobiles and driving miles to a shopping area.

In addition, homebuyers today are looking for neighborhood amenities, such as a trail, green belt, or park. Such an amenity can raise the quality of the buyer’s life and increase the value of the home significantly. A recreational area provides a place for people to get out in the fresh air, exercise, walk the dog, and meet neighbors. This can help create a neighborly community and a safe place for children to live.

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Here are the totals for star requirements:

1 STAR: 40–59 points

2 STAR: 60–84 points

3 STAR: 85-114 points including 2.07; 3.02 or 3.03; 5.08 or 5.09 or 5.10 or 5.11

4 STAR: 115-149 points, including all 3-Star requirements plus 7.14, 7.15, 7.17, and 8.01–8.03

5 STAR: 150 or more points, including all 4-Star requirements plus 2.08 and 2.09

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Austin is a Suburban Kind of Town

Covered porch on wooded hillside.

“Dear Roselind,

We are looking for a vibrant, artistic and friendly community, with lots of culture, and we are considering Austin. We have heard nothing but wonderful things. We are looking to live in a city with public transportation, shopping and cultural events outside our door, and good schools as well. We love outdoor markets, museums, live music, shopping at stores like Whole Foods and small boutiques. We love to cook and eat out at small, great restaurants where we can become regulars. We want to able to walk where we need to go as much as possible. Can you recommend some neighborhoods where we should start our home search?”

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I recently received the above note, and have received others like it. People hear of Austin’s laid back style, live music, and excellent quality of life. And, sometimes I think they imagine that Austin is a more urban style city than it really is. I understand what this person would like to find, but there are very few locations that even come close to their description.

I tell them that Austin is a suburban town. Even our older neighborhoods were developed as suburbs. Hyde Park and Travis Heights, for example, are suburban in nature. They are designed for cars to transport passengers in, out, and about the neighborhood. Strict zoning laws have always kept retail and residential areas apart. Commercial businesses are concentrated on high traffic streets on the edges of neighborhoods.

It is odd to see someone actually walking down a busy street and across parking lots to a grocery store. We assume their car must have broken down. It is certainly not safe for children. Let’s face it. Austin is not built for people to take care of everyday business on foot.

What about public transportation? It is certainly not widely used. In fact, it is considered a low income alternative.

To be sure, the explosion in residential and retail taking place downtown will create an eclectic mix, where people can walk out their doors to restaurants, music venues and stores. However, the person who wrote me did not want high rise living and could not afford the price of downtown lofts and condos.

The Site Selection part of the Green Building sourcebook suggests that we build or remodel in older neighborhoods, create small homes on smaller lots, walk or bike to grocery stores, and use public transportation. Lots of folks would like this, but the architecture of the city and historical precedent does not support it.

However, because a lot of people want these kinds of alternatives, there is momentum going in that direction. And, that’s a good thing.

Getting Into Hot Water

As we move the construction possess along, one of the discussions that came up is the type of water heater that we will use. Water heating is one of the top users of energy in the home, second only to the central heat/AC system. In the past, when we built homes, the decision was a simple choice between an electric or gas water heater. Today there are more choices. Here are some that we considered:

Tank Water Heater
1) Electric resistance heat
The electric resistance water heater has heating elements, similar to toaster coils, immersed in the water. The elements keep 20 – 120 gallons of water hot at all times. This type of water heater is cheaper to install compared to a gas system, because it does not need a fuel line, an exhaust flue, and combustion air for the burner. However, electric resistance water heaters cost more to operate because electricity is more expensive than natural gas.

In the city of Austin a recent change has been made to the building code: “In all one and two family units in excess of 500 square feet, the primary source of hot water may not be electric resistance. An electric resistance system is permitted if piped in series with (another type of) primary system.” So, in the city of Austin, electric resistance water heaters are no longer permitted in new homes. They are not a green alternative.

2) Gas heat (natural gas or propane)
In our previous homes we have had natural gas water heaters. In our current home, natural gas is not available, so we used propane. We have noticed that the cost of propane has gone up substantially during the past three years. As gasoline prices have gone up, so has propane. It is on a par with electricity, and may be higher in the future. For the house we are building on Taylor Road, natural gas is not available, and we would like to avoid propane.

3) Electric Heat with Heat pump

One alternative for our situation is an electric water heater with an added heat pump appliance, sometimes called a heat recovery or heat transfer unit. The cost is higher than a simple electric heat water, but the energy cost to run is lower. The heat pump appliance reduces energy use by capturing heat from the air and transferring it to the water tank.

This type of water heater works well with our floor plan, which has the laundry room outside the air conditioned area. We wanted to keep the clothes dryer out of the heated and cooled area because dryers pull a lot of air from the house (and vent it to the outside) while they are running. The water heater will be in the non air-conditioned laundry room space. It will take heat from the air in the laundry room and transfer it to the hot water tank. So the water heater will heat water, and will serve as an air conditioner for the laundry room space.

4) Solar Assisted
These were popular in the 1970-1980’s. They are designed to serve as pre-heaters for tank water heaters. Because the initial cost is high, we did not choose to go this route.

5) Desuperheater

This system combines the AC system for the house with the water heating system. Heat that is removed from the living space by the air conditioning system is moved to the water heater tank. During cold months, the water heater will use electricity or gas to heat water.

This type of system makes a lot of sense for our warm climate because it uses waste heat from the AC unit. On the AC side, it unloads the extra heat that is removed from the home without the need for an electric powered fan. On the water heater side, the water tank serves as an efficient transfer point for the AC waste heat, and water is heated without electricity or gas.

We would like to use this system. However, after talking with contractors and considering the installation cost, we decided that the technology is not developed enough for us to reasonably use at this time. So far as we know, there is not an AC package that offers the water heater combined with the AC equipment.

Tankless Water Heater
1) Electric
In all tank systems, there is some standby heat loss from the tank and from the pipes as water is pumped to the kitchen and bathrooms. The tankless water heater does not maintain hot water in a storage tank. It heats water as is passes through the water heater on it way to the fixture. The drawback of this system is the flash pull of electricity needed to heat water instantaneously. The load on the electrical panel is substantial. Tankless electric water heaters are not allowed in Austin Energy’s service area because of the high electric demand while they are operating.

2) Gas
Gas powered tankless systems provides better hot water flow rates than the electric models. A medium sized unit will raise water temperature about 45 degrees at a rate of 4 gallons per minute. Water temperatures in Austin range from 50 – 85 degrees.  This is the system we have chosen to go with.  We felt that it was the best alternative, in spite of having to use propane.

The tankless system, whether powered by electricity or gas, makes sense for bathrooms that are used only occasionally. Why keep a tank of water heated 24-7 for a guest bathroom? Another positive aspect of this system it that is does not require as much room as a tank system. The water heater can be placed near the point of use, reducing the loss of heat from piping water long distances.

Circulating pump system:

A continuous circulation system can be used with both tank and tankless water heaters. It moves hot water through pipes at all times. The positive aspect of this system is that it reduces water loss from waiting for hot water to arrive at the fixture.

We currently have this system in our home now, and do not recommend it. We can feel the warm pipes in the slab while walking on our concrete floor. While this is pleasant in winter, it works against the air conditioning in our mostly hot climate. And, there is a lot of heat loss from water constantly circulating through pipes. For the home that we are building, we will not have a continuous circulation system. We plan to use an “on demand” circulating system. This requires you to flip a switch to start the circulating system before drawing hot water. This will offset the heat loss from long piping needed to get hot water to all points of use.

Conclusion:
In choosing a water heating system for our house on Taylor Road, we looked for a balance between installation cost and operating cost. We found that the electric heat pump system was the best choice since we do not have natural gas available. The water heater can also serve to cool the laundry room, which is outside the air conditioned part of the house. An “on demand” circulation system will reduce water loss from waiting for hot water, as well as heat loss from hot water pipes.

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