green by design

My bride and I spent yesterday, Saturday, at an all-day seminar (8:30 am to 4:30 pm) to learn about building a green home. We heard some surprising things. First, Austin was the first city to have a green building program. Starting in 1985, the program resulted in the Energy Star program now used by the feds, and the green rating used by the city served as the inspiration for LEED certification (Leadership in Energy and Environmental Design). Impressive. As might be expected from such an influential program, the day’s seminars were also quite impressive and informative—as well as entertaining and inspiring.

Some (appropriately shaded and low wattage) highlites:

- Design for passive solar. Seems like a “duh” kinda deal, but most houses do not consider the sun in their design. Developers are more concerned about getting the house built, looking good, and sold rather than operating good. The city architect’s point was that how the house was designed with respect to the sun was the single most important “green” item to think about. Such houses use far less energy than houses dolloped onto lots with no solar consideration. I have to confess that I was fixated on active solar rather than passive before learning this. I’m happy to report that I am now solarly passive aggressive.

- Strawbale, adobe, and rammed earth aren’t good choices for Austin. These building techniques rely on large diurnal temperature swings to work their magic. Aside from earlier this week and the occasional blue norther, Austin doesn’t get those swings. Therefore, the thermal loading works against you in our nonswinging climate. Not that we were considering these building techniques, but they are definitely off the table now.

- In Austin, air conditioning in the big energy hog. Therefore, anything to lower cooling costs is paramount for lower energy consumption. There’s the aforementioned passive solar considerations (design for windows to be shaded in the summer but sunned in the winter), but there’s also the design of the central air system. AC contractors tend to oversize units (no one has ever been sued for oversizing a unit), but that increases electric usage and decreases dehumidifying. Also, architects don’t usually consider where the ductwork is going to go. The straighter the duct work, the more easily the air flows, the more efficient the system, the less tonnage you need, the less energy you use, the more money you save. Put the air handler and the ductwork inside the conditioned space of the house—You don’t have to worry about leaks (and cooling the attic) that way. The HVAC engineering guy gave one of the most entertaining and informative presentations of the day. He was awesome.

- The typical goal for an HVAC system is to have the ACH (air changes per hour) less than 0.5. This means that half the air in your house is replaced with air from outside your conditioned space every hour. Say what?!?!? On one hand, maybe this is a good thing: Nobody wants to breathe stale air. On the other hand, that’s a lot of hot air your house is pulling in and subsequently having to cool during the summer. If your house was perfectly sealed, an ACH of 0.5 means you have a hole 10 inches by 12 inches in it. Progressively sealed houses get down to 0.3. Hyper-sealed houses get down to 0.1. I reckon our current house is over 1.0…

- You need to run the vent in your bathroom for at least 30 minutes after you take a shower. It’s critical to get that moisture out of your house. It saves you in the long run.

- The vent over your stove is to remove heat, not smells or greasy air. Always have it on when your stovetop or oven is hot.

- Geothermal may not be such a good idea in Austin. Installers call it geothermal, but it’s actually a heat pump using the earth as a heat sink (in summer) or a heat source (in winter). Usually, these systems use boreholes drilled some 150 feet into the subsurface, one borehole per ton of cooling. What is happening is that the ground is warming up from the heat exchange during the summer months but, because our winters are so mild, the system is not bleeding off the heat enough during the winter months. Therefore, the ground is slowly heating up year after year decreasing the efficiency of the system. We were thinking about geothermal; we’re not thinking about it anymore.

- Heat pumps work well in Austin, but they fail to heat your house when temperatures fall below 37 degrees. The back up heating in these systems, electric strips, use a lot of power. On balance, a good idea, but pray for global warming.

- Your ceiling fans need curved blades.

- Solar water heating may not make sense for just two people.

- Annual heating and cooling loads should be 1 to 1.25 kilowatts per square-foot. Our current house, at 1,000 square feet, should have a load of 1,100 to 1,375 kilowatts. It actually has ranged between 5,600 to 8,700 kilowatts over the past four years. Ouch. That's what a 100 year + house gets you.

- Electric generation by solar runs about six bucks a watt.

- IKEA cabinetry is free of formaldehyde.

- Austin is not a good place for personal wind generation.

- There are some crazy women that go to these things.

- And finally, through good design choices and good building, it’s possible to build a net-zero “capable” home.

So there you have it. Highly recommended if you are interesting in attending and useful to anyone from around the country.

To learn more:

http://www.austinenergy.com/energy%20efficiency/Programs/Green%20Building/Resources/GreenByDesign/index.htm

http://www.austinenergy.com/energy%20efficiency/Programs/Green%20Building/index.htm

rain, rain, come this way...

If we ever build a house, it will harvest rainwater. We installed an 800 gallon tank behind our current house and love it. We use it to top off our cow trough pond and to water the garden and sometimes the grass. Truth be told, 800 gallons is not enough. We want more.

But how much more could we get with a new house? To help answer that question, the Texas Water Development Board has a helpful manual with ways to calculate and size a tank for your home.

The first thing to figure out is roof catchment. We're considering building a house in the two-story 2,500 square feet vicinity with a detached garage of about 400 square feet. Halving the 2,500 (to account for the two stories) and discounting possible "orphaned roofing", we have about 1,500 square feet of catchment to work with. Austin gets, on average, about 32 inches of rainfall a year. Now, there's nothing average about Austin, and there's sure nothing average about the rainfall here as well. We've had dry months (no rainfall) and gullywashers (15 inches in 30 days). The average monthly amounts that make up that average annual number range from 1.72 inches in July to 4.33 inches in May. We're fortunate to have two rainy seasons: May-June and then September-October. If we were planning to rely on rainwater as a sole source of water, I would use the median rainfall values, which are lower than the averages (and more reflective of central tendency, but we won't go there...). However, average is good enough for government work.

Based on that roof size and that rainfall, we should be able to capture, on average, 30,000 gallons a year (inches of rain divided by 12 [to convert inches to feet] multiplied by the catchment area in square feet multiplied by 7.5 [the approximate number of gallons per cubic foot]). Divided by 12 months, that equates to a storage estimate of about 2,500 gallons. This is probably on the low side because it would be ideal to have a larger nest egg of water going into the high demand summers. If we were relying on rainwater for all of our water needs, we would need to go through the detailed worksheet in the rainwater manual mentioned above (and have much more storage). But we're not. We're just looking for lawn and garden watering (and perhaps an occasional car wash).

It would be super cool to tap into rainwater for toilets and other uses such as showers and clothes washing, but some issues-that-cost-money arise. One is the need for a backflow preventer on the city-supplied water line. Water providers start getting sweaty-brow nervous when you use other sources of water in addition to theirs. Their primary concern is having water of unknown quality sucked into their system during a pressure loss. If that happens and your water has little wigglers in it, you could make your neighbors very sick or even kill them (now don't be getting any ideas...). There are ways of dealing with this potential siphoning, such as having an air break where the two sources of water potentially mix (having an air break means that there is always air between the city source and your source and there is never the potential of your water coming in direct contact with the outlet from the city source). But there's a lot of trust that has to occur between a rainwater collector and the water provider to rely solely on an airbreak. Hence the backflow preventor: No trust required. If you have to install a backflow preventor, you have to pay for it (upwards of $1,000) and pay for once-every-two-years testing by the city (upwards of $200 a test). Bringing the water indoors would also probably require some treatment such as filtering and a dash of UV to kill the little nasties. If you plan to drip irrigate, you may need to filter the water first as well to keep any sediments from clogging your drip emitters.

So how much would 2,500 gallons of storage run us? We're really partial to those gorgeous Texas Metal Cisterns metal cisterns: Shiny, metallic, and somewhat clean-lined modern. A 2,500 gallon tank runs $1,650. Still need piping to hook it up (and perhaps a sump pump?), but that's not too bad in the grand scheme of things. An additional 500 gallon tank for, say, the garage would cost another $645. Austin gives a $500 rebate for installing a city-approved rainwater harvesting system. And the State of Texas doesn't charge state sales tax on tanks and accoutremount purchased to install a system.

Rainwater harvesting in the city has to be more of a love affair than a financial-based decision. Water is cheap. Just to pay off the 2,500 gallon tank with saved city water will take over 622,000 gallons, enough water to meet our current lawn watering needs for more than 30 years (note that the economics of rainwater harvesting in the boonies if used as a sole source in lieu of a well are far more appealing). Nonetheless, it's a "right thing to do" sorta thing, it's fun ("Look! The tank is filling!!!"), and plants and ponds prefer rainwater.

So do we.

sweet agave

Cute little house up yonder at the Agave development east of Austin, one of our favorite places in town. Agave is a little too far out of town for us, and the houses, as designed, don't quite meet our needs (for a garage for small cars...).

does the lot vet out?

"Vet out" is horse slang. When you consider buying a horse, it's wise to have a vet take a close look at that horse to ensure the critter doesn't have a hidden or unnoted issue that would decrease or scuttle its value. It's a good idea to do the same thing for a lot. Who wants to buy a lot and build a house and then find out you have to sell it at a loss? And even if you think "I will die in this house", life can take unexpected twists and turns, so it behooves you (so to speak…) to ensure that you can get out of the house with your finances intact or, at the very least, know exactly what you are getting yourself into.

We've not found too much guidance in assessing whether or not a lot is a good deal. Real estate agents will tell you that it's worth what you or someone is willing to pay for it. Not terribly helpful. However, a real estate agent can get you comps: Comparable sales in the general area. However, comps are only helpful if there have been a fair number of lots that have sold in the area. If the area is too broad, then a number of other factors start to kick in (neighborhood, nearby amenities, nearby non-amenities, size, schools, slope). And folks selling lots outside the desirable core are usually pushing to get city core prices. Can’t blame them.

We've been using several techniques to assess the value of lots we've looked at: (1) comparison shopping, (2) comps, (3) county assessed value of the lot, (4) an analysis of county assessed value of neighboring houses, (5) an analysis of what our final house would cost, and (6) infatuation level. Whew! No wonder this process is tuckering us out!

Comparison shopping is simply knowing what other lots for sale are going for and what their pros and cons are as compared to the lot du jour. If a ho-hum lot in a suspect part of town is twice as expensive as a comparable lot in the nice part of town, then that ho-hum lot is most likely way overpriced (perhaps there's treasure under them thar hills!). Comparison shopping is even better when the lots are in the same part of town. However, some lots are real difficult to assess. For example, a lot with a view of the river located in a bad part of town has a river pulling the price higher while the neighborhood pulls the price in the opposite direction. Sellers, not surprisingly, root for the river (and emotional pull a river may have on a potential buyer). At the very least comparison shopping will let you know whether or not the price of your potential lot is in the ballpark.

Comps will tell you what lots actually sold for and also allow you to see what the owners asked for when they sold those lots. In a seller’s market, bidding wars may drive the price higher than asking. In a buyer’s market, selling prices may be lower than asking prices. If a seller is smart, she will highball the price in hopes of maximizing returns.

In Texas, the value of the property as assessed by the county appraisal office is public information. In Austin, this information is online. By law, the tax assessor is required to appraise the property to within five percent of what it would sell for on the open market. How that is assessed, I don't know, but I've found the county assessed values for residential properties to be pretty good. Keep in mind that these numbers are backward looking. If the market has warmed up, the tax assessor's numbers may underestimate the value, and if the market has cooled down, the tax assessor may overestimate the value of the property. Using their database, I can see what the value of the lot is as well as the value of the improvements. I don't know what their logic is in assessing values, but it appears that they determine what properties are selling for, subtract off $75 to $100 a square foot for improvements (the house), and assign the remaining to the land. Not an unreasonable assessment, in my humble opinion.

Using these county-assessed values as well as the comps, you can determine how your dream home fits financially into the neighborhood. You generally don’t want to have the most expensive house in the hood. This puts you on the cutting edge of prices, and you are likely to get cut by that edge if you have to sell. So if the lot is $100,000 and it costs you $250,000 to build a 2,000 square foot house, you can see if comparably sized houses in the hood are in the $350,000 range you would need to break even at the end of construction. If you need a substantial construction loan, you need to look at this because your bank certainly will.

Something to keep in mind is that the bigger the house, the more likely the lot will vet out. The cost per square foot of land for a 100K lot for a 2,000 square-foot house is $50. For a 4,000 square foot house, it’s $25. If houses are generally selling for $150 a square foot, your McMansion comes in at $150 (good) while your MiniMansion comes in at $175 (not so good). Sadly, there’s a financial incentive to build big on expensive lots, hence all the inner-city scraping going on.

And then there’s infatuation. For us, this is what pushes us to offer more for the dirt (Look at the view of the river!). In the end, it’s better to kill the mood with spreadsheets of reality than to wake up years later with regret. Spock v. Kirk.

how much does it cost to build?

Note: We have an updated (and much more informative [with numbers!]) post on this topic here.

One of the challenges of building a custom home is figuring out how much it costs to build. Some books state that you can forget about accurately estimating what it will cost to build a custom home--a disturbing prospect for a bud on a budget. Furthermore, it's important to know if whatever numbers you are comparing and contrasting are apples and apples and not oranges and apples. For example, we asked an architect friend how much it costs to build modern, and he replied "Plan on $200 a square foot." Another architect told us $125. For a 2,000 square foot house, that's a $150,000 difference (not to mention a scary amount of scratch to begin with). What gives?

The first thing to note is the difference between "soft" and "hard" costs. In short, soft costs occur before construction begins and hard costs occur after construction begins. Soft costs include the architectural planning, property acquisition, the permitting and approval process with the city, and any carrying costs (such as interest payments) before construction begins. Oftentimes, quoted cost per square foot only includes the hard costs, the costs once the concrete starts sloshing and nails start flying. Therefore, a quick question you should ask after receiving a back-of-the-envelope estimate is "Is that just hard costs?"

Another thing to ask is whether or not the price per square foot includes the garage and any patios as part of the square feet. In other words, is the price per square foot for conditioned space only? If not, you might walk away with a considerable underestimate of the total price to build. This is important not only for budgeting purposes but also for assessing the economics of building on a particular lot.

Costs vary, of course, across the country. For the Austin area it seems that building a cookie cutter suburban-style, a semi-custom, starts at about $100 a square foot. For custom, costs start at $125 for builder-grade finish out (in other words, not fancy). The fancier you want it, the more it costs. Modern tends to cost more because the materials and construction are less familiar to builders and the materials themselves can cost more. Building green also adds to the cost.

kouichi kimura

Love love love these houses designed by the Japanese firm, Kouichi Kimura. Very sculptural, calming, and zenny. The sides shown here are the privacy sides, something that seems to be a calling card for these architects on these urban and inwardly focused homes.

kouichi kimura

dirty deeds (done dirt cheap)

One enemy of modern architecture is the dreaded deed restriction. A deed restriction is a little goodie attached to the deed of the property, with or without a house, that dictates what you can or can’t do with the property. On one hand, this can be a good thing. It ensures an apartment building or gas station or business doesn’t get built or moves in right next to you. However, it can be a real mood killer if you want to build modern. For example, consider a lot we drooled over in the hills of northwest Austin. After reading through an inch-and-a-half thick stack of paperwork titled “Restrictions”, we discovered several items that were ultimately unworkable for us.

In the past, the neighborhood association had to approve your building plans. Given the standard architecture in the hood, it would have been highly unlikely that they would have approved a blocky, flat-roofed modern with lots of windows and steel. In short, our house would have been designed by committee. Yuck. We all know what comes out of committees… Fortunately, that provision had been removed several years ago. However, there were restrictions on the outside materials, the color of those materials (which explained the bland sameness of color up and down the street), and the configuration of the yard and whatever sat on the yard (posing potential problems for rainwater harvesting). Anything you did outside that upset a single neighbor could turn into the Spanish Inquisition.

More troubling were the building restrictions posed by the city on the lot. The lot was going to be a challenge to build on. Grade started at the curb at four feet above street level and wandered up from there to the back of the lot. Given the grade issues, it would make sense to place the driveway and garage on the western side of the lot where the slope was more gradual and there was more room to place a drive. However, the city had placed several restrictions on the lot that makes it impossible to build on without variances. First, the city required that any cut in the limestone could not be any greater than 4 feet deep. Second, the city required that the grade of the driveway be no smaller than 1 foot rise (or fall) per 10 feet of length. Third, the city required that the garage be 20 feet from the street. And fourth, the city required that the drive and garage be on the eastern side of this particular lot. Given those restrictions, it is impossible to build on the lot without a number of variances from the city. A friend in the neighborhood confirmed that the lot had gone unsold for many years because no one had figured out how to build on it. At first glance, after a hike about the property, I didn’t understand why. After reading the deed restrictions, it became real clear.

Yes, it’s possible to get variances from the city, but that adds time and cost, not to mention no guarantee of success. That, combined with color and yard restrictions (and the lack of western exposure to enjoy sunsets), caused us to bid ado to this little piece of hillside heaven. Furthermore, a previous owner, way back when during the days preceding prohibition, put a deed restriction on the property disallowing the brewing of beer. Not that I'm a brewer, but what if I wanted to?