Green Building in Denver

The Rubber is Starting to Meet the Road for Smart Grid City

2009-11-07T15:05:00.000-08:00

The Smart Grid pilot project in Boulder is now well enough along for the peak period re-pricing to be released.

http://www.dailycamera.com/schoolchoice/ci_13732272

This article missed answering an obvious question:

If you own a PV system that contributes to the grid during peak periods, will Xcel credit you at the higher peak retail rate?

My guess is yes. It's only fair. But this issue should be openly addressed soon because it will make your PV system pay off much quicker

LED Lighting Update

2009-11-06T07:32:00.000-08:00

Yes, CFL's suck.

So, we've been waiting for bright, affordable LED lighting to become available. Sam's Club has recently introduced 1.5W LED bulbs for $5 each. I believe Xcel energy is subsidizing some of this cost based on a flyer displayed in the aisle. If anyone knows more about that, please post a comment.

Anyway, 1.5W is only producing about 78 lumens, which means you'll need roughly six times the number of bulbs more than "normal". This is a daunting problem that will keep most folks out of the LED replacement business until a market solution or even brighter bulbs are introduced.

In the meantime, we developed a hack using "Medusa" floorlamps, which can be found for as little as $20 and will convert a standard octagon ceiling box into a fixture with five medium base openings. An added bonus is that you can direct the lighting to where you need it.

Let's say you have rentals or are doing fix and flips. You already know that fluorescent lighting and CFL conversions do NOT add value, even though operational cost is lower. The light quality of LED's and even lower operational costs SHOULD add value to your project. Don't be cheap - the $20 marginal cost per fixture is only a couple hundred $ for a house.

Dual Flush Toilets Now Affordable

2009-11-02T12:06:00.000-08:00

If you've been too cheap (like me) to get a Toto or Caroma Dual Flush Toilet, now you have no more excuses. For a long time, these toilets have averaged $400, making them difficult to pay for themselves.

Sam's Club is stocking the Alexis HET (high efficiency toilet) 1.1 gpf liquid, 1.6 gpf solid dual flush toilet for $99.

Since Denver Water is giving a $125 rebate for them, this is a real no-brainer.

Go get one while they still have 'em.

Solar Shading Cont'd

2009-09-23T08:43:00.000-07:00

The classic all-aluminum rollup design is my personal favorite solution for exterior window shades. They're economical, ( $150-$300), self-storing, accessible from inside the home, and infinitely adjustable depending on the season or your whims.

They can be ordered at Home Depot or online at http://www.screen-house.com/awnings_rollup_aluminum.htm

Sun Control - One of the Solutions to Summertime Overheating

2009-09-16T08:27:00.000-07:00

This topic is old news for those of you with those big, west-facing-mountain-view windows. They create an inferno for you in the summer. You may have even spent thousands on beautiful floor to ceiling blinds to shut out the sun.

However, unless the shades are physically outside the window, they are relatively ineffective. Once the sunshine comes in the window, it stays inside as heat.

So the shades must be on the outside.

The easiest, quickest, and least expensive way to install an exterior window shade without completely ruining the view just might be from Screenmobile. They are a national franchise, and I've used the local branch often for conventional screen replacement, and found them to be a good solution for an annoying problem.

Heat Pump Hot Water Heater

2009-08-28T08:12:00.000-07:00

So, you're trying to decide how to heat the domestic hot water in the zero energy house you are designing for Denver.

Solar hot water heaters are an excellent choice. However, the logistics of a solar thermal installation are daunting compared to a typical appliance installation.

A logistically easier solution is to use a heat pump water heater (HPWH) in conjunction with PV solar.

Rheem has just released a new nice-looking unit.

The jury is still out as to which configuration will be best. Recent test results and common sense are beginning to favor HPWH with PV. The reasons for this are that solar DHW is insufficient and inefficient in the winter, and underutilized in the summer. A grid-tied PV system has the advantage of constant efficiency and 100% utilization year round. In addition, large PV cost reductions are coming, but none are expected in solar thermal. State-of-the-art solar thermal collectors still use supply-restricted copper, aluminum, and glass. The labor content of solar thermal installations is also quite high.

Some puzzles remain with the implementation of HPWH systems. Per the manufacturer's recommendations: "Because the heat pump’s exhaust air is cooler than the surrounding atmosphere, these water heaters generally do not belong in or near busy living areas of the home." Since they pull the heat out of the surrounding air, a small, airtight mechanical room isn't the best place for it either.

Discussion of HPWH locations:

1. The garage. A new, well insulated garage might work. An uninsulated garage slab gives off enough low temperature free geothermal heat* to prevent freezing of the pipes to the heater. There are at least two problems with the garage, however: 1. In summer, the HPWH gives off cold air that would be more desirable inside the living space than in the garage. Ducting air from the garage to the house is a CO hazard, and not recommended. 2. If the (insulated) garage door is inadvertently left open in the winter for an extended period, the water lines to the HPWH are at risk of freezing.

2. Mechanical room with forced ventilation. The control scheme and ducting layout for this ventilation can get complicated and costly.

3. Basement. This is where you usually find the water heater in new construction, and will work just fine if you don't mind a cold basement in the winter. If you finish the basement and add heat to it, that heating system will be feeding the HPWH the heat it needs, and this will spoil the overall efficiency of your system.

"The House as a System" philosophy of home design will get a real workout on this one. Please enter a comment if you've heard of any other solutions.

*A perimeter insulated slab in an insulated garage gives off 5-15 Btu/hr/ft2, based on preliminary research. This is a great match for a 7000 btuh HPWH.

The Greenest Building is Usually the One Already Built, but Not Always

2009-08-18T02:00:00.000-07:00

I'm really not trying to anger preservationists or tree-huggers here, I'm just analyzing a trite slogan from an engineering perspective. I'm a pragmatic preservationist.

The question is whether or not you should rehab and do a green retrofit on an existing building or replace it with a well-designed low energy new building. The correct answer can only be found after making some reasonable assumptions, cost estimates, and estimates of resale value.

You don't "waste btu's" when you tear down an old building. Those btu's were spent when the building was originally built, and there's nothing you can do to get 'em back.

You can only choose not to spend new btu's on a new building.

And btu's are just another form of dollars.

So it's always an economic problem, eg., what's the present value of retrofitting the old building vs. building an entirely new one. This analysis must be done for every building using each case's unique problems and assumptions.

In residential at least, it's fairly easy to build a new "zero energy" replacement house, but fairly hard to retrofit an old house to zero energy. The cost of the new house can be estimated pretty accurately, but trying to estimate the retrofit cost of the old house is risky. Every old building is different.

The embodied energy of the new building is just part of the down payment on a really good investment. The value of that energy is in the cost of construction. The landfill space required for the old building is also given a dollar value in the cost of demolition. The embodied energy of the old building is a "sunk cost" and doesn't factor in the analysis.

The main thing that doesn't have a dollar value in this analysis is the generation of CO2. Lawmakers have begun trying to put a dollar value on that. Eventually this "carbon tax" will be pretty accurate, and will favor the old building.

Most estimates put the embodied energy of a new building at 5-15% of the lifetime energy usage of the building. That means the operating energy usage of the building is about ten times more important than the original energy content.

Therefore, it may be a catchy phrase, but it's very unscientific to generalize: "The Greenest Building is the One Already Built". Be sure to say "usually".

Mini-Splits or PTACS are the Key to Net Zero Energy Homes

2009-08-13T06:07:00.000-07:00

High SEER minisplit heat pumps have finally caught the attention of high efficiency homebuilders. Postgreen, a redeveloper in Philadelphia, touts "geothermal efficiency at a fraction of the cost": http://www.postgreenhomes.com/models/

When you add PV solar to a house and a high efficiency and lo-temp-capable heat pump, then you really don't need to pipe natural gas to the home. (Cooking meals with gas may be preferred by chefs, but it is neither healthy nor energy efficient. Gas ranges put out a lot of CO). That saves the $12/month gas hookup fee.

Besides, you can't send natural gas back to the utility like PV solar does. In superinsulated homes, this scenario also makes solar thermal obsolete for heating and domestic hot water (DHW)

Why? Because even at a solar conversion efficiency of only 10%, in the summer, you are putting energy back on the grid and dollars in your pocket Every. Single. Day. Thus, the yearly system efficiency and ROI is better than solar thermal.

It's becoming accepted worldwide that the only way to acheive true net zero energy is with an all-electric house and PV. Minisplits are part of the puzzle.

A few more of benefits of these heat pumps:

1. Less floor space used inside the house for mechanicals.

2. Compression-cycle air conditioning included "for free".

3. Better zoning is possible than with any sort of central forced air system.

4. In smaller homes, the installed cost is a fraction of a centrally ducted system.

Denver's New Zoning Map is Dropping the Ball on Sustainability

2009-07-19T14:21:00.000-07:00

Soon after being named in the top ten cities for sustainability , Denver may damage it's standing because the proposed new zoning code is largely ignoring the benefits of detached accessory dwelling units (dADU's).

First, a little history:

The zoning code rewrite was called for as far back as 1989. Mayor Hickenlooper hired Peter Park to shepherd it in 2004. Meanwhile, preservationists like Jim Lindberg were concerned how the old code was allowing redevelopers to potentially ruin our historic neighborhoods. Blueprint Denver was begun in about 1998 and released in 2002 as the guide for a new code. The Zoning Code Task Force (ZCTF) was appointed in early 2005, consultants were hired, problems identified, and neighborhood contexts were defined.

Along about early 2008, third parties realized that sustainability issues had been heretofore largely ignored by city staff and their consultants. Michael Henry and Don Tressler of INC (InterNeighborhood Cooperation, an RNO), are the most significant of these third parties. Although Greenprint Denver was initiated in 2006 and widely admired, it was two years before Greenprint representatives were spotted at any ZCTF or Blueprint meetings.

At the request of INC, Park then hired Doug Farr to recommend sustainability strategies for the new code. The author wonders why a Chicago based consultant, however well qualified, could be a better choice than a local firm. For example, does Farr know why evaporative coolers are such a great peak power solution for the Denver area? Probably not. It turns out that swamp coolers ARE a zoning issue. No matter, he wrote the book, and made an effort to interview local experts like Michael Tavel.

Also, in the spring of 2007, Bob Sperling and James Van Hemert organized the Friends of Granny Flats after they realized that the Zoning Code Task Force was almost unaware of the existence and popularity of thousands of historic carriage houses in Denver. They gave a presentation to city staff in April 2007 that was well-received and put dADU's on the radar.

Farr gave his report to the ZCTF in September 2008. At that meeting he was asked, "what are the biggest things we can do in Denver?" His reply, "Two things: Share cars and Solar Access". It looks like the private sector is already targeting the former. By solar access, he went on to explain, on north-south Denver streets it means allowing a taller garage with solar panels on the roof, with laws to prevent future shading of it. After the meeting, he took the concept further and proposed, "for sustainability reasons, the code should require the installation of an accessory dwelling unit whenever these alley structures are built."

(Coincidentally, at the same meeting, the housing affordability consultant, Don Elliot, was asked the same question. His reply, "ADU's, reduction of the minimum buildable lot size, and inclusionary zoning." The ZCTF took the first two choices to heart and they are well-represented in the draft code. The affordability recommendations promised ADU's "in a wide range of districts." )

After staff parsed Farr's report, they issued the Jan. 14, 2009 sustainability memo , and ADU's are prominent. Mention is made of future study of things like solar fences, kind of a tough putt in urban neighborhoods with mature trees. More on that here and here.

Unfortunately, the proposed zoning map is disallowing ADU zoning over most of the city.

Review the Map . Look for suffixes like -B1, - C1 etc. For example, if your neighborhood has U-SU-C you don't get ADU's, but if you have U-SU-C1, you get 'em. B2 & C2 zoning allows them only on some corners, which is better than nothing, but there isn't any B2 and C2 on the map. Why develop a zoning typology and then shelve it? There are a lot more questions like that once you study the map. Please do, and weigh in .

So, in 2009, after all this work, why is the city offering up ADU zoning in less than 5% of the city?

Edit: As of late August 2009, the areas with ADU zoning shown have increased, but they are still insignificant. There is a small amount of A2, B2 and C2 now shown.

Solar Access for Denver Neighborhoods

2009-04-14T14:47:00.000-07:00

The Denver Zoning Code has been rewritten, and is on the verge of release for public comment. The issue of Solar Access has been put on hold for at least a few months. This is understandable, as the release of a large, important document like this is very difficult.

Unfortunately, solar systems are being built in Denver with no protections against shading from neighbors.

For more, please see read this document:

Solar Access for Denver Neighborhoods

Connecting the Dots Between Google and the Smart Grid

2009-03-27T02:20:00.000-07:00

How the Google Math Adds Up:

1. Google is rapidly becoming the nation's largest single consumer of electrical energy.

2. 2007: Google announces their goal of producing renewable (solar) electricity as cheap as coal. The goal: $ 0.025/kwh

3. Plentiful solar electricity is generated during the common peak demand periods, hot summer afternoons.

4. 2009: Google announces the PowerMeter to help implement the "smart grid" as they envision it. A properly implemented smart grid could increase the selling price of peak demand power to $ 0.25/kwh or more.

Therefore, #4 causes a 3x to 10x increase in the profits of #2, while #3 + #2 solves problem #1.

The Return of the Carriage House, Denver 2009

2009-03-27T00:20:00.000-07:00

Detached accessory dwelling units will apparently be allowed in Denver's new zoning code. The sustainability benefits are so numerous that ADU's tend to be the darling of city planning staffs nationwide.

The following article was written by Becky Alexis, a Platt Park architect involved in sensitive redevelopment.

"The carriage house has been a part of our built environment since the beginning of the twentieth century. Found everywhere in our community from Country Club homes to low income areas, the accessory dwelling unit has historically provided home owners needed flexibility for guests, expanded family, boarding and household help. Today our need for a sustainable housing sector is eased if home owners have the same opportunity. By converting the rear zone of a property into the highest and best use, families, neighborhoods and municipalities benefit socially, economically and environmentally.

Giving home owners the opportunity to add functional value to their property helps all socio-economic levels. From the first time home buyer to the elderly, the added dwelling space helps all owner-occupants to stay in their home. Fabrication is less costly than conventional housing and uses include family living, child and elderly caregivers, workspace and rental income. This flexible space affords opportunity for families’ changing needs in a time where the risk of home loss is high. As a work space, the detached dwelling reduces costly commuting requirements. The building form adds security and beautification to the alley and creates intimate and properly scaled courtyards which require less water and maintenance needs. Simply, the carriage house aids in preserving single family living.

Keeping families in their home is critical for the stability of neighborhoods. Less housing turn-over means less speculator driven scrape-offs, and a preservation of the neighborhood character. The added benefit of a carriage house to a property increases the value of other homes in the area. The added activity also reduces crime, especially in the most vulnerable space, the alley. Conceived as 800-1200 s.f. apartments over a 2-3 bay garage, these units reduce existing and future off-street parking demand. Safety, secured property values, and an improved built environment make the neighborhood more livable and desirable for existing and new residents.

To the municipality, this non-obtrusive densification of our neighborhoods has numerous benefits. The existing utility infrastructure is currently under utilized, so adding more dwellings would be accommodated and would add a larger tax base to support the existing infrastructure. Families would not be financially forced into the suburbs. Children could stay at their schools. Commuting by vehicle would be minimized, and our local public transportation would be better utilized. Jobs would be created by the people that build these structures and by the folks that choose to work out of them. It is a win-win situation that reduces stress on families, reduces falling house prices, minimizes scrape-offs which fill our landfills, reduces water needs with more sensible backyards, and reduces our carbon footprint.
Denver’s own Peter Park, the City Planning Manager, has said, “When cities stop changing, they start dying.” This is a “Shovel-ready” opportunity for good design and correct context to fulfill real and perceived needs."

-Becky Alexis, HIVE Architecture, LLC

Polymer ISC Solar Collector Debuts

2009-02-26T20:20:00.000-08:00

Just a few days after my post about passive solar thermal water heating, the grandson of the Arthur D. Little collector design came to my attention. Called the Solar Cache by Harpiris Energy, it has been designed only for non-freezing climates. With PEX pipe, which may be considered freeze tolerant, this will be a great product for economy installations, costing far less than the usual $6k solar DHW systems for freezing climates.

I just hope it doesn't get installed in colder climates, freeze, burst and give the product a bad name. When drain-down systems were used in Denver in the 80's, many an attic was flooded because of Murphy's Law. Even though there were freeze protection controls and backup freeze protection controls, they still failed.

Ironically, a common complaint from solar DHW system owners may cause pumps to appear in these passive systems. See, most systems have a solar preheat tank (with the Sun Cache the solar tank is on the roof), and a backup (fossil fuel) tank piped downstream in series. If the homeowner doesn't consume any hot water (like all day when he's at work) then the backup tank fires to make up for standyby losses, even though the preheat tank may be 140F or higher. In the summer, a solar system should be providing 100% of the hot water load on sunny days, so some homeowners get peeved when their gas bill isn't zero and the backup tank is coming on every hour or so. A really tiny recirculating pump with a simple control is a way to prevent the problem, but now you've added a pump to an otherwise elegantly simple system. The other beef with the "uninsulated" storage tank on the roof is that you'll never have any solar hot water left for the morning shower, the storage water will drop close to outdoor ambient by morning.

Rheem has also come out with a passive collector with some freeze tolerance. The collector loop is charged with antifreeze. Again, great care should be used on the supply pipe, even in "non-freezing" climates.

Hail Resistive Roof Saves on Insurance

2009-02-08T08:07:00.000-08:00

State Farm just started putting this line on my insurance declaration page:

Premium Reduction:
Hail Resistive Roof: $521/yr.

My roof is a spanish tile look-alike made of stone coated steel from Gerard

I don't know if clay-based or concrete tile roofing qualifies for the discount, which is about 30%. Both of those systems, however, require a significantly stronger roof structure due to the higher dead load. (edited 2/10)

So, I got a premium-looking roof that pays for itself in ten years compared to asphalt shingles.

It's a very green choice because the steel is recyclable, and guaranteed for 50 years.

Green Roofs?

2009-02-06T10:50:00.000-08:00

I have remained on the sidelines with regard to promoting green roofs. I'm hesitant partly because many people in the multifamily industry have this saying that goes "flat roofs always leak".

In my own experience, the most frequent and worst leaks occur at the low spots where ponding occurs. A pond on your roof causes dust in the air to stick to the surface of the water. Over time, this dust builds up and starts looking like dirt, or soil. Seeds get blown into this muck, and sprout. I know this is a poorly designed ad-hoc green roof, but the fact remains that leaks never start in the dry spots on flat roofs.

I guess some sort of roof garden would be nice if you also had a roof deck and actually used it.

I'll let Dr. Joe L., every building scientist's hero, explain it:

"Green roofs? Grass and dirt are not energy efficient.Work with me here. Which saves more energy—2 inches of dirt or 2 inches of insulation? Which saves more energy—grass or a white colored membrane? Which is more expensive and does not save energy—grass and dirt or insulation and a white colored membrane? Which needs to be watered to keep the grass from dying and blowing away? But they are beautiful and look cool. And that apparently is more important than cost and energy savings. Okay, I can live with the beautiful and looking cool argument if that is in fact the argument—but don’t clutter it with half-truths such as heat island effects and water run-off. There are other (better) ways to deal with each."

He goes on to admit he won't win the argument, so he provides the proper drawing detail that works.

In semi-arid Denver, I'll posit that the money spent for the water needed to keep your roof alive will be far more than the dollar value of any perceived benefit.

Passive Solar DHW

2009-02-05T05:52:00.000-08:00

To some, the holy grail of solar thermal is a system without pumps and controls.

Himin of China manufactures a nice one:

At Solaron in the '80's, we purchased the manufacturing rights to a passive DHW design developed by Arthur D. Little. The problem was that the pipes going to the collector would freeze in the winter. Frozen pipes in the attic were so undesirable and difficult to eliminate that we ultimately abandoned the whole project. As far as I know, no one is pursuing this type of design in northern climates.

Now that building codes are beginning to actually recommend insulated roof planes and conditioned attics, the Chinese design looks very interesting. The pipes in the attic won't freeze because the attic is inside the house envelope. As long as the piping to the roof-mounted tank is kept extremely short, it won't freeze either. Natural convection within the pipe and heat conduction along the pipe from the tank and the attic area would prevent freezing.

Note that there is no water in the evacuated tubes, so they won't freeze. All the usual overheating issues have also been solved passively.

From Arthur D. Little, we also learned that the roof-mounted tank will never approach freezing temperatures anywhere in the continental US. (Basically there's enough solar insolation even on completely cloudy days to keep the tank above 40 degrees)

The main attraction of this design is that system efficiencies are far superior to pumped designs. Also, with no moving parts to fail, the life-cycle cost is held low, and the ROI is maximized.

It's Not Price-Pfister, but the "P" is Silent

2009-01-23T23:46:00.000-08:00

In a recent trip to the Wellington Webb building, a had a chance to use my first waterless urinal. I don't yet know how they work, but it was totally odorless and splashless, all in all very pleasant.

If your household has at least two guys, you should install one. The water savings will eventually pay for it.

Update: About six months after installation, I visited the restroom in the City and County Building, and one of these urinals was malfunctioning somehow. It was NASTY. Caveat Emptor, and train your maintenance staff!

Domestic Hot Water for Zero Energy Homes

2008-12-15T09:22:00.000-08:00

Zero energy homes (ZEH's) in the near future will be simple, all electric, and supplemented with PV.

Hybrid PV/thermal solar collectors may be the best solution as costs come down. Sun Drum Solar is now offering a product. Dawn Solar also offers a building integrated hybrid PV roofing system. PVTSolar uses an air-based approach. When I worked at Solaron in the 80's, we abandoned air-based systems, and we were the world leader in air-based until that point. These are the only entries so far in the hybrid market sector. I expect to see more manufacturers enter the fray soon.

Whether or not a solar thermal DHW system is used, a grid-sourced backup water heater is required.
An affordable heat pump hot water heater (HPWH) is now on the market:
https://airgenerate.3dcartstores.com/index.html

This type of system uses only 25%-35% as much electricity as a standard resistance water heater, making it the best choice for a ZEH without solar thermal.
Another bonus of these heat pumps is that they can supply "free" summer cooling for the house.

In the near future as costs stabilize, we'll learn if this $700 is worth it for a home with solar thermal or hybrid collectors. In Denver, a home with 100-150 ft2 of solar thermal or hybrid collectors probably won't need it. The $700 marginal cost would take too long to recoup because the solar is providing 90%+ of the domestic hot water load.

More on Advanced Wall Systems

2008-12-03T11:48:00.000-08:00

Joe Lstiburek was at the EnergyStar Summit this week, and was ranting about the wall system we should be using in this climate. Bottom line - for less money than than the historical R-13 2x4 wall system, you can build a styrofoam sheathed R30 2x6 wall. Truly a no brainer.

However, there are two significant barriers to implementation:

1. Your framers, who have such a difficult time coping with wall systems that use LESS wood.

2. Your structural engineer, who wants OSB sheathing used everywhere.

One slight potential problem within the assembly, vapor condensation on the inside surface of the styrofoam, has been bothering me for a few years. Joe explained that this has been addressed in IRC 2009 with a climate zone prescriptive solution. It specifies the minimum R value for the external insulation to avoid condensation. This value is also a function of the stud cavity R value, but Building Science Corp. typically recommends 1.5 inches of taped external foam.

What Ever Happened to Off-Peak Electric Rates?

2008-10-30T07:01:00.000-07:00

In the 1970's, PSCO introduced off peak electric rates, which were designed to flatten their demand profile. At the time, a kwh used between 10pm and 6am was priced at less than a third of the cost of an on-peak kwh. If utilities can just tweak their customers usage habits thru rate schedules, they can really drop their capital costs. That is, they won't have to build that new power plant just to cover three week long spikes in demand.

Over the years, the PUC added many "cost adjustments" to the electric bill, which watered down the off-peak savings to be had. Eventually, all customers lost interest in the whole program and it was cancelled. These cost adjustments are multiplied by the kwh usage, and now account for around 66% of a residential electric bill. It didn't matter if all the usage was off-peak, these adjustments were still there in full. So, in 1980 if you were saving 2/3 of your bill with off-peak rates, by 2008, your savings would be 2/3 of the remaining 34%, or only 22%.

Finally a Foolproof Toilet Fill Valve to Save Water

2008-10-12T17:32:00.000-07:00

We had three brand-new toilets that leaked slightly, apparently through the flapper. Even if it wasn't a significant amount of water, or caused a noticeable increase in the water bill, it caused an unsightly red mold to grow. Even though the toilets are cleaned weekly, the mold can be seen as vertical stripes in the bowl wherever the leak runs down the sides of the bowl.

Anyway, Fluidmaster now makes a new fill valve that refuses to refill if there is a slow leak. As soon as the handle is jiggled, however, it will refill. So a tenant can use it just fine with minimal inconvenience, but the normally wasted water is saved.

This may increase your callbacks in new single family construction, but it's the perfect solution for buildings with maintenance staff.

H4H Redefined the State of the Art for Zero Energy Homebuilding

2008-10-07T02:32:00.000-07:00

With NREL, Habitat for Humanity has built and tested the simplest Zero Energy home that I've seen to date. Lots to learn from the following final technical report:

http://www.nrel.gov/docs/fy08osti/43188.pdf

Perhaps the most surprising lesson is the poor overall system efficiency of the solar thermal DHW preheat system. It shows that these systems may be hardly worth the effort. Ongoing maintenance for a system like this will further degrade the cost/benefit ratio for this subsystem.

NREL Denver Tour of Solar Homes

2008-10-06T00:47:00.000-07:00

On Saturday, our East Wash Park home was on this year's Denver Tour of Solar Homes , sponsored by NREL.
Here's the blurb from the tour book:

Dickson Residence

This large house (4200 square feet) was completed in 2004 and is an updated version of the “Denver Square” design. The parcel was formerly a public service substation on three lots. The house uses a true direct gain passive solar design in that it has south facing glass and mass (concrete floors). Please note that the passive solar heating provides 90% of the space heating requirements – so much so that the radiant floor back up system is rarely used. If the owners were to do this again, they would install a less expensive backup system. In some places the concrete has been stained so that it is the actual floor. In other places, cork is laid over the concrete.

The house is joined to the building next door, which originally contained battery storage for the Denver Tramway system. Now the building houses an office and shop area.

The house is built using SIPs (structural insulated panels). In getting the permits for the house, the Denver plan review and inspection departments added eight months of delay in getting a building permit, according to the owner, because of their inexperience with SIPS. Greenprint Denver may be helping to alleviate the problems like this.

An interesting note is that three of the stained glass windows in the house were designed by a relative of Frank Lloyd Wright.

Passive Solar Features

Sunroom/mudroom

Mass of 2” of concrete on the floor

Trees planted on the east and west for shade control

Photovoltaic Panels

3.3 kW system

Grid tied

Utility bill has decreased $55 per month since installation

Thermal Envelope / Thermal Comfort

Insulated above code with SIPS

Low-e windows

Interior and exterior shades

Evaporative cooling (unique indoor cooler)

Expanding foam insulation around windows and outlets

Zoned heating

Night setback thermostats

Radiant floor backup heating system

Lighting

Some CFL lights

Motion sensors or timers in the mudroom and garage

Construction

6” thick SIPS walls

Thermal breaks at entry doors and perimeter of entire foundation

Pre-plumbed for solar thermal collectors

Lightweight Metal shingles

Appliances

Energy Star rated

Sealed combustion boiler/hot water heater

Transportation / Lifestyles

Hybrid SUV

50% of all errands are done by bicycle

Light rail is used once a week

Recycling

Composting

Vegetable gardening

Re-Use / Salvaged Materials / Recycle

Reclaimed brick

Reused existing building and converted into a home office from its original purpose

Unique Features

Homeowner trained in solar during the energy crisis of the 70’s

Homeowner holds patents for pneumatic fittings, valves, and a nose hair trimmer

Green Features

EPS insulation

Stained concrete floors

Reused an entire building and converted into a home office

No particle board was used

Steel roof

Cork floor

Water Features

Low flush toilets (5 out of 5)

Low flow shower heads (3 out of 3)

Xeriscaping

Drip irrigation

REC’s and Windsource

On demand hot water system: “Doorbells” in each bath summon hot water without wasting it

A little bit of nice publicity from the WPP....

2008-10-05T23:35:00.000-07:00

http://kevintesting.googlegroups.com/web/WPPKTD.pdf?gda=0Va3kDwAAAAnKIMncx6ukRKQXuLFP__Do_CwWda2FNSImGT2MKwxy2HpCSjbUfPiF0VurU3U4gL9Wm-ajmzVoAFUlE7c_fAt

My First Electric Vehicle

2008-09-28T08:06:00.000-07:00

Prices for low end Electric Bikes recently came down another notch, so I snapped one up.
It's fun, and really solves the problem of getting too hot when bicycling around town. You can let the electric motor do all the work on the way to a meeting, and arrive relatively fresh. It has pedals and a seven speed derailleur, so there is always the opportunity for exercise. The small 15-mile range has never been an issue, most bike trips are shorter than that. However, for $100, you can add a second battery to double the range, or to quick-swap batteries like a cordless drill.