Department of Energy Zero Energy Homes

After working through several projects to retrofit an existing home to make it more energy efficient, it’s hard not to think about what could be done by starting from scratch.  A clean slate isn’t something that everyone will get when it comes to living in an energy efficient dwelling but those that decide to build their own home should consider building a Zero Net Energy(ZNE) Home.

A home is considered ZNE when it produces more energy than it uses, typically, measured over a year.  This doesn’t mean that the home is “off the grid” or doesn’t use grid energy.  Actually, the home is connected to the local utility and pushes any excess power out to the grid for others to use.  For example, a solar PV array will generate electricity during the day but is dormant at night.  However, the array is usually sized to produce more than enough energy to offset the amount of grid power used at night or when energy is not being produced.  The net result is more energy flowing into the grid from the home than is used over a year.

There are two primary considerations when building a ZNE home.  First, you must have an energy generation system installed such as a solar array or wind turbine.  Second, you need to use building techniques that optimize the energy efficiency of the home with the goal of reducing your energy footprint to fit within the power generation capability of the home.

How do you build a Zero-Net Energy Home?  Below are ten steps to get you there.

1. Location, Location, Location. Do some research on the NREL site to find out if your region is good for solar or wind.  If solar works in your area, make sure you pick a lot that has great sun exposure and that will allow you to position your roof in a “true solar south” orientation.  Trees provide cool shade for humans but greatly reduce the energy output of a solar array.  If wind is an option, identify the optimum height for your wind tower and select a location within reach of your building site.  Selecting a location that is near your work and amenities will help you save on transportation energy costs.

Solar site selection: http://www1.eere.energy.gov/solar/want_pv.html

Wind Site Maps: http://rredc.nrel.gov/wind/pubs/atlas/maps.html#2-12

2. Insulated Concrete Forms (ICF) Consider building your home with insulated concrete forms.  This is accomplished using ICF blocks that are assembled and interlocked to form walls.  Once the walls are assembled, concrete is poured into the center of the insulated blocks.  The blocks have mounting mechanisms built in for drywall, siding, etc. to make for easy construction.  The resulting structure is a super-insulated envelope that will last 200-300 hundred years.

DOE site on ICF: http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11640

3. Foam Insulation Icynene spray foam insulation is a great choice for insulating the under roof and attic space in your new home.  The goal is to effectively seal the building envelope and then control the entry and exit of air to/from the home.

DOE site on insulation: http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11320

4. High Efficiency Windows.  Use triple-paned, krypton-filled windows or equivalent for best efficiency.  Orient most of the windows south to take advantage of passive solar heating and cooling effects, while ensuring plenty of light on all floors.  This completes the process of properly sealing the building envelope.

DOE site on High Efficiency Windows: http://www.energysavers.gov/your_home/windows_doors_skylights/index.cfm/mytopic=13330

5. Heat Recovery Ventilator (HRV) An HRV controls the exchange of incoming and outgoing air from the home.  If your building envelope is sealed using the products listed above, the HRV should provide the only exchange of air when all doors and windows are closed.
   When air enters and leaves your home, the new and old air are forced through a heat exchanger that transfers the energy to/from the incoming and outgoing air to help reduce the need to recondition the home.  In the winter, the heat from the outgoing air is transferred to the colder incoming air.  In the summer, the heat from the incoming air is transferred to the outgoing colder air to reduce the amount of energy required to recondition the air entering the home.
   HRVs can recover up to 80 percent of the energy from outgoing tempered air that is completely lost in conventional homes.  The system also allows for superior air quality and serves as a mechanism for removing humidity from the home.

DOE site on HRV/ERV Systems: http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11900

6. Climate Control System – Ground Source heat pump(GSHP) A GSHP provides heating and cooling using the constant temperature of the earth several feet below the surface.  As in caves, the temperature below the surface of the earth is warmer  than surface air in the winter months and colder in the summer months.  GSHP systems exchange the energy between surface air  and the ground using an underground loop of piping.  GSHPs are much more efficient than Air Source Heat Pumps, last much longer and require very little maintenance.  They can also provide some hot water via a pre-heat tank.

DOE site on Space Heating: http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12640

7. Electricity Generation – Solar Array/wind turbine One of the key factors of building a ZNE home is to find a way to generate electricity at the point of use.  Typically, we assume that the fuel source used comes from renewable sources such as wind and solar.  Choosing this fuel source depends on your location.  If you have access to plenty of sunlight, solar is your best choice.  If you are in an area with a good source of steady wind, a turbine is a great choice.  If you have access to both then you have done your homework and have picked a great location for a Zero Net Energy home.  Congratulations!  You can choose either or both sources for power generation.  Typically, you will want a system with an output of 8-10 kW to meet the demand of a 2500-3000 square foot home with a family of four using the building technologies described in this article.
   

Solar – http://www.eere.energy.gov/topics/solar.html

Wind – http://www.eere.energy.gov/topics/wind.html

8. Hot Water System – Solar Hot Water(SHW) If you have sun and a good south-facing roof area, add SHW collectors to your roof and a pre-heat tank to the hot water system in your home.  SHW uses the radiant heat of the sun to heat water.  This is much more efficient than solar photovoltaic systems that require conversion of photons into electricity.  They are also more forgiving with partial shading of the collectors and will provide energy in environments that would disable a solar electricity system.  If you are also using a Ground Source Heat Pump (above) you can use some of the waste heat to supplement the SHW.
   

DOE site on Solar Hot Water: http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12490

9. Energy Star Appliances When choosing appliances, make sure to visit the DOE Energy Star site to pick the most efficient appliances for your home.  Appliances are some of the most energy intensive devices in the home so you can save on efficiency by making good appliance choices.
   

DOE site on Energy Efficient Appliances: http://www.energysavers.gov/your_home/appliances/index.cfm/mytopic=10020

10. EV Charging Station This is an article on home efficiency but you can’t overlook ways to improve your transportation efficiency.  If you picked a location that doesn’t require a large commute to work and to local amenities consider buying an electric vehicle (EV) as your primary source of transportation.  If your budget permits, you can keep a fuel effieient gas or diesel vehicle for road trips or consider renting a car for trips that won’t allow for electric transport.  Install an EV charging station in your garage to refuel your EV.  The J1772 charging standard has been adopted by most EV manufacturers.  However, your best bet is to pick an EV and buy their charging station.  Many states offer incentives for buying and installing an EV charging station.  Make sure to check the DOE’s state incentive finder site to see if your location qualifies.
    DOE site on Electric Vehicles: http://www.fueleconomy.gov/feg/evtech.shtml

Here are some helpful links for more information on building Zero Net Energy Homes:

Link to DOE site for Zero Energy Home Design: http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10360

Link to Solar Today article on a Functioning ZNE Home: http://www.solartoday-digital.org/solartoday/20100708#pg48

Ground Source heat pump manufacturer – http://waterfurnace.com

Foam insulation – search for local installers:  http://icynene.com

Find an ICF manufacturer – http://www.forms.org

Heat Recovery Ventilator Manufacturer: http://lifebreath.com

An Example of a ZNE Builder in New Paltz, NY:  http://greenhillcontracting.com

Green Acres ZNE subdivision in New Paltz, NY: http://greenacresnewpaltz.com

Online courses offered by the Florida Solar Energy Center on building ZNE Homes: http://www.fsec.ucf.edu/en/education/cont_ed/bldg/zero.php

Come visit us on the Mapawatt Community to see what others are saying about Zero Net Energy Homes!

- The Mapawatt Team

Related posts:

1. Building your Green home tips
2. Do It Yourself Home Energy Audit
3. Building Envelope Intro

DIY Home Energy Audit

Having a professional Home Energy Audit is a great investment to make when you need help planning your home energy upgrades.  However, in the spirit of Mapawatt and empowering readers to take control of their energy usage, we’ll offer the reader a “Do it Yourself Home Energy Audit.”

There are four steps in this DIY Home Energy Audit:

1. Locate Air Leaks – One of the leading causes of energy loss in a home is through tempered air leaving the home or outside air entering the home through holes in the building envelope.  Do a visual walkthrough of your home, including attic and basement looking for areas where air can pass through the building envelope.  Common problems to look for are doors or windows with missing weatherstripping, uninsulated electrical outlets or switch plates, attic doors into unconditioned attics, etc.  You can do a basic pressure test on your home by closing all the doors and windows, closing the fireplace flue, turning off any combustion producing appliances and turning on all exhaust fans in the home such as in the kitchen or bathrooms.  Use a smoke pencil from a home improvement store or improvise by lighting an incense stick.  Place it around potential leak spots and watch to see if the smoke is blown by air sucking into the home.  A wet hand near potential leak areas will feel a cold breeze if there is a leak.  Leaks can be filled with caulk, weatherstripping or canned sprayfoam where applicable.

2. Inspecting Attic Insulation – If you have an unconditioned attic space, check the attic floor to make sure you have adequate insulation.  If the attic has batting, look for areas where the batting was pulled up or moved for service and put it back in place where necessary.  Insulation batting is not expensive.  Adding another layer if you think the insulation is lacking could save you on your energy bill.  For conditioned attics, check the eaves for proper insulation.  Consider adding more batting insulation or have a contractor spray in foam insulation for best R-value.

3. Inspect Heating and Cooling Systems -  Climate systems should be inspected regularly for proper operation.  Change air filters in systems regularly and consider getting a programmable thermostat and make sure you program it!  This could save major dollars if you are currently conditioning your whole home 24 hours a day.

4. Inspect Lighting – Upgrade your incandescent lighting to CFL or LED lighting if possible.  Lighting can be as much as 10% of your energy bill.  Installing motion sensors in rooms that automatically turn on and off lighting systems will also save money.

Make sure you keep a pad and pen with you as you conduct your audit to make an Energy Project List of issues that you can use later for your home energy upgrade projects!

If you give the DIY Home Energy Audit a try, visit our Energy 101 Community Forum and let us know how it worked for you!

For more information, please visit the Department of Energy site on Home Energy Assessments.

- The Mapawatt Team

Related posts:

1. Biggest Energy Vampire in your Home: Cable Box
2. Home Star a.k.a. Cash for Caulkers
3. Ten Steps to Building a Zero Net Energy Home

Insulation for your home’s attic is one of the most important aspects to ensuring that you save the most money and energy in regards to heating and air conditioning.  I briefly covered insulation in our insulation intro, but it was very basic.  While catching up on my energy conservation blogs I ran across Energy Vanguard and their blog; especially one of the features on insulation.  Energy Vanguard was started by Dr. Allison Bailes, who has his doctorate in Physics.  I like his explanation of why he decided to pursue a career in home efficiency from his quick biography:

What really started the ball rolling for my new career and the founding of Energy Vanguard, though, was when I built a house myself. In 2001, I bought a piece of land and spent the next two years building a green home that’s beautiful, efficient, and comfortable. Having never built anything bigger than a bookcase prior to taking on this project, I had a steep learning curve in front of me—and I loved it!

After finishing the house, I became a home energy rater and left academia for my new career in the field of high performance homes.

It turns out that Allison only lives about 25 minutes from my house so I was able to find another sustainable blogger in my home town!

I asked if I could repost his great article on proper installation of blown insulation: Flat or Lumpy – How would you like your insulation?.  The majority of the post appears below, but visit Allison’s site for the full post:

(From Energy Vanguard)

My dissertation in grad school was called “Flat or Lumpy.” (Of course, it had the requisite incomprehensibility in the subtitle, with words like ‘heteroepitaxy.’) Those two words in the title, which cut to the heart of what my surface physics research was all about, also describe a property of insulation that’s important in building science.

Let me put the question to you this way. If your attic is going to have 50 bags of insulation blown into it, does it make much of a difference if it goes in flat or lumpy?

Let’s look at an example. If the insulation goes in perfectly flat, let’s say we have a nice uniform R-value of 30 throughout the attic. (We’re going to ignore the complicating factor of the framing and assume it’s a continuous layer of blown insulation.)

There are all kinds of ways it can go in lumpy, but let’s assume that 50% of the attic has lumps of R-50 insulation, and the other 50% is valleys with only R-10. We want to find the average R-value of this lumpy configuration. It’s the same amount of insulation, and the average of R-50 and R-10 is R-30. But, how does it really perform?

Let’s do the math!

[Warning: This section contains mathematics. If you feel nausea or dizziness, skip to the conclusion below. If you feel excited by this discussion, see your local physics department. If your arousal lasts longer than 4 hours, you should work through the problems in Classical Electrodynamics by J.D. Jackson.]

Now, we can’t just average the R-values. If we did that here, we’d get R-30, and we’d be wrong. Heat will take the path of least resistance, and the less resistance you give it, the more heat will flow. If you’ve studied physics, engineering, or building science, you’ve probably seen the equation for heat flow by conduction:

(Mapawatt Note: Go to Energy Vanguard for section on Heat Transfer and R-Value calculations )

Conclusion

As I said above, heat takes the path of least resistance, so the amount of extra heat going through the R-10 half far exceeds the extra heat flow that’s stopped on the R-50 side. Instead of getting an R-30 average, the lumpy attic has an R-17 average.

In practical terms, this means that if you see an attic with lumpy insulation, get in there with a rake and smooth it out. In the example I just worked out, you’d nearly double the R-value without adding any extra insulation!

Another common example of the flat-or-lumpy conundrum is an attic that’s perfectly insulated except for one small area, say the pull-down attic stairs. We can go through the same steps as above and show that an attic that has a uniform R-30 over 99% of the area and 1% at R-1 (the pull-down stairs) will have an average R-value of 23.

That’s right, those pull-down stairs can decrease your overall R-value by 25%. One small uninsulated area reduces the R-value dramatically.

In my graduate research, getting smooth, flat layers was our goal. In the building science of insulation, flat also wins out over lumpy.

Related posts:

1. Building your Green home tips
2. Home Star a.k.a. Cash for Caulkers
3. Do It Yourself Home Energy Audit

The Solar Decathlon Europe (SD Europe) 2010 was created through an agreement signed between the Government of Spains Ministry of Housing and the United States Government, who committed to organize a sustainable solar architecture competition in Europe. In October 2007, both governments signed an agreement (a Memorandum of Understanding) as part of the Solar City framework of the Solar Decathlon 2007. Nineteen top universities from around the world were selected to participate in the 2010 competition, which will be held in Madrid. Their participation in the competition will undoubtedly serve to raise the visibility and prestige of those institutions.

• zero-energy home that is completely powered by the sun
• The PVs, arranged in a single array that covers the roof, are built into the house during construction. The panels are bifacial, meaning they use both sides to increase energy output by up to 15 percent.
• the entire PV array can be tilted to the optimal angle for each season (from zero degrees to a 17-degree angle in summer and to a 35-degree angle in winter).
• The concrete floor houses a radiant floor heating system. The system heats the house by means of a water-to-water heat pump that extracts heat from the earth in the winter and uses the earth as a coolant in the summer.
• the north and south walls are all glass, maximizing the owner’s exposure to bright, natural daylight
• The fully automated Eclipsis System, comprising independent sliding layers, permits a revolutionary design in a solar-powered house, while filtering light in beautiful, flowing patterns throughout the day.  It is an advanced building façade comprising two layers: a metal shutter shade and a translucent insulating panel. The shutter shade slides along the north and south façades, providing protection from direct sunlight while simultaneously allowing for indirect, natural lighting, views to the exterior and privacy to those inside.
• For convenience and energy efficiency, the home’s systems are monitored and connected to an iPhone application.
• LUMENHAUS epitomizes a “whole building design” construction approach, in which all the home’s components and systems have been designed to work together to maximize user comfort with environmental protection. It can operate completely self sufficiently, responding to environmental changes automatically to balance energy efficiency with user comfort
• optimizes the use of passive energy through day lighting, natural ventilation and natural passive heating and cooling.
• building materials that are from renewable and/or recyclable sources
• The wood decking around the house has been harvested from fast-growth, sustainable forests. The concrete floor, which collects heat in the winter, contains recycled fly ash, while the translucent insulation panels on the north and south façades have an R-value equal to that of a typical solid wall. The zinc cladding and aluminum framing on the exterior of the house are extremely durable and recyclable.
• The house has a computer interface that manages all of its systems. Many aspects of these systems can be controlled by the user, at home or remotely, through either a computer or a smartphone. The management system gives live feedback of the house’s energy consumption, allowing you to be more energy conscious and to easily make changes to be more efficient
• not only energy-efficient; it is water-efficient, too. The roof is sloped to collect rainwater that is filtered for potable (drinkable) use in the house, while water used in the house (greywater – from the shower, bathroom sink and clothes washer) goes through a series of bio-filters in the surrounding landscape where it is cleaned for non-potable use.
• a low-energy, long-lasting Light Emitting Diode (LED) lighting system. Built right into the insulating panels of the Eclipsis System and throughout the house in strategic spots, the interior and exterior spaces will be amply lit.

Solar PV, Passive solar energy, LED, Geothermal water heating, Greywater, Rainwater collection, Insulation, etc.  All of these are topics we’ve covered on Mapawatt and are great technologies to investigate for a new sustainable home or home retrofit.

I think one of the neatest features of the house is the Eclipsis System.  It basically is a way to allow more natural light into your home while also providing privacy and insulation.  It seems that the metal shutters don’t actually rotate, so you can’t open and close them, but I could be mistaken on this.  What do you think is the neatest feature or the most likely one that you would adopt?  I’m sure one of our community readers could use some of these ideas in his plans to modify a travel trailer to live off-grid.

Related posts:

1. Dow Solar Shingle: POWERHOUSE…Get it?
2. US Solar hot water heating market
3. Calculating Your Annual Solar Energy Output

I first wrote about Home Star in March, when Obama was in Savannah, GA proposing the program.  Three months later and Congress has passed H.B. 5019 – Home Star Energy Retrofit Act of 2010, a.k.a. Cash for Caulkers.  All of this was probably helped out by V.P. Biden’s report delivered in October of 2009 titled Recovery through Retrofit.  The bill still has to head through the Senate, but with all the renewed focus on home energy efficiency, let’s hope the bill will make it through.

Like most bills that go through D.C., this one is a little complicated, but here is a link to the best summary of the Home Star – Cash for Caulkers – bill.  The article was written by Houston Neal and is extremely comprehensive.  The table below is only an excerpt and I highly recommend reading his whole detailed analysis.

I’ve actually been considering window film installation so hopefully the bill will pass so I can take advantage of $500!  Of all of these options, which one would you choose?

Related posts:

1. Do It Yourself Home Energy Audit
2. Ten Steps to Building a Zero Net Energy Home
3. Measure your progress – Energy Star Yardstick

My Attic Air Duct

The following article was written by Rod MacKenzie, an energy auditor based in Atlanta. Rod operates Green Building Resources, which is a residential energy auditing firm that provides customers with the products and services they need to make their home more comfortable and more energy efficient – home improvements that pay you back 2 ways!

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We’re going to talk about how to detect leaks in the heating, ventilation and air conditioning system (aka the HVAC system).

Leaks in the duct system are quite common and even more invisible than air leaks around windows and doors. Why are they more invisible? Because duct system air leaks are in places you don’t usually go – like the attic or crawlspaces of your home. The most common place for duct system air leaks is near the HVAC unit itself or in the joints of the duct system.

Your HVAC system is working hard to cool air in the summer or heat it in the winter. But if your duct system leaks, you’re probably not getting the full benefit of your HVAC system and you may come to the false conclusion that you need a new system.

Detecting leaks in your HVAC system is possible with a Duct Air Leak Test. The machine used in this test is sometimes called a “Duct Blaster” which sounds ominous – but don’t be concerned – the machine will not harm your duct system. It simply blows air into the duct system and allows a technician to find any and all air leaks so they can be sealed.

The duct blower machine is a small fan attached to a flexible and expandable pipe that resembles a piece of the duct system. The end of the pipe is attached to the duct system by temporarily taping it to one of the HVAC system outlets (one of the grills where conditioned air comes out)

After some other prep work, the machine is turned on and it blows air through the duct system and measures how much air is escaping. If the duct blower machine operator is really fancy, he/she will flow some theatrical fog through the fan so you can actually see where the air leaks are.

Keep in mind that all duct system leaks are NOT the same. Duct leaks in the attic or other unconditioned places are the highest priority because you never get any benefit from those kind of leaks. However, duct system air leaks inside your interior walls or between conditioned floors are not so bad as the leaks will still work to heat or cool the home even if it doesn’t complete it’s trip through the duct system.

Related posts:

1. Do It Yourself Home Energy Audit
2. Home Star a.k.a. Cash for Caulkers
3. It’s Hot and your AC is tired

Below are the contents of an article written by Wendy Koch for USA Today that appeared on Earth Day titled, “Blueprint for a green house“.  Wendy also writes for a USA Today blog titled, “Green House“.

I’ve taken snippets of her 10 tips with a few comments by me in italics, but I highly recommend reading her whole article and following her blog.

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1. Don’t do what we did.

Obviously, selling a house in a horrific market is not a capital idea. I also wouldn’t recommend building a custom green-certified home unless you have time, money and patience……

2. Consider your goals.

If you want a greener home, look at retrofitting rather than building new. That’s probably more eco-friendly, because you’re not tearing down a house. (We’re disassembling, piece by piece, the old rambler that stood on the lot we bought in Falls Church, Va. We’ll salvage whatever possible.)

You can save a lot of energy and water with simple, low-cost changes: programmable thermostats, low-flow shower/faucet fixtures, dual-flush toilets, compact flourescent or LED lighting….

(Mapawatt has tons of posts on the above topics)

3. Look at production and pre-fab homes.

If you’re still intent on a new home, there’s good news. An increasing number of major builders such as Pulte and KB Homes are offering eco-friendly houses at competitive prices, many of which carry the U.S. Energy Star efficiency label and some even a USGBC certification…..

(My townhome is a Pulte home and I sure wish they put more efficient products in it before we bought it.  For instance, we have a standard AC unit, but I would have jumped at the chance to get a high efficiency unit – and paid more for the house – if given the option.)

4. Buy a flat, sunny lot in a walkable neighborhood.

Building green isn’t just about efficiency and recycled materials. It’s also walkability. If you’re close to stores and public transportation, you can drive less. Before buying a lot, check its rating on walkscore.com…..

(I’ve never heard of walkscore.com but it’s a great idea.  I can walk to the library and restaurants and ride my bike to a 40 mile “rail-t0-trail”.  Not having to rely on the car is freedom.)

5. Hire architects you like and builders who know green.

Want a distinctive house, one that stands out from the crowd? Then spend the money and hire an architect. Good design, which can obviate the need for bigger spaces, is worth the cost…..

6. Be prepared for change.

If you build a seriously green house, and you’re hip-deep in the process, you’ll change….

….The epitome came a couple of months ago at 11 p.m., after I finished blogging about a new $6,000 home windmill. “I really want it!” I told Alex, as he finished brushing his teeth. “We could go net zero!” I gushed, meaning our house could produce as much energy as it uses…..

(Mapawatt has covered windmills – which should actually be referred to as wind turbine, but… –  and where they work several times.  There are many manufacturers making unrealistic claims and you need to make sure you do a wind survey before you buy!)

7. Not all green makes sense.

Turns out, as Alex surmised, the windmill wasn’t a cost-effective idea. Given our area’s wind speed and our utility’s relatively low price per kilowatt, the windmill probably would never have paid for itself, or even produced much electricity.

I was more disappointed to find that geothermal heat pumps didn’t make economic sense. I got three bids, two for about $70,000 and a hybrid version for $50,000. Since we’re building a tight envelope (exterior), our energy modeling showed geothermal would save us only a few hundred dollars a year at current rates.

If our house were bigger, less efficient and had higher electric rates, geothermal might have been worthwhile. Instead, we’ll use a high-efficiency gas furnace.

Perhaps surprisingly, we’ll save almost as much energy as we would have with geothermal by switching from double-pane Jeld-Wen windows to super-efficient Serious Windows, which have an insulating film.

So our green home, modeled to earn top ratings, won’t have any chic green features such as solar panels, windmills or geothermal heat pumps.

8. Think passive.

New to the USA, but common in Germany, are “passive” homes that need almost no energy, because they are so well insulated. They use mechanical ventilation to circulate air and avoid sick-building syndrome…..

(Keep in mind that you need a fairly mild climate for a passive home.  Unfortunately it’s very tough to be passive in Atlanta when it is 99 degrees outside with 80% humidity.  It is definitely worthy to get as close to passive as possible!)

9. Be ready for delays and cost overruns.

We naively thought we’d be in our new house by now. We were told getting permits would take four to six weeks, but after three months, we’re still waiting….

10. Life goes on.

…I never doubt our decision to right-size our life. But sometimes, as the project gets bogged down, I question our decision to build a custom home. In those moments, I pull out the sketches and picture myself sipping tea at the breakfast bar and writing in my cozy, light-filled office. Would we do it again? Time will tell.

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So what has your experience been building or upgrading your green home?

Related posts:

1. Top Ten Home Conservation tips under $100
2. Ten Steps to Building a Zero Net Energy Home
3. Green Jobs: It isn’t easy being Green!

We humans are needy people.  We want cars and nice clothes and good beer and flashy jewelry.  But we only need water, food, and shelter to survive.  If you live in a single family home the shelter part is probably provided by a roof with shingles.  This is good news for Dow Chemical, who is about to release a solar panel that doubles as a roof shingle called the Powerhouse solar shingle (nice play on words).  Time Magazine also thought this was good news as they named the Dow solar shingle as one of the best inventions of 2009.

Dow summarizes their solar shingle on their website as follows:

The Dow POWERHOUSE™ Solar Shingle delivers true building-integrated aesthetics by integrating PV functionality into an asphalt roof-shingle form factor.  It utilizes high-efficiency, CIGS-based, PV cells manufactured on a flexible substrate.  These cells are laminated and subsequently over-molded into the final shingle design using conventional materials and polymer processing methods. Dow’s groundbreaking technology integrates low-cost thin-film photovoltaic cells into a roofing shingle design, which represents a multi-functional solar module.  The innovative product design reduces installation costs because the conventional roofing shingles and solar generating shingles  are installed simultaneously.

Consumer Reports has posted a great video about the Dow Solar shingle on their Facebook page.  They estimate the system will cost a user $25,000 to install but they don’t say how big of a system this will buy (in terms of kW) so this really doesn’t help consumers make a buying decision ($25k for a 5 kW system is wonderful.  $25k for a 2 kW system is lousy)!

My guess is that the Dow solar shingle is going to work best on a new home being built that doesn’t yet have a roof with traditional shingles on it.  This way you will only have to pay for roof shingles 1 time (as opposed to paying for traditional shingles, then paying again to replace them with solar shingles later on).  Also, if you are building a house it should be oriented with the longest side facing south, which will optimize solar PV output along with keeping your home warm in the winter.

Many other blogs covering the Dow solar shingle say the advantage over a traditional roof mounted solar PV system is that the solar shingles are easier to install and they are expected to cost 10-15% less; however they conveniently leave out one vital point: The thin-film solar cells used in the shingle are made by Global Solar and are only 10% efficient.  Compare this to a SunPower 225 panel, which is 18% efficient, and the solar shingles pale in comparison. You can’t just factor in initial costs of the system, you also have to figure in lifetime power output which relates to how much money you will save!

Basically, if you are going to look at putting solar on your roof you are going to have to take several things into consideration when comparing traditional PV panels against solar shingles:

• aesthetics (advantage solar shingle)
• initial cost (undecided)
• ease of installation (solar shingle on new roofs, undecided on retrofit applications)
• lifetime power output (traditional PV panels with their higher efficiency)

In any case, find some professional solar installers in your area once the panels are released and get several quotes with different types of systems.

Dow has slated the shingles for a limited released in 2010 and wide release in 2011.  As with many clean energy products, the solar shingles will be eligible for the 30% federal tax deduction and your state and/or utility may offer further tax credits/rebates.

Is anyone planning on installing these on their home?

Related posts:

1. Solar Financing Options with No Upfront Costs
2. U.S. university wins European Solar Home contest!
3. Solar PV monitoring – It’s a necessity

Horalby's LEED Gold home

Last week I had a reader reach out and say they really liked a blog post.  She also shared with me her experience with building a green home and the fact they were working to achieve LEED Gold status for their home.  Lorraine and Judd Horbaly are building their dream home on the banks of the Potomac river.  Lorraine has written two excellent posts for House and Home on their experience building a green home (click here for part 1 and part 2).  I highly recommend them.

Lorraine started part 1 of her series in House and Home off with:

From the time we bought this beautiful property we knew we had to “build green.” As owners of a cabinet company which is part of the building industry we have seen firsthand the negative impact that homebuilding can have on the environment. It was our passion, and our imperative, to be good stewards of this land and to build a house that preserved and protected the environment. As individuals, each of has the opportunity to make responsible choices that protect our natural resources and preserve the quality of the air and water which sustain us. Those choices can be as simple as changing light bulbs to building or remodeling a house using green products and technology.

After hearing Lorraine’s story I was most intrigued by her experience with LEED for Homes.  I have know about LEED for many years because one of their main proponents, Southface Institute, is located here in Atlanta (and their offices are LEED Platinum – the highest level).

I always understood the rationale behind commercial properties getting LEED certification.  For the commercial property’s owners it makes perfect sense;  it shows their customers, coworkers, and people who pass through the building that they care about the environment and the health of the building occupants.  LEED certification for commercial buildings is a very powerful statement about the leadership of the owners and operators of these properties.

In the past I have only thought about LEED for commercial property, so I asked Lorraine a little bit more about her experience and here is her response:

“Our passion and imperative, from the early stages, was to build a home in our beautiful setting overlooking the Potomac River which would preserve and protect the environment.  The high standards of the LEED for Homes program would help to ensure our goals.

The LEED for Homes program is relatively new, beginning in February 2008 after a 3-year pilot program.  It is the most rigorous of the many green homebuilding programs and the one by which we wanted our house rated.  There are 4 levels of certification, Certified, Silver, Gold and Platinum.  We expect to be Gold certified.  There are tests performed and inspections made during construction by a Green Rater based on the Home Energy Rating System (HERS).  The process is exacting, but not onerous, and is affordable.

Why build a LEED home?  Because a LEED-certified home uses less energy, water and natural resources, minimizes impact on its immediate environment, and ensures healthy indoor air quality.  The US Green Building Council estimates that the average LEED Platinum home could use as much as 60% less energy than a home built to the International Energy Conservation Code (IECC) standards.  And because the house is certified to meet the highest criteria, the market value of the home is higher.  An additional reason for us is that we will live in a supremely comfortable home with the knowledge that we are contributing to a healthier planet.”

———–

In the LEED for Home FAQ section they answer why a home-buyer would purchase a LEED home:

For the homebuyer, LEED is like the nutrition label on the side of a box of crackers: It clearly labels in measurable terms that the home has healthy, green, efficient features that have been third-party verified.

Basically, you can think of LEED for Homes as the “Cadillac” version of a car.  Sure, you can buy a regular ol’ home, but if you get a LEED home you know it will be a more energy efficient, healthier, and nicer home with a higher resale value  that will make you happier to live in.  Sounds like a pretty good return on investment for me!

Related posts:

1. Building your Green home tips
2. Greensburg, Kansas: Rebuilding Sustainably
3. PACE Financing in the Southeast

Blower Door Test

A key step to understanding how you use energy in your home is doing a home energy audit.  An energy audit usually means you walk through your home and analyze all the systems that impact how you use energy.  There are two ways to approach a home energy audit: finding a professional or doing your own.

Scientific American’s “Solar At Home” Blogger George Musser had a great blog discussing the tools needed to do your own energy audit. In addition, the U.S. DOE has a nice section related to doing your own home energy audit.  The main strategies they list for people doing their own home energy audits are finding air leaks, looking at insulation, inspecting heating/cooling systems, and looking at lighting.  TheDailyGreen has a nice post on the DIY home energy audit that include a nice checklist to use as a guide (although it leaves off lighting!).

While you can learn a lot from doing your own home energy audit, you gain a lot more by having an energy audit done by a professional.  There are probably three things that a professional brings to the home energy audit that most people just can’t do on their own:

• Experience – professionals have done this many, many times, so they know how to make the biggest impact
• Blower Door tests – equipment that measures how air flows through your home
• Thermographic Scan – equipment that shows where heat leaves your home (the high-tech/whole-home equivalent to the Black & Decker thermal leak detector)

For obvious reasons it is a must that a professional energy auditor have the first requirement, but you should question them if they dont have the second and third requirements.  In addition a professional home energy auditor will develop a detailed report for you detailing his/her findings.  While it’s hard to verify, chances are a professional energy auditor will save you more money in energy savings than what  their services cost.  It’s like a personal trainer; sure, you could do it your self, but you’d benefit that much more from an expert!

Energy Circle, which is a site with very similar goals to Mapawatt, had a great blog related to the top ten lessons learned in doing energy audits.

An energy audit usually only takes a few hours and provides a great understanding of what you’re doing well and what needs improvement.  I would recommend doing an energy audit twice a year, if not more.  It is important to benchmark how you use energy so you will know how to improve.  In between energy audits, make sure you monitor energy usage to get further tuned in to how you use energy on a daily basis.

If you aren’t ready to hire a professional home energy auditor that’s fine.  At least take a few moments and walk around your home while thinking about where your energy dollars go.  Energy audits are like a car inspection, they help you see how you can perform better, save more energy and save more money!

Related posts:

1. Biggest Energy Vampire in your Home: Cable Box
2. Do It Yourself Home Energy Audit
3. Ten Steps to Building a Zero Net Energy Home