Low-Watt Computers Offgrid Energy Efficiency

Save Money with Efficient Low-Power Computers

The airplane passenger’s computing problem is a microcosm of an off-grid system so we can use the jetsetter’s high-tech demands for our frugal needs. The choice is an old one: Increase computing by (1) increasing power (of the battery), or (2) decreasing usage (by the computer). We all know that conservation (minimizing load) is best. Minimize demand before you increase supply.

First, determine your needs. Many people overbuy. Not too long ago, I rigged a 100MHz machine to surf on DSL and it first-time-loaded most pages in a few seconds, used all email, used 128 encryption, and used some streaming video (but not most streaming video).

Next, realize that power consumption can vary even within a “name” processor. With the Intel Pentium 4, the ones with Northwood cores ran cooler than the ones with Prescott cores. New CRT monitors probably use less power than old CRTs but LCD monitors can use half the power of CRTs. Processors and monitors are two of the biggest energy hogs. Generally, speed needs power, so save money and buy a 7200rpm hard drive if you don’t need the speed difference of higher rpm (which most users probably wouldn’t notice anyway). For the power supply unit (PSU), many companies advertise peak power rather than constant load, PSUs operate best at 50-70% of capacity, "clean power" moderates power spikes and power surges, and PSUs have several sub-systems that each have a breaking point so you can crash if you exceed one limit even if overall draw is below overall capacity (plump for a high-quality PSU if you want peace of mind).

Laptops are more expensive because of (1) compact portability through custom "Form Factor" (FF) motherboards or smaller components such as the 2.5in. hard drive (on both “desktop replacement” and “mobile” models) and/or (2) power-saving technology (on mobile models). For instance, a “desktop replacement” laptop might have a cheaper “desktop” processor, whereas the mobile model will have a mobile processor that uses smart management (“power stepping,” etc.) to minimize power usage at ¼ of a desktop chip’s rated wattage (the proportion varies a lot by chip architecture).

Every chip maker has mobile versions of their chips. I think that Intel used “M” to denote its Pentium mobiles and now has a “Merom” chip. At least at one time, a laptop without wi-fi or other mobile accessories was a good indicator that it also lacked a mobile chip—but I’m not sure if that’s still true in the days of wireless home networks.

You have 3 basic choices:

1. Get almost any good mobile-laptop deal on eBay. An older mobile might use more power than cutting-edge technology but it will offer good power economy at a steep price discount.
2. Get a cutting-edge chip if the claims are true that it will draw 5W maximum (less than a compact fluorescent bulb, although that’s the chip and not the whole computer). Consider waiting longer until these become last year’s model.
3. Get a custom computer that uses a mobile chip with a compatible power-managing motherboard in a regular desktop with common, cheaper hard drive and other components (although desktop drives use more power than laptop drives). This method can be more or less expensive depending on if you or a friend can buy and assemble the components from newegg.com or elsewhere.

Compare computer components energy use.

Calculate computer components energy use to design your own computer system (watts calculator).

Carbon Footprints and Embodied Energy in Materials Choice

Some people have used straw*-bale walls for inexpensive building but I wonder about long-term strength, fire, rot, and infestation with straw.*

Some people choose straw* for a lower life-cycle impact or "footprint" on the environment. In practice, an efficiency goal often will overlap with low "embodied energy" (the resources needed to get your house ready for occupancy, including fuel costs to ship a roof shingle or bathroom tile from another state or country). However, embodied energy is not a deal-breaker for my project, except if it's reflected in my construction/maintenance cost effectiveness (bang for the buck).

*Corrected, do not confuse straw with hay (see comment).

How Appliances Affect Home Cost

Your appliance purchases are not afterthoughts. They are part of your home design. Not only do appliances from refrigerators to computers affect your operating costs (electric bills, etc.), but appliances can add considerable construction costs to an off-grid home to "size" your power system to your needs.

• Lights: Maximize natural lighting ("daylighting"), supplemented by compact fluorescents, LEDs, or photovoltaic lights.
• Refrigerators: Some say that chest freezers/refrigerators are more efficient than closet types. Reclaim the compressor's waste heat and put it to good use such as heating hot water or preheating air entering the home. Shield your refrigerator from that natural lighting unless you want to create a daily "cockfight" between the Sun and your electric meter.
• Computers: Few people other than graphic designers, engineers, and hardcore gamers need the latest power-hungry chips so size your computer to your needs. Generally, AMD chips have been considered less power hungry than Intel for a given performance level, although Intel has been challenging AMD on that score. Laptop computers generally use less power than desktop computers but the cheaper "desktop replacement" laptops are portable yet usually lack power-saving technology while the "Mobile" computer-processor chip laptops are the king of low-watt computing.
  

Best Insulation System, Home Wall and Roof?

"Stick-built" wood construction requires a cage of "studs" (vertical 2x4 or 2x6 beams) at regular intervals for structural support. The later insulation problem is:

• The studs "go through" the typical insulation (inside wall to outside wall) and bleed heat to outside like fins on a radiator.
• Each rectangle (between studs) is its own insulation project with a full perimeter to be sealed. Not sealing the edges is like installing a high-tech super-insulated window and then leaving it open.

Sprayed on (blown in) insulation could seal crevices but must be done correctly and some home owners reported that cellulose insulation shrank and needed re-application. Certain insulations lose effectiveness after shrinking, settling, getting wet, or being crushed. Like wearing layered clothing, batt insulation blankets (fiberglass, rockwool) rely on airspaces in the material and should not be compressed into the wall.

Your actual heat retention is not the advertised R rating of the insulation material, your "effective R value" is the "full wall" result of the entire system. You can check insulation without opening walls by measuring drafts (air leakage) or measuring temperature with thermometers or infrared (IR) cameras' thermograms (thermographic inspection).

Quick Tip: All else being equal (same sun time, etc.) , a roof which keeps its snow longer is insulated better than the roof next door which melts it snow faster from below by heat leaks.

I currently do not favor stick-built construction because every edge is an enemy to insulation. I currently am looking for solid information on the effective R value of an earth-sheltered solid-concrete construction with external foam board insulation. I also seek information on the value of radiant barriers and reflective paint (please leave a comment with tips).

Wood Species Energy BTU per Cord

Not all trees are created equal. Hard wood has more energy than soft wood does. The sapless, hardest woods are best for wood stoves. White Oak has double the energy of White Cedar.

The U.S. Forest Products Laboratory rated wood species energy in BTU per cord of seasoned, 20%-moisture wood, which I sorted with the highest-energy wood first:

Wood Species	Cord Weight Lbs.	Energy Content Million BTU/Cord
Hickory	4,327	27.7
Hornbeam, Eastern	4,267	27.3
Beech, Blue	3,890	26.8
Birch, Black	3,890	26.8
Locust, Black	3,890	26.8
Apple	4,140	26.5
Oak, White	4.012	25.7
Beech, High	3,757	24.0
Maple, Sugar	3,757	24.0
Oak, Red	3,757	24.0
Ash, White	3,689	23.6
Birch, Yellow	3,689	23.6
Hackberry	3,246	20.8
Tamarack	3,247	20.8
Fir, Douglas	3,196	20.6
Birch, Gray	3,179	20.3
Birch, Paper	3,179	20.3
Birch, White	3,179	20.3
Cherry	3,120	20.0
Cherry, Black	2.880	19.9
Elm, American	3,052	19.5
Elm, Oyen	3,052	19.5
Elm, White	3,052	19.5
Ash, Black	2,992	19.1
Maple, Red	2,924	18.7
Box Elder	2,797	17.9
Alder	2,708	17.6
Pine, Jack	2,669	17.1
Pine, Norway	2,669	17.1
Pine, Pitch	2,669	17.1
Hemlock	2,482	15.9
Spruce, Black	2,482	15.9
Pine, Ponderosa	2,380	15.2
Aspen	2,295	14.7
Butternut	2,100	14.5
Spruce	2,100	14.5
Fir, Balsam	2,236	14.3
Pine, Western	2,236	14.3
Basswood	2,108	13.5
Cottonwood	2,108	13.5
Cedar, White	1,913	12.2

Starting Your Car in Freezing Winter Weather

Batteries do not work well at low temperatures. A Battery blanket is an electric blanket for your installed car battery. Plug it in overnight to insure your car starts on a freezing cold morning. The electric warming is for convenience or peace of mind and not to save energy. Insulation, even parking in an unheated garage, car port, or other sheltered area, helps a lot.

The Myth of Geothermal Heating Efficiency?

Geothermal heat taps the Earth's heat "for free." An example of a passive system is a vertical tube driven below the frost line so the constant non-freezing temperature beneath most populated areas rises through the tube--simple to keep cattle's outside water trough from freezing. However, the typical home would use an active system:

1. Boosting the ballpark 50-ish-degree* earth temperature to typical room temperature and hot-shower temperature requires heat pumps/compressors to add heat--so you still need some type of "furnace" *(Edit: I had already mentioned the hotspot variance but here's more detail: Geothermal temperatures vary from hotspot hot springs like Yosemite park to permafrost like Alaskan tundra--and the contiguous 48 U.S. states vary in broad bands of 37-77 degrees F from north to south; it is better if your area has "room temperature" geothermal heat but unfortunately the lowest heats generally are in the north where you need heat most).
   
2. A typical home needs a vast underground radiator of tubes to "mine" the Earth's heat. This outdoor system is an additional up-front capital cost not needed by conventional heating systems (compare the vertical loop to well-digging and the horizontal loop to septic/sewer excavation to get some idea of cost).
3. A typical home still needs some type of indoor HVAC system to circulate the geothermal heat.

One showcase geothermal-heated home includes the waste heat from electrical machinery in its "geothermal" performance rating--so much of the reported "geothermal" heat is actually electric heat. The extracted geothermal heat in mid-latitude USA (Mc Henry MD) measured 49.6 degrees F and provided 17,250 BTUH. However, all the electrical pumps required for this geothermal system create an electrical load of up to 3,502 watts, equivalent to 11,952 BTUH of electric heat. In other words, if you could run all the geothermal system's electrical equipment under load in the middle of your living room but not connected to any geothermal heat source, you would generate electromechanical heat equal to about 70% of the potential geothermal heat--without the cost of excavation and underground equipment.

I read somewhere that a syndicated home energy show designed an HVAC system with:

• a Marathon water heater
• a geothermal heat system
• a heat exchanger so that the geothermal heat pump's heat would provide supplementary heat to the hot water

The owners enjoyed all the hot water they wanted for over a year before they accidentally discovered that they had forgotten to turn on the Marathon hot water heater--the entire household's hot water needs were met by the electric heat or waste heat of the heat pump for the geothermal system. That's a lot of expensive electric heat masquerading as a "free" "geothermal" heat system.

Rough comparative indicators of heating system efficiency suggest that geothermal costs 50% less than conventional annual HVAC to operate but geothermal costs 50-100% more to install. If you don't pay an extra $10,000 for geothermal installation in new construction and instead put the cash in a 5% money market account, the interest will pay $500 per year (before taxes). The $20,000- $30,000 cost of geothermal-converting an existing home instead put into a 5% Money Market would pay $1,000-$1,500 of your conventional HVAC--and you'll still have the principal cash as an emergency fund (your doctor or car mechanic might not accept geothermal tubes as payment). If you lack cash, borrowing the higher installation cost makes geothermal even less of a bargain. The government might subsidize a geothermal home system but government subsidy could be yet another telltale sign of active geothermal's inherent inefficiency.

Even though commercial geothermal systems might reach their break-even point after a decade or two (when net operating savings finally exceed the initial premium in constant dollars), I fear that the good geothermal idea fell victim to conventional, expensive thinking but with superficial appeal to gear heads, penny pinchers, and tree huggers (the new Green "Glam").

This article's title is a question, not an answer, but those are my concerns. I would like to see comparative data with a passive geothermal tube design, and also an earth-sheltered design without external tubing (with only the Earth against the walls as the passive geothermal heating system). Given a walkout-basement-style earth-sheltered design, what is the most cost-efficient heating system (initial and operating costs including risk of broken equipment) to maintain 65 degrees for room temperature?

Home Mortgage Costs Relative to Salary

Thanks to The Boston Housing Market, here is an interesting site on historical trends in home mortgage costs relative to salary (excluding taxes).

I would like to see similar trend data with

• income to sale price (i.e. excluding loan cost)
• per square foot (finished and unfinished, to account for growth in average house size)

Heating Homes with Wood Stoves

Earlier Post: Wood Stove Heating Systems

• An angled flue pipe that meanders through the living area transfers more heat to the living area than a vertical fluepipe, although some say that you get a cleaner burn with a vertical pipe.
• Magnetic flue-pipe thermometers are an easy way to monitor heating temperature.
  
• Below is an excerpt from a useful webpage on home-heating with wood (which says that efficiency is 10% for tradtional fireplaces, 20% for metal-lined fireplaces, and 55-65% for airtight, controlled, wood stoves):
  

Listed below are various species of wood, measured in one air-dried cord, and their equivalents to other heat sources (with a snapshot of prices but check your current, local prices for cost efficiency):

Hickory, Hop hornbeam (Ironwood), Black locust, White oak, and Apple are equal to 146 gallons of fuel oil ($314), 174 therms of natural gas ($73), and 3,800 KWH of electricity ($304) . - Mixed wood $55.00 - $80.00

Beech, Sugar maple, Red oak, Yellow birch, and White ash are equal to , 133 gallons of fuel oil ($287), 160 therms of natural gas ($67), and 3,500 KWH of electricity($280).- Mixed wood $60.00.

Gray and Paper birch, Black walnut, Black cherry, Red maple, Tamarack (Larch), and Pitch pine are equal to 114 gallons of fuel oil ($246), 136 therms of natural gas($57), and 3,000 KWH of electricity($240).- Mixed wood $60.00.

American elm, Black and Green ash, Sweet gum, Silver and Bigleaf maple, Red cedar, and Red pine are equal to, 103 gallons of fuel oil ($222), 123 therms of natural gas($52), and 2,700 KWH of electricity($216).- Mixed wood $60.00.

Poplar, Cottonwood, Black willow, Aspen, Butternut, Hemlock, and Spruce are equal to 86 gallons of fuel oil ($165), 102 therms of natural gas($43), and 2,200 KWH of electricity($176).- Mixed wood $60.00.

Basswood, White pine, Balsam fir, and White cedar are equal to, 73 gallons of fuel oil which costs about$163.67, 87 therms of natural gas which costs about $36.65, and 1,900 KLWH of electricity ($152). - Mixed Wood $60.00.

Ameriquest Mortgage Refinancing

I found this Wikipedia article interesting:

Ameriquest is one of the United States's leading wholesale sub-prime lenders. It is a private company, owned by Roland Arnall, founded in 1979, in Orange County, California, as a bank, Long Beach Savings & Loan. The bank moved to Orange County in 1991 and was converted to a pure mortgage lender in 1994, renamed Long Beach Mortgage Co. In 1997, the wholesale part of the business (funding loans made by independent brokers) was spun off as a publicly traded company, called Long Beach Mortgage; the retail part of the business was renamed Ameriquest Capital and remained private. (In 1999, Washington Mutual purchased Long Beach Mortgage.)

Ameriquest is best known for its subsidiary, Ameriquest Mortgage Company, which makes direct loans to customers. Its Argent Mortgage Company affiliate works with independent brokers. It has offices nationwide, and more than 12,000 employees. Other subsidiaries are Ameriquest Mortgage Securities, Long Beach Acceptance Corp., and Town & Country Credit.

Ameriquest was among the first mortgage companies to use computers to search for prospective borrowers, and to speed up the loan process.

...

Sub-prime lenders made $587 billion in new mortgages in 2004, up from $390 billion in 2003, according to National Mortgage News. Ameriquest's share of that is estimated at over $50 billion.

In 1996, , the company paid $3 million to settle a Justice Department lawsuit accusing it of gouging older, female and minority borrowers. Prosecutors accused it of allowing mortgage brokers and its employees to add a fee to these customers of as much as 12% of the loan amount.

In 2001, after being investigated by the Federal Trade Commission, the company settled a dispute with ACORN, a national organization of community groups, promising to offer $360 million in low-cost loans.

On 1 August 2005, Ameriquest announced that it would set aside $325 million to settle attorney general investigations in 30 states. In at least five of those states — California, Connecticut, Georgia, Massachusetts, and Florida — Ameriquest has already settled multimillion-dollar suits.

In May, 2006, Ameriquest Mortgage announced it was closing all of its retail offices, and will emphasize in the future its loans through brokers, a channel that is not covered by the predatory lending settlement with the Attorneys General.

The issues confronted by companies like Ameriquest are considered by many industry experts to be the major contributing factor to the rapid rise of Certified Mortgage Planners, certified industry experts that work in concert with Certified Financial Planners in harmonizing the home finance products utilized by consumers with their larger financial portfolios.

Housing Bubble: More abandoned house construction and home renovations in real estate MLS listings

Abandoned house construction and home renovation

Perhaps as another symptom of the bursting real estate housing bubble, I have noticed more MLS ads where realtors cheerily advertise for you to "finish as you want," not mentioning the implication that some poor soul or unskilled "house flipper" ran out of money and walked away.

This is a clear lesson to avoid over-extending yourself, anticipate cost overruns, and keep rainy day funds.