Twitterings
I've been posting "True and False" questions on Twitter through my GreenRater account there. As a result, some suggested it would be great to have them all in one place.
One note for those of you unfamiliar with Twitter... Each Twitter post is limited to 140 characters. Thus, besides thinking of the questions and answers, it was a challenge sometimes to get them to fit within that 140 character limit. It also explains why some of the abbreviations and sentence fragments below were necessary.
Here they are! See how well you do, have fun, and if you have any questions or concerns contact me here.
True or False: Cleaning refrigerator coils saves energy.
False. Efforts to actually measure this effect have typically come up empty-handed. Don't expect lower utility bills from it.
True or False: Duct tape may have many uses; however, sealing ducts is not one of them. Answer to follow...
True. Mastic (a type of caulk) is best. If you want to use tape, then use foil, butyl or fiberglass tape.
True or False: Simply closing a bedroom door can create serious safety, comfort, and health problems in a home. Answer to follow...
True. Today's air handlers move large volumes of air. Thus, even small changes can affect pressurization, pulling in or expelling air.
True or False: Air conditioners are a big contributer to indoor mold problems. Answer to follow...
False. If anything, they help. When properly sized and installed, they dehumidify a home.
True or False: Electric heating is more efficient than fuel-based heating. Answer to follow...
True, only if you don't count the energy that went into producing that electricity. Otherwise, electricity converts efficiently into heat.
True or False: Halogen lighting is superefficient. Answer to follow...
False. While they use slightly less than standard incandescent bulbs, they require transformers that can use extra energy & run hotter.
True or False: Fluorescent lighting is unhealthy. Answer to follow...
False. Today's fluorescents have greatly improved color quality & no flicker or hum. "Sapping people's vitamins" has no basis in fact.
True or False: Switching to electric room heaters will reduce your energy bill. Answer to follow...
True for those with electric central heating. False for everyone else.
True or False: Insulating the ceiling will just cause more heat to leak out of the windows. Answer to follow...
False. Adding insulation to one part of a home doesn't increase the heat losses in other parts of a home.
True or False: Energy efficiency increases the first cost of houses. Answer to follow...
False. Not necessarily so. Efficiency often reduces costs elsewhere, such as mechanicals sizing.
True or False: Leaving lights, computers, etc on uses less energy than turning them off and on repeatedly. Answer to follow...
False. The small surge needed to power up is much smaller than running the device when it's not needed. Doesn't make it last longer either.
True or False: Installing foam gaskets in electrical outlets will significantly reduce air leakage. Answer to follow...
False. Less than 1% of a home's air leakage is due to outlets. A lot of little holes can add up to one big hole, but, still, do this last.
True or False: Energy efficiency and energy conservation are one and the same thing. Answer to follow...
False. Energy efficiency means getting the same job done while using less energy. Conservation means reducing level of service.
True or False: Buying an efficient air conditioner or furnace will automatically reduce my energy bill. Answer to follow...
True. Generally. But not if the equipment is not sized or installed correctly, which can waste up to a 1/3 of their energy use.
True or False: In climates with cold winters, it's preferable to seal air leaks from the outside. Answer to follow...
False. It's best to seal inside so you'll prevent humid air from getting inside the wall.
True or False: 1 BTU (British Thermal Unit) is the amount of heat needed to raise 1 gallon of water 1 degree Fahrenheit. Answer to follow...
False. 1 BTU is the amount of heat needed to raise 1 pound of water 1 degree Fahrenheit.
True or False: Typical forced air duct systems leak very little. Answer to follow...
False. Typically, duct systems lose 25-40% of the heating or cooling energy passing through them. $$$ lost.
True or False: You only need to insulate ducts that are in unconditioned or partially conditioned spaces. Answer to follow...
True, in unconditioned or partially conditioned crawlspaces, garages, attics or basements.
True or False: There is a lack of evidence showing a health benefit of duct cleaning in most cases. Answer to follow...
True. The EPA does not recommend that air ducts be cleaned except on an as-needed basis.
T/F: Heat pumps use a cycle of pressure and depressurization to accentuate the movement of heat from outdoors (or ground) to home. Answer...
True. Heat and air conditioning, two sides of the same coin. Simply reverse the A/C cycle and you have have heat.
True or False: A joule equals one watt. Answer to follow...
False. Joules don't equal watts. One's a measurement of energy, one's a mesurement of power.
A quiet person generates 100 joules, as heat, every second - or 100 watt/seconds.
There is far more oil to be "found" in fuel-efficient cars than can be pumped out of ANWAR. Answer to follow...
True. Raising fuel standards to 35mpg by 2020 would save 3.6 million barrels a day by 2030
T/F: Main thermal functions of air sealing: increasing comfort, saving energy, protecting thermal integrity of insulation. Answer to follow
True. BTW, comfort and energy savings almost always go hand in hand.
T or F: Outdoor relative humidity & thermal resistance of the glass determines what outdoor temp will cause condensation inside. Answer...
False. Indoor relative humidity and thermal resistance of the glass or wall determines what outdoor temp will cause condensation.
T or F: In winter, an average home loses three to six times more heat through heat transmission (e.g., walls) than through air leakage.
True. Heat transmission is the leading cause of winter heat loss.
T or F: With 5% of the world's population, the US consumes 25% of the world's energy supply (& controls 8% of energy resources).
Simply, maybe sadly, of course, True. But for how long?
True or False: The Passive House standard is the most rigorous energy standard of Europe. Answer to follow...
True. It requires a home use no more than 1.35 kWh per sq. ft. per year for heating, or 10.8 kWh /sq. ft per year total energy consumption.
True or False: Most of the power consumed by home electronics is used while the devices are turned off. Answer to follow...
True. Up to 75% of the power consumed. It's called ghost or phantom usage. You can install power strips to mitigate.
Nice thing about lighting & appliance efficiency is that it's consistent throughout the year.
True/False: Using structural insulated panels (SIPs) produce a tighter home than one that is stick-built (2x4 framing). Answer to follow...
True. Oak Ridge National Laboratory studies have shown that air flow through SIP-built homes is 10% of standard built batt-insulated home.
T or F: High Solar Heat-Gain Coefficient (SHGC) windows are important in cooling-dominated (warm/hot) climates. Answer to follow...
False. SHGC is a measure of solar gain transmitted through a window to that striking the window. The lower, the less heat gets inside.
True or False: Air sealing a home in hot climates is different than air sealing in cold climates. Answer to follow...
True. In hot climates the air barrier should on the outside, in cold climates the air barrier should be on the inside. It's all about H2O.
True or False: "Home performance" is mostly about energy efficiency. Answer to follow...
False. A Phoenix Homeowner Satisfaction Survey found it's more about comfort, reliability, and healthiness. Efficiency then tags along.
True or False: Replacement windows can use the existing window frame, or replacing it. Answer to follow...
True. The former is simpler and more cost-effective, but most likely not as energy efficient. Replacements are all about good measurement!
True or False: The good energy efficient alternative to A/C (and conventional heating) is a geothermal heat pump. Answer to follow...
True. According to DOE a good geothermal unit will heat, cool, and provide hot water for 1,500 sq. ft. home for about $1/day.
True or False: Paper or plastic? Answer to follow...
Neither. Canvas bags are 14 x better than plastic bags & 39 x better than paper bags, assuming that canvas bags are used at least 500 x.
True or False: The Federal govt has a 30% tax credit for residential solar energy installations. Answer to follow...
True. It's set to expire at the end of 2008. The maximum credit is $2,000. There's a bill to extend it into 2009.
ZPH stands for "Zero Peak Home", one that draws no grid electricity during peak hours. Okay -- but so what?
Producing the extra electricity to meet peak demand is expensive. The marginal cost can be 10x that of off-peak electricity.
BTW, "ZEH" is a "Zero Energy Home", which creates as much energy as it uses over the course of a year.
True or False: Buildings generate more greenhouse gas emissions than automobiles. Answer to follow...
True. 39% and 21%, respectively. And existing homes are the largest contributer to the building sector's carbon footprint.
Retrofitting homes, of course, is much more expensive than constructing new energy efficient homes.
True or False: It's virtually impossible to make a solid masonry home energy efficient. Answer to follow...
False. German energy agency, dena, initiated successful Efficient Homes project in 2003. 86% of German homes are concrete, brick or block.
Average demand before = 336 kWh/m2. After = 44 kWh/m2. An average reduction of over 80%.
True or False: A 18 SEER A/C uses 50% more electricity to operate than a 12 SEER A/C. Answer to follow...
False. A 18 SEER A/C is 50% more efficient than a 12 SEER A/C (or costs a third less to run). The higher the SEER, the more efficient.
T/F: A/C uses a cycle of pressure and depressurization to leverage the movement of heat from home to outdoors (or ground). Answer 2 follow.
T: Heat > warms cold fluid > fluid pressurized & heats up > moved outside where cooled > moved back inside & depressurized > cold fluid :|
True/False. Timber Framing is the art of joining large timbers with interlocking joints, held in place with wooden pins. Answer to follow...
True. It's coming back. Flexible (interior walls don't bear load and can be moved). Durable. Little job-site waste. Adds up: sustainable.
True or False: Every watt of electricity used always generates 3.413 Btu of heat. Answer to follow...
True. That's why a running fan in a room without people is actually a heater, or why incandescent bulbs add to A/C load.
True or False: Widespread application of the Passive House design in the U.S. would have a dramatic impact on energy use. Answer 2 follow...
T. A Passive House has thick insulation, few thermal bridges, airtight envelope, insulated glazing, & balanced energy recovery ventilation.
The Smith House in Urbana, IL is the first N.American house built to a Passive House standard.
Repeat tweet: True or False: A fan will keep a room cool even when no one is in the room who would notice. And the answer is...
False. Fans only cool people (convection & skin), not rooms. Otherwise they're essentially only a heater (1 watt=3.412 Btu of heat)
T or F: According to National Audubon Society, 1/4 of US birds are at risk of extinction due to global climate change. Answer to follow...
True. 176 species in continental US, 38 in Hawaii.
True or False: At some point (soon?) we'll need to eliminate forced-air systems from homes altogether. Answer to follow...
True. Probably. We must dramatically reduce loads & install low-energy systems that heat both space and water.
True or False: What is called "green building" today will just be called "building" five to eight years from now. Answer to follow...
Of course, just a guess. But so says Great Dallas Home Builders Association President T.W. Bailey. Let's hope so. We'll see...
T or F: Achieving deep energy reductions in existing homes is more challenging & expensive than in new construction. Answer to follow...
True. But it's critical to somehow "tunnel through" (Amory Lovins) this cost barrier since we can't ignore existing housing stock.
We need an approach that realizes several benefits from each expenditure, adding efficiency to retrofits being done anyway.
T or F: Energy efficiency is the quickest, easiest, cheapest & most powerful way to counter the effects of climate change. Answer to follow
True. It's not sexy (like renewables), but it's the closest thing to a magic bullet. But we all have to do our part.
A good home performance contractor will test to assess, and then test again after improvements are made
True or False: Real-time feedback on energy usage actually leads to lower electricity usage. Answer to follow...
True. Test showed an average of 6.5% savings. Interested? Look for Blue Line Innovation's PowerCost Monitor.
True or False: Laptop computers use about 1/3 of the power of desktop PCs. Answer to follow...
True. With either kind please use the "sleep" mode and turn it off when you're not using it. You won't hurt it by turning if on and off.
True or False: There's more cost-effective "energy" to be had in efficiency than in any other available source. Answer to follow...
True. Instead of asking where we can get more oil, coal, solar, wind, etc., we'll be more effective asking how we can use less.
True or False: Retrofitting windows is not always the most cost-effective option. Answer to follow...
True, although it's usually the first thing homeowners think about doing. PVC replacements windows are especially to be avoided.
Because of leached plasticizers, outgassing, dioxin byproducts in production, even Wal*Mart and Target are phasing out PVC packaging.
True or False: Sheetrock, or drywall, is one building component that isn't a major player in greenhouse gases. Answer to follow...
False. To make sheetrock, gypsum is heated in large NG kilns to appox 300 F, then again dried with heat. Sheetrock was invented in 1917.
Did you know that gypsum the mineral, a semi-hydrous form of calcium sulfate is even used in Twinkies?
True or False: Juneau, AK was able to cut their electric consumption by 30% in a few weeks (without blackouts). Answer to follow...
True. An avalanche suddenly cut a transmission line and the price of their electricity suddenly jumped fivefold. April 2008.
How? Anecdotal evidence points to a populist move to energy conservation and efficiency. What would you do for $.55/kWh electricity?
True or False: Energy use is primarily a function of the volume of a home. Answer to follow...
True. And North Americans have quickly become the largest-housed people in the history of humanity. Efficiency-wise, small is beautiful.
Efficiency per sq. ft. doesn't means much in big honking houses. Efficiency-wise, small is beautiful.
True or False: "Cool roofs" absorb heat from the sun and transfer it to the attic (where temps can reach 130 F). Answer to follow...
False. That would be asphalt shingles - not "cool roofs". Shingles add 11M tons/year of waste to landfills & have higher long term costs.
It's also a losing cause to try and cool a building with a hot box (attic) sitting on top of it, especially if HVAC ducts are up there.
True or False: Cold air holds less moisture (absolute humidity) than warm air.
True. Hot air is thirsty air. One shower adds 1 lb. of moisture to the air (which your A/C then may have to remove).
True or False: ENERGY STAR labeled products use at least 10% less energy than standard models. Answer to follow...
True. And an ENERGY STAR certified home uses 15% less energy than a comparable standard home.
True or False: the "St." in "St. Louis" stands for "sticky". Answer to follow...
Little known, but true. Makes sense - at least feels that way today.
True or False: One out of three new Texas homes is ENERGY STAR qualified. Answer to follow...
True (February 2006). If "Live large, think big" Texas can do it, what gives "Show Me" Missouri?
True or False: A/C wasn't considered a necessity until recently. Answer to follow...
False. Technically, it's not a necessity. For ex, you can get an FHA mortgage without A/C, but not without heat.
Waste heat from A/C units also contributes to urban heat island effect.
True or False: "Home performance" is mostly about energy efficiency. Answer to follow...
False. A Phoenix Homeowner Satisfaction Survey found it's more about comfort, reliability, and healthiness. Efficiency then tags along.
Or - Comfort, reliability and healthiness = energy efficiency, but energy efficiency doesn't necessarily = performance.
True or False: Energy consumption in homes is fragmenting into an increasing number of small uses. Answer to follow...
True. A recent study showed that in an average home, over 40 products are drawing power all of the time.
True or False: Lighting doesn't account for a significant part of a home's electrical consumption. Answer to follow...
False. Converting bulbs to CFLs or installing dedicated high-efficiency fixtures offers long-term savings.
True or False: A goal of Net Zero-Energy homes (homes that consume zero or very little energy) is unrealistic. Answer to follow...
False. Australians are even talking about requiring all homes to be net energy exporters.
To find a good home energy auditor look for a local "Home Performance with Energy Star" program. Here in StL it's run by EarthWays Center.
True or False: One adult American in five thinks the Sun revolves around the Earth. Answer to follow...
True. Sadly. National Center for Science Education study (NY Times, August 30, 2005). An idea science abandoned by the 17th century.
True or False: Many states and the federal govt. have made efforts to stimulate energy efficiency in existing homes. Answer to follow...
False. A few. Yet there are 214 million dwellings in the US, representing a tremendous opportunity since 60% will still be occupied in 2050.
True or False: A single gallon of gas contains enough energy to replace 240 hours of human labor. Answer to follow...
True. Problem is: right now that's considerably more than oil's likely rivals. (R. Heinberg)
Boring engineering type True or False: Heat moves by three methods: conduction, convection, and reflection. Answer to follow...
It's False: convection (liquids,gases), conduction (solids) and RADIATION (space).
T or F: It's more effective to reduce a home's heating/cooling load than to increase the efficiency of its HVAC. Answer to follow...
True: air sealing, insulation, shading, and type and placement of windows. An extremely efficient HVAC can still consume large amount of energy.
We can start by assuming that net zero energy and carbon neutrality are achievable in existing homes here, too. It's happening in Germany.
True or False: The Earth has a carbon-carrying capacity of 10 billion tons per year. Answer to follow...
True. If population reaches 10 billion by 2050, that means 1 ton per person per year. US is currently 20 tons per person per year.
Europe is currently 10 tons per person per year and is actively taking steps to reduce theirs by a factor of ten.
T or F: A mandatory home energy-labeling program has been an important part of Danish energy saving policy since 1997. Answer to follow...
True. Since the beginning of 2006, labeling a home's energy usage has been mandatory for all European Union countries. What gives, US?
All houses (new and used) are rated/labeled before they are sold. Based on results, energy efficiency improvements are then recommended.
True or False: Maybe a heat recovery system could be devised to capture all that wasted hot air from Congress' chambers. Answer to follow...
I wish. The 2007 Energy Bill passed at the end of last year isn't fully funded. We can do better - SOOOO much better.
True or False: Most displays (TV, etc.) are shipped at maximum brightness and consumers never think to reset them. Answer to follow...
Obvious answer. True. An iMac power consumption fell by 30% when its screen was adjusted to a still tolerable level (Home Energy)
Philips introduced a new TV that monitors ambient light and adjust screen brightness, cutting consumption by 1/2 (CNET)
True or False: At the 2008 Consumer Electronic Show the % of products drawing standby power continues to decrease. Answer to follow...
False. Au contraire, products that drew zero power while "off" were the exception. Good news is that many are becoming more efficient.
T or F: Virtually all houses have a couple of BIG problems that, if repaired properly, will truly increase comfort & savings. Answer is...
True. In my experience. You just have to find them. All houses are different and "improve your home" articles go only so far.
True or False: Make your house energy efficient before thinking about installing renewable power in your home. Answer to follow...
Absolutely. Energy efficiency efforts, saving power, is less expensive than installing renewables. Save power before generating anew.
Appraisal Journal found that the market value of a home increases $10-$25 for every $1 decrease in utility bills.
T or F: The architecture & building community is responsible for almost 1/2 of all US greenhouse gas emissions annually. Answer to follow...
True. "Unknowingly", says Edward Mazriak, solar architect. Energy efficient design can counter the climate change threat.
T or F: The average homeowner can save up to 30% off his/her energy bill by making simple energy efficiency improvements. Answer to follow..
True, of course, says Paul Scheckel, energy auditor & author: http://snurl.com/2ghdx [www_amazon_com]
T or F: Air Sealing a home increases comfort, saves energy, reduces effect of outside temp. and limits moisture migration. Answer to follow.
True. It's usually much more effective to seal a home - safely - than to simply just add insulation.
True or False: The U.S. can achieve energy independence. Answer to follow...
Probably not. Besides, it would take years (maybe decades) of foreign energy to build that energy-independent infrastructure.
...while I'm at it, the phrase "energy independence" is often PR code for more drilling.
True or False: The U.S. can become energy independent by planting enough corn for enthanol to replace all our gasoline. Answer to follow...
Unlikely. We'd need to plant 71% of all our farmland with fuel crops. The coupling of food and energy today is unprecedented.
T or F: China uses about 37 million barrels of crude oil each year to manufacture plastic packaging material. Answer to follow...
True; however, as of June 1 the world's most populous country has banned the use of plastic shopping bags.
T or F: Many people, but especially home energy auditors, can accurately estimate the air leakage of a home. Answer to follow...
False. If you don't test - it's just a guess. Most home energy auditors use a blower door (as opposed to tracer gas) test.
T or F: In summer, an average home gains 3-6 x more heat thru heat transmission (e.g., walls) than thru air infiltration. Answer to follow...
True. Heat transmission is the leading cause of summer heat gain (and winter heat loss).
T or F: Heat transfer is slowest through dense continuous materials. Answer to follow...
You know this: False. Good insulators are made of light-weight materials with millions of tiny air pockets.
True or False: The cost to make a home energy efficient is usually more than the cost of purchasing more energy. Answer to follow later...
Generally, true. Energy is cheap short term (here). However, generating new energy is definitely more costly than energy efficiency.
100th Update: True or False: Windows have a relatively high heat transfer rate compared to walls. Answer to follow...
True. Generally. (Except, perhaps, in a solid masonry home) Window U-value: ~.18 to .55; Wall: ~.05 to .09. (Lower is better)
True or False: Comfort and energy efficiency almost always go hand-in-hand. Answer to follow...
True. Makes sense if you think about it. Comfort is consistency of proper air temp and humidity.
T or F: A home's thermal boundary should provide both an insulation and an air barrier. Answer to follow...
True. Insulation stops heat flow. The air barrier stops air flow. The insulation and air barrier must be aligned.
T or F: Using building cavities (such as covered floor joists) as ducts is both common and perfectly acceptable.
False. While this practice is very common, even in new homes, it's often the source of duct leakage to the outside.
T or F: Air leakage around windows is not usually a major source of air infiltration (or exfiltration). Answer to follow...
True. Nevertheless it's still a good practice to foam window to framing joints (new construction) or caulk around the frame (existing).
T or F: In humid climates, air conditioners should run a long time in order to remove that moisture from the air. Answer to follow...
True. Water vapor in the home contains a lot of heat (970 Btu's per equiv lb of liquid water). AC needs time to effectively remove it.
Which is also why nighttime temps usually won't dip below the dew point. All that heat gets released when water condenses.
T or F: A house should be tightened as much as possible. An ideal home would have no air leakage at all. Answer to follow...
True. The ideal is to have complete control over the ventilation rate, by then installing mechanical ventilation.
T or F: Small gaps in insulation significantly compromise that insulation's R-value. Answer to follow...
True. A gap along only 4% of insulation's edge can reduce R-19 to R-13, or 30%. Air movement through/around insulation reduces performance.
T or F. Heat pumps can be more than 100% efficient, providing more energy (in heat) than it takes to run them. Answer tomorrow...
True. How? They only move heat (as opposed to generating heat). They're almost always more than 100% efficient.
T or F: Generally, air leakage in the home overall is more serious than having leaky ductwork. Answer to follow...
False. The air in ductwork is conditioned (thus expensive), and pressurized. It's serious when it leaks to the outside.
T or F: All windows everywhere can be grouped into one of two types. Answer to follow...
True. 1) Those that leak, and 2) those that will leak. Just being silly (or maybe just dumb).
T or F: Stack-induced pressure is caused by the buoyancy of warm air exerting a positive pressure at the top of a house.
True, true, true. That's why it's elementary to seal top of a home first, if required.
Another? True or False: An increase in per capita economic output requires a corresponding per capita energy use increase.
False. Per capita US energy use in 2000 was the same as in '73, while per capita economic output increased more than 70%.
Retweet. T or F? Typical residential buildings use 1.5 to 2 times as much energy as is necessary.
True. Due to lack of insulation, excessive air leakage, and inefficient HVAC and hot water heater systems.
A fun one. True or False: A fan will keep a room cool even when no one is present in the room. And the answer is...
False. Fans only cool people (convection & skin). Otherwise for whatever elec they're using they're essentially a heater (1 watt=3.412 Btu)
Okay, easy one: T or F: Using CFLs for lighting reduces the load on your air conditioner, compared to using incandescents. Answer to follow.
Significantly True. 1 watt=3.412 Btu. Compare 75 watt incandescents to 25 watt CFLs, all over the home & you might just have 1/4+ ton A/C.
T or F: With draft gas water heater in basement, it's more dangerous for a home to leak air at the top (cf the basement). Answer 2 follow...
OK, no takers (or interest), but nevertheless True. Seal home from top down to hinder backdrafting and/or CO spillage.
More: T or F, adding insulation almost always makes a home more energy efficient. Answer to follow...
Yes, yes, yes - false - even with the "almost". Air flow and poor installation compromises insulation, sometimes making it nearly worthless.
OK, T or F: There are usually large air pressure differences at various locations in a home. Answer to follow...
Sorry, false. Let's say 10 Pascals average (raising 1/25 inch of water in a straw). Amazingly, that's significant, sometimes dangerous.
T or F: Ruling out other variables, an air-tight home is more energy efficient than a leaky one? Answer to follow...
True. But, a too tight house is not healthy and often has durability problems. (Think mold.) It's a trade-off with energy efficiency.
True or false: Generally, air quality is better indoors than out-of-doors?
False. Homes should have a complete exchange of air every 2.85 hours. Less = health and durability problems. Most homes are leakier.
