Tag Archives: energy efficient

Wealthier Americans have a larger carbon footprint in part due to larger homes

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Large homes and McMansions do not just take up land and resources at construction; according to a new study, they have larger carbon footprints. Here is the abstract:

aerial photography of gray houses

Photo by David McBee on Pexels.com

Residential energy use accounts for roughly 20% of greenhouse gas (GHG) emissions in the United States. Using data on 93 million individual households, we estimate these GHGs across the contiguous United States and clarify the respective influence of climate, affluence, energy infrastructure, urban form, and building attributes (age, housing type, heating fuel) in driving these emissions. A ranking by state reveals that GHGs (per unit floor space) are lowest in Western US states and highest in Central states. Wealthier Americans have per capita footprints ∼25% higher than those of lower-income residents, primarily due to larger homes. In especially affluent suburbs, these emissions can be 15 times higher than nearby neighborhoods. If the electrical grid is decarbonized, then the residential housing sector can meet the 28% emission reduction target for 2025 under the Paris Agreement. However, grid decarbonization will be insufficient to meet the 80% emissions reduction target for 2050 due to a growing housing stock and continued use of fossil fuels (natural gas, propane, and fuel oil) in homes. Meeting this target will also require deep energy retrofits and transitioning to distributed low-carbon energy sources, as well as reducing per capita floor space and zoning denser settlement patterns.

More from the study linking energy use, wealth, and housing size:

We find that both household energy use and emissions per square meter vary widely across the country, driven primarily by thermal energy demand and the fuel used in electricity production (“grid mix”). ZIP-code level analysis shows income is positively correlated with both per capita energy use and emissions, along with the tendency for wealth and living area to increase together. City and neighborhood analyses underscore the environmental benefits of denser settlement patterns and the degree to which carbon-intensive electrical grids counteract these benefits.

Bigger homes require more energy to heat, cool, and light. Wealthier people can afford these expenses. Indeed, being able to shoulder all of these costs with a larger home may be a form of conspicuous consumption: “I have enough resources to live in a larger home and maintain it.” Critics of McMansions argue that such homes are meant to impress those who see them, not necessarily great spaces for residents to inhabit.

The study also connects the findings to possibilities for making single-family homes more green. The models work with two options: (1) retrofitting homes to make them more energy efficient and (2) reducing power generated with fossil fuels (“grid decarbonization”). Yet, there are other options to pursue that could help with the situation:

1. Promoting the construction of or the inhabiting of smaller homes. This could range from tiny houses to the “not-so-big home” to smart-sizing or down-sizing. This may require more significant lifestyle changes – cutting on consumption would be difficult – that are too hard for many people.

2. Promoting fewer single-family homes. While they are the basis of suburban life and popular in many other American communities, multi-family housing is more energy efficient. Given the rhetoric surrounding suburbs (such as President Trump claiming Democrats want to abolish suburb), this may not be easy.

3. Promoting less energy use within homes. What if residents used less heat, air conditioning, and lighting? What if they watched less TV and used their phones and computers less? Again, this might require large lifestyle changes that many would find difficult.

4. Constructing newer homes with much stricter energy guidelines, perhaps even net-zero-energy homes or passive houses. Even if these are restricted to wealthier homeowners who can afford the changes, this could help limit the energy use of larger homes. Also, if such homes are viewed by the public as cool or desirable, perhaps these features trickle down.

5. Could wealthier homeowners purchase carbon offsets for their homes? This would allow them to keep their bigger structures while providing funds that could be put to good use elsewhere.

The scenarios in the paper as well as the ones I proposed all require working multiple sectors of society to get to a place where homes, particularly large ones, use less energy.

Six elements in a green home

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In order to avoid a greenwashed home, here are some things to look for to identify a truly green home:

?Site planning for the house that is sensitive to the immediate environment, minimizes tree destruction and is strong on managing water runoff.

?Energy efficiency throughout, including high-performance HVAC, lighting, insulation and appliances.

?Exceptional interior air quality through the use of advanced air filtration and exchange systems.

?Extensive use of nontoxic building materials.

?Water conservation efficiencies, such as water-saving toilets and shower fixtures and possibly some reuse of waste water.

?Ease of long-term operation and management.

I would guess most buyers would first think of #2 on the list: efficient lightbulbs, a newer furnace, AC unit, and appliances, good insulation and no obvious drafts or leaks. But, some of these other things are much harder to find, particularly it is an older home. Nontoxic building materials? How many homes – even new ones – have this? And air quality – isn’t this something that is used in the rare passive home? And #6 is interesting: the green features should be relatively to utilize and maintain.

This leads me to several questions:

  1. How many green homes would meet all six of these?
  2. What is the added cost of meeting all 6?
  3. Presumably, some of these six are more important than others. Which ones make for a greener home if you could only have/afford a few?

Expect to see more listings in coming years that emphasize green features.

Bigger American houses limit energy efficiency

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A new Pew report looks at how the growing size of American homes affects energy efficiency:

U.S. homes have become considerably more energy-efficient over the past four decades, according to government data. But homes also are a lot bigger than they used to be, and their growing girth wipes out nearly all the efficiency gains.

According to preliminary figures from the Department of Energy’s Office of Energy Efficiency and Renewable Energy, the average U.S. home used 101,800 British thermal units (Btu) of energy per square foot in 2012, the most recent year with available data. That’s 31% less than in 1970, after adjusting for weather effects and efficiency improvements in electricity generation…

While some homeowners do add onto their existing structures, the trend is driven largely by new construction. According to the Census Bureau, the average new single-family house completed last year was 2,657 square feet – 57% larger than four decades earlier. While the biggest new homes are being built in the South (an average of 2,711 square feet last year), home sizes have grown the most in the Northeast: a 64% increase in average new-home size over the past four decades…

What all of this means is that, after dropping sharply during the 1970s, the overall energy intensity of U.S. homes has changed little over the past three decades. Energy intensity is a metric that compares the amount of energy used against some unit of economic activity – households, in the case of the residential sector.

A logical question at the end of this is to ask what should be done in response. One line of argument would suggest Americans should cut their home size. When they build and purchase larger homes, they use more energy than they probably need to consume. (This is in addition to other arguments against building larger houses.) On the other hand, I imagine some would argue that we will continue to see gains in energy efficiency through technology and this will soon reduce energy use even in spite of larger homes. This second argument may be more appealing to many as then Americans could get even bigger homes and we get to utilize the benefits of technological progress.

American homes are bigger again but now more energy efficient

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A new government report shows American homes are more energy efficient than in the past:

Efficiency gains are offsetting more than 70 percent of the growth in energy use that would result from the increasing size and number of U.S. households, reports the U.S. Energy Information Administration.

In fact, energy intensity—energy used per square foot—was 37 percent lower (or better) in 2009 than in 1980. It meant a reduced use of coal, natural gas and nuclear fuel.

Why this progress? The EIA cites factors that include energy prices, shifts in fuel sources and stricter building codes. It also notes the broader use of more efficient technologies—from appliances and lighting to heating/cooling units, some of which were promoted via energy labeling programs such as the voluntary Energy Star.

That’s the good news. The EIA also gives the bad: “The gains from energy intensity improvements would have been even larger if it were not for consumer preferences for larger homes and increased adoption of home appliances and electronics.”

Two competing interests: trying to reduce energy usage but Americans, when they have the money, tending to purchase larger homes. Progress is being made on the efficiency front but the real gains would come if Americans had smaller and more energy-efficient homes. There are two possible courses of action:

1. Continue to try to convince Americans they don’t need such big homes. This might be done with psychological arguments (smaller homes will fit you better, feel more cozy), shame arguments (that size of space is unnecessary), environmental arguments (you are wasting energy), cost arguments (smaller homes could be cheaper both in purchase price and upkeep), or peer pressure (a smaller home may grant higher status or you don’t want to be the one who sticks out with your extra-large home).

2. Continue to keep improving energy efficiency so that the bigger homes aren’t as problematic. More passive houses? More net zero energy homes? Offer tax credits to improve energy efficiency?

In the short term, I imagine #2 is the most likely path with a small group continuing to work on the arguments of#1.

2.

Exposing Americans to passive houses

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A Chicago Tribune article suggests more Americans would like passive houses if they knew about them:

The idea of passive house design isn’t new. It was first promoted in the early 1990s…

Torres Moskovitz estimates there may be 40,000 certified passive house buildings in the world, but probably fewer than 50 projects in the United States…

The stringent passive house — or Passivhaus — standards and the Passive House Planning Package software were developed by the Passive House Institute in Germany. The U.S.-based Passive House Institute is currently formulating its own standards. The PHPP software incorporates a designer’s calculations and helps design a passive house.

A passive house saves up to 90 percent of space heating costs and 75 percent of overall energy costs, though some European studies indicate the numbers may be even higher…

“People learning about it are so into it, maybe it becomes a bottoms-up approach, comes from the public and then the government has to react to our demand,” Torres Moskovitz says. “There’s definitely interest in the building community, but it has a way to go before everyone understands.”

I think a lot of Americans would be very interested in the cost savings of passive houses. But, they would want to know: if I pay more upfront for such a home, what is the payoff in reduced utility costs down the road? Even if there are significant savings, I imagine these houses are going to be part of a niche market for a long time as more people learn about them and builders learn to see them as profitable options. Perhaps passive houses need some sort of public relations push like a recent initiative regarding public housing?

One way to destroy the planet: “heat a McMansion”

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Heating a McMansion is part of a list of 12 ways of “how to destroy the planet”:

The easiest way to waste extra energy in a large home is to keep the air conditioning and the heater on all the time, and adjust them both up until you’re comfortable. Space-heating makes up nearly half of the average home utility bill.

Heating water uses up more energy than anything other than heating air. For the profligate, that means long showers and always setting the washing machine for whites.

Perhaps this is why there is more interest in energy efficient homes or even net-zero energy homes. This argument would be even stronger if there were some numbers to compare larger and smaller homes. How much more energy does an average 3,000 square foot require compared to an average 1,800 square foot home? Or a 5,000 square foot house versus a 2,5000 square foot home?

One way around this would be to have home sellers include average utility bills as part of the documentation or listing of the property. Think of it like a MPG rating for a car – homeowners should also have the ability to assess the energy usage. Going further, home sellers might also list comparisons to other nearby homes. I’ve seen reports that using smart energy meters that give homeowners comparisons to their neighbors helps reduce usage so why not also make it part of the real estate process?

First passive house in Illinois completed

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The Chicago Tribune profiled a River Forest home that is the first in Illinois to be certified as a passive house:

To earn certification, the house had to pass a third-party audit that included a blower-door test to detect air leaks, a visual inspection to make sure specified products were used, and an air-flow test of the ventilation system to ensure that incoming and outgoing air was balanced.

Including the finished basement, the house has 3,800 square feet plus a detached, two-car garage. That includes three upstairs bedrooms, an open living area plus in-law suite for Corinna’s parents on the main level and a recreational room on the lower level.

The first thing a visitor notices about the Lemas’ house is its 18-inch-thick exterior walls. They contain the key to keeping the house airtight — Logix insulated concrete forms, which are Lego-like panels of concrete and foam. Outside of that is a 2-inch rigid foam layer, an air cavity and SmartSide engineered wood siding…

The Lemas figure they spent about $175 per square foot on the house, including site work and demolition of the house that used to occupy the property. That is on par with custom residences that are not passive houses, said Bassett-Dilley.

Interesting article though I wish more time was spent on the process of building the home, such as passing inspections and hearing from neighbors, rather than the particular pieces that went into the home.

While this is the first passive home in Illinois, I wonder what the resale market for such homes might look like in the near future. Is there a premium homesellers can ask for since such homes are rare?

Also, I have read a number of articles about such homes but haven’t really seen anyone discuss possible downsides. What happens if the air exchanger, needed to bring in air since the house is so sealed, goes out? Are there longer-term issues that come up amongst homeowners in such houses?

Dome sweet dome?

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Wired points to a recent Toronto Star article about the financial and environmental benefits of dome-style housing:

It’s earthquake-proof, tornado-proof, fireproof, can be buried into a hillside, and it’s impervious to insect and animal attacks.

Cost efficient, easily maintained, earth-friendly and extremely endurable….While typical new homes exceed an EnerGuide rating of 65 to 70 [link], high energy-efficient homes can push over 75, and R2000 houses can exceed 80, an Ottawa dome house hit 88 when constructed in 2006.

According to the article, the main problems with constructing a dome home are the local regulators and lenders suspicious of its current novelty:

[Collin] Cushnie and [Sunny] MacLeod [of the Great Lakes Dome Co.] realize that widespread appeal will only come through acceptance as an alternative to “stick and bricks” construction. In fact, they usually have to coach the local building inspector and mortgage holder for approval.

One common complaint leveled against McMansions is how “tacky” and “ugly” they are.  Given all the benefits of dome housing (environmental and otherwise), it will be interesting to see if domes can overcome similar perceptions and achieve widespread acceptance in the marketplace.