CFL Light Bulbs

CFL or compact fluorescent lamp light bulbs are pretty typical these days. A CFL bulb is made up of a ballast and a tube containing gas. The ballast turns the current from the wall outlet into high frequency current, which it sends into the gas tube. The high frequency current knocks excites electrons in the gas, causing them to produce ultraviolet (UV) light. When the UV light hits the fluorescent coating on the glass tube it produces visible light.

CFL light bulb
Light Bulb” by Pedro Lozano CCBY

Let’s compare CFL light bulbs directly to the pro and con list I put together last week about incandescent bulbs:

  • Light Quality: Mixed Reviews. The light quality can be all over the board with different brands of CFL light bulbs. We’ve grown accustomed to the warm, soft light produced by incandescent bulbs, and in comparison, some brands of CFL bulbs can produce cold, harsh light. However, many brands have improved their designs to provide warm light just like incandescent bulbs. You may have to shop around a couple brands to find the light quality that meets your expectations.
  • Price per bulb: Pro. While more expensive than filament bulbs, you can pick up CFL bulbs for around $2 per bulb.
  • Availability: Pro. You can get basic CFL bulbs pretty much everywhere you can get filament bulbs these days.
  • Style: Con. While CFLs fit pretty much any standard light bulb socket, you’ll have trouble finding specialty shaped bulbs of the CFL variety.
  • Energy use: Pro. A CFL bulb that produces a comparable amount of lumens as a 60 watt filament bulb requires only 14 watts.
  • Lifetime: Pro. 8000 hours! Which translates into about 7 years of burning for 3 hours a day.

And one more important point to consider when using CFL bulbs:

  • Toxicity and Disposal: Con. The gas inside the CFL tube contains mercury which is hazardous to come in contact with. This means you have to be careful not to break open the tube, and you really should not just be disposing of a CFL bulb in the trash. Used CFL bulbs should be disposed of by bringing them to an appropriate drop site for safe disposal.

If you’re looking for a disposal site near you, you can check out

So the tally when comparing CFLs to Incandescents is 4 pros, 2 cons, and 1 mixed review. Now let’s look at the long term cost.

10 year cost for burning filament bulbs in one lamp: (3 hours a day, $0.12/kwh cost of electricity, $2.00/bulb, 2 bulbs) = $22.40.

Pretty cheap when compared to the $96.84 it would cost to run the same light with a incandescent bulb.

Incandescent Light Bulbs

Shortly after we moved one of our lamps burnt out. The light bulb was the last of an old 6 pack of filament lights that we finally used up. For a while now, one of the items on our green living to-do list has been to upgrade to LED light bulbs, but since I already had that old pack of filament bulbs, we had to use those up first. Because one of our rules is use what you already have first.

So I ordered a 6 pack of LED lights. Maybe overkill considering we only have 2 lamps and these things have a 10 year guaranteed life. Real talk: sometimes I let the discount for buying in bulk counteract our desire to have less stuff. I need to work on that.

Anyhow, today I’m going to do a compare and contrast on the three most common types of light bulbs, so that next time you need to replace one, you can make the best choice.

Incandescent Light Bulbs

I mean, let’s hand it to Thomas Edison, this design for an electric light bulb has been around since 1878. Edison wasn’t the first to make a bulb that used a filament – about 20 others had done so with varying degrees of success starting in 1802 – but Edison’s design using a carbon filament had a long life and was the one that took off commercially. Filament lights work by passing an electric current through a material known as the filament. Today, filaments are typically made of tungsten.


  • Light Quality: Incandescent light bulbs produce the warm, soft light we’ve come to expect from our lamps.
  • Price per bulb: Incandescent light bulbs typically cost about $1 – $2 per bulb
  • Availability and style: You can easily pick up a filament light bulb at a grocery store, convenience store or hardware store. And you can get a wide variety of sizes and styles. If you have a chandelier that takes specially shaped bulbs, they are most likely going to be Incandescent light bulbs.


  • Energy use: A standard 60 watt incandescnet light bulb produces anywhere from 600-800 lumens. Lumens are the unit that the amount of visible light is measured in. As suggested, to do this it takes 60 watts of electricity flowing through the filament. Newer, more efficient filament bulbs claim to produce the same amount of lumens using about 45 watts, but that is still significantly more energy than other light bulbs require.
  • Fragility: Filaments are rather delicate things. If jostled too strongly, the filament can get dislodged or break without even being lit.
  • Lifetime: A 60 watt bulb will burn for about 985 hours. This translates to around 11 months of use if lit for 3 hours each day.

10 year cost for burning incandescent light bulbs in one lamp: (3 hours a day, $0.12/kwh cost of electricity, $1.50/bulb, 12 bulbs) = $96.84

You can find my report of the pros and cons of CFL light bulbs here, and LED light bulbs here to see how Incandescent light bulbs measure up.

About LEED certification

Have you ever walked into a building that has a LEED certified sticker on its door and wondered what exactly that means? Well, today I’m going to give an overview on LEED certification.

What is LEED

LEED, or Leader in Energy and Efficiency Design, is a certification program for buildings. The program was designed by the US Green Building Council (USGBC), and provides a rating system that certifies how environmentally friendly a building design is.

What can be LEED certified

The building can be certified in terms of design, construction, or operation. Neighborhoods and homes can be certified as well. In fact there are five different certifications based on the type of project:

  1. Building Design and Construction
  2. Interior Design and Construction
  3. Building Operations and Maintenance
  4. Neighborhood Development
  5. Homes

New construction, remodels and already existing buildings can LEED certified.

What is the LEED certification based on

Certification is based on the number of points that a building project earns in evaluations. Projects are scored out of 100 possible points. The points are earned across 6 categories: sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, and innovation in design. A building that earns 40-49 points is Certified, 50-59 points is Silver, 60-79 points is Gold, ad 80+ points is Platinum.

How does a building get LEED certification

First of all, in order to be LEED certified, a building or building project needs to apply for evaluation – The USGBC isn’t just going around to all the buildings and evaluating them willy nilly, it is an opt in certification that demonstrates the owner, and the architect, designer, and construction team’s dedication to green and sustainable building. When a building project has applied for certification the team then pursues various objectives in the 6 categories in order to earn points.  Credential holders who are trained in the LEED certification categories and goals perform an evaluation of the project throughout the building process, and submit the scores for certification.

Passive Cooling through Ventilation

Windcatchers near the Amir Chaqmagh Mosque Complex
Windcatchers near the Amir Chaqmagh Mosque Complex” by reibai CC BY

Our ancestors came from hot climates, so we’ve been working on keeping the shelters we live in cool for ages.  There are a number of different ways to accomplish this, and today I’m going to write specifically about ventilation. Moving air is incredibly effective at cooling – especially at cooling people -because it helps sweat or other water evaporate. Think about it, have you ever been sweaty and stood in front of a fan? You cool off quickly, even to the point of getting a chill as the moving air evaporates your sweat.

Here are four methods of ventilation that are used around the world to help keep our homes and other buildings cool.

Cross Ventilation

Cross ventilation relies on wind moving through a space. You’re probably already familiar with the fact that if you open two windows across the room from each other, you are going to get a better breeze through a space than if you only open windows on one side of a room. Because of this, open floor plans can be great for passive cooling through ventilation. An important factor to note is that the two openings – the inlet and the outlet – should be of equal size, or the outlet should be larger for optimal air flow.

Stack Ventilation

Have you ever noticed the slated window on the top level of a house? This is a gable vent, for stack ventilation. Hot air rises and escapes through these openings. As it does so, it causes a pressure difference between indoors and outdoors, and this causes cool air to be drawn into a house through vents strategically placed near to the ground.

gable ventilation
Untitled” by Wonderlane, CC BY


Some Indian architecture makes use of a lattice screen called a jaali (or jali). The Jaali will often be placed lower to the ground to allow cool air to enter a room, and the lattice screen provides diffused light, while also providing privacy. They are quite beautiful as well.

jaali for ventilation
Jaali” by Nagarjan Kandukuru, CC BY


Traditional Persian architecture often makes use of a structure known as a windcatcher (other names include shish-khan, a badgir, or a malqaf). When used effectively, windcatchers are able to cool a room enough to keep water at near freezing temperatures throughout the summer months. A windcatcher is a raised tower structure, typically on the roof of a building. It may have 4 or 8 sides, and has openings on 1, all 4, or all 8 sides, depending on typical air patterns in a location.   A windcatcher can work in three different ways. It can, as it’s name suggests, catch wind and direct it downwards into a room. It can also function as a solar chimney, allowing hot air to escape, cause a pressure gradient, and pull in cool air. In a climate that has a diurnal cycle – hot days and cold nights – this is especially useful. When paired with good building materials such as adobe, a windcatcher can keep the inside of a building quite cool. Thirdly, it can be paired with an underground canal. The windcatcher will pull warm air upwards, and with properly placed inlets, pull air in along the ground-cooled water. The water will cool the air, and the now cooled air will be pulled throughout the structure.

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Pre-construction passive heating

Since my post on passive lighting got a little unwieldy (900+ words! Who has time for that?) I decided to break this post in two in hopes of avoiding another monster post. So today I’ll be covering passive heating from the perspective of what should be done before or during construction of a building.

I know, I know, it’s the beginning of July, and probably the last thing you want to think about is keeping your house warm. But it might be better to think about this sort of thing now than in the middle of January when you open your heating bill. In fact, you might still be recovering from the number those polar vortex heating bills did on your budget this past winter. So I propose that it’s always a good time to think about how you can more efficiently (and cost effectively!) heat your home.

Passive heating ultimately comes down to two goals:

  1. Capture heat from the sun.
  2. Seal up your building so the heat doesn’t escape.

Just like with passive lighting, before construction begins is the best time to start thinking about passive heating. Some forethought on position and building materials can save all sorts of heat energy down the line.


The goal when siting a building for passive heating is to put the broad side of the building in direct sunlight. Here in the northern hemisphere, that means the south side of the building should be the broadest side. The west side is also a good choice because the afternoon sun is stronger and hotter than the morning sun.

Windows, Walls, and Floors, oh my

So, now that you’ve set up the position of your building to soak up the sun, you need to get that heat from the outside in. This can be done by putting nice big windows on the sunny side of your building. Some types of window glass are better at allowing heat to pass through them than others. For passive heating, look for a solar heat gain coefficient (SHGC) of 0.6 or higher.

And once the heat is inside, you want to hold it there. Flooring and wall materials such as concrete and tile are great at holding onto heat (this is called a solar mass). So put a tile flour under your big southern window.  And build that southern wall with bricks or concrete blocks.

Side note: In our neighborhood in Detroit, we often saw that flowers planted beside a brick building were among the first to pop up in the spring – the bricks held onto enough solar heat to convince those seeds to germinate a bit earlier!


Insulate. Insulate. Insulate.

Insulate more than the minimum recommendation. Insulate on the outside of the thermal mass (because you want to keep that heat inside!). Remember, heat rises and wants to dissipate into cold air, so insulate your roof especially well, and your north wall too.

So there you have it, three main areas of consideration when it comes to construction and passive heating. If you’re planning on getting your house re-roofed this summer, take some extra time to check the quality of your roof insulation, and add some more!

Are you looking for an introduction to passive design? You can find it here.

Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!

Passive Design for Lighting

One immediate way that we can cut our CO2 emissions is to just use less energy. Since our homes and other buildings are huge energy users they are good places to start. By using passive design practices, we can build and maintain more energy efficient homes by using energy from the sun or the ground instead of energy from the grid to serve our needs.

Natural Light and Proper Siting

Using the sun to provide most of our light can reduce the amount of electricity we use and can save money – both on our electric bill and in the cost of light bulbs.

The best time to think about using natural light in place of electric light is before construction. At this point, thinking about window placement can provide a building with adequate light for much of the day. In the summertime, well placed windows and an open floor plan can provide for plenty of light well into the evening hours.

To this end, siting a house properly can be very effective in providing natural light. We often think that the face of a house must be parallel to the street, but depending on the direction that the street runs, this may not be the best position for the windows and the walls. Taking into account the cardinal directions and the angle of the sun throughout the year can help determine the optimal position of windows to take advantage of natural light.

Continuing in this vein, thinking about the layout of the rooms in relation to how and when they will be used during the day before building can help optimize the use of natural light in a structure after it is built.

South facing windows

South facing windows are the workhorse of passive lighting in the northern hemisphere (in the southern hemisphere it would be north facing windows). Because of the tilt of the earth’s axis, in the northern hemisphere the sun is angled to the south. A south facing window, then, receives light throughout the whole day, not just in the morning or evening. South facing windows are put to best use in rooms that will be used all day long.

East facing windows

East facing windows receive the strongest light in the morning, and thus are best positioned in rooms that are primarily used in the morning through late afternoon, such as an office. If you are an early riser, you may prefer to have east facing windows in your bedroom. However you may not want east facing windows in a nursery if your baby wakes with the sun, or in your bedroom if you prefer to snooze a bit later in the morning or work the night shift.

West facing windows

West facing window are pretty much the opposite of east facing windows when it comes to lighting. (I’ll get into the differences in the heating and cooling sections of this series.) They are best positioned in rooms that are used in the evening, as they will provide the most light during the later part of the day. I do a lot of cooking in the evening, so I prefer to have a kitchen with western facing windows.

North facing windows

Due to the earth’s tilt, northern facing windows will receive the least amount of sunlight, and thus are useful in rooms that are used primarly during the middle of the day, or in rooms that are meant to be kept darker. An office might be the right choice for a room with north facing windows. Or maybe this means that depending on your sleep habits and preferences, north facing windows would work well in your bedroom. If you are building a basement cellar and your basement has windows on all four sides, choosing the north wall to build your cellar against makes the most sense.


Skylights can go a long way to lighting a room in the middle of a house. Depending on the direction they are positioned, the pitch of the roof they are installed in, and how far north or south the building is, they will provide different amounts of light during the day or evening.

So directionality and placement of windows is something that can be considered before a structure is built, but afterwards can be quite costly to change. Here are a couple examples of what can be done to improve passive lighting in your already built home or business:


Using sheer and light colored curtains during the day can allow light into a room while still providing a bit of privacy. They can also help temper the strong rays of a rising or setting sun on east and west facing windows.


Well placed mirrors can help spread light into darker areas of a room or into a windowless hallway.

Wall paint

Light colored paint will reflect more light around the room, whereas darker colors will absorb more light. So if you are partial to bold wall color but don’t want to greatly reduce your ability to use passive lighting, put the color in a room with south facing windows or with windows on multiple sides. Dark and light colored flooring can be used to the same effect.

Are you looking for an introduction to passive design? You can find it here.

Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!

An introduction to energy efficiency through passive design

The building industry uses about 75% of electricity production in the US. This means that if we can make our building-related-energy-use more efficient we can make a big dent in the amount of electricity that we need to produce, and thus make a dent in the amount of greenhouse gas emissions we are releasing into the atmosphere by burning coal and natural gas to make electricity.

Energy efficiency in our homes can come a few different forms, but for the next few weeks I will be focusing specifically on energy efficiency through passive design. To start, let’s break it down. Energy efficiency means using less energy to achieve the same ends. In terms of buildings, I am going to focus on are lighting, heating, cooling, and water use efficiency. Passive design is when a building is built in a certain way so that you don’t have to use energy to save energy. For example, using sunlight to light a room is a passive design element because the sun is already there. You don’t have to add any energy into the system (the building) to produce light. Using an LED light bulb to provide light is an active design element because, while you are using much less energy than a filament bulb or CFL, you are still adding energy to light the room with the LED.

As you might guess, the best time to incorporate passive design elements into a building is before it’s even built. But there are some things you can do to an already existing structure to make it more energy efficient through passive design. I’ll be sure to cover both areas as this series continues.

As always, if you have any questions up front about passive design, send them my way and I’ll do my best to answer them as we go.

Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!

Energy Round Up

I hope that over the past couple months I’ve helped you’ve gained a greater understanding of all the ways that we make electricity. To sum things up, I’ve put together a little chart to help compare and contrast the various energy sources we use.

current % in USA potential supply based on current use $/kWh cost of power plant average lifespan notes
conventional fossil fuel 67% known coal reserves will last ~200 years 0.02-0.05 $1 billion per plant 30-40 years produces ~40% of total CO2 emissions
clean coal / carbon sequestration 0% known coal reserves will last ~200 years 0.08-0.12 $5 billion per plant 30-40 years long term storage of CO2 has many unknowns
nuclear 20% 230 years with current technology at current production rate 0.03 $5-6 billion per plant 50-70 years containing and cooling radioactive material is an ongoing challenge
hydro 7% 16% 0.03-0.05 $2-3 billion per plant 50-100 years low cost and low mantenance, but disrupts ecosystems and communities that rely on the river
geothermal less than 1% 7% 0.01-0.03 $2-4 million per MW 30-40 years location matters; deep drilling is difficult and expensive; earthquakes
wind 4% 20% 0.04 $1-2 million per MW 25 years wind can be unreliable; best location is rural, but requires good transportation of electricity
solar 0.2% all of it forever and ever, or at least until the sun explodes 0.12-0.17 $4-6 million per MW 20-40 years efficiency, cost, and waste need to be improved

Just about 2 weeks ago the EPA released it’s preliminary regulations for CO2 emissions for electricity production. These regulations will be a good step in the right direction for America, one of the top most countries producing CO2. Making the changes necessary to cut our emissions will come with growing pains for sure. There is no one right answer to slowing or halting global climate change. Instead we need to use all of our tools, and that means it is important for us to know what tools we have.

The fastest way we can cut the CO2 emissions that come from electricity production is to use less electricity, and use it more efficiently. In that vein, in the coming months I’ll be exploring energy efficiency, and in particular passive design. Stay tuned!

For an introduction on sources of electricity, look here.
For an explanation of how we make electricity, look here.
Clean Coal
Nuclear Energy
Wind Power
Geothermal Electricity
Solar Power part 1
Solar Power part 2

Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!

Solar Power part 2

learn all about solar powerWhat Solar Power is:

Solar power is electricity made from the sun’s energy that reaches the earth. Fun aside: wind power, fossil fuels and biofuels are all ultimately made from the sun’s energy. But only solar cells directly change the sun’s light into electricity.

How Solar Power is made:

See Solar Power part 1, The basics: light from the sun hits a semiconductor and provides enough energy to make free electrons jump.

How much of our current electricity is produced by solar power:

In 2013, the US used over 8,000 MW hours of solar electricity. That is about 0.2% of the total electricity in the US.

Potential energy supply:

In one year, the entire world uses about 15 terawatts (a 15 followed by 12 zeroes) of electricity. That’s the same amount of sunlight that hits the earth in one hour. In other words, enough sun light hits the earth in one hour to provide electricity for everyone for one year! However, the challenges are collecting this energy, turning it into electricity, and storing it for use when needed (and not just when it’s sunny outside). But there is hope, Germany just reported producing 74% of their energy from renewables, and solar power played a large roll.

Materials and how we get them:

Solar cells are made of silicon crystals and silicon is the most abundant element on earth. However, it is almost always bound to oxygen in a molecule commonly called “sand” or “quartz”. We use electricity to get rid of the oxygen. The silicon is then heated and stretched like taffy. This stretching  draws impurities to one end. The impure end is removed and the remainder is pure enough to make solar cells. The pure silicon is then made into single crystal wafers and other elements are added.

Silicon is very shiny and reflective, which is not useful for collecting light. Titanium dioxide is used to help the silicon absorb more light.  Titanium dioxide is mined throughout the world.

The cells are sealed into rubber, put into an aluminum frame, and covered with a glass or plexiglass protective sheet.

Waste produced and how we deal with it:

Creating silicon wafers for solar cells is quite energy intensive because of the need for purity. A lot of heat and electricity is used in the process, which does produce carbon dioxide. Additionally, the manufacturing process makes industrial sludge and toxic waste, which need to be trucked to waste management sites for cleaning and containment.

Solar power produces no carbon dioxide after the cells have been made. However, the industrial wastes and CO2 produced during manufacture of the solar cells are siginificant. It is important for us to pursue cleaner and better managed outputs, as well as producing cheaper,  more efficient solar cells.


Large scale solar power plants currently produce electricity at the cost of about $0.12-$0.17 per kwh to the customer. The cost of installing solar panels onto the roof of your house is typically about $7-$9 per watt. A 5kW (the typical household consumption) array costs about $30,000. The good news is that it is estimated that solar will cost the same as fossil fuels within the decade. However, we need to act now to start combating our use of fossil fuels.


As I’ve mentioned above, cost and waste are both currently challenges to solar electricity. These challenges will be addressed by making solar cells that can more efficiently turn light into electricity. Currently, solar cells are able to convert about 20% of sunlight into electricity. Nearly 45% efficiency has recently been achieved by researchers in Europe. Being able to mass produce solar cells with that much efficiency will drive down the cost and reduce the number of solar panels needed to produce the amount of electricity that we use, reducing waste as well.

For an introduction on sources of electricity, look here.
For an explanation of how we make electricity, look here.
Clean Coal
Nuclear Energy
Wind Power
Geothermal Electricity
Solar Power part 1

Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!

Solar Power part 1

solar power photovoltaicsBecause the way we create electricity from solar power is completely different from all the other electricity generation I’ve written about, I’m going to break this topic into two parts. Today we’ll cover the science of how we make electricity from sunlight.


Photovoltaics or solar cells, are what we use to change the light from the sun into electricity. Solar cells are made of a semiconductor material, typically silicon. The silicon contains a small amount of phosphorus mixed into the crystal structure. This phosphorus provides free electrons. The light energy from the sun moves these free electrons. And voila, give the free electrons a pathway to move through and you have made electricity.

The trick is to get enough of those free electrons moving and to get them moving further.

Electrons move different distances depending on the energy in light that hits them. Light is composed of various wavelengths which which each have a different amount of energy. We see the wavelengths as different colors, electrons see the wavelengths as different distances to move. With solar power, we want to catch all the wavelengths of light, and we want it all to make the free electrons move. We also want the electrons to move as far as possible because this will produce the highest voltage. Using both low and high energy light is difficult, and so the structure of the semiconductor must be very well designed and controlled. As you might guess, this is a difficult and expensive process. Making even a slight increase in solar power efficiency represents a huge breakthrough in science.

If you’re interested in learning the more detailed science of solar cells, this article is a great place to start.

For an introduction on sources of electricity, look here.
For an explanation of how we make electricity, look here.
Clean Coal
Nuclear Energy
Wind Power
Geothermal Electricity

 Oh, hey, Building Earth has a facebook page now.  Keep up to date on posts and other interesting green news by liking us!