Light Bulb Cost Comparison

I did a presentation at the Garlic and Arts Festival in Orange Massachusetts this past weekend on home energy efficiency. For it, I prepared a slide comparing light bulb costs. The title of my slide on the topic became “Congratulations LED’s! You Did It!” Why? On Amazon, you can now by LED’s that are so cheap that they pay themselves in about 6 months! Here is a chart that shows off all the details:

Bulb Comparison 10/14 Cost of one bulb no shipping Watts Cost to run for 1 year Savings per year if replacing an incandescent bulb When replacing an incandescent, Pays for itself in… (months)
GE Incandescent (Amazon 4 Pack) $1.00 60 $14.89
 GE CFL (Amazon 8 Pack) $1.38 13 $3.23 $11.67 1.4
TCP LED (Amazon 6 Pack) $6.64 10 $2.48 $12.41 6.4
Philips LED (EFI Single Bulb) $12.95 11 $2.73 $12.16 13
Cost for one year assumes 4 hrs per day and cost of electricity .17 cents per kW

A PDF of the above chart with even more details including color temperature (all about 2700 K), lumens (all about 800), and dimmability is available here: Light bulb cost comparison.pdf

I can’t speak to the TCP bulb’s attributes personally so I included the Philips bulb which I love. I have about 20 of them in my house.

Light Bulb Comparison


America’s First Super-Insulated Buildings

America’s First Super-Insulated Buildings
In the 1800’s and into the early 20th century we used to get our refrigeration done using ice–including during the summer. Ice was harvested and stored in specially designed buildings and then distributed/used as needed. I recently happened across a thorough article on the topic in the journal of Early American Industries: The Chronicle Vol 66 #4. There is much interesting history in the article, but the relevant part was about the specially designed buildings. They were often made with none other than double stud walls with 10-12″ off sawdust insulation. In other words: cellulose! For those that are just starting to read this blog, our super-insulated home is exactly that: double stud, 2×4 and 2×4 walls, with 12.5″ of dense packed cellulose.  I thought we were on the forefront of super-insulation design by having such a wall system, but we are actually implementing designs that are over 100 years old!

The author of the article, Paul Wood, in addition to fielding questions, kindly sent me high resolution images of plan and layout designs for a typical farm (non-commercial) ice house. The images, shown below, are from The October 1914 Vermont Department of Agriculture Bulletin. Here are some of my observations of the assembly:
– The double stud wall has a 4″x10″ bottom plate, with 2 sets of offset 2×4’s connected and spaced with a single horizontal 2×4 roughly mid-way between the top and bottom of the balloon framed studs.
– The exterior sheathing consists of a single layer of 7/8″ tongue and groove boards faced with “waterproof insulating paper” and sided with novelty siding or similar. The interior is sheathed with 2 layers of 7/8″ tongue and groove boards sandwiching similar paper. Unfortunately, I am unable to provide any insight into what the composition of what this insulated paper might be. Perhaps it was simply tarred felt paper? The double layer of interior sheathing is interesting; perhaps this was just to protect the insulating paper?
– I was surprised and impressed to see that triple pane glazing was used!
– There is a sophisticated appreciation of air flow and drainage.
– “Tarred Felt” was extended vertically part way into the top of the stem-wall–a detail whose purpose I am not sure of.
– Although the diagrams below show more sawdust used for horizontal insulation above the ice, Paul Wood informs us that marsh grass, and occasionally straw, up to 24″ thick, was commonly used directly on top of the ice. Marsh grass was preferred for its rot resistance. I wonder if there is a lesson here that would be worth re-learning? Folks who are interested in natural building and straw-bale design need to be vigilant in protecting the bales from decay–perhaps marsh grass bales would be a useful alternative?
– Noted in Paul’s article and not on the diagrams, white-wash was sometimes used to keep the ice-house buildings cooler. Also, the sawdust would have to be replaced annually, since it would degrade.
Click on images for high-res versions

Early super-insulated design ice house

Layout and Iso-view of Ice House

Ice House Plan view 2

Plan view and assembly details of ice house. Note attention to ventilation and drainage.

Icehouse construction plan view 1

Another plan view of the ice house.

VT Dept of Agric Bulletin Cover

1914 Vermont Department of Agriculture Bulletin Cover

Back draft dampers

In our post a couple of years ago on thermal imaging of our home, we noted that we were losing quite a bit of heat through our 2 bathroom fans. In fact, if one were to put one’s hand next to the fan (while off) you could feel cold air coming right on in. While surfing the web for a solution I found these retrofit back draft dampers:

Aldes 4" Retrofit Backdraft Damper

Aldes 4″ Retrofit Back-draft Damper

Installing one in the first floor bathroom fan was easy since the duct-work was exposed in the mechanical room. After putting one in the duct, I was, however, disappointed to still feel cold air coming through the damper, primarily through the hinge. I have seen some models where the hinge is taped, and I considered adding tape myself, but I was worried that the tape may not last/or actually cause problems. Instead, I put two dampers in the duct, which satisfactorily blocked the flow of cold air.

The second floor bathroom fan duct-work is permanently not accessible so I removed the fan from its box exposing the beginning of the duct. This was challenging only because the fan is 12′ up on a cathedral ceiling.

The downstairs bathroom went from being drafty and cool to being the warm interior space you would expect. The fans make a bit more noise as a result of the added air resistance, but I am not too worried. The Panasonic fans have variable speed motors in them and are designed to compensate for duct-work resistance.

I would recommend these dampers to anyone who is looking for easy improvements to their home’s energy efficiency. I bought mine from IAQ Source which seemed to have a better price than most. If you are building new, it would be cheaper to use an in-line backdraft damper like Fantech’s which also wouldn’t restrict the air-flow as much.

Fresh indoor air with plants

Spider plant (Chlorophytum comosum) Snake PlantAzalea (Rhododendron simsii)Chinese evergreen (Aglaonema Crispum 'Deborah')

Remove VOC’s and improve indoor air quality with these 15 plants! Full article describing which toxins  are removed by which plant and some tips about caring for each type of plant at Mother Nature Network

  1. Aloe Vera
  2. Spider plant (Chlorophytum comosum)
  3. Gerber daisy (Gerbera jamesonii)
  4. Snake plant (Sansevieria trifasciata ‘Laurentii’)
  5. Golden pothos (Scindapsus aures)
  6. Chrysanthemum (Chrysantheium morifolium)
  7. Red-edged dracaena (Dracaena marginata)
  8. Weeping fig (Ficus benjamina)
  9. Azalea (Rhododendron simsii)
  10. English ivy (Hedera helix)
  11. Warneck dracaena (Dracaena deremensis ‘Warneckii’)
  12. Chinese evergreen (Aglaonema Crispum ‘Deborah’)
  13. Bamboo palm (Chamaedorea sefritzii)
  14. Heart leaf philodendron (Philodendron oxycardium)
  15. Peace lily (Spathiphyllum)

Monitoring for our PV System

WMECO gave us permission to turn on our PV system on October 23rd, so we have been creating solar power for 9 days now. Today, we hit the 100 kWh mark. That averages to 11 kWh per day, which is also our average daily usage throughout the year.

One of the great things about using a system with micro-inverters is that you can monitor each panel individually. Here is a screen shot from Enphase’s monitoring software for our system.

 PV monitoring screen shot Enlighten Enphase

The numbers on each panel represent the sum total of the past 7 days of power creation. You can see that the panels on the left are slightly lower than those on the right. These are the ones closest to our favorite silver maple tree. The “hole” in the middle of the system is where the solar hot water panels are.

Data logging! Average energy for cooking.

So I feel incredibly nerdy right now because I am very excited about the information that we are gleaning from the data loggers in place around the house. One of them, a TED 5000 installed May 2013, has been monitoring the electrical consumption for our cooking, which we do a lot of. Our stove is a standard glass-top. We now have a pretty good sample of time (mid-April through mid-October) including “canning season”. In an effort to create a more detailed picture I isolated the canning period: September 1st through October 4th.

  • Average energy consumed per day (non-canning season): 1.27kW
  • Average energy consumed per day (canning season): 3.35kW
  • Extrapolating out we can expect to use 535 kW/year cooking and canning, and, based on last year’s total electricity usage, this would be 13% of it.
  • The cost for electricity for us has been around 18.5 cents/kW so we can expect to spend about $100 per year cooking.
  • We spent an estimated $13 on energy for canning (70kW)

The TED 5000 is also monitoring our air source heat pump, which has pretty much been off since May. We used it for a total of 12 days this summer 11 of which were in June and 1 in September. A total of 35.7 kW was consumed at a cost of $6.60. Eventually I will get around to calculating how many Btu’s the heat pump is putting in (or taking out of) our home. This requires knowing how efficient the heat pump is at various outdoor temperatures, and what the outdoor temperatures are on, I would imagine, at least an hourly basis.

Speaking of the outdoor temperature brings me to more exciting news: we just purchased two more temperature loggers! Last winter I moved our one logger around the home which left us with no perspective when viewing the data. Going forward, we will be able to compare outdoor temperature to first to second floor temperature data. The outdoor logger is out of the sun about 8′ from the west side of the house and 4′ off the ground. The second floor logger is in our master bedroom.

Now that we have data logged our cooking use, I will be switch over to monitoring our refrigerator. Stay tuned!