Category Archives: energy

The Energy Efficiency Project: Month 3

energy efficiency project month 3

February 12th – March 11th, 28 days

This month we continued to paint and started building some bookshelves.  We also hosted a first birthday party and started getting ready for our upcoming outdoor projects. We were splitting our time between the house and our apartment in the city during this month, so the house was using minimal maintenance energy while we weren’t in it. For example, the furnace was set just high enough to keep our pipes from freezing while out of the house, and really only the fridge was using electricity most of the time. So this month won’t be the best representation of our energy use, but will hopefully serve as a good reminder to put your house into low-energy-use mode when you’re gone for extended periods of time. As far as energy efficiency initiatives went we:

  • Replaced a frequently used lamp’s CFL light bulb with an LED bulb. (The CFL bulb was still good, so it will be used to replace a bulb down the line when I run out of LED bulbs.)
  • Turned the thermostat down to about 55° while we were out of the house.
  • Made sure that all lights and other electricity users aside from the refrigerator were off while we were away.

This month’s upgrade cost: $8.82

Total upgrade cost to date: $17.64

Over 28 days we used 301 KWH. Which comes out to an average of 10.75 KWH/day. Which is an expected decrease from the last billing period average of 14.2 KWH/day since we spent so much time out of the house.

We are part of the Alliant Energy Second Nature renewable energy program, at the 100% level. (In this program you can choose the amount of your energy use that you want to be matched in renewables, and we chose 100%.) So the cost of our electricity is $0.13 per KWH, for a total of $39.41.

We also used 73 Therms of natural gas heat energy. Which averages out to 2.6 Therms/day. That’s only 0.1 Therm less per day than the previous month! Even though much of the month the furnace was only heating the house to 55°, this month was much colder than the first two months of the year. Looking at this, I’m very glad that we made sure to turn down the thermostat every time we left the house, or we would have had a much higher gas bill. Also, looking at degree days this month compared to last month: 1383 vs. 1286. Our furnace was working hard this month!

The natural gas market fluctuates in Wisconsin, so there is not an easy dollar per Therm number to give you, but during this billing period we paid $60.09 for our gas use.

Our energy bill also provides these numbers for helpful comparison:

Electricity used this month last year: 714 KWH

Gas used this month last year: 73 Therms. Average temperature this month: 16° F. This month last year: 19° F. I’m going to assume that the previous owners lived in the house for the full month last year – rather than just part time like we did – and kept it at a typical 68-72°. So it’s interesting to see how just a few degree change in average temperature really makes the furnace work a lot harder to heat the house.

Degree Days this month: 1383 vs this month last year: 1342. Degree days are the number of degrees below 65° F in one day, all added together for the total 28 days of the billing period.

Want to previous months of the Energy Efficiency Project? Here is Month 1 and Month 2

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The Energy Efficiency Project: Month 2

January 13th – February 12th, 30 days

This month we mostly spent our time picking paint colors, getting started with the painting, figuring out where our stuff should go, and getting our compost started. As far as energy efficiency initiatives went we:

  • Replaced a dead CFL light bulb with an LED bulb
  • Turned the thermostat down from 68° F to 66° F
  • Checked the air filter on our furnace to make sure it was new/didn’t need to be replaced. It was still clean, so we didn’t replace it.

This month’s upgrade cost: $8.82

Total upgrade cost to date: $8.82

So, we didn’t expect too much of a difference in our energy usage this month. Now let’s look at the numbers!

Over 30 days we used 427 KWH. Which comes out to an average of 14.2 KWH/day. This is actually slightly higher than the 14.0 KWH/day we used during our last billing period. Womp womp.

I’m guessing this is due to putting up some post-Christmas holiday lights which are not LEDs. I know, I know, but here’s the thing. We still have these strings of working fine holiday lights, and I can’t bring myself to replace them until they no longer work. Use what you have, right? We also started some citrus tree seedlings, and had them germinating on a heating pad 24/7.

We are part of the Alliant Energy Second Nature renewable energy program, at the 100% level. (In this program you can choose the amount of your energy use that you want to be matched in renewables, and we chose 100%.) So the cost of our electricity is $0.13 per KWH, for a total of $55.90.

We also used 80 Therms of natural gas heat energy. Which averages out to 2.7 Therms/day. Definitely less than the 3.1 Therms/day we used during the previous month! Dropping the temperature on our thermostat made a difference, and really the only way it affected our lifestyle is we that we wore slippers around the house more often. Also, looking at degree days this month compared to last month: 1286 vs. 1211. Even though this months number is a bit larger than last month’s, this month’s bill was for 30 day and last month’s was for 27 days. This means that our furnace didn’t have to work quite so hard to heat our house this month, which also helped out with reducing our gas use.

The natural gas market fluctuates in Wisconsin, so there is not an easy dollar per Therm number to give you, but during this billing period we paid $65.99 for our gas use.

Our energy bill also provides these numbers for helpful comparison:

Electricity used this month last year: 744 KWH

Gas used this month last year: 97 Therms. Average temperature this month: 22° F. This month last year: 10° F. So last year was quite a bit colder than this year.

Degree Days this month: 1286 vs this month last year: 1652. Degree days are the number of degrees below 65° F in one day, all added together for the total 30 days of the billing period.

Want to previous months of the Energy Efficiency Project? Here is Month 1.

This post contains affiliate links. Thanks for helping to support building earth!

Introducing The Energy Efficiency Project

Once upon a time, husby and I thought, what if we bought a house in the small town we’ll be moving to this spring. About a year ago, when I first starting envisioning this whole building earth project, I thought a good progression would be to have a house to demonstrate some of the energy efficiency, green building, and sustainable design ideas that I’ve been writing about. Not to mention we were ready to start investing in our own place inside and out.

One of the projects that I’m super excited about starting in regards to our new house is this series on The Energy Efficiency Project. Each month I’m going to explain what things we’ve done to reduce our houses energy use: upgrades, downgrades, or behavior changes. And then I’ll share the nitty-gritty with you: our monthly energy bill, and the costs, and pros and cons of the changes we’ve implemented. My goal is to be as transparent as possible in how we use energy and how we are attempting to save energy. My hope is to show how small changes can add up to significant energy savings, and maybe you’ll be inspired to adopt some of the same changes yourself.

power lines: the energy efficiency project

So first, let me share some details about our new home to give you the lay of the energy use land.

Size: 1,026 square feet. Single story, with an unfinished basement, rafter attic for insulation.
Energy using appliances: refrigerator, stove, washer, dryer, hot water heater, gas furnace, central air, garage door, coffee grinder, exhaust fan
Electronics: computer, cell phones, alarm clock, seedling starter heating pad
Light fixtures: 21 bulbs worth
Windows: approximately 100 square feet, most of which are fairly new with aluminum sills
Insulation: I’m not sure exactly, since I haven’t looked inside the walls yet, but I’m pretty sure it’s just your basic fiberglass batts. The attic has about 3-4 inches of blown insulation covering the house.
Occupants: 2 adults, one wee tender babe

The Energy Efficiency Project: Month 1

We’ve been living in the new house for about a month now. Long enough to get our first energy bill! So we have a bit of a baseline to start with.

For December 17th through January 13th this is what our energy usage looked like:

Over 27 days we used 379 KWH (kilowatt hours) of electricity. We are part of the Alliant Energy Second Nature renewable energy program, at the 100% level. (In this program you can choose the amount of your energy use that you want to be matched in renewables, and we chose 100%.) So the cost of our electricity is $0.13 per KWH, for a total of $49.62.

We also used 85 Therms of natural gas heat energy. The natural gas market fluctuates in Wisconsin, so there is not an easy dollar per Therm number to give you, but during this billing period we paid $72.90 for our gas use.

Our energy bill also provides these numbers for helpful comparison:

Electricity used this month last year: 834 KWH (!!! what did the former owners have plugged in that sucked more than twice as much electricity as we used?)

Gas used this month last year: 96 Therms. Average temperature this month: 20° F. This month last year: 14° F. So last year was a bit colder than this year which explains the higher gas usage.

Degree Days this month: 1211, vs this month last year: 1698. Degree days are the number of degrees below 65° F in one day, all added together for the total 27 days of the billing period

Now let’s see where we can go from here!

P.S. Interested in seeing a picture tour of our new house? You can check that out over on macnamania.com!

Happy 2015

Happy 2015Happy 2015!

How’s it feeling now that you’ve had a week to break it in?

Let’s start this year off with a bang: We bought a house!  Due to job related circumstances we will only be living in the house part time between now and June, and we will spend the rest of our time in our current apartment. This will provide us with plenty of time to get some updates and projects done before we move in for good this summer.

Now you might be wondering, what does this house have to do with this little blog? Well, it means that as we do house renovation projects, I’ll have plenty of opportunity to share with you all of those green building home renovation projects, like:

  • What are the most earth friendly paints, stains, and adhesives to use?
  • Which are the most sustainable flooring materials?
  • How do you go from lawn to organic garden (hopefully without your neighbors giving you the side-eye)?

Another blog series that I have in the works is on making a house more energy efficient. I’ll take a look at the energy usage of this house, and similar sized houses in the neighborhood, and do monthly updates on what we have done to bring that energy use down.

Aside from the house, in 2015 I’ll be continuing the series on “green” certifications in the construction and home furnishing areas. I’ll also continue to explore passive house design, integrative design, green living habits, and compost.

If there is anything you’d like to see in the upcoming year, be sure to leave a comment or drop me email.

I know I’m excited for everything that 2015 has to bring! I hope your new year is starting out shiny and bright and not too cold!

Adding Insulation for Energy Efficiency Part 1

adding insulation for energy efficiency

Untitled” by Jesus Rodriguez // CC BY

As we continue to explore the possibility of building a house that doesn’t require a heating and cooling system, the next step is to get to know the current standard for adding insulation for energy efficiency. This is a topic that involves a bit of math. In this post, I’ll walk you through the equations that are used to determine how much insulation to add. In the next post on insulation I’ll go through two simple examples of working out how much insulation to add.

Payback Period

The typical plan for adding insulation for energy efficiency is to add to the point where you are able to cover the costs of the added material with the money that you will be saving in heating and cooling costs. The time it takes to recoup the money for energy efficiency upgrades is called the payback period. For the insulation of a residential building the average payback period that most people are interested in waiting is between 4 and 5 years. So, in order to figure out the payback period we need to consider the R-value of the insulation, and the cost of heating and cooling the house per year.

Calculating the R-Value

As you may remember from my last post on insulation, the R-Value is a numerical value given to insulation that tells you how much the insulation is going to resist the flow of heat. Determining the R-Value of an insulation material depends on a number of different factors:

  • Initial indoor temperature (Ti)
  • Outdoor temperature (To)
  • time (t)
  • surface area of the building (A)
  • The heat loss indoors (dQ)

And the equation looks like this:

R = (Ti – To) * A *t / dQ

The good news about R-Value calculations is that you usually don’t have to do them. Since the measurements to complete the calculation are done in a lab setting in a controlled environment, the insulation manufacturer provides that information for you when you choose your material.

Calculating the Payback Period

In order to calculate the payback period of adding insulation, we need to take into account the insulation and the heat system.  The payback period depends on the following features:

  • R-value of the initial insulation (Ri)
  • R-value of the final insulation (Rf)
  • Cost of insulation (Ci)
  • Efficiency of the heat system (E)
  • Cost of energy (Ce)
  • Number of days that require heat per year (t)

And the equation looks like this:

P = (Ci * Ri * Rf * E) / (Ce * (R2 – R1) * t)

You can find more information on calculating the payback period of adding insulation here.

I know looking at all these equations can be intimidating if you are interested in figuring out how much insulation to add to your house to meet the 4 – 5 year payback period. But hopefully after I work through a couple examples in my next post on insulation, it will seem manageable. Maybe you’ll even be inspired to add insulation to your own house to make it more energy efficient.