Energy Diet

A 20% Increase in Energy Consumption

After tallying our water, electricity and gas usage, we determined one thing: We use too much. My wife and I were both actually quite shocked at how much we use when we look at this at an aggregate level. But when I did some research on what others with a house/family of our size in Colorado spend, we were not as far over as I thought. Or we are all using too much! Either way, we have some room for improvement in this category.

We walked the girls through things in the house that use gas, electricity and water. Gas was the one thing they had a harder time making the connection with. When I mentioned natural gas to Sophie, our 5-year-old, she said, you are supposed to run. My wife and I challenged them with a couple of ways to lower our bill like turning things off when not in use and not running the water when brushing their teeth. There was a hook, of course: Whatever we can lower our bill by, they can use at the toy store.

Digging through this data would have been a real task if it were not for the great online tools provided by Xcel Energy. Their reporting tools allow you to visualize the split between gas and electricity over the course of a two-year period. The data showed that we used more energy in 2010 then we did in 2009. So I dug deeper to try and understand why.

My hypothesis has a few of  factors. The first is that the average temperature was much colder in 2010 than in 2009 so we used more heat. The second, our son was an infant at the time and sleeps in a room that is the coldest in our house so we compensated by turning the heat up. The third is that our home office, which is a detached unit from our house, was running the heat when it was not needed.

Our water provider, which is a public utility, does not have nearly the same level of functionality. So I had to dig through bank statements to get an idea of our usage. This was not quite as surprising.  The bill goes up in the summer when we water our yard, but not by too much, because our yard is quite small.

Some things we will implement right away:
1. Place fans over the air ducts in our son’s room to help pull more hot air through.
2. Set our thermostat on a schedule for both our house and home office
3. Wash clothes in non-peak times
4. Setting up energy monitoring technology to schedule usage  (will write more about this one)

What other things would you suggest we do?


  1. Tom Sahagian
    January 31, 2011, 11:37 pm

    Hi Dirk — I’m one of the coaches and was interested to read your post. That graph you posted is quite impressive!

    Your post brings up a number of very important points. I won’t go into all of them right now, but I will focus on a couple I think are of particular interest.

    One problem we have in energy world is, how do we compare the severity of one winter to another? Because you’re correct — a colder winter will, all other things being equal, result in more heating fuel consumption.

    The measure most commonly used to do this is called Heating Degree-Days (HDD). It is an imperfect tool, but it is widely used and can be very helpful. I can go on about it at length, but I’m not sure this is the proper venue.

    Suffice it to say that you want to compare heating use on a per-degree-day-basis from one year to the next.

    Another major point is that it is generally better to compare energy use rather than energy cost. Of course, you want to know how much it’s costing you each year, but since energy prices fluctuate so much, it’s really consumption — gallons of oil, kWh of electricity, therms of gas, whatever — that is the crucial measure.

    i see that you’re planning 4 immediate steps to save energy. You may be surprised to know that item 1 may end up consuming more energy, and item 4 may not have a very good payback.

    I can talk your ear off about what I think are some good steps to take, but it’s past my bedtime and i have a few more comments to make.

    But in doing what you’ve done so far — quantifying your energy costs and starting to think hard about how to change things — you have taken what may prove to be the most important step of all.

  2. Christina
    February 1, 2011, 10:18 am

    Tom, that’s very interesting about fans potentially consuming more energy. Do you not recommend them as an option? I am very dependent on my ceiling fans!

  3. Tom Sahagian
    February 1, 2011, 11:20 am

    Every application is different! A fan of the sort Dirk was contemplating will very possibly use more energy (and a more expensive type of energy) than it would save. He’s probably better off adjusting the dampers in the ducts, although this can be a tricky job.

    It’s also possible the cold room is cold because of unexpected heat loss or air infiltration that could be cured by properly weatherizing the room.

    Ceiling fans are great — I have been able to get through two consecutive NYC summers with zero AC by using a ceiling fan in my bedroom and box fans in the other rooms. No one believes me, but it’s true.

    But their value as energy-savers in winter is dubious. I know of no hard data showing heating savings from ceiling fans, despite the many claims out there.

  4. clipton
    February 1, 2011, 11:52 am

    Dirk–Nice data presentation and tell Sophie she is not alone. I also fight the urge to run when I hear natural gas.

    There are many reasons for higher heating costs. More heating degree days (HDD) are one. Architecture, house construction, furnace and duct placement are major factors as well. I assume you have a furnace because you mentioned ducts. Without looking at your home, I will generalize. The largest inefficiencies in winter heating costs are (1) insufficient or improperly installed insulation and (2) air leaks. Both cause heat loss and discomfort. Fortunately, there are things you can do about this. Sealing up air leaks (most important in basements and attics) and properly installing insulation are relatively inexpensive compared to most residential renovation.

    Air leaks and inadequate insulation also contribute to large temperature gradients (temperature differential). This is why your son’s room is colder than other rooms. There are plenty of other factors why one room is colder than others, such as orientation (north-facing?), distance from room to furnace, duct leakage and undersize ducts (huge problem in most homes). Unfortunately, you can’t do much about these issues, except for duct leakage. For duct leakage, I would suggest sealing any joints on exposed ductwork with duct mastic, especially if the ducts are located in the attic. Most opportunities to seal duct leaks will be in the area immediately near the furnace. Here is a video demonstration:

    Other suggestions would be to ensure the bed is not located immediately next to or under a window, if possible. Also, make sure no furniture covers any vents, which would restrict airflow. I agree with Tom. The first item on your list is probably unnecessary and counterproductive for your bill.

    Less efficiency leads to greater discomfort and greater likelihood of using space heaters. Space heaters are costly and inefficient.

    The third item on your list may or may not make a difference in your bills. Some utilities provide the option of paying a fixed rate for all hours of the week or paying by “time of use”. “Time of use” differentiates kWh rates for peak, non-peak and intermediate hours. Your utility bill should map out how many peak and non-peak kWh consumed each month. If there is no distinction, it is likely you pay a general rate for all hours of the week and therefore loading discretionary energy consumption toward non-peak hours will not have an effect on your bill. Call your utility if you are unsure.

    Other thoughts: (1) how old is (are) your fridge(s)? (2) have you changed all lights to CFLs? Beware of dimmable lights. There are dimmable CFLs, however if you put a normal CFL in a dimmable switch, it will burn out very quick. (3) how old and what type of water heater do you have? What temperature is it at? If it is electric and older than, say, ten years, you should put a jacket on it. To determine the temperature, use a thermometer at the sink closest to the water heater. The temperature should not be higher than 120.

    Christina–Ceiling fans are not the same as the fans that Dirk mentioned, which are probably duct fans. Duct fans are less often used for residential purposes than for industrial. A duct fan may make a difference in comfort, but not without a likely energy penalty.

  5. Christina
    February 1, 2011, 12:13 pm

    Very interesting, thanks. I clearly misunderstood the fan type we were discussing, but it does raise the question of how much I can or should use my ceiling fan in winter — unfortunately, I’ve had to use it a bit this season as a cooling mechanism when my apartment overheats.

  6. Shaw Family
    February 1, 2011, 1:09 pm

    Hey Tom..

    Thanks for the insight.. Our house is only 5 years old but the builder put a very small furnace in our house and my sons room is the farthest point in the house. This is why the room is so cold.

    Are you suggesting the little fan i put over the duct could actually use more energy than simply turning the heat up?

    I will double check my bill to see what we actually consumed in terms of gallons of oil, kWh of electricity, therms of gas etc. This may require some excel work.. Yay…


  7. Tom Sahagian
    February 2, 2011, 6:45 am

    Christina — I’ll take care of your overheating problem when I am next in DC — but you gotta send me pix of your radiators.

    Dirk — I am suggesting that. Although it is possible the contractor undersized your furnace, it is unlikely.

    What is very likely, however, is that he (she?) did a poor job of sealing the ducts. As Chad mentioned, sealing the ducts could make all the difference to your son’s room’s heat.

    And as I mentioned earlier, it is entirely possible that the dampers inside the ducts (assuming the contractor installed them!) need to be adjusted.

  8. Dave Chameides
    February 10, 2011, 2:10 pm

    It sounds like you are hip to this already, but I’d suggest looking into a whole house energy unit like a T.E.D. It will give you real time assesments of how much energy (electricity that is) is being used. If you are an info kind of guy (which i believe you to be), you can actually chart what is using electricity adn how much by turning things on and off and recording what’s being used. You’ll be surprised by what some things use and some don’t and it will keep you in loop with what you are using.