Wednesday, December 26, 2012

On cold temperatures and gusty winds!

Can cold temperatures outside when combined with gusty winds rack up winter heating costs? That was the question that crossed my mind as I checked my power use for what turned out to be a very cold Christmas Day in December. ‘Why’, I wondered, ‘would windy conditions cause such a large heating surge especially when all the other factors were equal’? What came to mind was a very similar day earlier on the month, December 10, yet that day used 48.9 kWh while the 25th managed to chew through 71.1 kWh. which also represented a 32% increase in heating costs!! Following are the side by side by side stats for both days;

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You'll notice that the mean or average temperature for the 10th was 28.3F, while that of the 25th was 29.1F. So, Christmas Day was actually a tad warmer. Likewise the sky conditions, dew points and relative humidity figures were also very similar. Also, when I looked at furnace settings, appliances and electronics used; both days were about average. So, it was apparent to me that the only real difference in the two days was the wind! In fact, December the 10th was much less windy than the 25th! So, I felt this so-called 'wind effect' deserves a bit more research. I'll plan on doing a followup post later this winter season.

Thursday, November 29, 2012

New Nest thermostat is up and running!

I received my nest on this posting date and had it up and running in about thirty minutes. Between the technical support and what they send you with the unit, I have to admit it was easier than I had thought!

After I got it to communicate with the internet, the unit downloaded an update and then went into a setup mode that was sort of spooky as it was able to analyze my heat pump to a T. I then went to my computer and accessed the unit online (it works in the cloud) and was also able to set it up on my droid phone so that I can control everything from where ever I happen to be.

Weekly schedules can be easily set up
I was very happy with the simple interface that quickly allowed me to set up a custom schedule that can be changed on a whim. Also, this unit has a learning mode whereby it can figure out your heating and cooling preferences. Pretty neat little package all told.

At some point in the future, I plan to do a post on how well I feel the Nest performs overall.

Update: Well, that point in the future has come! The NEST has turned out to be one of my better purchases. It's performance has been flawless and being able to set up a custom schedule has saved me money - a lot of it! I also like the ability to access it via my smart cell phone.

Tuesday, November 27, 2012

Three day study of temperature versus power use

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 Here is an interesting chart that depicts indoor and outdoor conditions and the effects of cold temperatures on a 2 stage heat pump that has been set to heat a house to 60F. Auxiliary space heat was used to also heat one room to 71F. This test was part of an ongoing series of experiments to help determine how one could save money during the colder months of fall and winter.Note what happens when the temperature dropped below 35F outside and the heat pump was forced to change over to resistive heating as a result.

Saturday, November 24, 2012

Coming soon – The Nest!

After finishing up some studies concerning the saving of energy during cold bouts of weather, I decided to go ahead and purchase a learning thermostat device called the Nest! I’ve determined that, while I can save significant amounts of money by retreating to one room over the course of a cold spell, I still needed to address the house energy envelope as a whole.

I think the Nest is just the device to fill the ticket as it is not only programmable, but it is also network friendly meaning I can access it via a computer or my smart phone. I plan to write a few posts on this topic in the near future.

Wednesday, November 21, 2012

Where heat pumps end up costing money!

I have a dual stage heap pump that services my home and for the most part it does a great job. That is, as long as the outside temps don’t get much below 35°F that is…

The graph above represents actual data of high and low temperatures taken November 2012. For this far in the month, the temperatures have average spot on to historical averages for the last thirty years; about 47°F. So, in fact, this has been a pretty average month, so far. (The mean temperature standard was taken from the weather service's figures for West Plains Mo. for the month of November and rounded).

Now, take a look at the area I’ve marked in yellow – there were 10 out of the 20 days where the overnight lows got down below 35°F. I took these days and averaged out the kilowatt hours of power that was used for those days and came up with 26 kWh. Next, I took and averaged out the power consumed for the other 10 days where it didn’t get quite so cold and arrived at a figure of 18 kWh! Now, since the heap pump will tend to switch over to resistive heating elements below 35°F, I’m guessing that the difference in cost to me will be about 30% more in terms of the electric bill.I'm also guessing that, for a large part, it doesn't matter as much how warm it is during the daytime as it does how cold it gets at night. It'll be interesting to see what happens during the days when the thermometer never gets above freezing, should we experience that later on in the year.

Over the coming winter, I’ll keep an eye on this and see if it holds true.

Notes: During this period of time, the heat pump thermostat was set at 60°F.

Sunday, November 18, 2012

Night time lows below 35°F put the kibosh on energy savings!

This post concerns the effect of home heating when using a heat pump who’s T-Stat was been set down to 60°F for a home while a small 1,400 watt space heater was employed to heat just one room.

It may be interesting to note that many heat pumps become quite inefficient whenever the outside temperatures fall much below 35°F. It’s at that point that many of these units switch over to resistive heating in order to warm a home. Please read the excerpt below:

Heat pumps are only effective to about 35 degrees. Anything lower than that, and you have to use your emergency heat. The two reasons for this are that when the outdoor air temperature gets too cold, the unit cannot extract as much heat from the outdoor air to keep up with heating demand.

Second, condensation forms on the outdoor unit when it is running. In temps above 32 deg (freezing point of water), the condensation simply drains away from the unit. Below 32 deg the condensation freezes to the coil and blocks air flow. When this happens, the unit must go into defrost mode to clear the ice. During this time the heat pump is not heating your house. It’s heating the outdoor unit to clear the ice.

So, at about 35°F, your heat pump also switches over to a set of resistive heating coils located in the inside furnace. This form of heating is much less efficient and power consumption can soar. My heat pump is a two stage heat pump which can even be less efficient as will be explained below:

A single stage heat pump uses the same rate of transfer at all times during operation.  A dual stage (also called a 2-stage), uses 2 different rates of transfer.  Put simply, these 2 stages are kind of like a “high” and a “low”.  When the desired temperature and measured temperature are fairly close in number, the unit will not need to work as hard, thus using the “low” setting.  In this case, a low rate of transfer is all that is necessary for getting to the desired temperature, so why push it and use more energy than is necessary for the job?  Conversely, when the difference in temperature is high, and the unit needs to change the temperature several degrees quickly, the dual stage heat pump will switch over to the high rate of transfer and more energy will be used to get the job done.

This ability to go from a low setting to a high setting simply means that at the high setting, my house will get warmed more quickly. Useful if it’s really getting cold outside and the unit is struggling to keep up. However, not so good from an energy consumption standpoint!

Let’s see this from the standpoint of actual data. Below is a graph of what happened to the outside temperature during the night of November 17-18, 2012. As you can see, at about midnight the temperature dropped into the freezing range (yellow area of graph).

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 Correspondingly, the heat pump began to kick on into Stage 1 (note it never made it to Stage 2 due to both the low setting for the house proper and the fact that it never got seriously cold outside).Let's now look at the corresponding power graph for that period of time as measured by my TED energy monitor:

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All those little spikes represent my small space heater kicking on and off all night long. In spite of how it looks, this little unit did not consume much power as it was heating just a 1600 square foot area (my bedroom). The stage 1 spikes were indicative of the switch over by the heat pump sensor to relatively frequent bouts of resistive heating (5 from 12 midnight to 8AM). Once again, my low thermostat setting for the rest of the house combined with the fact that the lowest low was 27°F. is really what saved the overall situation. Had I been trying to heat the entire home using just the heat pump, the situation would have been much different. Now, take a look at the actual power consumed both before and after the mercury dipped below 35°F.:

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Wow! There was roughly a 50% increase in the amount of energy consumed (all things being equal) after the drop below 35F. I also noticed a residual effect as the house, once cooled, was reluctant to come back up to a 'normal' reading of 60°F.

Disclaimer: There is no way that the information present here could be construed as scientific. It was presented honestly but be forewarned that the author has absolutely no credentials in the areas of heating and cooling.

Thursday, October 4, 2012

My winterizing efforts for the 2012-13 winter season!

It’s October and nobody has to tell me that winter ain’t too far off! I’ve already noticed that some of the trees around my house are turning and every time I look out back, there are more of them lying on the ground. So, I got up off my butt and began to look at how best I could get the old homestead prepared for the cold months ahead.

The way I see things, when all the dust settles, there are two issues that have to be addressed for any all-electric home like mine; 1) how much money can I save on heating and 2) what amount of comfort will I have to give up in order to save on said heating? (Both these concepts are certainly at odds with each other in that if I keep the house warm all winter, say at 72F or so, I then get hit with large monthly electric bills). This going on at a time when I’m on a fixed income and slowly going broke. If, on the other hand, if I elect to freeze to death, I’ll save a few bucks to put towards my funeral costs. Either way, it seems to me a lose-lose situation.

Yet, there are some alternatives out there and they don’t have to cost very much. Here they are in no particular order:

Kill those Drafts

Almost any old house has what I call leakage. That is, air that come and goes through cracks either in the structure of the house itself or through various openings around holes through which plumbing pipes enter or exit the house. A can of foam costing about $6 bucks took care of those in short order. Weather stripping also works great to help seal outside doors!

Corral that Water Heater

Two simple things can be done here to lower your heating bill as much as 10%; 1) set the t-stat to 120F and 2) wrap that sucker in insulation.

Lower the Thermostat a few degrees

Some expert once told me that for every degree you lower the thermostat setting, expect a 12% savings in your monthly electric bills! I’m not sure if that’s the truth or not and would guess that there is probably a lower limit after which you really wouldn’t save and still freeze to death. This year, I’ve opted for a setting of 65F for the majority of the house with a small space heater to use for my office/bedroom. Oh, and an electric blanket also helps tons!

Manage those blinds and drapes

No matter what sort of window covering you have, keeping them open to let the sun in and closed at night to keep the cold out makes sense. You can also elect to use one of those plastic shrink wrap coverings like those sold by 3M. They can increase the R-Value of that opening by as much as 90% by creating a dead air space between the cold window surface and you.
There you go! That was pretty simple and it didn’t cost an arm or a leg to implement. I hope to do some additional postings as I go through the winter months to see if any saving actually materialize. Oh, and I'm hoping Global Warming really kicks in too, this year!

Sunday, September 30, 2012

LED light bulbs make cents!

 At some juncture, while looking at ways to winterize my home and make it more energy efficient, I got to looking at the light fixture by my bed. As is my habit, I like to read in bed and so inevitably leave the light on after I fall asleep. So, the light burns night after night for about eight hours. It’s a regular 60 watt incandescent bulb as opposed to a CFL light bulb which I found can cause skin cancer when used close to the body. Over time I found that this little bulb, being on every night, could cost around $18 per year to operate. Not a great savings, that’s true, but if there’s a cheaper alternative I'm all ears.

Enter the 40 watt LED light bulb from a company called Hitlights. An alternative light source that costs about $11but which boasts a 40,000 year lifespan! (That’s about 13 years if I were to use it 8 hours a day). And, at only a power consumption level of 6 watts (.006 kWh), that would bring the cost down from $18 for a 60 watt bulb to about $2 over the course of a year. Not a bad savings in my book! So, what’s the downside?? – In a word, color. This bulb’s color rating is 6500 K – which puts it more toward the blue end of the color spectrum when viewed by human eyes. (Note: for $18, they also offer a 75 watt bulb that uses 9 watts of electricity, but which is much closer to a regular incandescent at 2700 K). Will that work for a bedside lighting source? I’ll update this post when it arrives sometime in October.

Update: Hold the presses! My light came recently in the mail and when I installed it I was amazed at how good the light looked!  Here. Judge for yourselves....This photo was not altered in any way and shows just what the light looks like.

Saturday, September 22, 2012

My 2012-13 winter power goals!

Let me set the record straight! Last year's winter was pretty darn mild. And so were my electric bills when compared to the year before. Over the four month period November through February, I used 4,066 kilowatt hours of electricity to run and warm my home. That was 2,639 kwh less than the winter season before and represented a 39.4% savings in hard cash! Yowser! This year I'm hoping we have yet another warm winter thanks to Global Climate Change. (I think the odds makers are saying we have something like a 34% chance of a plus 3 degree winter over the norm). If that comes to pass and along with other improvements I've made, I'm hoping for a drop yet another 25% off last year. In real terms, that would be about 1000 kilowatt hours less over the four month period and would represent one heck of a drop when you average the past two years out!

I'll post updates on how well I'm doing after the winter season gets underway.

Wednesday, February 8, 2012

Energy saving comparision for 2010 versus 2012!

I finally go around to tabulating the results of my energy savings program’s effectiveness for the year 2010 compared to 2011 when many of the changes were put into place. I think it is apparent that this program was successful and I hope to continue to explore other ways to save a watt without sacrificing comfort or convenience!

Thursday, February 2, 2012

January 2012 – Another great energy month!

Actually January was a great month for me, energy wise, not so much because of anything done on my part, but rather due to the relative warmth. January was over seven degree warmer than the average and that play very well when it came time to pay the electric bill for the month.

In 2011 my bill was $182, and this year, it was all the way down to $121! That’s actually a thirty plus something savings as my rate was increased 13% this year versus last. Now, with the weather forecasters anticipating a warm February, I’m hoping to have done rather well for the entire winter season!