Documenting my attempt to cut my energy usage in half.

Saturday, April 23, 2011

Conservation Projects

As part of my half project I have identified several areas where I could reduce my energy usage for little to no cost.


I have three PC's in the house that are used infrequently (less than 2 hours per day) which used to be left on all the time.   The kill-a-watt meter showed that on average these systems used 150 watts of power.  All of the systems have now been set up to hibernate if inactive for 15 minutes. 

Energy Saving/Yr3175 kwh
Initial Cost$0
$'s Saved/Yr$349
CO2 Reduction3779 lbs


Most of the lights in the house have been converted over to CFL's.  However, there are three 75 watt incandescent floods that are in the main part of the house and are on 16 hours a day, every day.  These have recently been replaced with 8 watt LED floods.

Energy Saving/Yr1174 kwh
Initial Cost$66
$'s Saved/Yr$129
CO2 Reduction1397 lbs

Printer/Fax Thingy:

My HP PSC2510 which was detailed in a prior post has now been put on a power strip so that it really is off.  I may actually use the thing once a month.  It's pointless for it to be using power 24/7.

Energy Saving/Yr149 kwh
Initial Cost$3.50
$'s Saved/Yr$16.40
CO2 Reduction177 lbs

Phantom Loads:

A survey of the house with the kill-a-watt meter showed that several devices that are plugged in 24/7 are using power even when "off".  The TV sets in the two guest bedrooms, a CD player and treadmill in the exercise room, and the TV in the master bedroom that was swapped out for a new LG.  Individually these devices didn't use much power.  As a group, they do.

Energy Saving/Yr203 kwh
Initial Cost$0
$'s Saved/Yr$22.35
CO2 Reduction241 lbs

Water Heater:

The issues with the water heater which have been detailed here have been temporarily fixed while waiting on parts from the local hvac company I use.  The savings for not pumping heat into the garage should be noticeable.

Energy Saving/Yr670 kwh
Initial Cost$0
$'s Saved/Yr$73.75
CO2 Reduction797 lbs


For the changes listed above, which had almost zero cost other than I just needed to be aware of what was going on, I expect to see the following savings per year.

Energy Saving/Yr5373 kwh
Initial Cost$69
$'s Saved/Yr$591
CO2 Reduction6,394 lbs

This is a significant amount just for being more aware of what I'm doing.  The energy savings of 5373 kwh is roughly 12% of my yearly consumption.

Wednesday, April 20, 2011

Ductwork sealing and insulation

Today was "review the ductwork" day and I'm happy to say that for the most part it was still in good shape.  When the system was installed, all of the joints were sealed with duct mastic and then insulated.

The only issues I found were where the ductwork joined the heatpump itself.   Tape is an evil thing when exposed to attic temperatures for many years as it starts to gets brittle and either loses it's grip or tears easily.  The only option is to take out what's bad and replace it.

Since my ductwork was already sealed and insulated I'm not going to get a huge savings from the work I did today.  On the other hand, it only took about an hour to check it all out and I used maybe $0.50 worth of aluminum duct tape that was left over from a roll used on the solar air heater.

There are several sources (here and here) that suggest that 10% - 30% of the conditioned air in a typical home is lost via leaks in ductwork.  It's an easy and cheap thing to fix...

Thursday, April 14, 2011


We recently replaced an old 21" TV set with an LG 32" LCD model #: 32LD350.  One of the nice things about this TV is the energy saving modes which basically just turn down the screen brightness.  When the Lakers are playing and the wife is trying to sleep, it's nice to not have a screen that's so bright it looks like the overhead lights are on.  I plugged the TV into a kill-a-watt meter to see what affect the different energy saving modes had:

Energy Saving ModeWatts
Screen Off16.7
TV Off via remote0

I have found that the maximum mode is fine even for morning viewing when the sun is lighting up the room and thus the TV stays in that mode. One thing I did find interesting is that the Minimum mode actually consumes more energy than having the energy saving mode turned off.

CNET did a review of a lot of other TVs.

Monday, April 11, 2011

Water Heater Analysis - Part 2

After some discussions with Gary over at BuildItSolar I've decided that the hot water heater was coming on much more often than it should for its warming cycles when the desuperheater was turned off for the winter.  Over the past month it has averaged coming on for 5-6 minutes about every 90 minutes.   This results in about 90 minutes of "on" time per day just to keep the tank warm.  The graph below shows the warming cycles of a typical day.

90 minutes a day @ 5500 watts = 8.25kwh per day = $.90/day.  Since I keep the desuperheater off from Nov-March, that's about $140 per year in tank warming cycles.  The question is why is it coming on so often.  Gary suggested that I might have a thermosyphon loop occurring and after some investigation I believe he is correct.  The downstairs heatpump sits right next to the water heater and the plumbing between the two units looks like this:

When the valve on the cold water line at the top of the water heater is open (as it has to be when the desuperheater is on), there is an instant flow of hot water out of the top of the water heater, down through the heat pump and back into the base of the water heater.  Shutting the valve stops the flow and the lines stay cool.  Even though all the piping is insulated, shutting the valve had an immediate affect on the number of tank warming cycles that occur during the day as shown below.

The tank now cycles on for 7 minutes every 6 hours.  The "on" time for warming cycles has been reduced from 90 minutes to 30 minutes a day.  For my 5500 watt water heater, that's 825 kwh per winter that I'm not using and 982 pounds of CO2 that's not being pumped into the air.  In addition I'm also saving $.60 per day or $90 a year.

Thursday, April 7, 2011


The osprey are busy getting their nest ready for this year.  They arrived a couple of weeks ago and got right to work fixing what little damage occured during the winter.   This is nest #2 and sits on a "no wake" sign that's about 150 feet out in the river.   Nest #1 is made from a storm destroyed duck blind that I put a surface on for the osprey to build a nest.  It's about 500 ft out on the bay side of the property.

Friday, April 1, 2011

Water Heater Analysis

Since I've been able to work around the load profile problems with the TED 5000, I've started collecting enough data that I can start to change some things and see what affect it has on my hot water heater. 

This is a typical load profile for my hot water heater for a single day.  The heater was on for about 125 minutes of which 34 minutes was due to the shower at 8am.  The other 90 minutes of run time during the day was mostly just the tank keeping the hot water that I'm not using... hot.

I then turned on the desuperheater for the heat pump.  I usually keep this turned off during the winter and really had no way in the past of telling how much heat it supplied to the hot water tank.  Tank run time for this day was 68 minutes for the two showers.  Note that at no time during the day did the hot water heater come on to keep the tank warm.

Is this good?  I'm not sure.  During the summer months the desuperheater is always on as any heat that I can pull off the coil and put in the hot water tank is heat that doesn't get pumped out to the ground loops.  But during the winter, any heat that I pull off the coil and put in the tank is heat that's not going into the house.  So either the hot water tank comes on more often, or the heat pump runs longer.  I'm not sure which option is better.

Some of the issues/thoughts with using the desuperheater during the winter that I see are:

  1. If the desuperheater is off, the hot water heater will only come on when the temperature in the tank drops below a certain level and the water actually needs to be heated.
  2. If the desuperheater is on and it's a nice day outside such that the heat pump doesn't come on, it's the same as having the desuperheater off and the hot water heater supplies all of the hot water.
  3. If the desuperheater is on and it's cold outside, whenever the heat pump comes on, heat is pulled off of the coil and pumped into the tank even if it doesn't need it.
This last thought is the one that I have the most trouble with as it seems that I'm wasting money.