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Fuquay Varina, North Carolina, United States
A guy finding out if life really does begin at 50.

Sunday, December 28, 2014

Closet Air Return

Closet Air Return

In October 2013, I replaced my 25 year old heat pump with a new Rheem Prestige Heat Pump. It is a two stage heat pump with an ECM variable speed blower. During the summer, we left the unit's fan on so that the blower ran continuously (it sped up and slowed down as needed, but never stopped). I had hoped that would solve a damp condition in the master bedroom closet, but it didn't. I had removed the door to the closet and left a small fan on in the closet, but that didn't completely solve the dampness problem either. So the next thing I decided to try is to install an air return in the back of the closet. That will do two things. One it will make it easier for the blower since there will be less restriction in the return, and two the air will turn over in the closet whenever the blower runs. This album Closet Air Return documents the construction and installation of that additional air return.

I got the 12" collars, 12" R-6 insulated duct, and the 16" x 16" return grille with filter at my local home center along with the other supplies (mastic, plastic duct clamps, etc).  I had drywall supplies on hand as well as foam board.  I did the project in several phases spread out over a month.  Two of phases, framing and dry walling the return box and then installing the metal return grille with filter, required me to remove the equipment and clothes from the closet.  The rest of the work of making a transition box and running the duct I did with the clothes and equipment in place.   The only part of the project I left unfinished was sanding and painting the the drywall.  I decided I didn't want to deal with the dust.  No one is likely to see this unfinished bit. If I get 2-3 days when no one but me is here, I'll finish it.  If that doesn't happen, then I'll sand and paint it when I sell the house.

I won't know until next summer if this helps with the dampness. I've already noticed that the door to the master bedroom opens and closes easier now that the pressure differential is not as great between the den and master bedroom.

Saturday, November 1, 2014

GE GeoSpring Hybrid Heat Pump Water Heater

GE GeoSpring
Our new GE GeoSpring Hybrid Heat Pump Water Heater has been installed and operating since 1pm on October 2, 2014.  I've had an energy monitor measuring the kWh the GeoSpring has used since it was first installed and turned on. That same energy monitor was installed on the old water heater that the GeoSpring replaced, so I am able to compare the energy used by the two water heaters.

I have been resetting the energy monitor the 1st day of each month since March of this year (I installed the energy monitor in February).  The old electric 'storage tank' water heater energy is shown in the chart below for the months March through September.  The new GeoSpring energy starts in October. The drop in energy usage for October is noticeable (138 kWh vs 318 kWh average). At 10.5¢ per kWh, the GeoSpring monthly energy cost was $14.48 vs. $33.41 (average) for the old water heater. The result is a savings of $18.93.

The downward trend in April, May, and June I believe is as much due to an increase in the input (ground) water temperature, as any decrease in hot water usage. The ground water temperature is still quite cold in March and warms as the days warm. The increase in hot water usage in July and August then leveling off in September I think is the water heater leaking. The leak was at the top of the tank where the pipes thread into the tank. So all the water that leaked out was heated.

The temperature of the air in the crawl space in October was always above 65 F.  In November the crawl space will cool as will the ground water temperature.  The heat pump is used to heat water as long as the crawl space is above 45 F.  I'm expecting in the latter half of November that the crawl space will be below 45 F, and stay that way until late March.  During the cold weather months, the GeoSpring will use the 4500W element to heat the water, so it should perform similar to the old water heater it replaced.

I'm very happy with the performance and energy savings of the GeoSpring.  Maryann likes always having hot water again.  I had a timer on the old water heater, and often when she wanted hot water, there was none. She has noticed that we have used all the hot water the GeoSpring tank holds at least twice, but in both cases, she noticed it during her shower which was right after the two boys had taken theirs.  The GeoSpring has a 65 gallon first hour rating, so we adjusted the shower order to hers first and the boys get whatever hot water is left.  That may not be much...LOL.  Depending on how warm the crawl space stays, the only other adjustment in hot water use timing I plan to make is to run the dishwasher in the afternoon instead of after supper when everyone wants to take showers.  That'll make sure the water is as hot as possible when the dishes are washed.
01/01/2015 - Updated the chart with November (178 kWh $18.70) and December (201 kWh $21.18) usage.  The crawl space is now 53-55 F on average.  The savings is not as great in Nov/Dec because of the decrease in supply (ground) water temperature.  I didn't measure the supply water temperature in October, but I'm sure it was considerably warmer than the current January supply water temperature of 51 F.  Also there continues to be a high demand in the evenings for showers.  The high demand causes mixing of the much colder supply water (in the winter months) which causes the heat element to run longer to heat the ~51 F water to 120 F.  After showers the heat element typically runs for an hour to recover which is ~4.5 kWh.  Unless we can change our demand pattern the saving (vs standard electric) will not be as great especially in the winter months when the crawl space air and supply water are much colder.  I'm considering putting the water heater in heat pump only mode since the crawl space is staying above 45 F.  The heat element will not be used to recover which will save energy, but using just the heat pump will greatly increase the time needed to recover. 
01/03/014 - Pacific Gas and Electric Company Evaluation of the General Electric Heat Pump Water Heater Demand Response Module states "... heat pump that is approximately equivalent to a 1.5 kW element while using only 0.5 kW of power." (pg 5).  1.5kWh is ~5118 BTUs/hr. It also implies (Fig 9 pg 19) that the electric heating element is activated (and the heat pump disabled) with a 25 F drop in water temperature (if the thermostat is set at 135 F then the heat element will activate at 110 F).

Saturday, September 13, 2014

SmartThings - Home Automation is about Ready for Prime Time

I've been doing home automation since the early 80s.  I started with an X10 (back when they were called BSR).  Back in those early days, the only neat thing I did was turn on lights inside the house (about 4 lamps) when the garage door opened.  My Ex actually thanked me for doing that, and it worked well. A few years later, I added controls to close the garage door at 11pm each night (very handy).  I followed that with turning the water heater on and off as needed.  My water heater is on for less than 30 minutes a day.  By doing that, I estimate that I have saved $20 a month for 25 years.  That's at least $6000!

About 4 years ago, I bought a Vera.  Then a couple years ago a, Vera3.  Over the life of Vera, I've purchased 3 z-wave light switches, a couple appliance modules, and a of couple security modules.  Vera was powerful, and you could program it.  It would let you control lights and appliances (any z-wave device) using your smartphone - sort of. If I was at home on my local network, it worked well enough, but if I was away from home, I had to go to a web page to control devices. It worked, but it was not ready for prime time.  Vera showed way too much of the complexities, and I found it difficult to use (but it could do almost anything, and if it didn't, you could write your own code).

Earlier this month, I bought an Arduino WiFi development board from, and that lead me to the SmartThings Maker Kit that includes an Arduino shield.  I have watched/listened to a couple of YouTube videos on the "Internet of Things"  (IoT) which SmartThings is an implementer of.  SmarterThings supports z-wave, ZigBee, and WiFi (such as Hue LED Lights by Phillips). Vera does not support ZigBee, and since I have my eye on a GE GeoSpring Hybrid Water Heater which has an optional Zigbee controller, I decided to get the SmartThings Maker Kit.  The kit includes a hub that will allow me to control my existing z-wave devices and experiment with my Arduino kit.

I liked the SmartThings from the second I opened the box.  It was a snap to unbind my z-wave devices from Vera and pair them with the SmartThings hub.  Since Maryann mentioned that Joey needed a key for the house, I decided it was a perfect time to get a z-wave door lock.  Johnny and I installed the Schlage Keypad Lock With Lever and paired it to the SmartThing hub in less that 30 minutes.  It was so easy to program, that Johnny, who is 10, was able to do it on his own!  Now, the boys can use the keypad and their own personal number to unlock the door if necessary.

We're also implementing the SmartThings Presence Sensor.  I'm home when Joey gets home each day, but Maryann is in the van picking up Johnny.  Now, instead of asking me, SmartThings will notify her on her cell phone when Joey and his bookbag enter the house.

After installing the lock and programming it, I can say that home automation has came a long way since 1982 and the days of the X10.