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Page history last edited by Nate Begeman 10 years, 1 month ago

15 x 245W + Enphase micro-inverter solar array installed.  Rated capacity after panel and inverter losses is 3.24kW, contract production of 5525kWh/year.  Currently producing about 6000kWh/year.  PG&E does not provide split consumption + generation data, only net data, for this type of system, making exact break even calculation difficult, but it should be at about 7 years based on current data (no electric vehicle).


Total Net Import for first year was 1,911 kWh, at a cost of $123.


Per-panel monitoring: https://enlighten.enphaseenergy.com/public/systems/rF4g78297

Contract target monitoring: http://pvoutput.org/list.jsp?userid=9976 


Home energy audit performed by Solar City.  Several leaks around windows and baseboards that will require caulking, and all can lights are uninsulated and have direct access to attic, causing a huge amount of down-draft of cold air in the winter.


Attic and floor penetrations sealed with expanding foam, insulation installed between floor joists to keep floors relatively warm in winter.  Noticeable improvement in home comfort, house only drops from ~70 to ~66 overnight when outside temp is 48 degrees.  Ducts sealed and door sweep installed on front door.  This seems to be about a 15-20% energy improvement from my PG&E bill over the new furnace and attic insulation alone, which was about a 30% improvement over the house when I bought it (no insulation, 70% efficient furnace).


Replaced 6 40w B10 candelabra (E12-base) bulbs flanking garage door with 7w CFLs from Home Depot generic brand ($10/3pk).  The color temperature and brightness are very similar, but i think they'd be better without their diffuser.  They are just a tad larger, vs. the GE's which are MUCH larger and don't fit in many E12-socketed enclosures.


Replaced all 65w PAR30 6" can lamps with CREE CR6 10.5w dimmable 2700k LEDs, the first dimmable, energy efficient lighting I've found that appears to look the same as an incandescent and is therefore wife approved.  11 bulbs total.  Available at Home Depot under the "EcoSmart" house brand, but you can see the Cree label through the box window.  Note: I have found that the standard Lutron dimmers (DV-600P) work much better at dimming the CR6 than the "LED Dimmer" model (DVC-153P).


Purchased 2 x RP46384 after review on Shower Heads and my wife and I find it to be an improvement over the old shower head that came with the house, despite the lower flow.  I haven't noticed having to adjust the temperature higher to compensate and flow is adequate to wash long hair.  The main problem with these shower heads is that they seem to require a bath in CLR every 4-6 months to restore full pressure.  I consider this "worth it".


New Refrigerator-Freezer (BI36U) & Wine Fridge (WS30) combined use about 1.5kWhr/day, vs. old fridge at 2.9kWhr/day.

New lawn sprinkler controller (CyberRain XCI) saving about 40% of water vs. old fixed-interval clock by logging into weather underground to figure out current temp and humidity and adjusting schedule accordingly.  While I like it, and it has a vaguely acceptable iOS app, configuration is only available via a silverlight web app that is frustrating to use on OS X, and you'll need a free ethernet port somewhere in your house to attach its gateway to.  CyberRain claims that they will be moving to an HTML-based configuration by the end of the 2013.


Attic Insulated, 97% efficient furnace & 16 SEER air conditioner installed.  Heating costs YoY down about 30% over last 9 months compared to same 9 months previous year.


Replaced old TV (25w standby) with HDMI-CEC compatible TV which turns off receiver and DVR when it powers down, and has <1w standby.  Baseline for the house is now about 230W when I am not home, which is mostly networking equipment and appliance standby.


Ford Focus now equipped with Automatic bluetooth diagnostics dongle, which emits audible alerts when driving style is causing a decrease in fuel efficiency. Automotive efficiency data available at Fuelly.




Figure out if there is such a thing as a dryer that lets you delay the start of the drying cycle until a particular time of day.  Would be great to throw in clothes at 6:30 but say wait until 7pm for part-peak or 9pm for off-peak in summer.


Get an electric car.


Comments (3)

Jonah said

at 6:26 am on Mar 16, 2010

Re: leaving the receiver on
An automatic power strip is pretty good with this kind of scenario. You train it on your lightest-load standby device, and then the entire power strip switches on/off when that device switches on/off. If you've got at least one device with good standby power, that could be a great solution for you.

Soren said

at 11:05 am on May 8, 2012

Thanks for posting your energy audit, though I was sorry it didn't have any sort of "big picture" or per-area breakdown. It's cool that you'd already done several sensible upgrades before they came through. One of the main "system" challenges when upgrading HVAC is that often HVAC people don't size things for the house you should have (after sealing, insulation, etc) but rather for the house you currently have.

Regarding the fridge upgrades, I hadn't seen real numbers for a "bad" fridge. My 1996 fridge is drawing ~1kWh/day (varies by season) which I am happy to see stacks up well against your new (but perhaps larger/fancier) fridge(s). I still want to try adding some rigid foam to the back. :)

Nate Begeman said

at 11:20 am on May 8, 2012

Yeah, I was also sort of bummed there was no thermal imaging work done, but for $99, it wasn't bad. Furnace is now definitely oversized for house, now that it's insulated, but A/C is about right. The thermostat will almost never use the second-stage heat now because the first stage is enough to heat the house relatively quickly.

The bad fridge numbers were taken with a kilawatt agreggating over a week, then dividing KWhr by hours in a week. It was definitely much worse than I had expected, and the coils looked pretty clean. It's possible it had leaked most of the coolant and needed to be recharged, but I didn't like it anyway so PG&E came and paid me $50? $75? to take it away for recycling under some program they were running.

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