LED light bulbs

OK, so I'm finally fully LED or CFL in the house.   Due to the energy efficiency lighting grant, I got myself some MR16 and candelabra bulbs among the other bulbs i ordered for the neighborhood.   So i gotta say...they look great!  I thought i might be disappointed...but no!

I posted some pics below.  The MR16 are Slyvania 5.5w bulbs (from Lowe's) which replaced 50w bulbs.  So that's 27.5w instead of 250w or a 89% reduction.  One issue is that these are non-dimmable apparently because they buzzed something awful until i replaced the dimmer switch.

Our kitchen light with the 5@5.5W LED bulbs, an 89% energy savings

Now the other lights are using the candelabra bulbs.  I put these into the chandeliers in our breakfast nook and dining room as well as our entry light.  Combined those used 620W through a combination of 11@40W and 3@60W bulbs.  They were replaced with Utilitech 3.5W bulbs (dimmable!) which now total 49W or 92% savings.  They were easy to install, even though removing those individual little light shades on the chandeliers was annoying.  Pics are provided below.

Our breakfast nook chandelier (ignore the mess, please)

The dining room chandelier.  Looks nice!

Optimize Geothermal with new Thermostat?

So I've mentioned this before in previous posts, but I'm not too happy with my Honeywell Prestige HD thermostat.  It's pretty looking, yes.  But for being a $300 thermostat, it's control options are not all that great. 



Honeywell Prestige HD Thermostat

One of things that I'm most unhappy about is the inability to control how the unit calls for Stage 1 and Stage 2.  Why is this important to me?  Well, Stage 1 is more efficient than Stage 2.  And it seems whenever I walk by the thermostat, the unit is registering that Stage 2 is running. 

Let's take a closer look....

In Cooling mode, Stage 1 has an EER (Energy Efficiency Rating) of 26.8 while Stage 2 is 18.6.  So Stage 1 is 44% MORE EFFICIENT than Stage 2. (FYI..in terms of SEER, Stage 1 should be about a 31 and Stage 2 is 21).  However, Stage 2 has a greater capacity:  27,200 BTUh vs 21,500 BTUh.  So Stage 1 would have to run 1 hour and 15.9 minutes to achieve the same heat transfer as Stage 2 in 1 hour.  However, even if you factor in the longer run time, Stage 1 is still 31% more efficient than Stage 2.  So it's definitely beneficial to run Stage 1.  This assumes that the desuperheater benefit is the negligible, which in reality probably factors Stage 1 (longer run times means closer to steady state operation and higher heat transfer efficiencies).   And longer run times and means less Start and Stops on the compressor which is beneficial to maintenance. 

Now let's look Heating.  This benefit is no where near as great.  Stage 1 has a COP (coefficient of Performance) of 4.7 while Stage 2 is 4.2.  This translates to a HSPF (Heating Seasonal Performance Factor) of 16.05 for Stage 1 and 14.34 for Stage 2, so Stage 1 is about 12% more efficient,  Stage 1 has a heat transfer rating of 16,200 BTUh while Stage 2 is 19,500 BTUh. So Stage 1 would have to run 12 minutes longer to achieve the same heating as Stage 2.  Inclduing the extra run time, Stage 1 is still 10.6% more efficient.  Now, if I assume the desuperheater is running scalping 5% of Stage 1 (it automatically turns off for Stage 2), then the savings plummets to 5.9%.  But it's still a savings, albiet small. 

So what does this mean in terms of dollars? I create the following table below using the 2011 Cooling Bills.  The savings do not include the last 7% increase in Duke Energy rates for this summer.

2011 Summer Cooling Bills:
	Energy	Days	kWh/d	Bill	Rev Bill	Savings
06/01/11	1086	33	32.91	103.14	71.58	31.56
07/01/11	888	28	31.71	86.97	60.36	26.61
08/01/11	941	31	30.35	90.65	62.91	27.74
09/01/11	771	32	24.09	79.75	55.35	18.30	(Red by 25%)
					total	104.21	per year
2011 Winter Heating Bills:
	Energy	Days	kWh/d	Bill	Rev Bill	Savings
11/01/11	963	30	32.10	92	86.54	5.46
12/01/11	1318	33	39.94	121	113.82	7.18
01/01/12	1075	29	37.07	103.18	97.06	6.12
02/01/12	1051	29	36.24	107.9	101.50	6.40
					total	25.17	per year
			Estimated Total Annual Savings	129.37	per year

So during the 2011 summer months, there's a chance for about $100 in savings.  During the winter...not a lot at only $25.  I could roughly double the winter savings if I disabled the desuperheater in the winter.  Overall...even at $125/year that's not bad at all.  A HUGE decrease...no...but still measureable.



Ecobee Smart Thermostat.  It also has web-enable features too.

 So how can I fix this?  Well, I was looking at the Ecobee Smart thermostat.  This thermostat would allow me to set Upstage timers such that the system will stay in Stage 1 as long as possible as long as it doesn't violate any rules (such as...the temperature continues to rise or drop by X degreesd during operation or the timer doesn't "time out' before reaching the goal temperature). 
If I go with the Smart thermostat, then it could cost me about $600 ($300/thermostat).  Being conservative, the ROI would be about 5 years.  If I were to go with the Smart's new cousin...the Smart Si (not nearly as cool as the Smart, slighly harder to install, etc)...then the ROI would be 3 years as the thermostats only cost about $200 each.  I could also do one of each too. 

And all of that is before I talk about the really cool (nerdy) features such as reports that track the inside temperature, your setpoint, and the systsem run time.  And it's web-enabled so I can control it from anywhere (my wife will not be happy about that)

What do y'all think?  The downside is that my thermostats are brand new...however that could be a blessing because I could probably sell them to offset the cost of the new one. 

Energy Audit Results! HERS Index = 71

Well, I finally got my energy efficiency results in....drum roll please....

I got a HERS index rating of 71. 

So, what does this mean?  Well, let's start with the basics...HERS (Home Energy Rating System) is the standard by which a home's energy efficiency is measured.  Here's a good explanation:  http://www.resnet.us/hers-index

From above my house is roughly 30% more efficeint that a standard newly built home in the US (HRES = 100).  As compared to "existing homes" (HERS = 130), I'm about 55% more efficient. 

Based on ASHRAE 90.2 (1993) Annual Energy Consumption Compliance, my home surpasses the minimum compliance by 22.1%.  For a house of my size, ASHRAE has an annual consumption score of 2,197 while my house has a score of 1,737.  My house also exceeds 2003 IECC compiance by 10.3% (IECC = 67.9 MMBTU vs 60.9 MMBTU).

The blower door test confirmed by infilration at 0.29 ACH (Natural).  This exceeds the ASHRAE 62.2 standard of 0.35 ACH. This also means that I need some mechanical ventilation because my house is becominng 'too tight'.  An Energy Recovery Ventilator (ERV) was recommended to maintain "healthy air".

What else was recommeded?  See below:

1) Radiant Barrier in the Attic to reduce radiant heat loads to the upstairs and to the upstairs HVAC system.  (I was planning on this, however, I need a ridge vent first so all the hot air can be directled out of the attic efficiently).
2) Tighten the ducts on the first floor (I already knew this and this should already be fixed when I HVAC taped the filter door shut.
3)  Install ERV (see previous comments).
4)  Seal all holes/cracks/ and seams @ the Garage to the House.  (I'm not sure what this means since we didn't find any cracks/seams with the garage).
5)  Block joists at rim band at bay windows (OK...I can probably do this with some polystyrene foam board)
6)  Block Floor Band at Bay Window with blue board and foam (Same as #5 as I can best figure)

7)  Conidtion Crawl space to improve HVAC performance.  (I was getting to this.  I just need to insulate the crawl space walls and I'll be ready to allow some conditioned air into the crawl space.
8)  Condition attic to improve HVAC performance.  (I have no intention of doing this.  At most I'm planning is the radiant barrier- #1).
9)  Replace windows to improve wall u-value.  Yeah...at most I'll probably just replace all my window shades to be the "light filtering" double wall cellulose shades.  These should increase the R-value of the window (with the shade closed) substantially.

What I found interesting was the annual energy profile:

 One note...due to RESNET standards (I believe), this is based on a worst case scenario (4 bedrooms + 1) Family of 5 living in my house.  So I'm not actually spenting ~$1750/yr on my home.  Last year is was only $1050.  And the "Family of 5" is what is pushing my Lighting and Appliances up so high.

This table is neat because it says what's contributing to heating/cooling. 

So ignoring lights/appliances for now since it's way overinflated...this essentially shows that heating is predominate followed by cooling and water heating.  To reduce heating costs, it appears I need to do the siding project which would reduce infiltration and add insulation to the above grade walls.  However...if you really think about it...that project doesn't save me such.  Let's say I can reduce the infiltration and wall costs by 50%...That only saves me $137 per YEAR.  The siding project will cost me at least $10k for an ROI of 73.3 years.  Yes, it will make my house look nicer, but it isn't the energy monster I was hoping for.

For cooling, I really don't have a big winner unless I can reduce the internal gains...uhh...how do I do that?  Stop the fridge?  No indoor cooking during the summer?  Sleep outside?

And then there's hot water.  If I install one of those air source heat pump hot water heaters (such as a GE Geospring) then I could probably reduce that number to about $90/year.  And if you count reducing the crawl space dehumidifer usage by 50%, then I get about $180 per YEAR savings.  Yes...again...not a lot..even with the further optimization of my geothermal desuperheater (using two tanks in series).

Going back to the lighting and appliances.  If I look at the months that I am not using any HVAC, I'm essentially using 610 kWh/mo (20 kWh/d) of electricity.  About 30% of this goes directly to the crawl space dehumidifier (6 kWh/day).   Then there's hot water which is currenly about 20% (4 kWh/day).  So 50% is going to two things. Best as I can tell...after that is the fridge (709 kWh/yr * 1/365 = 1.94 kWh/d), the HTPC (1.64 kWh/d), then the dryer (6 kW * 1.5hrs/week * 52 weeks/365 days = 1.28 kWh/day).  Then maybe we have cooking (who knows where this math pans out...maybe 1 kWh/d?) and then freezer at 0.7 Kwh/d. 

So if I really want to make a large dent in my energy usage, my next target really should be the Air Source Heat Pump Hot Water Heater which should save me roughly 2,000 kWh/year (5.5 kWh/d) if I assume a 60% reduction in hot water generation cost (using GE's value) and a 50% reduction in dehumidifer usage since the hot water heater is a glorified dehumidifer.   I'm more than liklely going to hold off on this project until November for the "Energy Star Tax Holiday" in NC where we get a tax free day for Energy Star appliances.  The total project cost will probably be about $1.2k.

May Energy Usage, Dehumidifer

Hello all, I'm back.

Below is my May 2012 Energy Usage numbers from Duke Energy:

Total KWH:  689  (TED measured = 696 kWh)
No. of Days:  33
May 2012 Average Daily Usage:  20.88 kWh/day
May 2011 Average Daily Usage:  17.53 kWh/day
Comparison:  -19.1%

I'm not surprised by these numbers.  It was a hot May and we were forced to use our A/C for at least a week.  In addition, in May 2011, I had not yet installed the crawl space dehumidifier.  That was installed on June 6, 2011 (exactly 1 year ago...look at that).  One thing I have found since then, is that the dehumidifer is an energy hog (and it's Energy Star rated!).  I plugged it into my Kill-a-watt meter and measured the usage for  a couple days.  I found out that the unit is using roughly 7 kWh/day.  Wowza!  That's 33% of my average daily usage during the 'fringe' seasons (when the HVAC is not in use).

So what do I do about it?  Well...I think the only thing I CAN do about it, is to go ahead with my house residing project.  When I do this, I plan to install housewrap (maybe even some polystyrene insulation).  The housewrap is supposed to help reduce air movement (and thus MOIST air movement) which should help significantly and reduce crawl space dehumidifer usage.

Why do I think that?  Well...here's my thoughts:  When I turned on the A/C (which dehumidifies) last month I did not notice any reduction in crawl space dehumidifer usage (and I was watching)...as my initial theory was that the rest of the house was responsible for the permeation of humidity in the crawl space.  To test this out,  moved the dehumidifer to the house and ran it.  Guess what?  The crawls space humidity increased to 65% (slowly) even though the rest of the house was at 55%.    So that wasn't it...so my next theory formed...the humidity is entering the crawl space from the wall cavaties.  This would make sense because the walls terminate at the crawl space.  Because I have painted walls (who knows how many layers), this creates a fairly impermeable membrane on the interior walls...so where does the humidity go?  Well...down to the crawl space where the dehumidifer is drawing air and creating a gradient.  Thus, by putting on the houswrap/insulation...I'll create an effective air barrier on the EXTERIOR walls...which should significantly reduce the amount of moist air entering the crawl space. And I'm certain air is entering the wall cavity beause most of my exterior lights have holes directly to the interior wall. 

That re-siding project is going to be pretty expensive ($8-10k), but at least it will help my house look nice while simutaneously increasing energy efficiency.  I highly doubt I'm going to emark on the project soon.  Maybe this fall at the earliest...