Hot Water Heater

So I've been trying to figure out what else I need to do to reduce my energy usage.  There's things like:

1) Install high efficiency hot water heater
2) Replace siding on the house and put on house wrap
3) Install solar panels
4) Replace fridge
5) etc.

Well...I don't have a ton of money to spend so #2 and #3 are automatically out as those cost multiple thousands of dollars...if not above $10k.  That leaves me with the fridge and HW heater.  Well...at most the fridge might cost me $60-70/yr.  And while I could get a bigger fridge that is more energy efficient...I'd still only save maybe $5-$10/yr.  Yeah...that's not worth it.  So that really leaves me with looking at the HW heater.  I checked out TED from the last 48 hrs and it looks like the HW heater runs roughly 7x/day for about 10 minutes.   The Geothermal system is not operating...it's that nice fall weather so I'm not heating or cooling.   That also means the desuperheater is not generating hot water.  At 4.8kW, that means the HW heater is using 5.6kWh/day.  And I'm currently using 22 kWh/d.  Thus, my HW is accounting for ~25% of my current total daily electricity usage.  Obviously that value will change with increased HVAC usage...but its the numbers I have now.

OK...so one of those hybrid hot water heaters (http://www.geappliances.com/heat-pump-hot-water-heater/ claims a 62% reduction in energy usage compared to a standard hot water heater.   I verified this by looking at that yellow tag energy information.  My current 50-gal HW heater says it'll cost me $520/year and 4879 kWh/year.  The hybrid says $198/yr and 1856 kWh/yr.  There's lots of assumptions included in there (family of 4, using XX gallons per day, $0.105/kWh, yadda yadda)...but let's assume that this is relative and be scalable to my usage. I can't see why it wouldn't since it's based on usage.

This would mean I could expect my energy usage to reudce from 5.6kWh/day to 2.1 kWh/d.  From a cost standpoint, that's $66/year in savings.  My return on investment:   $1000-$300 (tax rebate) = $700/$66 = 10.6 years.  Not a great return, but it's a return...and its within a 'lifetime'.  I should note that next year my electricity rates are going up 15%.  And Dook Energy is trying to raise them another 15% the following year.  Using just the one rate increases bring my savings up to $76/yr and make my ROI to 9.2 years.

One thing I should also note is that the hybrid HW heater is essentially an air source heat pump (ASHP) attached to a hot water heater.  So when it runs...it's essentially an air conditioner.  It's taking the heat from the air and transferring it to the hot water.  That means my crawl space (where my HW heater is located) will become 'conditioned'.  So no more dehumidifier needed (that's an extra 3 kWh/d minimum which isn't included here).  So that's cool.

However, I'm a little worried if there's enough 'heat' down in the crawl space during the winter.  I know last winter, the crawl space hung around 68F...and I had crappy vents in there.  I know i probably had duct leakage...but it wasn't too signficant as I had the energy audit guys down there and I fixed the places that had bad leakage.  I was reading online and some folks saw the unit drop temperatures down to 45-47F in their basements....which required them to drop a duct to give it some heat. 

So I'm thinking what I'll do this winter is I'll insulated the door to he crawl space and then monitor the temperature in the crawl space to see what happens.  If temperatures stay fairly warm, maybe I'll swap out the hot water heater...

Any thoughts out there?  

UPDATE:  Now there's always switching to gas to save moeny.  But that's not cheap either.  First, my hot water heater is in my crawl space.  And I'd need to vent the exhaust....which I doubt I have space for.  So for a standard gas hot water heater, I'd probably have to move it someplace else (garage?)...and I'd need an electrician and plumber for that.  And that isn't cheap.  I could go tankless and gas.  Again I'd need to move things around...and that unit is ~$1500.  And a 7.4 gpm unit ("2 uses") would still cost $223/mo @ 1.22/therm (using the Energy Guide).  So its still not better than the hybrid uni...not to mention it'll be more expensive to purchase and install.

UPDATE 2:  I just found this in the WaterFurnace Desuperheater User manual.  Apparently, it's more efficient to install two HWs in series to allow the first one to be a preheat tank to maximize the desuperheater usage.  I'll definitely have to think about this...

Energy/Cost Savings...What to do next?

Ok...I Friday and yesterday I spent countless hours trying to get my HTPC to shutdown and wakeup automatically.  When I manually told it to turn on in 5 minutes and shut it down manually, it worked fine, turning on automatically.  When I let it automatically turn off, it did just fine, but then it wouldn't turn back on.  It appears that I just can't get the system to pass the correct date/time in there.  Not sure why...Long story short...I'm fed up with it.  I'm no linux computer expert and I spent most of my time on Google trying to figure out commands.  I know enough to get by, but that's it.

So, I thought the next most logical step was to finally start looking at an upgrade to reduce power usage since this is on 24/7.  Well...a question arose...are there better investments?  Let's take a look...

I measured all my HTPC components with a Killawatt meter and the total usage is 120W when idle.  The computer itself uses 92W.  Reading online, a nice Intel Core i3 system (with all the accessories) uses around 40W when idle.  So that would save me 52W.  On a daily basis thats 1.2kWh which would save me $0.106/day = $3.23/mo = $38.72/yr.  Generally I would invest about $300 into this which gives me a simple return on investment (ROI) of 7.75 years.  Not all that great, right?

Well...looking at my TED, it's pretty obvious the one thing that is using the most power in my home is the hot water heater (see large single spikes).  The graph above shows last weeks worth of hourly energy usage.  The block on the first day (Sunday) is from doing laundry so that's a mix of hot water and dryer usage.  Overall, It's that time of the year when I don't need heating or cooling, so my geothermal is turned off (House stays between 67 and 75...comfy!).  With the system off, my desuperheater isn't heating my hot water.  So...does it make sense to upgrade my hot water heater?

Well, one of those GE hybrid hot water systems costs about $1400 from Lowe's (I'm not including the tax credit because I can't buy it this year).  If my current hot water heater (4.8kW) is on, say for 2 hrs/day (only 1 hr shown above, but let's factor in winter), then that I'd use 9.6kWh/d which is $0.82/day = $24.8/mo = $298/yr.  A hybrid hot water heater (according to the website) would save me 62%.  So, without factoring in the desuperheater, my ROI is 7.6 years.  With the desuperheater reducing hot water by 40% (a conservative value) then the ROI rises to 12.64 years.  Overall, I'd say this fix isn't worth it unless my hot water heater decides to break.

Out of curiosity, how about solar hot water?  Well...first, I'm not sure if my desuperheater and solar hot water can work together...but let's assume they can.  A solar hot water system (which is not a do-it-yourself job for me given my roof is so steep) would probably cost about $5000 installed.  This is just a guess looking online for similar systems.  What's the ROI?  16.8 years...so yeah, that's out of the question.

Out of these 3, upgrading the computer has the best ROI, albeit the overall savings are small.

However, I think my best bet is going to be contacting my geothermal MFR to see if there's a way for my desuperheater system to heat my hot water.  All the parts are there...there just needs to be some way for the hot water tank to contact the geothermal system to turn on.  And in hot water only mode, then the geothermal system would not turn on the fan.