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.