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| My Ubuntu Linux Mythtv Home Theater PC (HTPC) |
Hey folks-
So I finally was able to get my Dad (aka...someone with Linux experience) to help me set up my HTPC for maximum power savings. So what's a HTPC or Home Theater PC? Think of a Tivo or Digital Video Reorder (DVR) that your cable company makes you pay for. Except this is homemade, stores significantly more than just TV recordings, but also my movies, music, and pictures. Well...it will eventually...in my last upgrade I still have slacked in moving my pictures and music back over to it.
OK...so after my last upgrade, I was able to reduce my overall power usage from 120W to 95W. I use the term "overall" because the power usage is not just the PC itself. I have the following additional equipment:
1) Network switch for multiple ethernet using devices
2) HDPVR to record TV off the cable box
3) Crappy Cable Box from Time Warner Cable
4) Signal Booster because I have to split the Cable TV signal 4x
5) HDHomerun tuner to record my local QAM TV
I also have a remote frontend unit (think mini-computer) that allows me to stream everything from the main HTPC to the downstairs TV. That unit is small and only uses 19W. I had already setup this frontend to 'sleep' when I shut off.
Well...of course, for me, 95W running 24x7 was not acceptable. So I emarked on the next level of upgrade. Luckily, this was a software upgade, not hardware. With significant help from my Dad, we setup the HTPC to shut down between recordings. So, once a recording is finished and it's been commercial flagged, the system reviews when the next recording is upcoming. If its a long enough time (20 mintues), it will shut down the PC. It will not shutdown the PC if (a) someone is logged in (such as when I'm using it) or (b) if the downstairs frontend is running. So it's not going to shut down right in middle of someone watching a recording.
It took a lot of tweaks to get everything operating right, but it seems to be running well. I have since grabbed a smart power strip to shut down as many accessories as I can when the PC shuts down. This is mainly the HDHomeRun and the HDPVR. I tried to use the signal booster, but I found out that if the Cable Box reboots, then it can't connect/fully reboot until the signal booster is on. And it takes frickin' 8 minutes to boot! So if I want to start recording something right away, I can't do it because I have to wait for the box to finish booting.
So, what has this done for me? Well, I just plugged in the Kill-a-watt meter and I've gotten some preliminary results. They are as follows:
HTPC Running with all accessories: 95W
HTPC Off with all accessories: 41W
HTPC Off with some accessories off: 29W
Accessory Power Usage:
Signal Booster: 3W
Network Switch: 3W
Cable Box: 23W
Before I go on a rant about my #$*&# cable box, this is showing a 67% reduction in "always on" power usage. More than likely this will end up being bigger when we factor in operational time and start talking killowatt-hours. I just started collecting data so I don't have official results...but let's talk about some theorectical values (not counting the frontend since its the same usage regardless):
Before (Operating 24x7):
95W x 24 hrs/day * 1 kWh/1000W = 2.28 kWh/day
After (Assumes used 4 hrs/day:
95W x 4 hrs/day * 1 kWh/1000W + 29W * 20 hrs/day * 1 kWh/1000W = 0.96 kWh/day. (58% Energy Savings)
What did this cost me? Well...i did have to buy a new solid state hard drive (SSD) for my frontend so I the system could shutdown instead of 'sleep'. This also significanly sped up the reboot to something like 10seconds and allowed me to write some code that when the frontend turns on, it 'pings' the HTPC to turn it on. After it waits for the HTPC to boot (that takes 10seconds), then it connects and starts Mythtv. That cost me $57.
1.32 kWh/day savings * $0.10/kwh * 365 = $48.18/yr. So my ROI is 1.18 years. Yeah, I'll take that.
Now for that &*#$& cable box. I can't believe it uses 23W! And the sad thing is that when you 'turn it off', it doesn't save any energy. Seriously!!!! I checked it with the kill-a-watt meter! Not even 1W. Why is this device sucking down this much energy?!? And to top it off...why the heck does it take 8 minutes to boot? I TIMED THIS! In the age of superfast computers that use little energy this is ridiculous!!! My frontend computer uses less energy (19W) and is equipped with a 30GB SSD, a dual core 1.8 GHZ processor, and boots in 10 seconds. And it probably decodes HD TV faster. It certainly makes you wonder what the heck is going on with these companies. I know my TWC service blows and I'm just waiting for the day that there is sufficient competition in NC so they will come out of the dark ages. My only real alternative is AT&T and their "digital" internet service is nearly half the speed of TWCs.
OK...*pant pant*...calm down boy....off the soap box.
The long story short...this was a fairly painless upgrade that'll knock off some kWh's. With my new fridge knocking off about 0.5 kWh/day, I'm reduced my baseload usage by ~1.8 kWh/day. My 'always on' energy usage is down to about 165W (3.96 kWh/day). There's a couple things I can do to get this down a little futher, but not much. At least 85W of this power is the upstairs and downstair geothermal systems on standby (~30W each) and then the frickin' cable box (23W). Then there's things like the alarm clocks, the internet cable modem, and the router. Yeah...these are staying on. However, it would only take 500W of solar capacity to completely negate this energy usage. We'll see when that happens....
