Gas log costs

OK...so my bro gave me a call last night and we discussed all the fun stuff that I've been doing while he was trying to convince me to go to Mexico with him.  Well...he did have one good point.  I have this vented natural gas log in my fireplace.  I haven't used it because I just see the vent (aka...the chimney) as a place for all my heat to be sucked up and out.  Also, it doesn't help that we never got our service started...which was because we only have natural gas to fuel the fireplace and the gas company charges us $10/month for service...so we pay $10/mo...used or unused.

OK...getting back on track...the gas log is rated for 90,000 BTU/hr or 26.4 kWh.  In electricity terms, that amount of heat would cost me about $2.24/hr.  For natural gas (we pay by the therm or 100,000 BTU), that equals 0.9 therm or roughly $1.18/hr.  However, we need to factor in that $10 somehow.  This is where the math gets tricky because  I don't have a handle on how often my auxiliary heat runs.  I'm going to make an assumption...looking at my TED graph for the last 24 hrs, I'd say the aux heat was on 25% of the time.  However, I only only going to count when I'm home since my gas log is manual. So, let's downgrade that to 10%.  That's 2.4 hrs.  When that occurs my aux heat boosts electricity use by 10 kWh.  So 10 kWh x 2.4 hrs x $0.085/kWh = $2.04/day x 30 days = $61.20/mo.

So, if I use my gas log instead, it's a little harder to control because its not on a thermostat.  But for comparison sake, I'm going to only add in an equivalent amount of heat.  That will cost me (10/26.4) x 2.4 = 0.91 hrs x $1.18/hr = $1.07/day x 30 days = $32.21 + $10 = $42.21/mo.  So I'd save $20/mo.

Now, there's a lot of assumptions here...first it assumes that all that 90k BTU/hr goes into the house.  Let's not forget that I have a chimney right above it.  So, let's assume we have 33% fugitive heat loss.   Is this number good?  I don't know.  Now that cost changes from $1.07/day to $1.60/day x 30 days = $48 + $10 = $58/mo.  So now it's nearly equal.  And that doesn't even factor in the fact that the gas log doesn't have a thermostat (BTW...it cost roughly $300 to purchase on for my set), so I'd have to sit diligently next to the thermostat to turn the heat off when its not needed.  Or I'd have to set a timer to make sure the gas log is not used more than 1.36 hrs/day (or 0.68 hrs in the AM and 0.68 hrs in the PM).  Oh...and I have to be diligent and close the chimney vent when I'm done using it.

Now I might try to remove some assumptions later by using TED to find 10 kWh jumps, but until then...this is how I see the math.  I'm going to try out using the gas log to see how it goes anyway.

Any thoughts?

Interference confirmed...I hope

OK...so I think I've confirmed the interference.  Above is a 36-hr graph....the inline filter was installed by 19:00 hours. Check out 7am yesterday versus 7am today...SIGNIFICANTLY lower peaks.  Today's peaks max out around 17 kW while yesterday's peaks reached 29 kW.  I'm guessing the interference may have been a result of the heat pump supplemental heat strips as it seems the extremes were exaggerated as you can see that the smaller loads appear to be consistent.  I'm a little hesitant to declare victory as it's 36 degrees outside today. Well...the past two days it was ~25F.   Well, that 10 degrees makes a difference in how/if the electric heat operates, as I explained yesterday.  So, we'll see, I guess.  This weekend show lows in the 20s again...

Yesterday's Energy Usage

OK...so here's the last couple days of energy usage for my home:

Can you tell when the heat turns on when I get up?  Yeah...pretty obvious.  Not to mention that it's been in the 20s outside the past couple of AMs (highs around 50).  To set the stage...I currently have air source 2 heat pumps for heating and cooling, one upstairs and one downstairs.  They are old...11-12 years old.  The air handlers are even OLDER....they were MFRed in 1984 (my house was built in 1986).  Well...air source heat pumps really don't work under 32-35F.  So they are equipped with electric heat strips (10kW) for days of low temperatures.  Well...these heat pumps are just killing me.  Over the last two days I've used the following amounts of power according to TED:
Tuesday 1/4:  84 kWh
Monday 1/3: 68 kWh
Sunday 1/2:  32 kWh (low temp ~40F, high temp ~64F)
So, when I look at where my power is going....it's nearly all going to heating...with a significant chunk by the auxiliary heat.  There's some going to hot water (electric again) after showers, but generally that's short-term, but that still adds to the peaks.  If you compare to Sunday...when we were home all day, we used half as much power because temperatures were warmer which meant there wasn't a need for the auxiliary heat.

And before you ask...I do use programmable thermostats.  My upstairs heating temperatures moves from 62F (away/sleeping) to 67F (home/awake)...while downstairs I'm a little more 'liberal' at 62F to 68F.  As my wife says every winter, "say goodbye to this" as she bundles up.  If we have company (which isn't all that often), I may splurge and bump up the downstairs temperature to 69F.

Anyhow, "luckily" my air source heat pumps are dying, according to my HVAC tech.  I've already spent around $600 on those units since I've moved in (March 2010).  This is one of the main reasons why I'm going to replace that system with a ground source (geothermal) heat pump.  These units are somewhere around 3-5x more efficient at heating, 1.5-2x more efficient for cooling, and they can produce my hot water.  For more information see:  http://www.geoexchange.org/.  Fear not...I'll keep you posted when this endeavor kicks off.