I was thinking 200 , heck I burned 120 last month and Im at 83% with a toasty 64 degree max in 1200 sq. feet

Hey Geofan,
You are correct. (It must have been the initial shock of seeing a $568 dollar electric bill! I missed a week. I went back and double checked my oil receipts from last year and here are the revised figures, with some further adjustments:

Oil receipts - first delivery: 11/26/07, next delivery: 12/26/07 (30 days). Assuming they filled ‘er up, it was 147 gallons. So I’m pretty sure that is accurate for the given period.

Electric bill from 12/11/08 to 01/10/09, (29 days) was 3114 kWh, minus last year’s usage (-1465), gives me 1649 kWh.

(I’m fairly confident that this is a very conservative electricity estimate, as my daughter was born 09/07, and I had an electric oil filled heater in the nursery all winter.)

Although the number of days per period are close, I realize that there is a about a 15 day shift into January for my electric usage period vs. my oil usage period, so the temp was probably a little colder into Jan. In other words, I most probably used a little more oil if I were to guess and make the periods the same, but its impossible for me to tell exactly. I do know that from 12/26 to 1/29 I used 177 gallons. So let’s say I used another 20 gallons for guesstimational purposes:

Here we go.

If 167 gallons (@85% eff) = 13,823,550 BTUs and
If 1649 Kw (@100% eff) = 5,628,037 BTUs

COP = 3.5 (that’s a little better than my original but doesn’t take into account I had a space heater running at night, all last winter.) And if I take Geofan’s 175g, I still end up with 3.67 COP.

I guess what I’m trying to understand is the expected 4.2 vs. the observed (and understandably ugly guess at this point) 3.5? Is this expected?

In other words, if I was to be observing a 4.2 COP, I’d either have to be off with my non-geo kWh usage by 250 kWh or, burned closer to 200 gallons of oil (or somewhere in between).

I’m going hunting for my ‘04, ‘05, and ‘06 electric & oil bills tomorrow and see if that firms up some of these squishy numbers…I’m probably trying to split hairs with a dull axe here but thanks for bearing with me and entertaining my numbers.

Look into a Wattnode , easy to install , and will keep track of KWH for the unit
What is the temp split from return to supply ( for all that have not figured it out I work for the company that installed )
at start up your amp draw was 17 heat at 70 degrees , 19 water at 105 your voltage was 235 ( but factor for fluctuations lets call it 240 )
its a 5 ton and herman always sized right so lets call you cfm an even 2050 , with you temp split and an estimated power factor
be sure to have both zones going when you take temp measurements and measure at a grill close to the air handler .I (or others )can give you a fairly accurate COP and btu output , Hows the run time this week?

I'll have to get a hold of a proper thermometer to measure the line temps. But, as far as run times, and general performance, when this cold snap started, the the system couldn't handle both zones being at 68. Specifically, on 1/15, (The outside temp hit -4 F) overnight the basement dropped to 63 and the upstairs dropped to 65, with the unit running continuously. (I have aux turned off.) I would have expected a 5 ton system to handle 3000 sq/ft, but maybe it was just too cold?

Since then, I've set the basement to 55 and the upstairs stays at 69-70. (Keep in mind the upstairs is about 1600 and the basement is 1400.)

Right now, its 22 F outside and its running about 10 min on/ 10 min off.

This is the only way to get somewhat close
Oil guys rarely fill up anything , they pump into the tank so quickly that to attempt to do so would likely give you an occasional spill ( unacceptable in the delivery world ) this is why when an oil tank is put in the vent pipe is fitted with a whistler , it whistles louder as the oil gets closer to the top , to say that 30 or more gal. variation in a 260 gal. tank would be normal , also the off chance that your stop emptied the truck is possible .
In short first thing you do when a problem comes up is question your measurements ( remember the 2 sets of gauges :) )

Not worried about line temps just yet , air temps coming out and in to the vents

Oh, I misunderstood. Let me take some measurements as you suggest and I'll post them up as soon as I have them.

A quick thought to add on electric usage (and frankly not sure where to express it), in crunching numbers for a friend of this site I had occasion to look at the bin averages for Lansing MI area. Annual hours at 7*=76, 2*=33,-3*=12 and -8*=2. I think we exceeded most of that in the last 5 days. If you are comparing to same time last years oil bill (and your weather has been abnormal as well), you'll like your electric bill even more next year:)
J