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Old 12-21-09, 04:47 PM   #1
Xringer
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Default New heat pump saves some money..

We installed the Sanyo heat pump on 11/05/09 and have been using it to heat the house every day since.

I've been looking at the bills and just read the meter for December.
(Meter is read around the 20th to 23th every month).

Nov 2008 859 kWh $172
Nov 2009 632 kWh $129

Dec 2008 831 kWh $167
Dec 2009 745 kWh $150

No more resistance space heaters this year. Instead, we are using the Sanyo.

Plus, we are saving 2 or 3 gallons of oil a day too. The burner motor
is running a lot less and the circulator pumps never come on.

Oil Use:
We burn oil to heat the hot water. Our 76 gallon burner is rarely used for space heating.
The only time we have used the oil heat, is during heavy snow storms
and when the temperatures are going down below 15 degrees for more than a couple of hours..
Not using the circulator pumps, but just opening the Free-Flow valve on
the Taco check-valve. That allows limited amount of BTUs to flow up into the house.

Hybrid Mode: Oil & HP
Free-flow heating (baseboard feed using convection) works very nicely
with the Sanyo heat pump when the outside temperature is under 15 deg.

If the outdoor temp goes above 20F for a few hours at night,
the Sanyo goes into low-mode and the house starts getting
a little too warm for comfortable sleeping. (The new attic insulation is working?)

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Old 12-22-09, 07:15 AM   #2
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Default

Not bad. Is it colder this year or last?
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Old 12-22-09, 09:31 AM   #3
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Default It was a bit colder last year.

According to a weather station in Bedford, a few miles from here,
and it was 2.8 degrees colder in Dec 08, and 4.2 colder in Nov 08.

Weather Station History : Weather Underground

Plus, we installed a bunch of extra insulation in the attic near the end of Nov 08.
(Which was working very well in Dec 08).


Since solar gain in this house is a big factor, I'm not sure how to get good data.
Maybe degree days take south-facing windows into consideration.?.

Does it matter much? My wife is just very happy to see lower NStar & oil bills!
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Old 12-22-09, 09:40 AM   #4
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Degree days is the best way I know of.

I think it matters a lot. It could be 2x as cold as the last year and that'd have a huge impact on bills.
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Old 12-22-09, 03:48 PM   #5
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Default Problems using HDD data

Heating degree day - Wikipedia, the free encyclopedia

"Calculations using HDD have several problems. Heat requirements are not linear with temperature,[2] and heavily insulated buildings have a lower "balance point". The amount of heating and cooling required depends on several factors besides outdoor temperature: How well insulated a particular building is, the amount of solar radiation reaching the interior of a house, the number of electrical appliances running (e.g. computers raise their surrounding temperature) the amount of wind outside, and individuals' opinions about what constitutes a comfortable indoor temperature. Another important factor is the amount of relative humidity indoors; this is important in determining how comfortable an individual will be. Other variables such as wind speed, precipitation, cloud cover, heat index, and snow cover can also alter a buildings thermal response."



I don't have a lot of windows out front, but they are facing south.
And, when you have a day like today, where it's been just above 30 degs
for the last 4 hours with plenty of sun, it gets warm in here..
All that snow in the front yard adds a bit to the solar gain..

I just got back from the movies (Avatar 3D) and my wife had set back
the Sanyo to 68, because it was getting too hot in the living room.

Right now, it's back to 70 in here, and the Sanyo was coasting using 470 watts.
But as the sun is disappearing, the usage is slowing climbing up to 600 W.

Since this is really a Tribrid heating system, I have to look at the solar gain for last year too.
Was it cloudy much last year?

We are seeing a reduction in our power bill right now, and it seems that
running the Sanyo when it's 15 deg outdoors is still cheaper than burning oil.

The oil truck was due here on Dec 21, but I called them to delay the delivery,
because we still have 3/4 of a tank of oil. (Down from 7/8 after the last fill).
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Old 12-23-09, 01:04 PM   #6
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Default Speak of the devil !

The oil truck came today and delivered 73.4 gallons.
The last fill up was back on 10-19-09, 66 days ago.
That comes out to about 1.112 gallons per day. (About 1 hour burner run time).
This only slightly more than we use in the summer (for hot water).

Cost @ $2.39 a gallon is $2.65768 per day.

Last winter, we were burning between 2 and 3 gallons a day.
(Plus we were also using resistance space heaters too).

So, by not using the oil heat very much, we are seeing better than 50% savings.
And, of course we aren't using as much electricity either!
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Old 12-30-09, 08:49 AM   #7
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Default Sanyo performs in single digits!

Weather Station History : Weather Underground
The average temperature since midnight was 9.2 degrees F.

We used the Hybrid mode (oil heat in free-flow) since last night, so the Sanyo only used 2.8 kWh.
This morning at 7AM, when I set the thermostat warmer (from 66 to 68), the unit
went into a 10 minute defrost mode (flashing LED) and then started pumping out
the heat.

Edit:
After defrost mode ran, and the Sanyo seemed to be putting out some heat.
I was out of the house for a few hours, so I set the thermostat down to 66 F.
Leaving the oil heat in free-flow. Upon my return, the Sanyo didn't respond
to calls for heat. It's only drawing 700 watts peak, so it seems like the
compressor isn't turning over. Time to trouble shoot..

Last edited by Xringer; 12-31-09 at 11:43 AM.. Reason: Adding failure note.
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Old 02-01-10, 11:30 AM   #8
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Default Dec was good, Jan was rotten..

Dec 2009
Day, kWh, Temps
1, 9.26, 38
2, 7.23, 44
3, 2.88, 60
4, 5.62, 49
5, 9.17, 36
6, 10.5, 27
7, 12.9, 29
8, 12.2, 29
9, 9.23, 36
10, 8.77, 32
11, 14.2, 23
12, 14.3, 24
13, 12.9, 28
14, 9.95, 37
15, 8.58, 40
16, 10.4, 29
17, 16.9, 16
18, 14.5, 16
19, 11.5, 20
20, 11.5, 21
21, 14.2, 25.3
22, 15.2, 23.3
23, 14.8, 15.2
24, 8.17, 28.7
25, 13.8, 27.1
26, 10.5, 36.2
27, 8.35, 44.6
28, 13.8, 31.7
29, 15.3, 21.0
30, 10.5, 17.0
>>>March, 2010 w/ new outdoor unit<<<
26, 8.56, 38.8
27, 13.9, 26.0
28, 9.37, 37.2
29, 7.05, 49.9


March 30, 2010 note:
On rainy or cloudy days, the power usage will be higher than normal, since there is no solar gain from the south facing windows.


It looks like we spent $67.76 on power for the heat pump in Dec.. (Ave temp 29.9F)

We had an oil delivery on 12-23-09 (see above) but used very little oil in Dec..
(One 1-1-2010, the gauge was still at 7/8. It had dropped to just under 1/2 as of 2/1/2010).

BUT, after the heat-pump broke down, the very cold month of January has been very costly.. (Ave temp 26.9F)
Weather Station History : Weather Underground


The bad news:
Today the oil man delivered 137.4 gallons of oil. $342.12

So, it seems like oil heat cost (in Jan) is about FIVE times more than we paid for running the heat pump in Dec..

According to my quickie calculation, (14 kWh per day x 30= 420 x .201=$84)
IF the heat pump had been working in Jan, it would have cost us between 80 and 90 bucks for electricity . (1/4 oil?)

We do use oil for hot water, so there would have been some oil consumed regardless.


NStar Bill info:
Last month 740 kWh ($150.40) Using Sanyo Heat pump
Current month 615 kWh ($125.93) Using oil heat.
It seems the motors on my oil burner use a good bit of electricity too.
(We have not deployed the old resistive space heaters)..

Conclusion:

A Mini-spit heat pump can save a considerable amount of energy.
(When compared to oil heat).

Once we get the Sanyo working again, I'll be a happy camper..

Note 03/26/2010:
Sanyo is working again!

Last edited by Xringer; 03-30-10 at 08:48 AM.. Reason: March 2010 is here!
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Old 04-01-10, 01:40 PM   #9
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Default Getting ready for summer!

As of 03/26/2010, the Sanyo has been repaired and is working well.
It's starting to get a little warmer now (44.6F on average) ,
so the average kWh is down to about 9kWh a day.
$1.80 a day isn't too bad for the amount of heat we are getting..
Most of the time, it's at 72F and we sleep with it set at 68 these days.
If it's too warm in the bedrooms, we just close the door to keep out the heat.

We are using a little more power at night, because we have started to leave
the den doors open 24-7. The den has a lot of glass (and heat loss),
but we find it gets used more if we keep it warmer. (Our best TV is in there)!

I have turned down the Aquastat on the boiler to it's summer hot water settings of 120F min & 140F max. (Less leakage cycling).


I hear it might get up into the 80s for the weekend.. So, I can do some AC mode testing..


The power log that I'm trying to keep up to date is at:
http://ecorenovator.org/forum/projec....html#post5090

If were not for the floods in the basement, this would be a much more enjoyable spring..
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Old 04-01-10, 01:53 PM   #10
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I'm curious. What happened to the Sanyo that put it out of commission for so long? I would think a unit that's only about a year old would not have had such a failure.

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