I'm in the Detroit area...

I have compiled by gas usage from 9/1/04 to 2/3/06 by billing dates, as
well as heating degree days for those same range of dates.

Since I have been refinishing my basement, AND turned the thermostat
down from 70-71 to 67, I would like to anaylze how much more efficient
my house is. The basement is no longer pouring cold air into the
upstairs since I have insulated and drywalled the outside walls.

So how do I compare these with different heating degree days? If the
heating degree days is 10% less this year from last, would you expect
10% less gas usage? Or is it not linear?

For a great example:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage (that's how much was used during july/august
when the heater was off completely).

Is this a good savings? It looks pretty good to me!

One thing you have to be wary of is that some Gas Meter Readers get lazy in
Winter and just sit at home and estimate your gas meter reading while
watching game shows on TV or whatever.
I have had it happen twice to me. Once at a large Mfg. Plant where I was
the Accountant and noticed the gas billings seemed odd. When I brought it
to the attention of the Manager of the Gas Company, they caught the lazy
meter reader and he was fired.
Rick

"Larry Bud" wrote in message
oups.com...
I'm in the Detroit area...

I have compiled by gas usage from 9/1/04 to 2/3/06 by billing dates, as
well as heating degree days for those same range of dates.

Since I have been refinishing my basement, AND turned the thermostat
down from 70-71 to 67, I would like to anaylze how much more efficient
my house is. The basement is no longer pouring cold air into the
upstairs since I have insulated and drywalled the outside walls.

So how do I compare these with different heating degree days? If the
heating degree days is 10% less this year from last, would you expect
10% less gas usage? Or is it not linear?

For a great example:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage (that's how much was used during july/august
when the heater was off completely).

Is this a good savings? It looks pretty good to me!

Larry Bud wrote:
I'm in the Detroit area...

I have compiled by gas usage from 9/1/04 to 2/3/06 by billing dates,
as well as heating degree days for those same range of dates.

Since I have been refinishing my basement, AND turned the thermostat
down from 70-71 to 67, I would like to anaylze how much more efficient
my house is. The basement is no longer pouring cold air into the
upstairs since I have insulated and drywalled the outside walls.

So how do I compare these with different heating degree days? If the
heating degree days is 10% less this year from last, would you expect
10% less gas usage? Or is it not linear?

It is linear, but I'll bet you also have a water heater and that also
uses gas and it does not change due to heating degree days. In fact it is a
month or two behind the effect.

The other problem you may face is if you are looking at your bill rather
than the meter. The bill is often estimated every other moth or so.


For a great example:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage (that's how much was used during july/august
when the heater was off completely).

Is this a good savings? It looks pretty good to me!

--
Joseph Meehan

Dia duit

Rick Shaw wrote:


"Larry Bud" wrote in message
oups.com...
I'm in the Detroit area...

I have compiled by gas usage from 9/1/04 to 2/3/06 by billing dates, as
well as heating degree days for those same range of dates.

Since I have been refinishing my basement, AND turned the thermostat
down from 70-71 to 67, I would like to anaylze how much more efficient
my house is. The basement is no longer pouring cold air into the
upstairs since I have insulated and drywalled the outside walls.

So how do I compare these with different heating degree days? If the
heating degree days is 10% less this year from last, would you expect
10% less gas usage? Or is it not linear?

For a great example:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage (that's how much was used during july/august
when the heater was off completely).

One thing you have to be wary of is that some Gas Meter Readers get lazy in
Winter and just sit at home and estimate your gas meter reading while
watching game shows on TV or whatever.

Even if it says "actual"??

I have had it happen twice to me. Once at a large Mfg. Plant where I was
the Accountant and noticed the gas billings seemed odd. When I brought it
to the attention of the Manager of the Gas Company, they caught the lazy
meter reader and he was fired.

more heat/cool calculators at:
http://www.hvacopcost.com/

double check your basement insulation and more at:
http://www.buildingscience.com/resources/basements.htm

"Larry Bud" wrote:

I'm in the Detroit area...

I grew up there. Moved south as soon as I could...

For a great example:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage (that's how much was used during july/august
when the heater was off completely).

2005: (12.433-0.65)ccf/day divided by 43.9 heating degree/days = 0.268
ccf/heating degree

2006: (8.1-0.65)ccf/day divided by 30.54 heating degree/days = 0.244 ccf/heating
degree.

Is this a good savings? It looks pretty good to me!


About a 9% savings.

-- Doug

"Larry Bud" wrote:

1/6/05-2/5/05 -- 30 days, 43.9 heating degrees PER day, 12.433 ccf/day
1/6/06-2/3/05 -- 28 days, 30.54 heating degrees PER day, 8.1 ccf/day

You are probably talking about "degree-days," ie degrees TIMES days vs
degrees PER day. A degree-day is a 1 F temp diff maintained for 1 day...
43.9 DD would be a temp diff of 43.9 F maintained for 1 day.

I should also note that I would estimate approx 0.65 ccf/day for non
furnace related gas usage...

That may not matter in January, if the heat ends up in the house.

If you know your furnace efficiency and therms/ccf and indoor electrical
energy usage, you can estimate the thermal conductance of your house. For
instance, with an 80% furnace and 1 therm/ccf and 600 kWh/mo (68K Btu/day)
of indoor electrical use, the first record would correspond to a house with
(100Kx12.433/0.8+68KBtu)/43.9F/24h = 1540 Btu/h-F and the second would make
(100Kx8.1/0.8+68KBtu)/30.54F/24h = 1474, both being quite high, compared to
a new energy-efficient house with a thermal conductance of 200-400 Btu/h-F.

Nick