The 24 hour plot is the core element in the suite of GasTrac analytics.
Like an EKG for gas usage!
What the Chart Shows
The green line is the outside temperature. The peak temperature occurred at about 2 PM.
The red line is the indoor air temperature. The temperature declines gradually until about 6 AM when the first setback program starts. Spikes from 6 AM until about 7:30 show the furnace cycling. A steady cooling then follows until 4 PM, when the setback thermostat evening program starts. The furnace then cycles regularly from 4 PM until midnight, when the setback program ends
The teal line is the furnace. Each cycle is clearly shown by the strong spike. The furnace cycled 17 times on this day, which seems to be typical. The start and stop of the setback programs are clearly visible. The furnace is on (burning gas) on the inclining portion of each spike.
The purple line is the hot water tank. The hot water tank ran briefly between 2 AM and 3 AM. In this installation the hot water tank was in the same closet as the furnace so some false signals (lower peaks) are visible. GasTrac analytics detects and ignores this “noise”. Feb. 10, 2018 was a Saturday so the hot water tank gas use was delayed a little from a normal weekday.
Why it is Important
Poorly insulated homes show a much steeper decline in ambient temperature compared to tighter building envelopes.
Homes without setback thermostats will show gas usage through the night and during the middle of the day. This information can be used to calculate the cost savings expected from a setback thermostat.
Faulty equipment can be easily spotted. For example, heating systems that cycle frequently (more than 20 times a day) may indicate a faulty furnace component or thermostat.
GasTrac records high resolution data for appliance gas consumption which can be used to: