TREAT FAQ: True-Up
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Truing up a TREAT model. What if the model and billing do not match? (e. g. 25% difference where the bills are higher than the model)
DOUBLE CHECK YOUR MODELING FOR SIMPLE MISTAKES (missing walls, roofs, floors, typos, etc.) Under "Infiltration" increase the ACH (only if ACH was used ). Increase the setting on the thermostat and increase the # of hours occupied. Under "Heating / Cooling" hit the "Edit Primary Distribution" button and relocate ducts to an unheated space (e. g. ducts in an unheated basement or attic will affect usage). Baseload adjustments -In the "Appliances" menu, increase or decrease the kWh per year on appliances. Increase or decrease the # of loads by the washer or dishwasher by increasing DHW usage + electric. Return to Top
Can I true up the model against billing if I only have common area bills in a multifamily?
You can not true up a model with billing if complete billing data is not available. However, you may use bills for common area lighting to verify the model inputs. Instead of entering Watts and hours per day usage of common area lighting on the Lighting screen, you may create the following record on Appliances screen:
- Appliance Name: Common Area Lighting
- Electricity Usage kWh/ year: annual value calculated using the utility bills for the common area
- Second Fuel: None
- % Heat Loss to Space: 100%
- Quantity: 1 You may also convert common lighting kWh from utility bills to Watts / hours per day and enter the values on Lighting screen.
This approach will require slightly more manual calculations. Return to Top
Do I do to true up building model values and not the billing data values?
Generally this is true. However, sometimes you may feel that a particular utility bill is not reliable/ realistic. For example, there may have been construction work done at the site that resulted in very high electricity usage during one billing period. In this case, you may set Include Bill in Analysis to No for this bill, and run billing analysis again to see how this affects results. Only true up values, if and only if the TREAT calculated values are too less than the actual or too high than the actual.
I would not aim for 100% match, but they should be close, at least within 10%-15%. Return to Top
I know there is a high possibility that the water heater is undersized, or not sized for the correct number of current occupants. Should I true up? Why?
You should True up hot water usage for the following reasons:
- Since both space and hot water fuel is Oil# 2, each Oil# 2 bill will include heating and hot water consumption. If you do not enter hot water heater in the model, TREAT will assume that OIL# 2 bills are 100% heating, thus overestimating building heat loss.
- If water heater stand by loss is significant, accuracy of heating calculations may be compromised because interaction between stand by loss and heating will be ignored.
- If you plan to replace undersized DHW heater, it might be beneficial to predict additional energy consumption. Note that TREAT does not handle undersized water heaters very well. It assumes that required hot water is always generated. The only way to model it is by artificially reducing the amount of needed hot water in the existing building and increasing it in improvement. This may be done using the Appliances Hot Water Usage input. Return to Top
Truing up a Model: Baseload - Billing vs. Model
The difference in the baseload between billing and model often results from insufficient lighting and appliance load entered in the model. Statistics for single family houses may serve as a benchmark. A typical lighting load is 3Watt-hr/ SqFt/ day. This is higher for multifamily buildings as they are more densely occupied. A common mistake is a very low input for the estimated load for misc. appliances. You may use typical small appliances listed in the Appliance Library to get a better estimate. Return to Top
How should I adjust my model to match actual billing?
DOUBLE CHECK YOUR MODELING FOR SIMPLE MISTAKES (missing walls, roofs, floors, typos, etc.) Under "Infiltration" increase the ACH (only if ACH was used ). Anumbergeneral rule is .6 ACH for a tight building. .9 for moderate and 1.2 for leaky. Increase the setting on the thermostat and increase the number of hours occupied. Under "Heating / Cooling" hit the "Edit Primary Distribution" button and relocate ducts to an unheated space (e. g. ducts in an unheated basement or attic will affect usage). Baseload adjustments , in the Appliances menu, increase or decrease the kWh per year on appliances. Increase or decrease the number of loads by the washer or dishwasher by increasing DHW usage + electric. Return to Top
How do I true up the values?
Similarly for the gallon's/ yr baseload for fuel, there is a high possibility that the water heater may be undersized, or not sized for the number of current occupants. Increasing the baseload will not save energy. I would not aim for 100% match, but they should be close, at least within 10%-15%. months.
The Cooling Month Threshold, HDD/ month, is used to identify the bills that do not include cooling. The procedure is similar to the one described for the winter threshold. This algorithm is applied to all the bills that have a base and/ or heating load in addition to the cooling load.
For more instruction on how to use the True-Up feature, view our TREAT Tutor.
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