In order to model partial cooling correctly, you need to enter two different thermostats on Thermostats screen -one heating/ cooling thermostat for Cooled Space and one heating-only thermostat for Non-cooled Space. Splitting the building in two spaces does not have any value without entering two separate thermostats -with and without cooling.

I would not try to match billing and model cooling to within 10%-15%, because room AC usage depends so strongly on behavioral factors. . The common area lighting of 14 Wh/ SqFt/ day seems low compared to living area lighting. I read in one research paper that fixtures in living areas are used on average 2.3 hours per day. We may speculate that common area lighting is lit 24 hours per day, so its power consumption should be 24/ 2.3= 10. 4 times higher then for living areas. You specified some exterior and garage lighting. It is impossible for me to comment on whether your inputs are accurate. In general, if you entered estimated billing base load based on the assumption that September bill is 100% base load, then you need to enter enough lighting/ appliances in the model part to justify this assumption. Treat does not generate any inputs -it just adds up electricity consumption specified on lighting/ appliances screen and compares it to estimated base load usage entered on Analysis Periods screen. Return to Top

Do I have to model every room in a building?

Answer: Formulate a Modeling Strategy - Decided whether to model a building as a single space, floor by floor, or room by room. -Building as a single space is the most common and will suffice for most applications -Floor by floor works well in multi-zone and buildings where walls systems differ on each level (block on 1 st level, wood on 2 nd ) -Room by room is rarely necessary but works well in scenarios where a secondary heating system is used or any single space is under or overheated. Return to Top

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

How do I model a sliding glass door? What about a wood door with a glass window?

Glass doors are modeled as windows (e. g. sliding glass doors are considered operable windows) A 3'x 7' wood door with a 2'x3' window is modeled as a 3'x5' wood door and a separate 2'x3' window. Remember, TREAT's calculation engine is concerned with U value * surface area. Return to Top

Where do I enter the duct blaster results? How do I allocate this value between supply and return?

Duct Blaster results can be entered under the "Heating / Cooling" menu. Click the "Edit Primary Distribution" button and see "Duct Test Leakage at 25Pa". Either allocate the duct leakage evenly to supply and return (300CFM @ 25Pa = 150CFM each to supply and return) or 2/ 3 of leakage to return and 1/ 3 to supply. Return to Top

How do I model a rim joist?

Rim Joist Modeling - create an unheated basement with 7' block walls (or other appropriate material) set it adjacent to "ground". Then create a 1' high uninsulated wall by the appropriate width. Set the exposure adjacent to air and choose orientation (N, S, E, or West). In a simple rectangular structure this creates a basement with 8 walls -4 adjacent to ground and 4 adjacent to air. The rim joists have been defined and now can be insulated. Be sure to add an air sealing improvement as well. Insulating and sealing the rim joists also affects the infiltration to the basement. Create an improvement that reduces the "Unheated space infiltration". Aggregate the Rim Joist Insulation and Rim Joist Air Sealing into a single package. Otherwise, TREAT will only calculate the change in R-value and savings will be too low. Return to Top

How do I model a secondary heating appliance such as a pellet stove or electric radiant baseboard?

Modeling a secondary heating plant (electric radiant baseboard, wood stove, pellet stove). Add the secondary heating plant fuel under the "fuels / rates" menu. Adjust the Btu output of the primary heating plant in the "heating / cooling" menu. (e. g. if a home owner says they burn 2 tons of pellets per year at a cost of $300 then decrease the Btu input of the primary heating plant until the pellet usage hits 2 tons.) Return to Top

Do I have to enter all the lighting and appliances if I am performing insulation and HVAC improvements? Are there any shortcuts?

TREAT calculates the heat gain for both appliances and lighting, thus omission of all lighting and appliances will affect heating and cooling in addition to electric and hot water usage.

NASEO HERS default Btus per day internal gain 72000 People gain 16 hours 4 people 300 each 19200 Lighting and appliance gain per day 52800 Conversion to KWh 3413

KWh per day 15. 47026 Kwh Per Hour 0. 644594 Suggested Default Watts 600 One shortcut for users is to include one 600 watt light bulb running 24 hours per day, instead of the actual appliances and lighting. If you want to put in a few lights or appliances, reduce the 600 watts accordingly. Include a clothes washer and dishwasher to properly account for domestic hot water (reduce the 600 watts accordingly). Return to Top

If an existing building does not have air conditioning can it be added as an improvement?

Put AC in the base building, but set the >thermostat setpoint very high and the pre-retrofit AC efficiency very high. This will minimize/ eliminate existing AC usage. Then put in >whatever AC you want for an improvement, with proper temperature >setpoints and AC efficiency. (Probably need to do this as a package, >with thermostat change as one improvement and AC efficiency as >another.) Energy savings will be negative (increase in kwh use), but >it should model this situation well, as a work-around.

Another way to do it is to enter proposed AC system for the base building with capacity equal to 1Btu/ hr (lowest allowed by TREAT). Enter heating/ cooling thermostat for the base building with realistic cooling setpoints. Existing building cooling usage will be limited by system capacity (close to 0). Then you may create cooling system improvement and enter actual AC capacity. This improvement with model cooling usage -no need to create a package. Return to Top

When working with large buildings the entry of each window is cumbersome and time consuming. Is there any way to speed it up?

Generally you do not have to enter each window separately. You may enter a single record for each window type on each wall. Use Quantity field on Windows screen to specify the number of such windows. Use Weather/ Defaults screen to specify typical window frame/ glazing to avoid the need to open frame/ glazing library each time a window is entered. Return to Top

TREAT allows only one fan space making it necessary to combine all fans into one. Is correct representation of actual ventilation possible?

You may model complex ventilation system with Treat if you define each space that have unique mechanical ventilation rate/ schedule separately. For example, building corridors are ventilated 24 hr/ day. There are also exhaust fans in each bathroom. To model mechanical ventilation in the building you need to split the building into three spaces: -space that represents the portion of the building with no mechanical ventilation (whole building minus bathrooms and corridors) -all corridors with mechanical ventilation -all bathrooms Then you may enter two fans -one for corridors, and one for bathrooms. Note that each fan may serve more than one space. Combining spaces and fans allow very flexible input of mechanical ventilation. Remember that you have to accurately allocate floor area, walls and windows to each space. Return to Top

Can I add a new fuel type as an improvement?

Yes. For example, your building has electric heat and you want to change it to natural gas. To model that you need to enter electricity and natural gas on the Fuels/ Rates screen. Then you may create heat plant improvement and specify natural gas as new heating fuel. Return to Top

I modeled window unit air conditioners but no electricity appears in the Cooling kWh/ year section?

In order to enter complete cooling system information in TREAT it is not enough to describe the cooling system on Heating/ Cooling screen. You must also specify which spaces are cooled on Thermostats screen by setting Is Area Cooled box to Yes for such spaces. If you enter cooling system but have not entered cooling setpoints on the Thermostats screen, TREAT warns you about the possibility of incomplete input when you start model calculations. It displays a warning message "At least one thermostat in the project is heating only." In other words, if you have not specified cooling setpoint for any of the spaces in the project, TREAT assumes that air conditioner never operates. The criterion is used for the model and billing analysis period that is compared to that model. Return to Top

What happens if I model room AC units in the appliance section?

Entering air conditioning on Appliances screen is not a good idea, because Treat assumes that appliances are used uniformly throughout the year, while cooling usage is weather-dependent. Return to Top

How do I model mechanical ventilation in a multifamily?

Multifamily buildings often have multiple forms of mechanical ventilation - common area ventilating fan (includes corridors and stairs) plus individual fans serving the kitchens and bathrooms within each apartment (may also be ducted to a single exhaust). The mechanical room will often has a fresh air intake fan.

The corridors should be modeled as a space. All apartments modeled as a space (divided into 2 spaces named Apartments cooled or uncooled if partially cooled) The basement mechanical room should be modeled as a space. Assign a mechanical ventilation fan that serves "all apartments" with a ventilation rate equal to the sum of all individual kitchen/ bath fans (80 CFM *10 units = 800CFM) Set the operating hours to reflect behavior. Assign a separate fan to specify ventilation for the corridors as fixed CFM (instead of ACH) to model corridor ventilation. Follow the same step for the fresh air makeup fan in the mechanical room. The result is three separate fans serving three separate space (common area, apartments, mechanical room). Return to Top

What should the ACH be in a leaky building?

The "Weather / Defaults" menu in TREAT includes a dropdown menu which asks the user to define the building as "very leaky" "leaky" "average" "tight" or "very tight". This sets the natural ventilation ACH to. 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 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

I know there is a high possibility that the water heater is undersized, or not sized for the correct # of current occupants. Should I true up? Why?

True up hot water usage for the following reasons: 1. 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. 2. 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. 3. 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 I can think of is by artificially reducing amount of needed hot water in the existing building and increasing it in improvement. This may be done using Appliances Hot Water Usage input. Return to Top

Do I to true up building model values and not the billing data values?

Generally this is true. However, sometimes you may feel that 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 on 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. I should only true up values, if and only if treat calculated values >are too less than the actual or too high than the actual.

This is correct. I would not aim for 100% match, but they should be close, at least within 10%-15%. Return to Top

From the modeling point of view it does not matter whether the same thermostat controls both heating and cooling or there are two different thermostats?

You should use the thermostat to define cooling setpoint and hours of usage. Return to Top

If we just put the cooling thermostat on to the existing thermostat, doesn't the program assume that the air conditioners are trying to cool the whole space?

Yes it does. Not all of the apartments have air conditioners. In order to model the building accurately you need to split it into two spaces -one space that includes all air-conditioned areas and another space without air conditioning. Same rule applies to modeling mechanical ventilation, overheated areas or areas with different indoor temperatures/ schedules. Return to Top

I dont know what should be my Heating month threshold and cooling month threshold. I would put 50 and 55 as the value for both the fields? What is recommended.?

Below is the abstract from TREAT manual with the answer to your question. Heating Month Threshold HDD/ month is used to identify the bills that do not have significant heating usage and are candidates for base load estimation. TREAT uses the reference temperature and average daily temperatures to calculate heating degree-days in each utility bill. It compares the HDD value to the entered winter bill threshold. If the difference for a 30-day bill is less then the threshold, the bill is assumed to be a non-heating bill. This algorithm is applied to all the bills that have base and/ or cooling load in addition to the heating load. Heating threshold depends on the building heat loss rate, reference temperature, and specifics of heating system control. Example: You anticipate that the building has the heat loss rate (slope) of 15Btu/ SF-HDD and you set your Heating Month Threshold to 50 HDD/ month. Then all the months during which the heating energy usage was less than 15* 50= 750Btu/ SF-month will be used to calculate the base load. This input will work out well for the buildings where the heating system is turned off during warm months. 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. Return to Top

What is this reality check? It gives me a message saying that the reference temp. 36.83 F is not in the expected interval. But I have not mentioned this value as a reference temp. anywhere.

The reference temperature is calculated by TREAT based on your model inputs. Reference temperature of 36F means that your building requires heating only when the outdoor temperature falls below 36F. This is unusually low. Typical reasons for that is very high heat gains from lighting, appliances or DHW along with very low infiltration/ mechanical ventilation rate and high wall R-values. Return to Top

What is the Btu/ SqFt-HDD default target value?

Default target heating energy usage Btu/ SqFt-HDD is a default target value that may be later adjusted for each analysis period on the Analysis Periods screen. The value is used to calculate the investment potential of the building, which is illustrated on Heating Energy Scorecard and Investment Potential reports. The target is different for different buildings, however you may use the following numbers as guideline: best new homes -2Btu/ SqFt-HDD ENERGY STAR® homes -5Btu/ SqFt-HDD low usage existing homes -7Btu/ SqFt-HDD medium usage existing homes -11Btu/ SqFt-HDD high usage existing homes -15Btu/ SqFt-HDD Return to Top

What is the "Heating Month HDD/ month?

Heating Month Threshold HDD/ month is used to identify the bills that do not have significant heating usage and are candidates for base load estimation. The heating threshold is used for all analysis periods. TREAT uses the reference temperature and average daily temperatures to calculate heating degree-days in each utility bill. It compares the HDD value to the entered winter bill threshold. If the difference for a 30-day bill is less then the threshold, the bill is assumed to be a non-heating bill. This algorithm is applied to all the bills that have base and/ or cooling load in addition to the heating load. Heating threshold depends on the building heat loss rate, reference temperature, and specifics of heating system control. For example, you anticipate that the building has the heat loss rate (slope) of 15Btu/ SF-HDD and you set your Heating Month Threshold to 50 HDD/ month. Then all the months during which the heating energy usage was less than 15* 50= 750Btu/ SF-month will be used to calculate the base load. This input will work out well for the buildings where the heating system is turned off during warm months. Similar logic applies to cooling threshold.

Unfortunately, breaking the space into a cooled space and an uncooled >space is not very plausible because we are working with a large, >multifamily building (188 units and 181407 square feet), and while we >know how many air conditioners there are, we do not know what rooms or >what square footage they cool. From this lack of data, we feel that >number of assumptions we would have to make in order to create a >second space would make our final results so unreliable that they >would not justify the effort put in to come up with these >approximations. Do you think this fear is founded, or would our >results be reliable enough to serve as the basis of our recommendations to our client? The quality of modeling outputs is never better than the quality of modeling inputs. The best approach would be to survey the building and record in which rooms the AC units are installed.

Would we be able to simplify the model by adjusting the number of >hours the air conditioner is on? If we estimate that 25% of the space >is cooled, for example, and then set the unoccupied hours to 4 (which >is 25% of the 16 hours we think the building is actually unoccupied), >would that compensate for the discrepancy in the space cooled versus >the entire space? Is that a reasonable estimation, or would it give >us completely unreliable results? You could use the same assumption (25% of space is cooled) to create a separate cooled space. Then assign walls, windows, appliances, lights, etc. to this space in the same proportion.

You may try using your approach, but you would need to reverse the math. Treat unoccupied hours are hours with higher thermostat setpoint which leads to lower cooling load. If the building is unoccupied for 16 hours per day, then it is occupied only 8 hr/ day. If you apply your logic, you would have to change hours occupied to 8*. 25= 2hr/ day, which would mean 24-2= 22 hours unoccupied. I see many possible problems with this approach. Below are just a few of them: 1. TREAT limits monthly cooling energy to available monthly capacity of the cooling system. Reduced occupied hours for larger space will lead to higher load during shorter periods of time. This high load will be limited with available cooling system capacity, which will likely lead to incorrect monthly usage. 2. Cooling system may still operate during unoccupied hours to maintain the building at cooling setback temperature. 3. The interactions with space heat gains/ solar gains will be underestimated due to shorter cooling system runtime. About the amount of billing data we are using: We get the error >message that there is not enough billing data. We have 17 months >worth of bills. Return to Top

How much do we need for TREAT to be able to calculate a base load for a space that is both heated and cooled?

Is your building electrically heated? Generally in order to calculate base load TREAT needs at least one actual bill during which there was no cooling or heating (if electric heat). Heating and cooling usage for a billing period is determined base on average daily temperature for the time of the bill from Daily Weather Data Library and heating/ cooling threshold entered on General Billing Data and Analysis Periods screen. See User Manual, General Billing Data section for more details on the threshold. Return to Top

When I mark the box to have it use our estimated base load numbers, it does not let me enter a value for the natural gas.

TREAT should let you enter the esimated base load values for all the fuels that are checked in Fuels Used For Base Load area of Analysis Periods screen. Note that if the analysis period is compared to model, this information is not editable on Analysis Periods screen because it is taken directly from the model part. Return to Top

Does TREAT require an AFUE or Steady State Efficiency?( Under Heating /Cooling)

Typically equipment efficiencies are stated in terms of AFUE (annual fuel utilization efficiency). This number is usually less than the steady state output, significantly less for older equipment. Sometimes this is very

different, such as older equipment that might have a steady state efficiency of 80% and a AFUE of 60-70%. The efficiency is used when we convert heating load to units of fuel or $ used for heating. In this regard seasonal efficiency makes most sense. For larger systems AFUE is not available and must be estimated based upon steady state efficiency. Return to Top

Total room loads do not add up to equipment capacity.

The equipment capacity is not equal to the sum of the room loads because Treat calculates the peak simultaneous load on the building, which may typically does not coincide with the peak load on each room.

The difference between space load and equipment load is covered in notes 3 and 5 of the report. Please let me know if you want to add other explanations. Return to Top

How building load was turned into equipment capacity, using the equipment and distribution efficiencies, and the safety factor?

RequiredOutputCapacity= BuildingLoad* SafetyFactor/ DistributionEfficiency This logic is described in Note 5 or the report. Note that diversity is built in Building Load, which is based on SUNREL™ output. Return to Top

What if part of the building envelope is directly adjacent to another building? (a. k. a party wall)

User should create a thermal model of the building in Treat, not geometrical model. A wall should be entered in Treat only if there is significant heat exchange through it. Notice that in Treat we ignore (disallow) walls between heated spaces. If the wall separate heated spaces with similar temperatures, user may simply ignore it, because there is no significant temperature difference on the opposite sides of the wall. A user once asked me how to model a wall that is adjacent to hot bakery and is warm year round. I suggested to model it as additional base load in the space. The equivalent wattage may be estimated using R-value and area of the common wall and approximate temperature difference on both sides of the wall. Watt= UA( T1-T2)/ 3.412 Return to Top

Billing Analysis won't run?

Billing analysis in the current version of Treat requires that there is at least one actual bill in the analysis period for each metered space. E. g: Several metered spaces in a database had a single actual bill OUTSIDE the user defined analysis period. For example, space 2D had a single actual bill with start date of 4/ 16/ 2001 and 31 elapsed days. The user defined analysis period had an end date of 4/ 2001, which is equivalent to 4/ 30/ 2001. Since the actual bill was not completely inside the analysis period (it ended on 5/ 15/ 2001), it was not included in the calculations for this analysis period. Changing the analysis period end month from 4 to 6 will fix the problems and TREAT will perform the calculations. Return to Top

Under Heating / Cooling - Is the efficiency an AFUE value or the Steady State Efficiency?

The efficiency one should enter in TREAT is the AFUE (a number which can only be guessed at for large steam boilers).

Generally, the primary goal of your modeling is to calculate annual energy usage in the building. You verify it against billing, calibrate the model and predict annual savings from recommended improvement packages. For this purpose AFUE makes more sense then steady state efficiency, which may be significantly higher than AFUE, especially for older systems. If you use steady state efficiency you may underestimate annual energy usage and annual savings from improvements. Return to Top

When we put in an AFUE figure for efficiency we often get the message that the heating system is too small. This is false, as most of these buildings are in fact overheated?

I do not see contradiction here. On a typical day the building may be overheated due to system imbalance, high distribution losses, inadequate heating control, etc. However, on a few days when outdoor temperature falls to design heating conditions the building may become underheated. Also, as part of load sizing, TREAT applies user-specified heating safety factor to required heating input. Default value for the factor is 25%. TREAT reports insufficient heating system capacity if the load is met but not exceeded by the specified safety factor. You may choose to reduce the safety factor to compensate for difference between steady state efficiency and AFUE for load sizing.

To establish the adequacy of the size of the heating system, I believe it is more correct to use the steady state efficiency. AFUE takes off-cycle and other losses into account that do not affect usable boiler output. I agree that steady state efficiency makes the most sense for determining required input capacity. However, our load sizing report presents required heating output capacity. You may choose to use steady state efficiency to convert it to required input capacity manually. Return to Top

Both Natural Gas and Electricity are checked in the Fuels Used in Base Load box, but it still won't let me enter in an estimated base load for the gas, and it still doesn't calculate the gas information. The 75 Btu/ day/ sq. foot heated area is a very rough estimate -we are working on finding a better one.

TREAT does not allow you to enter estimated base load because gas is not a heating fuel. The annual gas usage is not shown in the lower part of the screen due to a bug that will be fixed in the next version. For now, you may convert the value of calculated base load Btu/ day/ SqFt for gas displayed in the center of Analysis Periods screen to annual gas usage. Multiply it by heated area (181407 SqFt), by 365 days/ year (to convert to annual) and divide by 100000 (Btu/ Therm). Return to Top

Why are there no energy savings in an electric to gas dryer conversion:

My understanding of this is that there are no energy savings involved in the fuel switchover just a large cost savings. Energy usage depends on your inputs. You can estimate it as follows: AnnualEnergyUsage[ Btu] = ElectricityUsage[ kWh/ year]* 3414 +AnnualSecondFuelUsage[ Therm/ year]* 100000 The final number might be different due to interaction between internal heat gains and heating/ cooling. Return to Top

Electric Clothes Dryers vs. Gas Dryers

I'm thinking about it from another angle. For any given load of clothes that need to be dried, it will require a certain amount of Btus. Whether those Btus come from gas or electricity does not affect the amount of energy required to evaporate the water. The gas will be less efficient (not counting power plant and transmission losses), so >if anything there would be "negative" savings. This is a reasonable way to look at it We could ask user to enter number of loads and assume some Btu per load to calculate energy usage. However, Btu per load are probably different for different dryers. For example, imagine an extreme case when the drum does not rotate and the clothes being dried just sits in a pile inside the drier. Intuitively it seems that in this case it would take more Btus to dry the same amount of clothes. I am sure that dryer manufactures experiment with drum size, rotation speed, hot air CFM/ temperature, etc. To account for different efficiencies of dryers, TREAT asks user to enter the annual fuel consumption of the dryer instead of the number of loads. The gas dryers in TREAT appliance library do use more Btu per year than electric dryers, just as you expect. I would check the annual usage input for the dryers that gives the questionable results. Return to Top

The savings projected by TREAT for a lighting improvement is lower than the results of my spreadsheet.

Payback and SIR for lighting may be lower than you expect due to interaction between lighting and space heating. Make sure that your spreadsheet accounts for this. Return to Top

Truing up a Model: Baseload - Billing vs. Model

The difference in base load 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

Mechanical Ventilation in Multifamily Buildings

Typically only corridors are mechanically ventilated in multifamily buildings .Users often enter mechanical ventilation (Fan screen) of 0.63ACH for the entire building which is very unusual for a residential building. Individual apartments may also be ventilated via individual kitchen and bath exhaust fans. If the apartments are modeled as a single space (very common) then add a single fan to this space equal to sum of all the kitchen and bath exhaust fans. E. g. 10 kitchen fans @ 80CFM = 800CFM total operating 1 hour per day. Return to Top

Basements -Should they be modeled as heated or unheated spaces.

1. If basement is entered as heated space, then CFM50/ ACH input for all heated spaces would automatically apply to it. In reality, basement would probably not be included in blower door test and its infiltration rate would be different from the rest of the house. 2. There will be no way to model the floor adjacent to basement because Treat does not allow surfaces between conditioned spaces. 3. We would not be able to model many improvements, because losses will be considered to be useful heat. 4. We do include internal heat gains in energy balance calculations of unheated spaces. The only exception is heat plant stand-by loss. Typically, if the basement is finished, then boiler/ furnace is located in a separate mechanical room. In this case the heat plant loss contributes to overheating of the mechanical room and not to useful heating. If there is a need to model stand-by loss, this can be done by increasing surface area of piping/ ductwork in the basement. This assumption would produce more realistic results than assuming that the basement is maintained at the fixed temperature. Mark says it makes a big difference in the modeling of ducts in basements with the heated basement having a much lower total usage. The difference here, as in REMRate, is in defining what is heated. People use basement losses to heat basements so the space is more usable. The heat from distribution losses and heating plant of cycle losses in these spaces typically maintains a reasonable temperature for the full heating season, unless the space is very leaky. So is the space heated? We (Bob K and I) tend to say yes. I would love to see the basement temperatures being generated by TREAT, so that information could be used in truing up the performance of the model. But barring that, I think that modeling the basement as heated at 55-65 degrees is the safest way to proceed.

>> This is an important difference between REMRate and TREAT since REM >> generally suggests that the basements be outside. This is a matter of much >> contention in the rating community. Since TREAT can handle a zone with a >> different temperature schedule, TREAT can put the basement inside and at >> the >> temperature that is typically maintained in the basement. Return to Top

How should I adjust my model to match actual billing?

Truing up a TREAT model against billing DOUBLE CHECK YOUR MODELING FOR SIMPLE MISTAKES (missing walls, roofs, floors, typos, etc.) Under "Infiltration" increase the ACH (only if ACH was used ). A general 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 # 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

How do I model a glass door or a wooden door with a small glass window?

Glass doors are modeled as windows (e. g. sliding glass doors are considered operable windows) 3'x 7' wood door with a 2'x3' window is modeled as a 3'x5' wood door and a separate 2'x3' window. Remember, TREAT's calculation engine is concerned with R value * surface area. Return to Top

Where do I enter my Duct Blaster results? How do I allocate the leakage between supply and return?

How do I model a Rim Joist Improvement?

Rim Joist Modeling - create an unheated basement with 7' block walls (or other appropriate material) set it adjacent to "ground". Then create a 1' high uninsulated wall by the appropriate width. Set the exposure adjacent to air and choose N, S, E, or West. We end up with 8 walls in the basement -4 adjacent to ground and 4 adjacent to air. The rim joists have been defined and now can be insulated. Be sure to add an air sealing improvement as well. Insulating the rim joists significantly affects the infiltration to the basement. Create an improvement that reduces the "Unheated space infiltration". Aggregate the Rim Joist Insulation and Rim Joist Air Sealing into a single package. Otherwise, TREAT will only calculate the change in R-value and savings are low. Return to Top

How do I model a wood or pellet stove? What about supplemental electric baseboard?.

Modeling a secondary heating plant (electric radiant baseboard, wood stove, pellet stove). Add the secondary heating plant fuel under the "fuels / rates" menu. Add the secondary heating plant under the "Heating / Cooling" menu. Adjust the Btu output of the primary heating plant in the "heating / cooling" menu until the Btu input of the primary heating plant records the known usage. (e. g. if a home owner says they burn 2 tons of pellets per year at a cost of $350 keep adjusting the Btu output of the primary plant until 2 tons of pellets are used by the secondary plant. A primary plant may never operate at capacity due to the secondary plant) Return to Top

Do I have to model appliances for every model?

There is a "work around" for eliminating the input of lighting and appliances. TREAT calculates the heat gain for both appliances and lighting, thus omission of all lighting and appliances will affect heating and cooling in addition to electric and hot water usage.

NASEO HERS default Btus per day internal gain 72000 People gain 16 hours 4 people 300 each 19200 Lighting and appliance gain per day 52800 Conversion to KWh 3413

KWh per day 15. 47026 Kwh Per Hour 0. 644594 Suggested Default Watts per hour 600 One shortcut for users is to include one 600 watt light bulb running 24 hours per day, instead of the actual appliances and lighting. If you want to put in a few lights or appliances, reduce the 600 watts accordingly. Include a clothes washer and dishwasher to properly account for domestic hot water (reduce the 600 watts accordingly). Return to Top

Does TREAT calculate the baseload for the entire building in a multifamily model?

Yes, TREAT calculates the baseload of the entire building including common area. In multifamily buildings the baseload may include common area lighting, common area laundry facilities, exterior lighting, all lighting and appliances used within all apartments. Return to Top

How do I true up the values?

You can not true up 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 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.

1. I dont know what should be my Heating month threshold and cooling >month threshold. I would put 50 and 55 as the value for both the fields? what is recommended.? Below is the abstract from TREAT manual with the answer to your question. Heating Month Threshold HDD/ month is used to identify the bills that do not have significant heating usage and are candidates for base load estimation. TREAT uses the reference temperature and average daily temperatures to calculate heating degree-days in each utility bill. It compares the HDD value to the entered winter bill threshold. If the difference for a 30-day bill is less then the threshold, the bill is assumed to be a non-heating bill. This algorithm is applied to all the bills that have base and/ or cooling load in addition to the heating load. Heating threshold depends on the building heat loss rate, reference temperature, and specifics of heating system control.

Example: You anticipate that the building has the heat loss rate (slope) of 15Btu/ SF-HDD and you set your Heating Month Threshold to 50 HDD/ month. Then all the months during which the heating energy usage was less than 15* 50= 750Btu/ SF-month will be used to calculate the base load. This input will work out well for the buildings where the heating system is turned off during warm 1. Refer to General billing Data the target heating energy usage is in BTU/ SQ-FT/ HDD and the same in the Analysis Periods section is referred as BTU/ YEAR/ HDD/ SQ-FT, so do I divide by the no. of days in the year? >or is this a typo, as this refers to the BTU/ SQ-FT/ HDD value in >general billing data. This is a typo. We will correct it, thanks for pointing it out. 2. When I click on calculate base load analysis or run billing analysis

button it gives me an error, which says( but the calculate model button works) Type mismatch in expression Billingcalc module: calc and store meter data( 2) I will check it out and get back to you. 3. In case of lighting, I only have bills for the common areas. The base load that treat calculates is for the entire building, right?

Yes How do I true up the values? You can not true up 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 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.

4. Similarly for the gallon's/ yr baseload for fuel, I know there is a >high pssibilty that the water heater is undersized, or not sized for no. of current occupants. Should I true up? and why?( bcos increasing the baseload will not save energy) This is correct. I would not aim for 100% match, but they should be close, at least within 10%-15%. months.

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.

2. Also what is this reality check? It gives me a message saying that the reference temp. 36. 83 F is not in the expected interval. But I have not mentioned this value as a reference temp. anywhere. The reference temperature is calculated by TREAT based on your model inputs. Reference temperature of 36F means that your building requires heating only when the outdoor temperature falls below 36F. This is unusually low. Typical reasons for that is very high heat gains from lighting, appliances or DHW along with very low infiltration/ mechanical ventilation rate and high wall R-values. Return to Top

How do I model a tankless hot water heater with Treat?

Use a very small capacity (1 gallon) and an input Btu equal to the input Btu of the boiler (eg. 4, 200, 000Btu). Return to Top

When I change the value of "Default Conditioned Area" on the General Billing Data screen, then re-calculate, fuel usage for the building does not change.

Answer: The conditioned area input on the billing screen is only used in billing calculations. To change the area of the building, you must change the input value for Floor Sq Ft on the Spaces screen. Return to Top

In the ACEEE website, why is the energy usage of their dishwashers, in kWh per year, much higher than the values given in the Treat Appliance Library?

Answer: The "Electricity Usage kWh per Year" in the Appliance Library does not include energy used to heat hot water that is used by the appliance. The figure that is given on dishwasher labels, etc, for dishwasher energy use includes the energy to heat the hot water. Treat uses a separate field to enter hot water usage for appliances, "Hot Water Usage Gallons / Year". A high-efficiency dishwasher has a value of 1560 gallons = 6 loads per week * 52 weeks per year * 5 gallons per load. Treat has a domestic hot water algorithm that calculates hot water energy usage based on all domestic hot water loads in the project. Return to Top

How to model the reduced infiltration that results from window replacement.

Answer: Create 2 improvements and combine them into a package. Window Replacement Improvement assumes only a change in R-value and solar gain. Infiltration Improvement is needed if there is also a reduction in infiltration as a result of replacing windows. Combining both in a package will account for the lesser savings from reduced infiltration due to the greater insulation of the buuilding envelope with the new windows. Give the infiltration improvement a cost of $1. SIR of the package will be the SIR of the window replacement project.