Warnings
Title 24 Section 140.4 specifies the design conditions to be used in the load calculations when doing Prescriptive compliance calculations. You have chosen to change those design conditions to a different criteria than what is specified in the code. Click on the Calculations, bottom left and you will see the list of calculations appear in the list above. Select Loads from the list and on the right you will see the Options. The Options should be set as follows:
Winter Design Conditions: Median of Extremes
Summer Design Conditions: 0.5%
Mean Coincident Wetbulb
Ignore Design Day for Schedules.
At the Zone level of the Building Tree, Lighting tab, we offer the option to “Override” the Lighting Power Density (LPD) for a Zone (ie to input your own LPD instead of listing the fixtures). Taking this approach when doing Prescriptive compliance is not appropriate since Prescriptive requires you to document the installed lighting fixtures, not just indicate the LPD. The Use Installed LPD option should be selected, and the actual light fixtures should be input into the Room level of the Building Tree.
Your Zone Lighting Power Density (LPD) is zero. This may be because you forgot to input light fixtures into the room, or you deliberately set the value to zero. However, the CEC CBECC engine is designed to automatically assign a Standard LPD to any Zones with no lighting. Check your inputs at the Zone level of the Building Tree, Lighting tab for correct inputs. Verify the Rooms have light fixtures added.
It is acceptable to have a Ceiling Height less than 7 feet or greater than 20 feet for a Zone, but this is reported as a warning to ensure you have not made an input mistake. At the Zone level of the Building Tree, click on the Building Story button and verify the correct input for Ceiling Height.
The normal Occupancy Density for a Zone is set based upon the Occupancy Type selected in the General tab of the Zone. Based upon the California Building Code (CBC) this then determines how many people will be in a space. While it is acceptable to deviate from this number for non-Title 24 calculation purposes, for Title 24 purposes this input will be ignored and the CBC value will be used.
This value can be changed at the Room level of the Building Tree, Occupant tab.
Section 120.1 of the Title 24 Standards dictates the ventilation rate (cfm/person) for a particular occupancy. At the Room level of the Building Tree, Occupant tab, your input for the ventilation rate is lower than the value in the Standards. While this is acceptable for non-Title 24 purposes, this input will be ignored for Title 24 purposes and the value from the Standards will be used.
The selected New Construction Assembly is a certain type (Wall, Slab, Roof, Door) but you have it selected incorrectly. For instance, you may have selected this assembly in the tree under the Slab On Grade entry, then modified the type in the library to be a raised floor. Click on the Libraries selection at the bottom left, select the assembly in the Assembly Library and change the type by using the green Import button and selecting the correct type.
The selected Existing Construction Assembly is a certain type (Wall, Slab, Roof, Door) but you have it selected incorrectly. For instance, you may have selected this assembly in the tree under the Slab On Grade entry, then modified the type in the library to be a raised floor. Click on the Libraries selection at the bottom left, select the assembly in the Assembly Library and change the type by using the green Import button and selecting the correct type.
Prescriptive compliance specifies things like maximum U-Factors for walls, roofs, floors and windows, as well as maximum Solar Heat Gain Coefficient values and minimum Visible Transmittance values. Please review Section 140.3 for Nonresidential Buildings, and Section 150.2 for Residential Buildings on the code requirements and correct this feature in the inputs.
Prescriptive compliance specifies a maximum U-Factor (rate of heat loss) for opaque surfaces including Walls, Roofs and Floors. You must thermally improve this component by adding more insulation to the construction assembly. In the Construction Assembly Editor, select the JA4 tab and either Import a better assembly, or add additional Interior or Exterior Insulation to the assembly.
Based upon the Climate Zone of this home, the simplified Prescriptive compliance approach requires the installation of a Cool Roof for the new roof in the addition. The roof must have a minimum Solar Reflectance as outlined in Section 150.1. At the Construction Assembly editor, check the box for CRRC-1 Roof and enter a Solar Reflectance for the roofing product.
Based upon the Climate Zone of this home, the simplified Prescriptive compliance approach requires the installation of a Cool Roof for the new roof in the addition. The roof must have a minimum Thermal Emittance of 0.75. At the Construction Assembly editor, check the box for CRRC-1 Roof and enter a Thermal Emittance of 0.75 or above.
Based upon the Climate Zone of this home, the simplified Prescriptive compliance approach requires the installation of an Attic Radiant Barrier for the new attic in the addition. At the Construction Assembly editor, check the box for Radiant Barrier in Attic to indicate this feature.
The simplified Prescriptive compliance approach for additions is limited to additions that are 1,000 sqft or less, however, additions greater than 700 sqft now require QII and HERS verification. As such, you cannot use the simplified approach. For additions larger than 700 sqft, you will be required to use the Performance approach, since this addition will required HERS registration and testing for the QII inspections and IAQ fans, and possibly other measures. Under the Calculations, select the NR T24 Performance for your calculation.
Modifications to the HVAC system that involve replacing the system or components require that the project be registered with a HERS provided. The simplified Addition and Alteration methods allow for no registration, and as such cannot be used in this case. Your options would be to use the Performance Approach (which will still required registration) or indicate the HVAC is not being altered, and then submit a separate document via a HERS provider (see www.cheers2016.org) for the HVAC alterations in addition to the envelope documents prepared in EnergyPro.
Modifications to the HVAC duct system that either involve altering the existing ducts, or extending the ducts more than 40 feet require that the project be registered with a HERS provided. The simplified Addition and Alteration methods allow for no registration, and as such cannot be used in this case. Your options would be to use the Performance Approach (which will still requires registration) or indicate the ducts are not being altered, and then submit a separate document via a HERS provider (see www.cheers2016.org) for the duct alterations in addition to the envelope documents prepared in EnergyPro.
The residential Prescriptive compliance rules for alterations limits the window area to 20% of the floor area when your alteration includes an increase of more than 75 sqft of window. You can either decrease your new window area (altered windows do not count) or use the performance approach for the alteration calculation.
When doing an addition over 700 sqft or a new home, Prescriptive compliance requires all roofs have an attic and a radiant barrier. If your roof has no attic, you must use the Performance Approach for compliance. At the Construction Assembly editor, edit the roof assembly to include an attic.
Title 24 requires the installation of a High Performance Attic as describe in Section 150.1 of the Standards. You need to add either R-6 (tile roof) or R-8 (other roofs) for the exterior insulation, or R-13 (tile roof) or R-18 (other roofs) for the interior insulation in the JA4 tab of the construction assembly editor. In addition, you must have the cavity insulation at R-38 or higher.
Title 24 does not permit you to install a new electric resistance or gas tank style water heater as part of an addition, when using the Prescriptive Approach to compliance. You must select either a Gas Tankless or Heat Pump water heater to show compliance using this method.
At the Plant level of the tree, in the Domestic Hot Water Tab, change your water heater selection.
When doing a simulation with the EnergyPlus based CBECC engine, the software generally expects that the airflow rate on the cooling system be within a certain range. The valid range for a successful simulation is going to be a cooling system that has a cfm airflow to tonnage ratio between 300 and 450 cfm per ton.
Review the Cooling output of the system and the airflow rate of the system for conformance with this rule in the Central System library. Either change the cooling output (tonnage) or the airflow rate (CFM) to ensure the system falls within this range should the simulation fail to run.
When an Overhang or Sidefin has been specified on a window in a given wall, it is a requirement that a complete set of inputs for the wall, and all surfaces in that wall (windows and doors) be provided.
Inputs needed for the walls, windows and doors include the Area of the surface and the Width and Height of the surface. The Width and Height must equal the Area of the surface.
In addition, each window and door must include an X and Y input describing the location of the bottom left corner of the surface relative to the bottom left corner of the wall as viewed from the outside.
Note that when describing the X and Y positions, it is important to ensure that no two surfaces on that wall overlap each other.
When an Overhang or Sidefin has been specified on a window in a given wall, it is a requirement that a complete set of inputs for the wall, and all surfaces in that wall (windows and doors) be provided.
Inputs needed for the walls, windows and doors include the Area of the surface and the Width and Height of the surface. The Width and Height must equal the Area of the surface.
In addition, each window and door must include an X and Y input describing the location of the bottom left corner of the surface relative to the bottom left corner of the wall as viewed from the outside.
Note that when describing the X and Y positions, it is important to ensure that no two surfaces on that wall overlap each other.
When an Overhang or Sidefin has been specified on a window in a given wall, it is a requirement that a complete set of inputs for the wall, and all surfaces in that wall (windows and doors) be provided.
Inputs needed for the walls, windows and doors include the Area of the surface and the Width and Height of the surface. The Width and Height must equal the Area of the surface.
In addition, each window and door must include an X and Y input describing the location of the bottom left corner of the surface relative to the bottom left corner of the wall as viewed from the outside.
Note that when describing the X and Y positions, it is important to ensure that no two surfaces on that wall overlap each other.