COMcheck & REScheck

Walk-through

05.06.2020

Providing effective energy strategies for buildings and communities

ICC Preferred Provider # 2396ICC Course # 21526

• SEDAC is a Preferred Education Provider with the International Code

Council (ICC). Credits earned on completion of this program will be

reported to ICC for ICC members. Certificates of Completion will be

issued to all participants.

• This workshop is approved for 1 LU/HSW CES credits from the

American Institute of Architects (AIA). Credits earned on completion

will be reported for AIA members.

Learning Objectives

1. Understand the basic functions of COMcheck and

REScheck software tools.

2. Be able to identify the construction documents

needed to complete a compliance check and learn how

to enter that data into COMcheck and REScheck

3. Be able to understand the output reports and how to

address non-compliance.

• We assist buildings and communities in achieving energy efficiency, saving money, and becoming more sustainable.

• We are an applied research program at University of Illinois, working in collaboration with 360 Energy Group.

Our goal: Reduce the energy footprint of Illinois.

Who we are

• Technical support

• energycode@sedac.org

• 800.214.7954

• Online resources at sedac.org/energy-code

• Workshops

• Webinars

• Online on-demand training modules

Upcoming SEDAC Online Workshops

Energy Code Key Requirements in Illinois

• May 26, 1PM – Commercial

• June 2, 1PM – Residential

Registration: https://smartenergy.illinois.edu/energy-code/energy-code-workshops/

COMCheckOverview

Desktop version – planned phase-out

User Options

Web version

Process Flow Overview

Image courtesy PNNL Building Energy Codes Program

Process Flow Overview

Image courtesy PNNL Building Energy Codes Program

Gather drawings, specifications

Area take-offs and entry into COMcheck

Building Area or Space-By-Space Method, lighting counts, total kW

Identify and Enter Mechanical System Types

Verify Compliance

Basic Project Data Entry – Important!• Code version• State• City• Project type

New ConstructionAdditionRenovation

• Building Area type(s)• Compliance Options

Efficiency Pkg optionAir Barrier optionsEach option has help

text explaining each option, any entry restrictions, etc…

Each selection pre-populates maximum allowances based on this information.

• Depending on efficiency

option selected, COMcheck

may limit future entries:

• High Perf. HVAC – limits

future equipment entries• Can’t enter CV or Mixing VAV boxes for

multi-zone system type.

• Reduced LPD – COMcheck-

Web must use building area

method, can’t use space-by-

space.• COMcheck desktop does not have this

restriction.

• Web version to be corrected in next update.

• IECC 2012 restriction removed in IECC 2018

Restrictions on Entries

• Helps to build take-off sheet for entry• COMcheck does not have an area calculator like

REScheck.

• Work from individual floors, wall types,

windows, orientations, etc.• Helps to color-code types and/or orientations• Sum like types for single area to enter into

COMCheck

Proceed to Envelope Entry

• Same for window/door types• Window/door types will need to be

associated with wall types.

• Only include floors exposed to unconditioned air/space, or at-grade• Ignore basement slabs >2ft below

grade.• Slab-on-grade exposed perimeter

length is entered, not slab area.

• List of envelope entries can be

extensive, especially with

multiple wall types/orientations.

• A take-off sheet helps avoid

missing data.

• Window and door areas will

subtract from associated wall

areas when entered.

• This building had concrete

walls, brick-faced steel studs,

limestone-faced steel studs,

and curtain walls in all 4

orientations.

Enter Take-Off In COMcheck Envelope Tab

Note: Orientation is not necessary unless modeling for solar gains (U-factor, Thermal Mass, SHGC trade-off compliance)

• Level of code compliance updates as

entries are made.

• Envelope compliance will show “TBD” in

the following cases:

• Missing area for walls, fenestration, roofs, floors

• Missing perimeter for slab-on-grade

• If R-value/U-value missing, calculates as if

0 is entered.

• Double check all entries to ensure proper data is entered and none is missed

• Check for abnormally high U-factors to check for potential missing/incorrect insulation levels.

COMCheck Envelope Compliance

Roof insulation 3” polyiso, no cont. wall insulation (from plans)

Roof insulation 5” polyiso, 1” XPS wall cont. insulation

Missing slab-on-grade perimeter data

“TBD” also displayed if a window area is larger than the associated wall

…

• To add a curtain wall• Look-up specs and find wall U-

value

• Enter curtain wall area as “other” wall type

• Will need to enter component heat capacity

• Program assumes insulation integral to wall mass

• Attach windows/doors with same area as wall item so appropriate wall areas are adjusted.

Curtain Walls

• Building Area Lighting

Method• Allowance based on

area type and efficiency package selected.

• Enter all lighting types• Exceptions for LPD

can be selected for Exit signs, task lights, etc…

• Choosing Reduced

LPD Efficiency option

on Project tab will

reduce allowed

wattage by 10%

Interior Lighting Allowances and Entry

Space-by-Space method is more flexible, but entry is more detailed – same as above but will have multiple space types, each with LPD allowance based on assigned square footage.

• Exterior lighting zone

selection determines W/sf

allowance.

• Project tab entry SF shown

for reference, calcs total

allowance.

• Entries in each section

update to count against

allowance.

• If all proposed wattage is

<total allowable, lighting will

pass code check, else text

turns red and results show

“TBD”

Exterior Lighting Allowances and Entry

• Enter capacities of systems,

associate fans with each

system, and add heating and

cooling plant data (no pump

data)

• Data only used to check fan

sizing and plant efficiency

against prescriptive code

requirements.

• Selections for system types

here populate final checklists

(Requirements Tab)

Mechanical Systems

• Fan systems display

whether system fan

HP is in compliance or

not.

• X next to fan system

indicates HP or BHP

exceeds code

• X next to fan system

indicates HP or BHP

complies with code

Mechanical Systems (cont.)

• When adding fan systems,

include supply and return

fans for AHUs, and any fan–

powered VAVs associated

with that AHU.

• Based on system airflow, max

allowable fan power is

calculated

• Entry for nameplate HP is

straightforward – Compliance

Table below

Fan System Entry – Nameplate HP

• Note that system Maximum allowed HP is calculated based on the 1st row CFM only. Subsequent rows only add fan HP to the proposed box, but CFM entries do not further increase the HP allowance.

• Fan Efficiency Grade is not efficiency of motor, it is AMCA Fan Efficiency for the fan device, not the motor.

Fan System Entry – Brake HorsepowerDevice Adjustment

CreditsFully ducted return and/or exhaust air systems 0.5"w.c. (2.15"w.c. for lab and vivarium systems)Return and/or exhaust airflow control devices 0.5"w.c.

Exhaust filters, scrubbers, or other treatment Pressure drop of device at fan system designParticulate filtration credit: MERV 9 thru 12 0.5"w.c.Particulate filtration credit: MERV 13 thru 15 0.9"w.c.Particulate filtration credit: MERV 16 and greater and electrically enhanced filters

Pressure drop = 2x clean filter pressure drop at fan system design condition

Carbon and other gas-phase air cleaners Clean filter pressure drop at fan system designBiosafety cabinet pressure drop at fan system design

Energy recovery device, other than runaround loop(2.2xenergy recovery effectiveness)-0.5"w.c. for each

airstreamCoil runaround loop 0.6"w.c. for each airstream

Evap. humidifier/cooler in series with cooling coil Pressure drop of device at fan system designSound attenuation section (fans serving spaces with design background noise goals below NC35) 0.15"w.c.Exhaust system serving fume hoods 0.35"w.c.

Laboratory and vivarium exhaust in high-rise bldgs 0.25"w.c./100ft of vertical duct exceeding 75ftDeductions

Systems without central cooling device -0.6"w.c.Systems without central heating device -0.3"w.c.Systems with central electric resistance heat -0.2"w.c.

• BHP method of entry allows

more flexibility

• Note, same system as the

previous page

• Max allowed brake HP

increased from 18.85

BHP to 22.54 BHP by

credits.

• Credit calculated by

entering design airflow

through device (Table

from IECC at right)

Table C403.2.12.1(2) – Fan Power Limitation Pressure Drop Adjustment (2015 IECC)

• Specific documentation

and field tests required

for compliance are

included in

“Requirements” tab

• Useful to ensure all

information is supplied

to AHJ.

• Many include reference

entry to assist AHJ with

finding the proper

documents for each

requirement.

Code Requirements Checklist

• COMCheck will output

tabular report summaries for

Envelopes, Interior Lighting,

Exterior Lighting, Mechanical

Systems, and Checklists.

COMCheck Output Reports

• Only Envelope and

Lighting reports

display a Pass/Fail

output.

• Mech. System pass

fail attached to each

fan system. Easy to

miss.

REScheck Overview

• Interface is slightly

different, but essentially

same formulaic entry as

COMcheck

• System type -> system components

• Unlike COMcheck, has a

basic performance

compliance alternative.

• Requires more inputs and detail than UA-trade-off or Prescriptive entries.

REScheck Overview

Gathering Information• Again, need to gather

plan drawings and

specifications for data

input.

• Be careful at start to

identify the thermal

envelope: exclude

unconditioned spaces.

• REScheck desktop has a

take-off sheet that will

import to REScheck to

reduce transcription

errors.

Similar to Commercial, can have complex geometries

Look out for sloped ceilings, partial-height exterior walls (common for partial 2nd floor rooms.

Don’t need to separate attic/unconditioned space-facing walls from outdoor-facing walls.

Items To Be Aware Of (Attics)

• If crawl space is vented/unconditioned, need to identify the sections of floor over the crawl space to enter into REScheckfor accurate results.

Items To Be Aware Of (Crawl Spaces)

Also, walls facing basement will have short section “above grade” facing the crawlspace, instead of full depth below grade.

• Example of mixed flat and sloped ceiling areas

• Area-Calc can’t automatically remove area of sloped ceiling from area of flat ceiling. Can automate in Excel or other spreadsheet.

Limitations of Area-Calc Tool

Flat +

Flat -

Slope +Total

Project Tab Entries• Select location• Select project type• Select compliance path• Input conditioned floor area• Input orientation

• Optional for UA Trade-Off• Required for Performance

• Select home features with mandatory code requirements• Duct location• Sunroom• Pool• Fireplace

• Completed by assembly (roof/wall/foundation)

• Each assembly type has construction options

• Example shown for roof types.

• Walls can be masonry, framed 16”O.C. or 24”O.C., log, SIP, or ICF.

• Foundations can be masonry, framed, or ICF, and split between below & above grade.

Envelope Entry

Envelope Entry (Continued)

Foundations and Above-Grade Wall Input Examples

• Orientation only required for Performance Path model, not necessary for UA Trade-off compliance

• Can simplify inputs if orientation not included

• No other inputs to REScheck if UA path is being followed.

• Compliance for lighting and HVAC completed in requirements checklists.

Envelope Entry (Continued)

• Above Grade Walls and Roofs – mass/ wood to match proposed, U-factor from Table R402.1.4, solar absorptance of 0.75 & emittance of 0.90.

• Foundation walls, ceilings, windows U-factor matches Table R402.1.4

• Duct insulation matching Section R403.3.1, leakage of 4cfm/100sf.

• Window area is max 15% of conditioned floor area (matches proposed if <15%), SHGC all 0.40

• Air Exchange 3 ACH

• If proposed model has mechanical ventilation, is based on prescriptive requirement.

2018 IECC Performance Path Reference Design

All other points match the proposed design specifications

I.E. Changing to high efficiency mechanical system does not improve model beyond reference model, since the systems will be modeled as the same.Impact on compliance is based on interaction with envelope alone.

• Must list conditioned floor area

• Must have at minimum 4 walls with unique orientations, 1 roof, and 1 floor

• Orientation of the “Front” of the building (N, S, E, W or 45°offsets)

• Otherwise, most detailed inputs are still envelope construction

• Mechanical details include only the efficiency of the proposed systems.

What Performance Path Requires in REScheck

Questions?

info@sedac.org

800-214-7954