WATTMETER

Economics Engine

ABACUS

Life-cycle cost, payback, NPV, IRR, and savings-to-investment ratio.

Shared by all modules

Investment

Initial cost capital expenditure

$

Rebates & incentives one-time, reduces investment

$

Salvage value at end of life

$

Annual Savings

Electricity (energy)

kWh/yr

Electricity (demand)

kW peak

Fuel natural gas, propane, oil

therm/yr

Water

kgal/yr

O&M change positive = added cost

$/yr

Financial

Project life

years

Discount rate real or nominal, match escalation

%

Energy escalation

%/yr

Fuel escalation

%/yr

O&M escalation general inflation proxy

%/yr

Simple Payback

. years

undiscounted

Net Present Value

$ .

at discount rate

Internal Rate of Return

. %

solved

Savings-to-Investment

.

SIR

Discounted Payback

. years

PV cumulative crossing

Year-1 Net Savings

$ .

before discounting

Cumulative Cash Flow

Cumulative PV Payback

Yr	Savings $	O&M $	Net $	PV $	Cum. PV $

Blower-Door Math

ENVELOPE

Air leakage from a single-point fan pressurization. ACH50, NACH, ELA, EqLA, and code comparison.

Zone & volume from header

Test Result

CFM50

cfm

Flow exponent n, typically 0.6-0.7

Volume

Derive from header area × ceiling height

Ceiling height

ft

Conditioned volume override

ft³

Envelope surface area walls + roof + floor (optional)

sf

ACH50

. /hr

air changes at 50 Pa

NACH

. /hr

natural infiltration

ELA @ 4 Pa

. in²

effective leakage area

EqLA @ 10 Pa

. cm²

equivalent leakage area

CFM75 / sf envelope

. cfm/sf

commercial metric

N-factor

.

from climate zone

Code & Standard Comparisons

Passes Borderline Fails

N-factor uses single-story, normal-shielding defaults from the LBL Sherman-Grimsrud method. Multi-story and shielding corrections arrive in v0.2. Use measured infiltration data for detailed energy modeling.

NEC 220 Electrical Load

MANIFEST

Standard method service calculation. Connected load, calculated demand, and minimum service ampacity.

Occupancy & area

Calculation Method

NEC method choose service calc approach

Standard method applies to all occupancies. Optional method is for one-family dwellings only and uses a simplified general-load demand factor (100% to 10 kVA, 40% above).

Service

Occupancy NEC 220.12 lighting VA/sf

Voltage / phase

Lighting Load

Auto from occupancy × conditioned area

NEC value VA/sf for this occupancy

. VA/sf

Continuous load (applies 125% factor per NEC 210.20)

Receptacles

General-use count 15A and 20A, at 180 VA each

ea

Special-purpose VA dedicated circuits, kitchen, EV, etc.

VA

HVAC

Heating equipment

VA

Cooling equipment

VA

NEC 220.51: larger of heating or cooling is used. The other is omitted from the calculation.

Motors & Other

Largest motor 125% adder per NEC 430.24

hp

Other motors total VA

VA

Other loads signs, water heating, misc

VA

Dwelling General Load

Per NEC 220.82(B). General lighting and receptacle load auto-computes at 3 VA/sf from the conditioned area in the project header.

Lighting + receptacles 3 VA/sf × conditioned area

. VA

Small-appliance circuits 220.52(A), min 2 at 1500 VA each

ckt

Laundry circuits 220.52(B), min 1 at 1500 VA each

ckt

Appliance nameplates range, dryer, water heater, etc.

VA

Subtotal before demand factor

. VA

Demand factor per 220.82(B): 100% of first 10 kVA, 40% of remainder. HVAC (above) and largest motor adders apply.

Service Ampacity

. A

minimum required

Connected Load

. VA

all loads at 100%

Calculated Demand

. VA

after demand factors

Standard Size

. A

next std service size

Lighting Share

. %

of demand

HVAC Share

. %

of demand

Load Breakdown

NEC References

Lighting (220.12).

Demand factor (220.42).

Continuous adjustment (210.20).

Receptacle load (220.14).

HVAC (220.51).

Largest motor (430.24).

Screening-level calculation. Final service sizing requires a registered Professional Engineer or licensed electrician to review per the AHJ.

Simplified Thermal Load

CHAMBER

Two modes: whole-building U·A (quick) or per-room with orientation-aware solar (detailed).

Design temps from zone

Calculation Mode

Quick mode aggregates the whole building as one envelope. Detailed mode lets you build a room-by-room model with N/E/S/W orientation, peak SHGF solar gains, and per-room internal gains.

Setpoints & Design

Heating indoor

°F

Cooling indoor

°F

Outdoor 99% heating design DB

°F

Outdoor 1% cooling design DB

°F

Leave at zero to auto-default from the project climate zone. Override for specific site data.

Envelope Assemblies

Assembly	Area (sf)	U-value	SHGC

U-values default to ASHRAE 90.1 climate-zone minimums. SHGC applies to windows only.

Infiltration

Design CFM at design pressure differential

cfm

Internal Gains

Occupants at design

people

Lighting

W/sf

Equipment / plug

W/sf

Shared Assemblies U-values used by all rooms

Wall U-value

Btu/hr-sf-F

Roof / ceiling U-value

Btu/hr-sf-F

Floor U-value

Btu/hr-sf-F

Window U-value

Btu/hr-sf-F

Window SHGC

Interior shading coef blinds, drapes

These U-values and SHGC apply to all rooms. Define once, used everywhere. Override per-assembly in a future version.

Rooms / Zones

Peak solar heat gain factors (Btu/hr-sf at 40°N latitude): N 38, E 195, S 110, W 195. Cooling glass gain = area × SHGC × SHGF × shading.

Sizing

Oversize factor

×

Common: 1.15 for cooling, 1.20-1.40 for heating in cold climates. Manual S provides detailed guidance.

DRYBULB Psychrometric Tool ▸

Enter any two psychrometric properties; the rest compute via ASHRAE Hyland-Wexler formulation. Use to justify CHAMBER design conditions or compute mixed-air states for HVAC sizing.

Elevation

ft

Input pair

Dry-bulb

°F

Relative humidity

%

Wet-bulb

°F

Dew point

°F

Humidity ratio

lb/lb

Mixed-Air Calculator

Blend outdoor and return air at a chosen ratio. Outputs mixed-air dry-bulb, humidity ratio, and enthalpy for AHU coil sizing.

Outdoor DB

°F

Outdoor W

lb/lb

Return DB

°F

Return W

lb/lb

OA fraction

Heating Load

. kBtu/h

design conditions

Cooling Load

. kBtu/h

sensible + latent

Heating Equipment

. kBtu/h

load × oversize

Cooling Tonnage

. tons

12,000 Btu/h per ton

Heating sf/Btu/h

. sf/kBtuh

load intensity

Cooling sf/ton

.

300-500 typical

Heating Load Breakdown

Cooling Load Breakdown

Quick mode: whole-building U·A with simplified solar through glass. Detailed mode: per-room with cardinal-orientation peak SHGF values.

Per-Room Loads

Lighting Retrofit ROI

BALLAST

Fixture-by-fixture existing vs proposed. Energy, demand, and LPD compliance, with ABACUS handoff.

LPD check ready

Location	Qty	Exist W/ea	Prop W/ea	Hr/yr	$/fixture	kWh/yr saved	kW saved	$/yr saved
Total	.				.	.	.	.

Coincidence Factor

Fraction of connected load at peak demand 0-1, typically 0.7-0.9

Annual Energy Saved

. kWh/yr

across all fixtures

Demand Saved

. kW

at coincidence factor

Annual $ Saved

$ .

energy + demand

Investment

$ .

total fixture cost

Simple Payback

. years

investment / annual $

% kWh Reduction

. %

vs existing lighting

Lighting Power Density (LPD)

Below limit At limit Over

LPD compares connected lighting watts to ASHRAE 90.1-2019 Building Area Method limits. Compliance requires the Space-by-Space Method for code submittal; this is for screening only.

ABACUS Handoff

Compute first to enable sending the retrofit package to ABACUS for life-cycle economics.

Motor Retrofit

ARMATURE

Existing vs NEMA Premium efficiency, TEFC and ODP enclosures, 2/4/6-pole. kWh and demand savings with ABACUS handoff.

Replacement % auto-fills from HP

Motor	HP	Type	Exist %	Repl %	LF	Hr/yr	$/motor	kWh/yr saved	kW saved
Total	.						.	.	.

Coincidence Factor

Fraction of motor load at peak demand 0-1, typically 0.6-0.9

Annual Energy Saved

. kWh/yr

across all motors

Demand Saved

. kW

at coincidence factor

Annual $ Saved

$ .

energy + demand

Investment

$ .

total replacement cost

Simple Payback

. years

investment / annual $

Total HP

. hp

sum of motors

NEMA Premium Reference

NEMA Premium efficiency for 4-pole TEFC enclosed motors, per NEMA MG 1-2016 Table 12-12. Open drip-proof (ODP) motors typically run 0.5-1.0 percentage points lower. Values are for 60 Hz, 230/460V.

ABACUS Handoff

Compute first to enable sending the motor package to ABACUS for life-cycle economics.

Degree-Day Estimator

BELLOWS

Heating and cooling degree-days, base 65°F. Static city table with NOAA fetch as a future option.

Source: NOAA 30-year normals (static)

City Lookup

Reference city

Pick the city nearest to your project site. Climate zone tags help narrow the list.

Manual Override

Annual HDD base 65°F

°F-day

Annual CDD base 65°F

°F-day

Use manual values instead of city lookup

Non-65°F base temperatures need daily data and arrive in v0.2.

Heating DD

. °F-day/yr

base 65°F

Cooling DD

. °F-day/yr

base 65°F

Climate Profile

.

heating vs cooling load

Total DD

. °F-day/yr

HDD + CDD

Heating vs Cooling Load

HDD CDD

Reference Comparisons

Demand Charges

PEAK

Monthly billable demand under ratchet rules, with a single-shed scenario and ABACUS handoff.

Demand rate from header

Monthly Peak Demand

Month	Peak kW
Max	.

Set all months to

kW

Tariff

Demand rate

$/ kW-mo

Ratchet % of annual max as monthly floor

%

Fixed customer charge

$/mo

Shed Scenario

Demand reduction kW shaved off peak

kW

Apply to all months

Apply only to top 3 peak months

Annual Demand Cost

$ .

current, with ratchet

Annual Max kW

. kW

.

Avg Billable

. kW

after ratchet

Scenario Savings

$ .

vs current

Scenario Annual

$ .

after shed

Ratchet Impact

. %

share of cost from floor

Billable Demand by Month

Current Scenario Ratchet floor

ABACUS Handoff

Run a shed scenario to enable sending the annual demand savings to ABACUS as a kW peak savings input.

Standards Navigator

CODEX

ASHRAE 90.1 plain-English topic map. Section pointers, climate-zone applicability, no verbatim text.

Edition

About this navigator

CODEX is a navigator and not a substitute for the standard. Topic summaries are plain-English paraphrases. Section and table references are publicly known structural pointers. Specific values cited as "approximate" or "typical" are illustrative ranges, not the published requirements. For permitting, code submittal, energy modeling baselines, or design compliance, use the actual published edition of ASHRAE Standard 90.1 from ashrae.org.

.

Domestic Water Audit

WATERWORKS

Twelve-month water bills, fixture inventory with WaterSense retrofit ROI, and hot water recirculation analysis. Combined water + energy savings handoff to ABACUS.

Set water rate in header

Monthly Water Bills

Month	Use (kgal)	Cost ($)	Eff $/kgal
Annual	.	.	.

Use kgal (thousand gallons). Common bill unit is CCF (hundred cubic feet); 1 CCF = 0.748 kgal.

Hot Water Source

Fuel

Heater efficiency EF or thermal

Cold water temp

°F

Hot water setpoint

°F

Hot water energy use computed for fixtures marked as hot-water-fed. Heat pump water heater COP commonly 2.5-3.5; gas storage 0.60-0.80 EF; gas condensing 0.90-0.96.

Use Frequency

Occupants daily population

ppl

Workdays per year

days

Workdays is days/year fixtures are used. Office: 250. Hotel/healthcare: 365. School: 180.

Fixture	Type	Qty	Exist flow	Prop flow	Secs/use	Uses/day	Hot frac	kgal/yr saved	$/yr saved
Total		.						.	.

Existing flows: pre-EPAct toilets 3.5-5.0 gpf, EPAct toilets 1.6 gpf, lavatory faucets 2.2 gpm, showerheads 2.5 gpm. WaterSense proposed: toilets 1.28 gpf, lavatory 1.5 or 1.0 gpm, showerheads 2.0 or 1.5 gpm, urinals 0.5 or 0.125 gpf.

Hot Water Recirculation

Building has continuously circulating hot water loop

Annual Water Saved

. kgal

from fixture retrofit

Annual Dollars Saved

.

water + hot water energy

Hot Water Energy Saved

. kBtu

fixtures only

Recirc Savings

.

pump + standby

Total Annual Use

. kgal

from bills

Indoor vs Bills

. %

fixture share of bills

Send to ABACUS

Compute first to enable sending the water + recirc package to ABACUS for life-cycle economics.

Combustion Equipment Audit

COMBUSTION

Stack analysis, jacket loss, short-cycling diagnosis, and condensing-equipment retrofit ROI. Siegert formula for dry-gas loss with O2 or CO2 measurement.

No combustion units defined

Annual Fuel Saved

. therms

across all units

Annual Dollars Saved

.

retrofit to proposed efficiency

Avg Measured Efficiency

. %

load-weighted

Avg Stack Loss

. %

dry gas + moisture

Excess Air

. %

tuning indicator

Annual Input

. MMBtu

all units

Send to ABACUS

Compute first to enable sending the retrofit package to ABACUS for life-cycle economics.

Compressed Air Audit

COMPRESSOR

Three high-ROI findings: leak load from cycle-test method, pressure reduction at the DOE 1%-per-2psi rule, and heat recovery for space or process heat.

Configure compressor inputs

System Baseline

Compressor

Control

Motor HP

hp

Motor efficiency

Full-load CFM

scfm

Operating pressure

psig

Operating hrs/yr

hr

Avg load fraction

Typical rotary screw at full load: 4-5 scfm per HP. Modulating control wastes 70-80% of full-load energy at part load; load-unload wastes 25-30%; VSD wastes <5%.

Finding 1: Leak Load (Cycle Test)

Include leak load finding

Field test: shut off all production equipment, leave compressor running. Time loaded and unloaded periods over several cycles. Average values below.

Loaded time

sec

Unloaded time

sec

Loaded duty fraction = loaded / (loaded + unloaded). Leak CFM = full-load CFM × duty fraction. Typical findings: 10-30% leak load in untreated systems, <5% in well-maintained ones.

Finding 2: Pressure Reduction

Include pressure reduction finding

Pressure reduction

psi

Min required pressure

psig

DOE Compressed Air Challenge rule: roughly 1% energy savings per 2 psi reduction. Survey end uses for actual minimum required pressure; many shops run 20+ psi above minimum needed.

Finding 3: Heat Recovery

Include heat recovery finding

Annual Savings

.

all enabled findings

Baseline Annual kWh

. kWh

compressor as configured

Leak Load

. % of cap

.

Leak Savings

.

fix 50% of leaks

Pressure Savings

.

Heat Recovery

.

offset fuel cost

Send to ABACUS

Compute first to enable sending the package to ABACUS for life-cycle economics.

Functional Performance Testing

COMMISSIONING

Pre-built FPT script library covering common cx scope (economizer, VAV, boiler reset, lighting controls, DCV, ERV). Per-test step verification with witness records and pass/fail tracking.

No tests added

Add Test from Library

Test template

Templates are starting points with original-writing step scripts. Edit step text, expected values, and observations to match the site-specific design intent.

Tests Scheduled

.

in this project

Completion

. %

tests fully resolved

Passed

.

all steps pass

Failed

.

at least one step failed

Pending

.

unresolved steps

Total Steps

.

across all tests

ECM Master Ledger

REGISTER

Aggregate findings panel: every retrofit measure with capital, savings, payback, NPV, and IRR. Use ABACUS to compute an ECM, then save it here as a permanent finding for the audit report.

No ECMs in register

View Options

Sort by

Filter

Manual ECMs are for operations & maintenance recommendations and other findings without a calculation module. Module-sourced ECMs come from the "+ Save to REGISTER" button in ABACUS after running a retrofit calculation.

Total Investment

.

recommended ECMs

Total Annual Savings

.

recommended ECMs

Portfolio Payback

. yr

weighted average

Portfolio NPV

.

sum of recommended NPVs

ECMs Total

.

in register

Energy Saved

. MMBtu

site, all fuels

EUI Benchmarking

BAROMETER

Site and source energy intensity, ranked against CBECS 2018 medians with climate-zone refinement.

Set building type & area in header

Annual Energy Use

Electricity

kWh/yr

Natural gas

therm/yr

Fuel oil #2 fuel oil

gal/yr

Propane LPG

gal/yr

District steam

Mlbs/yr

District chilled water

ton-hr/yr

Gasoline fleet, equipment

gal/yr

Context

Building type .

Conditioned area .

Climate zone .

Pulled from project header. Change there to update here.

Site EUI

. kBtu/sf-yr

all fuels combined

Source EUI

. kBtu/sf-yr

primary energy

CBECS Median

. kBtu/sf-yr

for this building type

vs Median

. %

positive = above median

Annual Cost

$ .

at header rates

Total Energy

. MMBtu/yr

site, all fuels

Site EUI vs CBECS Median

Efficient Median Inefficient

CBECS 2018 national median site EUI by principal building activity (EIA). Climate-zone refinement requires PUMS analysis and is not applied at this version.

Energy Mix

Utility Bill Analysis

LEDGER

Twelve months of bills in, totals and shape out. Weather normalization arrives in v0.2.

Billing year

Month	Days	kWh	Electric $	Therms	Gas $	$/kWh	$/therm
Total	.	.	.	.	.	.	.

Annual Electric

. kWh

12-month total

Annual Gas

. therms

12-month total

Annual Cost

$ .

electric + gas

Actual $/kWh

$ .

vs header rate

Actual $/therm

$ .

vs header rate

Baseload kWh/day

.

lowest-month proxy

Monthly Usage Shape

kWh therms

Peak month and minimum month identify when the building works hardest. The minimum month is a rough baseload proxy.

BAROMETER Handoff

Compute first to enable sending the annual totals to BAROMETER as the energy use inputs.

Energy Audit

Investment

Annual Savings

Financial

Cumulative Cash Flow

Test Result

Volume

Code & Standard Comparisons

Calculation Method

Service

Lighting Load

Receptacles

HVAC

Motors & Other

Dwelling General Load

Load Breakdown

NEC References

Calculation Mode

Setpoints & Design

Envelope Assemblies

Infiltration

Internal Gains

Shared Assemblies U-values used by all rooms

Rooms / Zones

Sizing

DRYBULB Psychrometric Tool ▸

Mixed-Air Calculator

Heating Load Breakdown

Cooling Load Breakdown

Per-Room Loads

Coincidence Factor

Lighting Power Density (LPD)

ABACUS Handoff

Coincidence Factor

NEMA Premium Reference

ABACUS Handoff

City Lookup

Manual Override

Heating vs Cooling Load

Reference Comparisons

Monthly Peak Demand

Tariff

Shed Scenario

Billable Demand by Month

ABACUS Handoff

About this navigator

Monthly Water Bills

Hot Water Source

Use Frequency

Hot Water Recirculation

Send to ABACUS

Send to ABACUS

System Baseline

Finding 1: Leak Load (Cycle Test)

Finding 2: Pressure Reduction

Finding 3: Heat Recovery

Send to ABACUS

Add Test from Library

View Options

Findings Table

Annual Energy Use

Context

Site EUI vs CBECS Median

Energy Mix

Monthly Usage Shape

BAROMETER Handoff

Export Project

Choose Theme

Photo