ICC Res Energy cheat sheet

Residential scope covers detached one- and two-family dwellings and townhouses not more than three stories above grade plane, plus associated systems and sites.

Construction documents must identify the compliance path and show envelope, mechanical, water heating, and lighting information needed for inspection.

A permit is required before new construction, alteration, addition, or change of occupancy regulated by the code.

The building official enforces the code and may require approved inspections, tests, and third-party verification.

A permanent energy certificate must list insulation R-values, fenestration U-factors/SHGC, HVAC efficiencies, and water heating efficiencies.

Mandatory provisions-such as air sealing and equipment efficiency-apply even when the project uses a performance or ERI path.

Alternate materials or methods require approval by the building official based on demonstrated compliance with code intent.

Additions, alterations, repairs, and changes of occupancy must comply with the provisions applicable to the scope of work; unaltered portions are generally not retrofitted.

Envelope compliance requires meeting insulation, fenestration, and air-leakage requirements for the project's climate zone.

Insulation R-values are selected from the adopted envelope table based on assembly type: ceiling, wall, floor, slab edge, basement, or crawl space.

Fenestration must meet maximum U-factor and, where required, maximum SHGC values; skylights often have separate limits.

The building thermal envelope must be continuously sealed to form an air barrier at joints, penetrations, sill plates, and fenestration.

Tested air leakage must not exceed 5 ACH50 in climate zones 3–8 or 6 ACH50 in climate zones 1–2 under the 2021 residential provisions.

Recessed luminaires in insulated ceilings must be IC-rated and sealed to limit air leakage into or out of the envelope.

Access hatches and doors to unconditioned attics or crawl spaces must be insulated and weatherstripped.

Slab-edge and foundation insulation requirements depend on climate zone and assembly; insulation must be installed to the required depth or R-value.

Insulation must fill cavities and be installed without gaps, compression, or misalignment that reduce rated R-value.

HVAC equipment must be sized with ACCA Manual J or an approved load calculation, and ducts designed with Manual D.

Equipment must meet the minimum efficiency ratings in the adopted code or federal standards; ratings are verified by AHRI or manufacturer data.

Ducts outside conditioned space must be insulated to the adopted table R-value; supply ducts in attics often need higher R-value.

Ducts, plenums, boots, and air handlers must be sealed; duct leakage testing is required unless all ducts and air handler are in conditioned space.

Duct leakage limit is commonly 4 cfm per 100 ft² of conditioned floor area at 0.1 in. w.c. (25 Pa) across the system.

Whole-house mechanical ventilation must be provided and sized per ASHRAE 62.2 or an approved method.

Bath exhaust must be ducted outdoors; intermittent rates are commonly 50 cfm for baths and 100 cfm for kitchens, with lower continuous rates.

HVAC piping and refrigerant lines requiring insulation must be insulated per the adopted table to prevent energy loss.

Heating and cooling systems must have a thermostat capable of controlling the system; some adopted editions require setback or programmable capability.

Water heaters must meet minimum efficiency standards for fuel type and size; verify with AHRI or manufacturer ratings.

Hot water piping from the water heater and in unconditioned spaces must be insulated to the code-required R-value.

Circulating hot water systems require insulated piping and automatic controls that disable circulation when demand is low.

Heated pools require a vapor-retardant cover or approved evaporation-reducing measure and may require pool heater controls.

Pool heaters must have a readily accessible on/off switch and may require time clocks or automatic shutoff controls.

Solar water heating systems and drain-water heat recovery must be listed and installed per manufacturer instructions and referenced standards.

Water heater tanks and piping must be installed to limit heat loss, with insulation not covering safety devices or access.

Point-of-use water heaters must meet efficiency and installation requirements; storage units are subject to standby loss limits.

Lighting efficacy is lumens per watt; high-efficacy fixtures use lamps such as LEDs that meet the adopted threshold.

A minimum percentage of permanently installed lighting fixtures must contain high-efficacy lamps where the adopted edition retains that requirement.

Exterior lighting must be controlled by a photocell, time switch, or other automatic control.

Solar-ready provisions, where adopted, require a designated roof area and conduit pathway to the service panel.

EV-ready provisions, where adopted, require reserved electrical capacity and a pathway for future EV charging.

Electrical power provisions may require energy monitoring or metering in some adopted editions; verify the edition in force.

Lighting and electrical equipment must be listed and labeled for the application and installed per manufacturer instructions.

Dwelling-unit electrical distribution must provide capacity for required equipment; load calculations follow the electrical code, not energy code tables.

Permanently installed lighting fixtures must meet efficacy requirements; the percentage and efficacy threshold depend on the adopted code edition.

Federal appliance efficiency standards set minimum performance for refrigerators, dishwashers, clothes washers, and similar appliances.

EnergyGuide labels disclose estimated annual energy use or cost but do not replace code or federal compliance documentation.

Clothes dryers, ranges, and ovens are generally covered by federal standards or labeling rather than residential energy-code tables.

Pool pumps and heaters must have controls such as timers; larger pools may require variable-speed pumps under adopted provisions.

Ceiling fans and other appliances may be subject to labeling or efficiency rules; verify the adopted edition and federal preemption.

Lighting controls such as vacancy sensors may be required in some adopted editions for specific spaces.

Appliances and lighting must be installed per listing and manufacturer instructions; improper installation can void efficiency ratings.

Prescriptive path: each envelope, mechanical, water heating, and lighting component meets its individual code requirement.

Performance path: approved software shows proposed annual energy cost is no greater than the standard reference design.

ERI path: a certified rater calculates an Energy Rating Index; lower scores mean better performance and must meet the climate-zone threshold.

Mandatory requirements apply to every compliance path and cannot be traded away in performance or ERI modeling.

The total UA alternative allows envelope trade-offs when overall heat loss coefficient does not exceed the baseline.

Performance and ERI software must be approved by the code official and use the code's standard reference design assumptions.

Compliance documentation must be retained and available to the building official; ERI requires a certified HERS or equivalent report.

Additions and alterations may use prescriptive or performance methods where allowed, but the scope of work determines which requirements apply.

Referenced standards are enforceable parts of the code; the edition cited in the adopted code governs.

ASHRAE 62.2 is referenced for residential ventilation sizing and indoor air quality.

ACCA Manual J, D, and S are referenced for load calculation, duct design, and equipment selection.

ANSI/RESNET/ICC 380 is referenced for duct and envelope leakage testing where adopted.

AHRI directories or manufacturer data verify equipment efficiency ratings used for compliance.

Existing buildings: additions and alterations must comply for the scope of work; repairs have limited requirements.

Historic buildings may be exempt or subject to alternative requirements where the code official determines compliance would be infeasible.

The building official may approve alternative materials or methods when performance is demonstrated by test data or approved analysis.

Replacement equipment must meet the efficiency requirements of the adopted code unless a specific existing-building exception applies.