InterNACHI HEA study plan

Define conduction, convection, and radiation in your own words and give one building-envelope example of each

Calculate U-factor from R-value and compute heat flux through a wall assembly for three different insulation levels

Explain the three modes of moisture movement (bulk, capillary, vapor diffusion) and rank them by typical magnitude in a wall

Draw and label the stack effect, wind effect, and mechanical imbalance on a simple section sketch, noting pressure direction at top and bottom

Solve five practice problems converting between R-value, U-factor, and BTU/h·ft²·°F

Describe thermal bridging at studs, plates, and rim joists and estimate the effective R-value penalty for a wood-frame wall

Identify the four control layers (water, air, vapor, thermal) and state where each belongs in a cold-climate wall assembly

Compare batt, blown-in, rigid foam, and spray foam on installed R-value per inch, air-sealing ability, and moisture risk

Locate the condensing plane in a wall given indoor/outdoor temperature and dew point, and explain how a vapor retarder changes it

List the common air-leakage paths in a house from attic to foundation and rank them by likely impact

Evaluate window performance using U-factor, SHGC, VT, and air leakage ratings, and explain which matters in which climate

Distinguish window replacement from storm windows, interior panels, and air sealing, and state the cost-effectiveness tradeoffs

Diagnose common door and window air-leakage problems (weatherstripping, thresholds, sash locks, framing gaps) and prescribe fixes

Explain how to inspect and air-seal an attic plane, rim joist, and cantilever without creating moisture or combustion-air problems

Practice describing envelope defects to a client in plain language without overstating savings

Trace the combustion appliance zone concept and explain why a blower door or exhaust fan can backdraft a naturally drafting appliance

Interpret combustion analyzer readings for O2, CO, CO2, stack temperature, and draft, and identify when readings indicate a problem

Explain the difference between spillage, backdrafting, and flame roll-out, and list the conditions that cause each

Describe the inspection sequence for a gas furnace, water heater, and vent connector, including draft verification and spillage testing

State the roles of CO alarms, UL 2034 listing, and manufacturer instructions in a combustion safety response

Compare exhaust-only, supply-only, balanced, HRV, and ERV ventilation strategies on cost, climate suitability, and pressure effects

Size a ventilation system to ASHRAE 62.2 using floor area and bedroom count, and show the calculation

Set up a blower door correctly: prepare the house, establish baseline pressure, choose the right range and configuration, and record data

Convert CFM50 to ACH50 and estimate natural infiltration using a documented method, stating the assumptions

Explain duct leakage testing setup and interpret total, exterior, and to-outside leakage results

Explain the operating principle and correct use of infrared thermography, including emissivity, reflectivity, and Delta-T requirements

Describe when to use a pressure pan, smoke pencil, or theatrical fog to locate leaks, and interpret each result

List the limits of blower door testing and explain why a single ACH50 number does not locate or prioritize leaks

Identify common sources of diagnostic error (wind, stack effect, temperature drift, gauge calibration, hose placement) and how to control them

Practice interpreting a thermogram described in text and state what is and is not provable from it

Read a utility bill and separate base load from seasonal load, then compute annual consumption and cost per square foot

Compare billed consumption against a simple energy model and explain the main sources of divergence

Build a prioritized improvement list using savings, cost, payback, and risk, and justify the ranking

Explain why measure interaction matters, such as how air sealing changes duct and ventilation performance

Identify when modeling uncertainty is too high to promise a specific savings figure

Structure a written assessment report with scope, methods, findings, limitations, and prioritized recommendations

Explain test results and limitations to a client in plain language, including what was not inspected

Apply ethical rules on conflicts of interest, disclosure of referral relationships, data handling, and avoiding overstated claims

Map your report against common program and standard requirements for documentation and quality assurance

Review your weakest two domains and close remaining gaps with targeted practice