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Quick Answer
A home energy audit identifies where your home wastes energy — air leaks, insulation gaps, inefficient HVAC, and ductwork problems. In most Northeast states (MA, CT, RI, NH, ME, VT), professional audits are completely free through utility programs. Getting an audit before solar or heat pump installation saves thousands by right-sizing your system.
What to expect, what it costs (often $0), what auditors check, and why getting an audit before solar or heat pump installation saves you thousands.
A home energy audit (also called a home energy assessment) is a systematic evaluation of how your home uses — and wastes — energy. A certified auditor examines your building envelope, HVAC system, insulation, ductwork, windows, and electrical infrastructure to identify exactly where energy is being lost and what upgrades will have the biggest impact on your comfort and utility bills.
Think of it as a physical exam for your home. Just as a doctor uses diagnostic tools to find health issues you cannot see, an energy auditor uses specialized equipment to reveal problems that are invisible during a normal walk-through.
A calibrated fan is mounted in your door frame and depressurizes the house to 50 Pascals. This measures your total air leakage in CFM50 — revealing exactly how “leaky” your home is. The average older home leaks 3,000–5,000 CFM50; a well-sealed home is under 1,500.
An infrared camera reveals temperature differences invisible to the eye: missing insulation behind walls, air leaks around windows and electrical outlets, moisture intrusion, and thermal bridges through framing. Works best with 20+ degree F indoor/outdoor difference.
A duct blaster measures how much conditioned air leaks out of your ductwork before reaching living spaces. The average home loses 20–30% of heated or cooled air through duct leaks, which is like heating or cooling your attic and basement for free.
You can catch some obvious energy problems on your own, but professional auditors use specialized equipment that reveals issues a visual inspection simply cannot detect. Since most Northeast states offer free professional audits, there is rarely a reason to skip the real thing.
| What to Check | DIY | Pro | Notes |
|---|---|---|---|
| Visual inspection of weatherstripping | Check doors, windows, attic hatches for gaps | ||
| Check insulation levels (attic) | Measure attic insulation depth; look for bare spots | ||
| Inspect ductwork for visible leaks | Look for disconnected or damaged ducts in basement/attic | ||
| Review utility bills for usage trends | Compare month-over-month and year-over-year usage | ||
| Blower door test (air infiltration) | — | Measures total air leakage in CFM50; requires specialized equipment | |
| Thermal imaging / infrared scan | — | Reveals hidden air leaks, missing insulation, thermal bridges | |
| Duct leakage testing (duct blaster) | — | Measures duct system leakage; typical homes lose 20-30% of conditioned air | |
| Combustion safety testing | — | Tests gas appliances for CO leaks, draft, and backdrafting risk | |
| Manual J load calculation | — | Determines correct HVAC sizing; critical for heat pump installations | |
| Electrical panel capacity assessment | — | Evaluates if panel can support solar, heat pump, EV charger additions |
A DIY walk-through catches surface-level problems, but the five professional-only tests — blower door, thermal imaging, duct leakage, combustion safety, and Manual J — reveal the hidden issues that account for 60–80% of typical energy waste. In states where the audit is free, there is no reason to rely on DIY alone.
A thorough professional energy audit examines six key areas of your home. Each area has specific diagnostic criteria that inform the auditor's final recommendations and the prioritized upgrade plan you receive after the assessment.
One of the biggest advantages of living in the Northeast: most states offer completely free professional energy audits through utility-sponsored programs. These are not stripped-down walk-throughs — they include blower door testing, thermal imaging, and comprehensive reports.
Mass Save Home Energy Assessment
No-cost assessment for all ratepayers. Includes free air sealing + insulation discounts.
Energize CT Home Energy Solutions (HES)
Free for Eversource and UI customers. Includes blower door test + thermal scan.
RI Energy Efficiency Program
No-cost audit for RI Energy customers. Includes free LED bulbs + weatherization discounts.
Efficiency Maine Home Energy Assessment
No-cost assessment. Includes air sealing recommendations + rebate pathway.
Efficiency Vermont
Free energy audit for all Vermont ratepayers. Button Up Vermont weatherization support.
NJ Home Performance with ENERGY STAR
Free or low-cost through participating contractors. Income-eligible households get no-cost audit.
PECO, PPL, Duquesne Light Programs
Varies by utility. PECO offers free assessments; PPL and Duquesne Light offer subsidized audits.
No statewide free program
Private auditors only. Austin Energy offers subsidized audits (~$99) for city utility customers.
If you live in Massachusetts, Connecticut, Rhode Island, New Hampshire, Maine, or Vermont, you are eligible for a no-cost professional energy audit funded by your utility ratepayer charges. These programs often include free air sealing, LED bulbs, and smart thermostats as part of the visit — plus access to deeply discounted insulation rebates.
This is one of the most overlooked money-saving strategies in residential solar: get your energy audit before your solar consultation. Here is why the order matters.
Solar installers size your system based on your current electricity usage. If your home is leaking conditioned air through gaps, has insufficient insulation, or runs an oversized HVAC system, your electricity bills are artificially inflated. That inflated number gets used to size your solar array — meaning you buy and install more panels than you actually need.
A free energy audit + $2,000–$4,000 in insulation upgrades (often 75–100% rebated in NE states) can save you $5,000–$8,000 on your solar installation by reducing the system size you need. The audit literally pays for itself before you even install the first panel.
Heat pump sizing is even more critical than solar sizing. An oversized heat pump does not just waste money — it actively harms comfort and efficiency. An energy audit provides the data needed for a proper Manual J load calculation, which is the industry-standard method for determining the correct heating and cooling capacity.
Manual J is an ACCA (Air Conditioning Contractors of America) standard that calculates the exact heating and cooling load for your home based on its specific characteristics: square footage, window area and orientation, insulation R-values, air infiltration rate, climate zone, and occupancy patterns. The energy audit provides most of these inputs through direct measurement rather than estimation.
Many contractors use “rules of thumb” (e.g., 1 ton per 600 sq ft) instead of Manual J. This almost always results in an oversized system. An oversized heat pump causes three problems:
We require a Manual J load calculation before designing any heat pump installation. If you have not had an energy audit, we recommend scheduling one through your utility program first — the audit data makes the Manual J calculation more accurate, and any envelope improvements you make afterward can reduce the heat pump capacity (and cost) you need.
The order in which you make energy upgrades matters significantly. Each step reduces the size (and cost) of the next step. Skipping ahead — for example, installing solar before fixing insulation — means overspending on equipment you would not have needed.
The most cost-effective upgrade. Seal air leaks first, then add insulation. This reduces your heating and cooling load by 15-30%, which means you can install a smaller (cheaper) heat pump and fewer solar panels.
After tightening the envelope, your heating and cooling load is lower. A Manual J calculation performed after air sealing ensures your heat pump is right-sized — not oversized, which wastes money and causes short-cycling.
With an efficient envelope and high-performance HVAC, your electricity needs are optimized. Now you can size a solar system to match your actual usage — not the inflated usage of a leaky, inefficient home.
Add battery storage for backup power and demand response revenue. In states with ConnectedSolutions or similar programs, batteries can earn $200-$275/kW annually while providing outage protection.
The final piece of home electrification. With solar already offsetting your electricity, charging at home is essentially free. A Level 2 charger adds 25-30 miles of range per hour.
Most homeowners space these upgrades out over 1–3 years. The energy audit gives you a prioritized roadmap so you can start with the highest-impact, lowest-cost improvements and work your way up. Each step makes the next one more effective and less expensive.
Find your state's energy audit program and explore solar and heat pump incentives available after your assessment. Each state page includes detailed rebate information, utility rate comparisons, and cost calculators.
Mass Save
Free audit availableView state guideEnergize CT
Free audit availableView state guideRI Energy
Free audit availableView state guideNHSaves
Free audit availableView state guideEfficiency Maine
Free audit availableView state guideEfficiency Vermont
Free audit availableView state guideHome Performance w/ ENERGY STAR
Free audit availableView state guideUtility programs (PECO, PPL)
Free audit availableView state guidePrivate auditors
View state guideA comprehensive professional home energy audit typically takes 2-4 hours depending on the size of your home. This includes a blower door test (30-45 minutes), thermal imaging scan, duct leakage test, combustion safety testing, and a thorough visual inspection. You will receive a detailed report with prioritized recommendations within 1-2 weeks.
Absolutely. An energy audit before solar installation can save you thousands of dollars. By improving insulation and air sealing first, you reduce your energy consumption by 15-30%. This means you need fewer solar panels to offset your usage, lowering your total project cost. It also ensures your solar system is right-sized for your actual needs rather than an artificially inflated energy load.
In New England states (MA, CT, RI, NH, ME, VT), home energy audits are completely FREE through utility-sponsored programs like Mass Save, Energize CT, and NHSaves. In New Jersey, costs range from $0-$150 depending on income. In Pennsylvania, costs range from $0-$50 depending on your utility. In Texas, expect $150-$500 for a private audit, though Austin Energy offers subsidized audits for about $99.
A blower door test measures the total air leakage in your home. A calibrated fan is temporarily mounted in an exterior door frame, depressurizing the house to a standard 50 Pascals. The fan speed required to maintain this pressure tells the auditor exactly how "leaky" your home is, measured in CFM50 (cubic feet per minute at 50 Pascals). A typical older home might measure 3,000-5,000 CFM50, while a well-sealed home is under 1,500 CFM50.
Thermal imaging (infrared photography) reveals temperature differences in walls, ceilings, and floors that are invisible to the naked eye. It shows missing insulation as cold spots in winter, air leaks around windows and penetrations as temperature streaks, moisture problems behind walls, and thermal bridging through framing. It is most effective when there is at least a 20-degree F difference between indoor and outdoor temperatures.
You can perform a basic DIY energy audit by checking for drafts around windows and doors, inspecting visible insulation levels in your attic, reviewing your utility bills for usage trends, and looking at ductwork for obvious disconnections. However, you cannot replicate professional tests like blower door testing, duct leakage testing, combustion safety analysis, or thermal imaging without specialized equipment. The free professional audits available in most Northeast states are far more thorough and cost nothing.
An energy audit includes or informs a Manual J load calculation, which is the industry-standard method for determining the correct heating and cooling capacity for your home. Without this calculation, contractors often oversize heat pumps based on rules of thumb. An oversized heat pump costs more upfront, short-cycles (turning on and off frequently), reduces efficiency, and fails to properly dehumidify your home. Proper sizing after an audit ensures comfort and maximum efficiency.
Follow the recommended upgrade order: (1) Air sealing and insulation first — this is the most cost-effective upgrade and reduces your heating/cooling load by 15-30%. (2) HVAC or heat pump upgrade, now properly sized for your tightened envelope. (3) Solar panels, sized to match your reduced energy consumption. (4) Battery storage for backup and demand response revenue. (5) EV charger as the final electrification step. This order maximizes savings and avoids oversizing any single system.
Yes. Most utility-sponsored audit programs in the Northeast are gateways to significant rebates. Mass Save offers 75-100% insulation rebates after an audit. Energize CT provides up to $7,500 for weatherization. NHSaves covers up to 75% of insulation costs. Efficiency Maine offers rebates on heat pumps and insulation. These rebates are typically only accessible after completing the audit, making the audit a prerequisite for the best incentives.
Most homeowners should get a professional energy audit every 5-10 years, or whenever you are planning a major renovation, HVAC replacement, or solar installation. If you have recently completed significant upgrades (insulation, windows, HVAC), a follow-up audit can verify that the work was done correctly and quantify your actual energy savings. Building science changes over time, and newer audits may identify opportunities that previous audits missed.
In most of our service area, a professional home energy audit costs nothing. Schedule your free assessment, get a prioritized upgrade plan, and find out exactly how much solar and heat pumps can save you — based on your home's actual efficiency profile.
Available in MA, CT, RI, NH, ME, VT, NJ, PA, and TX