A thorough DIY energy audit takes about 2-3 hours and can identify $200-$800 per year in wasted energy — sometimes more in older homes. You don't need expensive equipment or professional training. A flashlight, a stick of incense, and a systematic room-by-room approach will reveal the biggest energy drains in your home.
Professional energy audits cost $200-$500 and use specialized tools like blower doors and thermal cameras. They're worth it for complex homes, but this DIY audit covers 80% of what a pro would find and costs nothing but your time.
What You'll Need
| Item | Purpose | Cost |
|---|---|---|
| Flashlight | Inspect dark areas (attic, crawlspace) | Already own |
| Incense stick or tissue paper | Detect air leaks | $1-$3 |
| Notepad or phone | Document findings | Already own |
| Infrared thermometer (optional) | Check surface temperatures | $15-$30 |
| Plug-in energy meter (optional) | Measure appliance power draw | $20-$30 |
| Step ladder | Access attic hatch | Already own |
| Last 12 months of utility bills | Establish baseline | Free (utility portal) |
The best time to perform a DIY energy audit is on a cold, windy day (winter) or a hot day (summer). Temperature differences make air leaks much easier to detect.
Step 1: Analyze Your Utility Bills (15 Minutes)
Pull 12 months of bills from your utility portal. Identify your lowest-usage month (baseload) and peak months.
Calculate your baseload. Your mildest month (April or October) represents non-HVAC consumption: refrigeration, lighting, water heating, electronics.
Calculate HVAC overhead. Subtract baseload from peak months. This tells you exactly what heating and cooling costs.
Red Flags in Your Bills
| Red Flag | Indicates | Potential Savings |
|---|---|---|
| Baseload over 30 kWh/day (gas-heated) | Phantom loads, old appliances, water heater issues | $100-$300/year |
| Cooling overhead over 20 kWh/day | Inefficient AC, duct leaks, poor insulation | $150-$400/year |
| Year-over-year increase over 15% | Declining equipment efficiency | Varies |
| Sudden spike in one month | Equipment malfunction or meter error | $50-$200+/month |
Step 2: Exterior Walk-Around (20 Minutes)
Walk the entire perimeter looking for:
Foundation cracks. Even hairline cracks allow air infiltration. Seal with hydraulic cement or polyurethane caulk ($20-$60/year savings).
Utility penetration gaps. Every pipe, wire, cable, and vent through exterior walls leaks air. Seal with caulk or spray foam ($10-$40/year total).
Window and door caulking. Failed exterior caulk lets air and water in. Recaulking costs $20-$50 and saves $30-$80/year.
Door weatherstripping. Close each door and look for daylight around edges. Visible light means air is leaking. Replacement costs $5-$15 per door, saves $10-$30/year each.
Step 3: Attic Inspection (30 Minutes)
The attic is the number one area where energy escapes. This step alone can identify $200-$500/year in savings.
Safety first: Walk only on joists or boards across them. Never step on drywall between joists. Wear a dust mask and gloves with fiberglass insulation. Watch for electrical wiring.
Insulation Depth Check
Measure with a ruler and compare to recommended R-values:
| Climate Zone | Example States | Recommended R-Value | Fiberglass Depth |
|---|---|---|---|
| Zone 1-2 | HI, South FL, TX, AZ | R-38 to R-60 | 12-20 inches |
| Zone 3 | NC, TN, AR, NM | R-38 to R-60 | 12-20 inches |
| Zone 4-5 | VA, MO, OH, PA, CO | R-49 to R-60 | 16-20 inches |
| Zone 6-7 | MN, WI, ME, MT | R-49 to R-60 | 16-20 inches |
Under 10 inches means you're under-insulated. Adding blown-in to R-49 costs $1,500-$2,500 and saves $200-$500/year.
Attic Air Leak Hot Spots
| Location | How to Seal | Savings |
|---|---|---|
| Attic hatch | Weatherstrip and insulate the door | $30-$70/year |
| Plumbing penetrations | Spray foam around pipes | $10-$30/year |
| Electrical penetrations | Fire-rated caulk | $10-$25/year |
| Recessed lights | IC-rated covers + spray foam | $15-$40/year |
| HVAC duct boots | Mastic sealant | $15-$35/year |
| Chimney chase | Sheet metal + fire-rated caulk (not spray foam) | $20-$50/year |
| Dropped soffits | Rigid foam + canned foam | $15-$40/year |
Step 4: Interior Walkthrough (45 Minutes)
Air Leak Detection
Light an incense stick and slowly move it along window frames, door frames, electrical outlets on exterior walls, baseboards, and ceiling/wall joints. Smoke flickering sideways indicates a leak. Mark each with painter's tape.
HVAC System Check
Filter: Pull it out. Dirty and clogged filters increase energy use 5-15%. Replace immediately and check monthly.
Thermostat: Is it programmed? Proper setback schedules save 10% annually. A smart thermostat ($130-$250) pays for itself in 1-2 years.
Registers: Walk every room. Confirm supply registers are open and unblocked. Return grilles should be clear. Hold tissue near registers to verify airflow.
Ductwork (accessible areas): Look for disconnected sections, visible gaps, missing insulation on ducts in unconditioned spaces, and kinked flex duct. Sealing with mastic costs $10-$25 and saves $100-$300/year.
Water Heater
| Check | Action | Savings |
|---|---|---|
| Temp above 120F | Lower to 120F | $50-$95/year |
| Over 10 years old | Plan replacement (consider heat pump) | Varies |
| Warm to touch | Add insulation blanket ($25) | $20-$45/year |
| Uninsulated hot pipes | Add foam insulation ($15) | $15-$30/year |
| Popping/rumbling sounds | Flush sediment (free) | Restores efficiency |
Lighting Audit
Count incandescent, CFL, and LED bulbs. Each incandescent-to-LED swap saves $7-$10/year. A 30-fixture whole-home retrofit saves $200-$300/year for $60-$150.
Phantom Load Hunt
| Device | Standby Power | Annual Cost |
|---|---|---|
| Cable/Satellite Box | 15-30W | $22-$44 |
| Gaming Console (older) | 10-25W | $15-$37 |
| Desktop Computer (sleep) | 5-15W | $7-$22 |
| Printer | 5-10W | $7-$15 |
| Microwave display | 3-5W | $4-$7 |
| Phone Charger (empty) | 0.5-2W | $0.75-$3 |
Total phantom load: 40-80W constant, costing $60-$120/year. Smart power strips ($25-$40 each) eliminate most of this.
Step 5: Basement and Crawlspace (20 Minutes)
Rim joist: Seal with rigid foam and spray foam ($100-$300, saves $50-$150/year). This is one of the biggest leak areas.
Foundation walls: Uninsulated basement walls lose significant heat. Rigid foam (R-10 to R-15) costs $500-$2,000 DIY, saves $100-$300/year.
Crawlspace vapor barrier: A 6-mil poly barrier ($50-$150) prevents ground moisture from degrading insulation.
Floor insulation: Ensure it's intact and supported. Fallen insulation provides zero benefit.
Step 6: Create Your Priority Action Plan
| Priority | Action | Cost | Annual Savings | Payback |
|---|---|---|---|---|
| 1 | Change filter, program thermostat | $10-$20 | $80-$150 | Immediate |
| 2 | Lower water heater to 120F | $0 | $50-$95 | Immediate |
| 3 | Seal major air leaks | $30-$100 | $100-$300 | 1-4 months |
| 4 | Install smart power strips | $50-$100 | $60-$120 | 5-10 months |
| 5 | LED retrofit | $60-$150 | $150-$250 | 3-7 months |
| 6 | Insulate water heater + pipes | $30-$50 | $35-$75 | 5-9 months |
| 7 | Seal accessible ductwork | $25-$100 | $100-$300 | 1-4 months |
| 8 | Add attic insulation | $1,500-$2,500 | $200-$500 | 3-5 years |
| 9 | Heat pump water heater | $1,800-$3,500 | $300-$450 | 4-8 years |
| 10 | High-efficiency HVAC | $5,000-$12,000 | $300-$800 | 6-12 years |
Real-World Audit Examples
Example 1: 1985 Ranch in Dallas, TX
Findings: R-8 attic insulation (needs R-38+), unsealed attic hatch, 15 recessed lights penetrating ceiling, duct leak at plenum connection, water heater set to 140F, 12 incandescent bulbs remaining.
Actions and savings: Blew insulation to R-38 ($1,800), sealed attic penetrations ($150 DIY), sealed duct leak ($25 mastic), lowered water heater ($0), LED retrofit ($45). Total cost: $2,020. Annual savings: $680. Payback: 3.0 years.
Example 2: 2005 Colonial in New Jersey
Findings: Adequate attic insulation (R-38), but attic hatch unsealed, gap around chimney chase, 3 exterior doors with worn weatherstripping, 40W of phantom loads identified, thermostat not programmed.
Actions and savings: Sealed attic hatch ($25), sealed chimney gap ($40 DIY), replaced weatherstripping ($35), smart power strips ($75), programmed existing thermostat ($0). Total cost: $175. Annual savings: $345. Payback: 6 months.
Example 3: 1960s Apartment in Boston, MA
Findings (renter-friendly): Drafty windows, no door sweep on entry, 8 phantom load devices, 6 remaining CFL bulbs, thermostat at constant 72F.
Actions: Weatherstripped windows ($40), installed door sweep ($12), smart power strips ($50), LED bulbs ($18), programmed thermostat setbacks ($0). Total cost: $120. Annual savings: $290. Payback: 5 months.
Example 4: 2015 Home in Denver, CO
Findings: Home is relatively well-built. Only issues: dirty HVAC filter, uninsulated water heater pipes, 25W phantom loads, water heater at 130F.
Actions: New filter ($12), pipe insulation ($15), smart strip ($35), lowered water heater ($0). Total cost: $62. Annual savings: $145. Payback: 5 months. Even newer homes have easy wins.
Understanding Your Home's Energy Performance Score
After completing your audit, you can benchmark your home's overall efficiency.
Energy Use Intensity (EUI) Benchmark
Energy Use Intensity measures kBTU per square foot per year. Calculate yours by converting your total annual energy use (electric + gas) to kBTU and dividing by your home's square footage.
| EUI Range (kBTU/sq ft/year) | Rating | Meaning |
|---|---|---|
| Under 30 | Excellent | Top 10% efficiency, minimal improvements needed |
| 30-50 | Good | Above average, some improvement opportunities |
| 50-75 | Average | Typical US home, significant savings available |
| 75-100 | Below average | Multiple efficiency issues, 25-40% savings potential |
| Over 100 | Poor | Major upgrades needed, 40-60% savings potential |
To calculate: Add your annual electric kWh x 3.412 (converts to kBTU) plus annual gas therms x 100 (converts to kBTU). Divide the total by your home's square footage.
Example: 10,000 kWh electric + 600 therms gas = 34,120 + 60,000 = 94,120 kBTU. For a 2,000 sq ft home: 94,120 / 2,000 = 47.1 kBTU/sq ft/year — Good range.
You can also use ENERGY STAR's Home Energy Yardstick tool (free online) to compare your home to similar homes in your area. It provides a 1-10 score based on your utility data.
When to Call a Professional
A professional audit ($200-$500) adds value when:
- Bills are significantly above benchmarks with no obvious cause
- Home was built before 1980 and never audited
- You suspect major duct leakage (rooms that won't heat/cool)
- You want blower door testing and thermal imaging
- You're planning major renovations
- Your utility offers free or subsidized audits
The 30% federal tax credit covers up to $150 of a professional audit cost.
Key Takeaways:
- A DIY audit takes 2-3 hours and finds $200-$800/year in savings
- Start with utility bills to establish baselines and spot patterns
- The attic is usually the biggest source of energy waste
- Air sealing delivers the highest ROI in most homes
- Phantom loads waste $60-$120/year — smart strips fix this
- Do the free and cheap fixes first: filter, thermostat, water heater temp
- Professional audits are worth it for pre-1980 homes or unexplained high bills
Frequently Asked Questions
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