DIY Home Energy Audit: Find Where You're Wasting Money

Your home is leaking money right now. Not in some abstract, metaphorical way, but literally: heated or cooled air is escaping through cracks, gaps, and poorly insulated surfaces. Appliances are drawing power when nobody is using them. Your HVAC system might be working twice as hard as it needs to because of problems you cannot see.

The average American household spends about $2,000 per year on energy bills, and the Department of Energy estimates that 25 to 40 percent of that is wasted. That means $500 to $800 per year is going toward heating the outdoors, cooling the attic, or powering devices that are supposedly turned off.

A professional energy audit can identify exactly where that waste is happening, but it costs $200 to $600 or more. The good news is that you can find most of the same problems yourself, for free or close to it, in a single afternoon. A DIY home energy audit covers roughly 70 to 80 percent of what a professional assessment would reveal, and it gives you a clear, prioritized list of fixes that can save you hundreds of dollars per year.

This guide walks you through every step, room by room, with specific tools and techniques. By the end, you will know exactly where your home is wasting energy and what to do about it.

Why a Home Energy Audit Matters

You might already be doing the obvious things: turning off lights, adjusting the thermostat, running full loads of laundry. Those habits help, but they only scratch the surface. The biggest sources of energy waste in most homes are hidden. Air leaks you cannot feel. Insulation gaps you cannot see. Ductwork that is dumping conditioned air into your attic. An aging water heater that is running at half its original efficiency.

Without a systematic audit, you are guessing at where to spend your money on improvements. You might replace your windows for $15,000 when a $200 air sealing job on your attic floor would have saved you more. You might buy a new furnace when your real problem is leaky ductwork.

An energy audit replaces guesswork with data. It tells you:

Where air is leaking in and out of your home
Whether your insulation is adequate for your climate
How efficiently your HVAC system and water heater are operating
Which appliances and electronics are costing you the most
Which improvements will give you the biggest return on investment

Households that act on comprehensive audit findings typically save 5 to 30 percent on their total energy bills, according to the DOE. For the average home, that translates to $100 to $600 per year in savings, with most improvements paying for themselves within one to three years. If you want to see how those savings stack up alongside other strategies, our guide on how to cut your electric bill in half covers the full range of options.

What You Will Need

You can do a basic energy audit with nothing more than your hands, your eyes, and a windy day. But a few inexpensive tools make the process much more effective and precise.

Free or Already in Your Home

Your hand (dampened): Hold a damp hand near suspected air leak sites. Moving air will feel cool against wet skin, even on a warm day.
Incense stick or candle: Light it and hold it near windows, doors, outlets, and other potential leak sites. If the smoke wavers or the flame flickers, you have found an air leak.
Flashlight: Essential for inspecting the attic, crawlspace, and behind appliances.
Tape measure: Measure insulation depth in the attic and walls (if accessible).
Notepad or phone: Document everything you find. Take photos of problem areas.

Worth Buying ($25 to $60 Each)

Kill-A-Watt meter ($25 to $35): Plug any device into this meter and it shows you exactly how much electricity it consumes, both when active and in standby. This is the single most useful tool for finding phantom loads and energy-hogging appliances. If you want whole-house monitoring instead, check out our roundup of the best home energy monitors.
Thermal leak detector ($30 to $50): Devices like the Black+Decker TLD100 use an infrared sensor to detect temperature differences on surfaces. Point it at a wall, window, or ceiling and it tells you if that area is significantly warmer or cooler than the surrounding surface, which indicates an insulation gap or air leak.
Infrared thermometer ($20 to $30): A point-and-shoot temperature gun. Useful for checking surface temperatures on walls, windows, ductwork, and around outlets.

For a More Thorough Audit ($100+)

Thermal imaging camera or phone attachment ($150 to $400): Products like the FLIR ONE camera attachment for smartphones show heat patterns across entire walls and ceilings. They reveal insulation gaps, thermal bridges, moisture issues, and air leaks that are invisible to the eye. This is the closest you can get to a professional-grade tool.
Anemometer ($20 to $40): Measures airflow speed from HVAC vents. Useful for confirming whether certain rooms are getting adequate airflow or if ductwork issues are restricting delivery.

You do not need all of these tools to do a useful audit. Start with the free methods and a Kill-A-Watt meter. If you find significant issues, the thermal leak detector or camera will help you pinpoint exactly where the problems are.

Room-by-Room Walkthrough

The most effective approach is to work through your home systematically, starting from the outside and working inward. Grab your tools, your notepad, and set aside two to four hours on a day when the temperature difference between inside and outside is at least 20 degrees Fahrenheit. The bigger the temperature difference, the easier it is to detect air leaks and insulation problems.

The Exterior

Start outside and walk the full perimeter of your home. You are looking for visible gaps, cracks, and deterioration in the building envelope.

Check these areas:

Foundation: Look for cracks in the foundation wall, especially where it meets the siding. Even hairline cracks can allow air infiltration and moisture entry. Seal small cracks with exterior caulk or hydraulic cement.
Siding and trim: Check where different building materials meet, such as where wood siding meets brick, or where trim meets the wall. These joints are common air leak sites. Look for gaps, deteriorated caulking, or separated joints.
Exterior faucets and spigots: The holes cut for outdoor faucets are often oversized and poorly sealed. Check for gaps around each one.
Utility penetrations: Where electrical lines, gas pipes, cable/internet lines, and dryer vents enter the house, there are often unsealed gaps. These are some of the easiest and cheapest air leaks to fix with a tube of caulk or a can of expanding foam.
Dryer vent: Make sure the exterior flap closes completely when the dryer is not running. A stuck-open dryer vent is a direct hole to the outdoors.
Soffit and fascia: Look for gaps or damage where the roof overhangs meet the walls. These areas connect to the attic and can be major air leak pathways.

Cost to fix most exterior issues: $10 to $50 in caulk, expanding foam, and weatherstripping.

The Attic

The attic is the single most important area to inspect because heat rises. In winter, warm air from your living space pushes upward through every gap in your attic floor, carrying your heating dollars with it. In summer, a poorly insulated attic radiates heat downward into your living space, making your air conditioner work harder.

Insulation check:

Carefully enter your attic (step only on joists or laid boards, never on the drywall between joists) and measure the insulation depth with your tape measure.

If you have fiberglass batts, each inch provides roughly R-3.2. So 12 inches of fiberglass gives you about R-38.
If you have blown cellulose, each inch provides roughly R-3.5.
If you have blown fiberglass, each inch provides roughly R-2.5.

The DOE recommends R-38 to R-60 for attics, depending on your climate zone. Homes in cold climates (zones 5-8) should aim for R-49 to R-60, or roughly 14 to 17 inches of fiberglass or 13 to 16 inches of cellulose. Homes in mild climates (zones 1-3) can get by with R-30 to R-49.

If your insulation is less than 10 inches deep, or if it is uneven with visible gaps over the joists, you have a significant opportunity for improvement. Our attic insulation guide covers materials, costs, and step-by-step instructions. Adding attic insulation from R-11 to R-49 can save $200 to $600 per year in heating and cooling costs, depending on your climate.

Air leak check:

Even perfect insulation will not help much if your attic floor is full of air leaks. On a cold day, go into the attic and look and feel for the following:

Gaps around plumbing and electrical penetrations: Anywhere a pipe, wire, or duct passes through the attic floor, there is typically an unsealed gap. These are often the biggest leaks in a home.
Recessed light fixtures: Older recessed lights (non-IC rated) create large, unsealed openings in the attic floor. Each one can leak as much air as a small open window.
Attic hatch or pull-down stair: This is almost always a major leak site. The hatch itself is usually uninsulated, and the frame rarely has weatherstripping. A $15 attic hatch cover can make a noticeable difference.
Ductwork joints: If your HVAC ducts run through the attic, check every joint and connection. Hold your hand near each joint while the system is running. If you feel air, that duct is leaking conditioned air directly into the attic. Seal joints with mastic sealant (not duct tape, which fails within a few years).
Top plates of interior walls: Where interior walls meet the attic floor, there are often gaps in the drywall or framing. These create pathways for air to travel between your wall cavities and the attic.
Chimney and flue chases: The gap between a chimney or furnace flue and the surrounding framing is required to be open for fire safety but should be sealed with sheet metal and high-temperature caulk, not spray foam.

Potential savings from attic air sealing and insulation improvements: $300 to $800 per year.

Windows and Doors

Windows and doors are the most obvious suspects for air leaks, but they are often not the biggest ones. Still, they deserve careful inspection.

For each exterior window:

Lock the window and check the seal. Locking a window pulls the sash tight against the frame. If you can see daylight around a closed and locked window, the weatherstripping has failed.
Run the incense or candle test. Slowly move a lit incense stick around the entire perimeter of the window frame, including where the frame meets the wall. Any smoke movement indicates an air leak.
Check the caulking on the exterior where the window frame meets the siding. Cracked, peeling, or missing caulk should be replaced.
Assess the glass. If you have single-pane windows (one layer of glass), they provide virtually no insulation, roughly R-1. Double-pane windows are R-2 to R-3, and modern low-E double-pane windows reach R-3 to R-4. If you hold your hand near a single-pane window on a cold day, you will feel the cold radiating off the glass.
Look for condensation between panes. If you see fog or moisture between the glass layers of a double-pane window, the seal has failed and the insulating gas has escaped. That window is now performing like a single-pane.
Use your thermal leak detector. Point it at the center of the glass and compare the reading to the surrounding wall. A difference of more than 10 to 15 degrees Fahrenheit on a cold day suggests the window is a significant source of heat loss.

For each exterior door:

Check the weatherstripping around all four sides of the door. Close the door and look for daylight. Try to slide a piece of paper under the door. If it slides through easily, the sweep or threshold needs replacement.
Check the door sweep or threshold. The bottom of the door should seal tightly against the threshold. A worn or missing sweep is one of the most common air leak points in any home.
Inspect the door frame for gaps between the frame and the wall. These should be sealed with caulk or foam.

Quick fixes: Replacing weatherstripping ($5 to $15 per door/window), adding a door sweep ($8 to $20), re-caulking window frames ($5 per tube for 3-4 windows).

When to consider replacement: Full window replacement is expensive ($300 to $1,000+ per window installed) and typically takes 15 to 30 years to pay back in energy savings alone. Before replacing windows, consider these cheaper alternatives that capture much of the benefit:

Interior window insulation film ($5 to $10 per window): Shrink-fit plastic film creates a dead air space, improving insulation by 40 to 70 percent.
Exterior storm windows ($50 to $100 per window): Add a second layer of glass/acrylic over single-pane windows, delivering 25 to 50 percent improvement.
Cellular shades ($30 to $80 per window): Honeycomb-structured shades trap air and provide meaningful insulation.

HVAC System

Your heating and cooling system accounts for roughly 46 percent of your home energy use, making it the single biggest target for savings. Even if you are not ready to replace your system, maintenance and duct sealing can dramatically improve its performance.

Check the filter:

Pull out your HVAC filter and inspect it. A dirty, clogged filter restricts airflow and forces the system to work harder. The DOE estimates that replacing a dirty filter with a clean one can reduce HVAC energy consumption by 5 to 15 percent. At $2,000 to $3,000 per year in HVAC costs for an average home, that is $100 to $450 in annual savings from a $5 to $20 filter.

Check your filter monthly and replace it every one to three months, or as recommended by the manufacturer. If you have pets, allergies, or live in a dusty area, lean toward monthly replacement.

Assess the system age and type:

How old is your furnace, boiler, heat pump, or air conditioner? Check the nameplate or manual.
Systems older than 15 to 20 years are typically operating well below their rated efficiency. A furnace rated at 80 percent AFUE when new may be running at 60 to 70 percent after two decades.
Modern high-efficiency furnaces are 95 to 98 percent AFUE. Modern heat pumps achieve 300 to 400 percent effective efficiency (COP of 3 to 4), meaning they deliver three to four watts of heat for every watt of electricity consumed.
If your system is older than 15 years, get a professional assessment of its current efficiency. Upgrading to a modern heat pump can cut heating and cooling costs by 30 to 50 percent. Our guide to heat pumps covers everything you need to know.

Inspect accessible ductwork:

If you can see your ductwork in the basement, crawlspace, or attic, inspect it carefully:

Feel for leaks at joints. Turn the HVAC system on and hold your hand near every joint, seam, and connection you can reach. Air escaping from ducts in unconditioned spaces is pure waste.
Look for disconnected sections. Flex duct in attics and crawlspaces is notorious for pulling loose from connections or getting crushed.
Check duct insulation. Ducts in unconditioned spaces (attic, crawlspace, garage) should be wrapped in R-6 to R-8 insulation. Uninsulated ducts in a 130-degree attic or a 35-degree crawlspace are fighting against massive temperature differences.
Measure airflow at vents. If some rooms are consistently too hot or too cold, hold your hand (or an anemometer) at the supply vents. Weak airflow compared to other rooms suggests duct problems: leaks, kinks, or blocked runs.

The typical home loses 20 to 30 percent of its conditioned air through duct leaks. Sealing ducts with mastic sealant (a thick paste applied with a brush) at all joints and connections can save 10 to 20 percent on HVAC costs, or $200 to $600 per year.

Check the thermostat:

Do you have a programmable or smart thermostat? If you are still running a basic manual thermostat, upgrading to a programmable model ($25 to $50) or a smart thermostat ($100 to $250) and actually using the scheduling features can save 8 to 15 percent on heating and cooling costs.
If you already have a programmable thermostat, check that it is actually programmed. The EPA found that nearly 40 percent of households with programmable thermostats never actually program them.

Water Heater

Water heating accounts for 14 to 18 percent of your home energy use, making it the second largest energy consumer after HVAC.

Check the temperature setting:

Many water heaters ship with the thermostat set to 140 degrees Fahrenheit, but 120 degrees is sufficient for most households and saves 6 to 10 percent on water heating costs. Find the thermostat dial on your water heater (it is usually behind a small panel on electric models, or on the gas valve on gas models) and turn it to 120 degrees or the "warm" setting.

Assess the age and type:

Check the nameplate for the manufacture date. Tank water heaters typically last 8 to 12 years. If yours is approaching or past that age, it is likely operating at reduced efficiency due to sediment buildup and component wear.
If you have a standard electric resistance water heater, it is running at an energy factor (UEF) of 0.90 to 0.95, meaning 5 to 10 percent of the electricity is wasted.
Heat pump water heaters achieve a UEF of 3.5 to 4.0, meaning they are three to four times more efficient than standard electric models. Switching saves the average household $300 to $550 per year. The upfront cost ($1,200 to $2,500 installed) is partially offset by the federal tax credit of up to $2,000 under the Inflation Reduction Act. See our detailed breakdown of heat pump water heaters.

Check for insulation:

Tank insulation: Touch the outside of the tank. If it feels warm, the tank is losing heat to the surrounding air. Older tanks (pre-2015) often benefit from an insulation blanket ($20 to $30), which can reduce standby heat loss by 25 to 45 percent and save $30 to $60 per year. Newer tanks are already well-insulated and do not benefit from an added blanket.
Pipe insulation: Check the hot water pipes, especially the first 3 to 5 feet leaving the tank. Uninsulated hot water pipes lose heat as the water travels to your faucets, and they also lose heat between uses as standing water in the pipes cools down. Foam pipe insulation costs $1 to $3 per 6-foot section and takes minutes to install.

Listen for sediment:

If your water heater makes popping, rumbling, or banging sounds during heating, sediment has built up on the bottom of the tank. This layer of mineral deposits acts as an insulator between the heating element and the water, forcing the system to work harder and reducing its lifespan. Flushing the tank annually is a simple DIY maintenance task.

Appliances

Appliances account for a significant chunk of your electricity bill, and the age of your appliances matters enormously.

Use the Kill-A-Watt meter:

Plug your Kill-A-Watt meter into each major appliance and monitor it for at least 24 hours (a full week is better for intermittent-use appliances). Record the kWh reading and multiply by your electricity rate to calculate the annual cost.

Appliances to prioritize:

Refrigerator and freezer: These run 24/7 and can be major energy hogs if they are old. A refrigerator from 2000 may use 600 to 800 kWh per year. A current ENERGY STAR model uses 350 to 450 kWh. If your Kill-A-Watt reading shows your fridge using more than 500 kWh/year, replacement should be on your list. Also check the door seals: close the door on a dollar bill and try to pull it out. If it slides out easily, the seal is not tight enough and cold air is leaking out.
Chest freezer or garage fridge: Second refrigerators and standalone freezers are often old, inefficient models running in unconditioned spaces. They can easily cost $100 to $200 per year to operate. Consider whether you really need that second fridge, and if you do, replace it with an ENERGY STAR model.
Washer and dryer: An older top-loading washer can use 40 to 50 gallons of water per load. A modern ENERGY STAR front-loader uses 13 to 15 gallons, saving both water and the energy to heat it. Heat pump dryers use 50 percent less energy than conventional dryers, though they take longer per cycle.
Dishwasher: Modern ENERGY STAR dishwashers use less water and energy than hand-washing. If your dishwasher is over 10 years old, upgrading can save $35 to $50 per year in energy and water costs.

Check the age of everything: As a rule of thumb, any major appliance over 10 to 15 years old is worth evaluating for replacement, especially if it lacks an ENERGY STAR rating. The combination of higher efficiency and potential rebate programs often makes replacement cost-effective.

Lighting

Lighting accounts for roughly 9 percent of home electricity use. The fix here is straightforward and one of the highest-ROI improvements you can make.

Do a bulb inventory:

Walk through every room and count the total number of light sockets and the type of bulb in each:

Incandescent bulbs (the old round glass type): These waste 90 percent of their energy as heat. A 60-watt incandescent produces the same light as a 9-watt LED.
CFL bulbs (the spiral compact fluorescents): Better than incandescent (13 to 15 watts for the same light as a 60-watt incandescent) but contain mercury and take time to reach full brightness.
LED bulbs: The clear winner. They use 75 to 80 percent less energy than incandescent bulbs, last 15 to 25 times longer, and produce almost no waste heat.

Calculate your savings potential:

If you still have 20 incandescent bulbs running an average of 3 hours per day:

Incandescent cost: 20 bulbs x 60W x 3 hours x 365 days = 1,314 kWh/year = roughly $197/year at $0.15/kWh
LED cost: 20 bulbs x 9W x 3 hours x 365 days = 197 kWh/year = roughly $30/year
Annual savings: about $167 per year
Cost of 20 LED bulbs: $20 to $40 (about $1 to $2 each in multipacks)
Payback: roughly 2 to 3 months

Even if you only have a handful of incandescent bulbs left, replacing them is one of the fastest payback improvements in this entire guide.

Do not forget outdoor lights: Porch lights, garage lights, and landscape lighting often run for long hours. Switch any remaining incandescent or halogen outdoor bulbs to LED. Consider adding motion sensors ($15 to $30) to outdoor lights that do not need to be on all night.

Phantom Loads and Electronics

Phantom loads, sometimes called vampire loads, are the electricity consumed by devices that are plugged in but not actively being used. They account for 5 to 10 percent of household electricity use, costing the average home $75 to $200 per year.

Use the Kill-A-Watt meter to test:

Plug devices into the Kill-A-Watt meter and check their draw when "off" or in standby mode. Common offenders include:

Cable/satellite boxes: 15 to 30 watts in standby, 24/7. That is 130 to 260 kWh/year, or $20 to $40/year per box, just sitting there "off."
Game consoles: 5 to 25 watts in standby (older Xbox and PlayStation models are the worst offenders). Some draw nearly as much power in "instant on" mode as when actively gaming.
Desktop computers and monitors: 5 to 15 watts each in sleep mode. A desktop PC and dual monitors in sleep draw about 25 watts around the clock when not in use.
Printers and scanners: 5 to 10 watts in standby, always ready for a print job that comes once a week.
Phone and laptop chargers: 0.5 to 5 watts each when plugged in with no device attached. Small individually, but most homes have 5 to 10 of these.
Smart speakers and displays: 3 to 6 watts each, always listening.
Older televisions: Some older TVs draw 10 to 15 watts in standby for features like "instant on."

Solutions:

Smart power strips ($15 to $35): These cut power to peripheral devices when the primary device is turned off. For example, when you turn off your TV, the smart strip cuts power to the soundbar, streaming device, and game console automatically.
Simple power strips with a switch: Plug entertainment centers, computer setups, and other device clusters into a power strip and flip it off when not in use. This costs $5 to $10 and eliminates the phantom load entirely.
Unplug rarely used devices: That printer you use once a month? Unplug it. The charger in the guest room? Unplug it. Make it a habit to unplug anything that does not need to stay on.
Check device settings: Many game consoles and streaming devices have an "energy saving" mode that dramatically reduces standby power. Enable it.

Potential savings from addressing phantom loads: $75 to $200 per year with virtually no upfront cost.

Putting It All Together: Prioritizing Your Fixes

After completing your walkthrough, you will likely have a list of findings ranging from quick, free fixes to major investments. Here is how to prioritize them for maximum impact.

Tier 1: Do It This Weekend (Free to $50)

These fixes cost almost nothing and deliver immediate savings:

| Fix | Cost | Estimated Annual Savings | |---|---|---| | Replace HVAC filter | $5 to $20 | $100 to $450 | | Seal exterior penetrations with caulk/foam | $10 to $30 | $50 to $150 | | Lower water heater to 120 degrees | Free | $30 to $60 | | Replace incandescent bulbs with LEDs | $20 to $40 | $100 to $300 | | Address phantom loads with power strips | $10 to $40 | $75 to $200 | | Weatherstrip doors and windows | $20 to $50 | $50 to $150 | | Program your thermostat | Free | $100 to $200 |

Total Tier 1 cost: $65 to $230 Total Tier 1 savings: $505 to $1,510 per year Payback: Immediate to 3 months

Tier 2: Worth Doing This Month ($50 to $500)

These require a bit more time and investment but still pay for themselves quickly:

| Fix | Cost | Estimated Annual Savings | |---|---|---| | Seal attic air leaks (foam, caulk, sheet metal) | $50 to $200 | $100 to $300 | | Add attic insulation | $200 to $500 (DIY blown-in) | $150 to $400 | | Seal accessible ductwork with mastic | $30 to $80 | $100 to $300 | | Insulate hot water pipes | $10 to $30 | $20 to $50 | | Add a water heater insulation blanket | $20 to $30 | $30 to $60 | | Install a smart thermostat | $100 to $250 | $100 to $200 | | Add window insulation film | $30 to $60 | $30 to $80 |

Total Tier 2 cost: $440 to $1,150 Total Tier 2 savings: $530 to $1,390 per year Payback: 4 to 12 months

Tier 3: Plan and Budget ($500+)

These are larger investments that deliver major savings over time but require planning:

| Fix | Cost | Estimated Annual Savings | |---|---|---| | Replace old HVAC with heat pump | $4,000 to $12,000 (before rebates) | $500 to $1,500 | | Replace electric water heater with heat pump model | $1,200 to $2,500 (before credits) | $300 to $550 | | Replace old refrigerator | $600 to $1,200 | $50 to $150 | | Add storm windows | $50 to $100/window | $20 to $50/window | | Insulate basement rim joists | $200 to $500 (DIY) | $100 to $200 |

For Tier 3 items, research available rebates and tax credits before committing. The Inflation Reduction Act provides significant incentives for heat pumps (up to $8,000 for whole-home, up to $2,000 for water heaters), and many utilities offer additional rebates on top of federal credits.

When to Go Pro: Hiring a Professional Energy Auditor

A DIY audit is a powerful starting point, but there are situations where a professional audit is worth the $200 to $600 investment.

Consider hiring a professional if:

Your home is older than 30 years and has never been audited. Older homes have more complex air sealing challenges, including balloon-framed walls, knob-and-tube wiring, and asbestos insulation that should not be disturbed without expertise.
Your energy bills are significantly higher than comparable neighbors. If you are paying 30 to 50 percent more than similar-sized homes in your area, there may be hidden problems a professional's equipment can find.
You have persistent comfort problems. Rooms that are always too hot or too cold, excessive humidity, or ice dams on the roof in winter all point to issues that benefit from professional diagnosis.
You are planning major renovations or HVAC replacement. A professional audit provides the data you need to size a new HVAC system correctly and prioritize envelope improvements before investing in new equipment.
You need a professional audit for rebates. Many utility rebate programs and federal incentive programs require a certified audit (BPI or RESNET certified) before they will approve incentive payments.
You suspect combustion safety issues. If you have gas appliances (furnace, water heater, stove), a professional can perform combustion safety testing to ensure they are not backdrafting carbon monoxide into your home. This is a safety issue, not just an efficiency issue.

What a professional audit includes that DIY cannot replicate:

Blower door test: A calibrated fan mounted in an exterior door depressurizes your home to a standard pressure (50 Pascals) and measures total air leakage in cubic feet per minute (CFM50). This gives you a single number that quantifies how leaky your home is compared to standards and benchmarks. A typical existing home measures 2,000 to 4,000 CFM50. A tight, well-sealed home is under 1,500 CFM50.
Professional infrared thermography: While consumer thermal cameras are useful, a professional-grade camera (costing $5,000 to $15,000) provides higher resolution and more accurate readings, especially when combined with the blower door test. Depressurizing the home with the blower door while scanning with an infrared camera reveals air leaks that are invisible under normal conditions.
Duct leakage testing: A duct blaster test pressurizes your duct system and measures exactly how much air is leaking. The typical home has 20 to 30 percent duct leakage. A professional can tell you whether sealing is worth the effort or if duct replacement is more cost-effective.
Combustion appliance zone (CAZ) testing: Ensures gas appliances are drafting properly and not creating carbon monoxide hazards.

How to find a qualified auditor:

Look for BPI (Building Performance Institute) certified professionals
Check with your utility company, many offer subsidized or free audits
Search the RESNET directory for HERS raters in your area
Ask for references and verify they will perform a blower door test (not just a visual walkthrough)

Frequently Asked Questions

How long does a DIY energy audit take?

Plan for two to four hours for a thorough walk-through of an average-sized home (1,500 to 2,500 square feet). You can break it into smaller sessions if needed, tackling one or two areas per session. The attic inspection and the Kill-A-Watt measurements take the most time.

What is the best time of year to do an energy audit?

The ideal time is during heating season (late fall through early spring) when the temperature difference between inside and outside is greatest. This makes air leaks much easier to detect. A cold, windy day is perfect for finding drafts. That said, you can do a useful audit any time of year. Summer is a good time to check attic insulation (the heat up there will make inadequate insulation painfully obvious) and to measure cooling-related energy use.

How much money will I actually save?

It depends entirely on what you find and what you fix. Homes that have never been audited or improved typically have the most to gain. Based on DOE data and real-world results, here are realistic ranges:

Quick fixes only (Tier 1): $500 to $1,500 per year
Quick fixes plus insulation and duct sealing (Tier 1 + 2): $1,000 to $2,500 per year
Comprehensive improvements including equipment upgrades (all tiers): $1,500 to $3,500 per year

Most households find that the Tier 1 fixes alone, which cost under $250 total, save $500 or more annually.

Do I need to turn off my HVAC system during the audit?

No. In fact, having the HVAC system running helps you identify duct leaks (you can feel air escaping from duct joints) and check airflow at vents. The only time you might turn it off briefly is when using the incense stick test near return air vents, since the suction from the return can mask or create false readings.

Is a DIY audit worth doing if I plan to hire a professional?

Absolutely. A DIY audit helps you fix the easy, obvious problems right away without waiting for a professional appointment. It also helps you have a more informed conversation with the auditor when they arrive, and you will be better equipped to evaluate their recommendations and cost estimates.

Can renters do an energy audit?

Yes, and you should. Many of the findings, phantom loads, lighting upgrades, thermostat adjustments, window film, and weatherstripping, are things you can address yourself at low cost. For larger issues like insulation or HVAC problems, document your findings and present them to your landlord. Many landlords will address efficiency issues when presented with specific, documented problems, especially if you frame them in terms of reduced maintenance costs and tenant retention.

How often should I repeat an energy audit?

Do a comprehensive audit once, then repeat a quick check annually, focusing on HVAC filters, weatherstripping condition, and any new appliance additions. If you make major changes to your home (renovation, new addition, HVAC replacement), do a full audit of the affected areas afterward.

What is a HERS score and do I need one?

A HERS (Home Energy Rating System) score is a standardized rating of your home's energy efficiency, where 100 represents a standard new home and lower is better. A HERS score requires a professional RESNET-certified rater and costs $300 to $500. You do not need one for a DIY audit, but it is useful if you are buying or selling a home or applying for energy efficiency mortgages.

Your Next Steps

You now have everything you need to find where your home is wasting energy and money. Here is how to get started:

Schedule your audit. Pick a day this week and set aside two to four hours. Choose a cold or windy day if possible.
Grab your tools. At minimum, get an incense stick and a flashlight. A Kill-A-Watt meter is worth the $30 investment.
Work through the house systematically. Start with the exterior, then the attic, then work room by room through the interior.
Document everything. Take photos, write down findings, and note which tier of fix each issue falls into.
Start with Tier 1 fixes. Most can be done the same weekend as your audit.
Plan your Tier 2 improvements for the following month. Research rebates and incentives before buying.
Track your results. Compare your energy bills before and after improvements to see real savings. A home energy monitor makes this easy to do in real time.

The hardest part of saving energy is knowing where to focus. After completing your DIY energy audit, you will not be guessing anymore. You will have a clear map of where your money is going and exactly what to do about it.