A DIY home energy audit is a room-by-room walk-through with a few household tools, done to find where air leaks in or out and where insulation is thin, before you spend money sealing or insulating anything. It will not replace a professional's blower door test, but it will point you to the worst offenders: the attic hatch, the rim joist, window and door frames, and duct connections in unconditioned space. Do it before you buy materials, not after.
What a DIY Home Energy Audit Can and Cannot Tell You
A homeowner walk-through is detective work, not measurement. You are looking for symptoms: a draft you can feel, a cold wall you can touch, a room that never holds temperature. A professional home energy assessment adds tools a homeowner does not own: a blower door that depressurizes the whole house to make every leak findable at once, and an infrared camera that shows surface temperature differences across a wall or ceiling. That combination catches leaks a walk-through misses entirely, particularly inside finished walls.
Be honest with yourself about what a handheld thermal leak detector or an infrared thermometer actually shows you. It reads surface temperature, not airflow. A cold reading at an outlet can mean a real air leak, or it can just mean thin insulation with no leak at all, or a stud behind the drywall conducting cold straight through. The tool tells you where it is cold. It does not tell you why. Treat every reading as a place to look closer, not as a diagnosis.
Tools you likely already own
Before buying anything, use what is in the house:
- A thin tissue or a sheet of paper, held at window and door frames. If it flutters or gets pulled when the frame is closed, air is moving through the seal.
- A flashlight, used after dark from outside while someone stands inside a darkened room and marks where light shows through a frame or a gap.
- A feather or a length of thread, held near outlets, baseboards, and attic hatches. Airflow it barely takes to move a feather is airflow worth sealing.
- A dirty furnace filter is its own finding. If it has gone from white or light gray to visibly gray or clogged, the system is working harder than it should.
If you decide to add a purchase, an infrared thermometer or a basic thermal leak detector are the two categories worth the money, and they range from budget handheld models to premium units with imaging screens. Pick based on how much of the house you plan to check and how precisely you want to compare spots, not on a specific brand claim; this guide does not sell or recommend one over another.
Where to check first, room by room
Work the building envelope in order, not at random:
- Baseboards and where walls meet ceilings, especially on exterior walls, are common indoor leak points the DOE's do-it-yourself home energy assessment guide names directly (read 2026-09-18).
- Window and door frames, top and bottom, not just the sides.
- Outlets and switch plates on exterior walls. Look, do not touch anything live. If you plan to add foam gaskets behind the plates later, switch the circuit off at the breaker first and confirm it is dead with a non-contact tester before removing any cover.
- Where two different materials meet outside: siding to foundation, brick to trim, the point a dryer vent or hose bib passes through the wall.
- The rim joist, the band of framing that sits on the foundation between floors. It is often the single largest cold surface in a basement, and our guide to insulating a rim joist covers what to check for before sealing it.
- Knee walls, if the house has a bonus room over a garage or under a sloped roof. These short attic-side walls are a frequent reason that one room never holds temperature; see knee wall insulation for what is usually wrong behind them.
The attic: fall and heat hazards first
Most of a house's stack-effect air loss runs through the attic floor, so it deserves the most time, but it is also where the walk-through gets physically risky. State this plainly before you go up: a residential attic is a fall hazard and, in summer or in direct sun, a heat hazard.
Before you climb:
- Use a stable, properly footed ladder and keep three points of contact going up and down.
- Step only on ceiling joists or a laid walkway board. The insulation between joists hides the drywall underneath, and drywall does not hold a person's weight; stepping between joists is how people fall through their own ceiling.
- Wear a dust mask (N95 or better) and gloves. Fiberglass and cellulose insulation both irritate skin and lungs.
- Check the temperature before you go. An attic in full summer sun can be dangerously hot; do this work in the morning or in cooler weather instead.
- Do not disturb insulation over soffit vents while you are up there; if you find it blocking airflow, that is a separate job, and our guide to attic baffles and soffit vents explains why they have to stay clear.
Once you are safely positioned, look for dirty, compressed, or discolored insulation. Dirty insulation is often a sign that air has been filtering through it for years, carrying dust with it, which points to a leak below rather than a manufacturing defect in the insulation itself.
Testing for drafts without a blower door
A rough version of a professional's depressurization test uses a lit incense stick or a smoke pencil and your kitchen and bathroom exhaust fans. State both hazards plainly before you try it. First, an open flame or ember: keep it well clear of curtains, paper, and stored items, and never run this test near an open gas flame, a pilot light, or a burning fireplace or wood stove. Second, the exhaust fans lower indoor air pressure, so if your home has a gas furnace, gas water heater, or a fireplace, turn those appliances off first and confirm you already have a working carbon monoxide detector installed; depressurizing a house while a combustion appliance is running can pull exhaust gases back down a flue instead of venting them outside.
With both of those handled: turn on every exhaust fan that vents outside (bathroom fans, the range hood, the clothes dryer) to depressurize the house slightly, then walk the same leak points listed above holding the lit incense stick or smoke pencil a few inches away. Smoke that gets pulled toward a gap, or pushed away from it, marks a leak.
What the numbers actually say
Two figures are worth carrying into this project, both traceable to a named source rather than a guess. The DOE's guide states that reducing drafts in a home can save in the range of 10% to 20% a year on energy costs (read 2026-09-18). Separately, ENERGY STAR cites an EPA estimate that sealing air leaks and adding insulation in attics, floors over crawl spaces, and basements saves an average of 15% on heating and cooling costs, or about 11% on total energy costs (read 2026-09-18). Both are averages across typical existing US homes, not a promise for your specific house, and neither source publishes a dollar figure that holds up across regions and utility rates. Where your own utility bill and local rate are the only inputs that would make a dollar number real, this guide states the variables instead of inventing one.
When to bring in a professional
A DIY walk-through is step one, not the whole project. Once you have a list of suspected leak points and a sense of how much of the house is affected, a certified home energy auditor (often BPI-certified, Building Performance Institute) can run the blower door and infrared camera tests that find what a walk-through misses, and produce a written report ranking the findings.
Reading that report is where the DIY part of this project ends and your own judgment takes over. The report will typically prioritize fixes by expected impact, but it is not a purchase order: which contractor does the sealing or insulation work, which materials they use, and in what order, is a decision for you to make based on your own quotes, references, and comfort with the contractor. This guide does not tell you which company to hire or which product to buy from a report's recommendations; that call is yours.
Turning findings into a plan
Once you know where the losses are, the order of work generally follows the size of the problem, not the easiest fix first. Attic air sealing and insulation upgrades typically address the largest area, so if your walk-through points there, our attic insulation tools guide lists what a DIY attic project actually requires before you start buying materials. Smaller, sealed jobs at rim joists, knee walls, and penetrations are worth doing regardless of what a professional later recommends, since sealing them costs little and causes no harm if a pro later confirms the same finding.
FAQ
Does a DIY home energy audit cost anything?
Most of it uses tools already in the house: paper, a flashlight, a feather or thread. An infrared thermometer or thermal leak detector, if you choose to buy one, adds a modest cost and ranges from basic handheld models to premium imaging units.
Can a DIY audit replace a professional energy audit?
No. A walk-through finds visible and felt leaks. A professional's blower door test and infrared camera find leaks inside walls and ceilings that a walk-through cannot detect, and produce a written, prioritized report.
What time of year is best for a DIY home energy audit?
A day with a noticeable temperature difference between inside and outside makes leaks easier to feel and to see with an infrared thermometer. Avoid attic work during extreme heat for safety reasons; cooler mornings are safer and more comfortable.
Is it safe to use a lit incense stick to test for drafts?
Only away from anything flammable and never near an open flame, a pilot light, or a running gas appliance. Turn off combustion appliances and confirm a working carbon monoxide detector is installed before running any exhaust-fan depressurization test.
Do I need to go into the attic to do a DIY energy audit?
Much of the walk-through happens at floor level: baseboards, outlets, window and door frames. The attic adds real value because that is where the largest area of loss usually is, but only go up with a stable ladder, three points of contact, and by stepping on joists or a walkway board, never between them.