Posted On: May 23, 2026
Author: Jason H.
energy-efficiency save-money DIY
A weekend, a flashlight, an incense stick, and a notepad. That's the whole kit for a DIY energy audit. You're not going to match what a pro with a blower door rig and a thermal camera finds, but you'll get probably 60 to 70% of the way there, and the 30% the pro catches is mostly inside walls you can't open yourself anyway.
Most homes lose energy through a small number of obvious places. Once you find them, the fixes are cheap. The hardest part is making yourself spend the Saturday morning looking.
In a typical house, air leakage accounts for somewhere between 25 and 40 percent of total heating and cooling cost. Wherever your conditioned air is escaping, you're paying to heat or cool the outdoors. The good news is that finding the leaks doesn't require equipment.
The places to check, in order of how often I find leaks:
Window and door frames. Look for gaps between the frame and the wall. Run a hand around the perimeter on a windy day. If you can feel a draft, there's a leak. Door bottoms wear out their sweep first, usually within a few years. A new sweep at the hardware store is $8 and takes ten minutes.
Outlet and switch plates on exterior walls. Most homeowners never think about these because the holes look small, but together they add up. A foam gasket that fits behind the cover plate is about $0.50 each and stops the draft. Buy a 10-pack and do them all in an afternoon.
Recessed lights. These are the biggest hidden offenders in two-story homes. The cans punch through the ceiling into the attic, and unless they're rated and sealed as airtight, they leak heated air upward all winter. The fix depends on the fixture type, but airtight LED retrofits are available for most.
Plumbing and electrical penetrations. Under sinks where the pipes come through the wall. Behind the washing machine. Where the cable line enters the house. Wherever something punches through the exterior, there's usually a gap. Spray foam in a can ($6) fills these. Use the "minimal expanding" variety unless you want to spend the next hour cleaning it off your hands.
The attic hatch. If you have a pull-down attic ladder, it's almost certainly leaking. The hatch is essentially an uninsulated panel in your ceiling. You can buy an attic stairs insulator (basically a foam box that sits over the hatch from the attic side) for about $40. It's the highest-ROI energy purchase in most houses.
For finding subtler leaks, the incense test still works. Light an incense stick on a cool, breezy day, walk it slowly around suspected spots, and watch the smoke. Smoke pulled sharply in one direction or another is a leak.
Climb into the attic. Bring a flashlight. Look at the insulation level relative to the floor joists (the wood beams running across the attic floor).
If you can see the tops of the joists, you don't have enough insulation. The current recommendation for most U.S. climates is R-49 to R-60 in the attic, which usually means 14 to 18 inches of fiberglass or cellulose. If yours is six inches and old, that's probably the single biggest comfort-and-savings upgrade available to you.
Adding more is straightforward and you can DIY it. Blown-in cellulose is the easiest for retrofits. Most hardware stores rent the blower for free if you buy the insulation, and a typical attic takes a few hours.
While you're up there, look at the soffit vents (the small openings under the roof eaves) and make sure insulation isn't blocking them. They're what allow the attic to breathe in summer, which keeps your roof shingles from cooking and your attic from baking.
The HVAC filter. I'm not going to belabor this one. Pull yours out right now. If you can't read a newspaper through it, replace it. A clean filter saves energy by reducing the load on the blower motor, and it extends the life of the system itself.
Ductwork. If you have any of your ducts in unconditioned space (basement, crawlspace, attic), look at the joints. Feel for air movement at the seams. Leaky ducts can lose 20-30% of the conditioned air before it ever reaches your registers. Seal joints with metal-foil tape rated for HVAC use, or with mastic sealant. Skip standard duct tape, which is misnamed and falls apart on actual ducts within a few years.
The water heater temperature. Pull the cover and check the thermostat. Many are factory-set to 140°F. The Department of Energy recommends 120°F for most households, which is hot enough for showers and dishwashing, cool enough to reduce mineral buildup, and uses about 10% less energy. Households with infants or immunocompromised members may have specific medical guidance to stay higher, but 120 is the default starting point for the rest of us.
If your water heater is in an unheated basement or garage, an insulating blanket is $25 and pays for itself in a year. They're easy to install with the included straps.
The pattern most homes follow: spend $50-100 on the cheap stuff (weatherstripping, outlet gaskets, attic hatch insulator, water heater blanket) over one weekend. Then bigger projects (attic insulation, duct sealing) as budget allows.
The reason the order matters is that air sealing has to come before adding insulation. If you blow more insulation over a leaky ceiling, you're just adding R-value to air that's still escaping. Seal first, insulate second.
Properteer logs your home's components and reminds you when each one needs attention. Filter changes, water heater flushes, the recurring tasks that keep efficient systems efficient. Plus a place to log the stuff you found in your audit so the to-do list doesn't live on a sticky note.
