How to Lower Your Heating Bill in the US: Part 2 — Seal the Drafts and Stop Heat Escaping

If you set your thermostat carefully in Part 1 and your house still feels cold in one room, warm in another, and expensive everywhere, the problem is probably not the thermostat at all. It is the house itself leaking the heat you already paid for.

That is actually hopeful news. Drafts, gaps around doors, and thin attic insulation are some of the cheapest heating problems to fix, and many of them take an afternoon, not a renovation. This second and final part of our winter heating series shows you how to find the leaks, which material seals which gap, where insulation pays off first, and what free help exists if money is tight.

About this series: “How to Lower Your Heating Bill in the US” is a two-part series. Part 1 covered thermostat settings and daily heating habits — read Part 1 here. Part 2 (this post) covers sealing drafts, weatherstripping, caulking, and insulation basics. Read together, the two parts cover both sides of the bill: how you run the heat, and how well your home keeps it.

Caption: A drafty door can undo a careful thermostat schedule — sealing it is the cheapest fix in this guide. (Symbolic generated image)

Key points

Sealing plus insulation is a proven package: EPA’s ENERGY STAR program estimates homeowners can save an average of 15% on heating and cooling costs (or an average of 11% on total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces, and basements.
Simple fixes alone help: ENERGY STAR also notes that tackling sealing and insulating together can save up to 10% on annual energy bills, starting with weatherstripping on doors and caulking around windows.
Use the right material for the gap: The U.S. Department of Energy (DOE) rule is simple — caulk seals cracks between parts that do not move, weatherstripping seals parts that do move, such as doors and operable windows.
Most homes need this: ENERGY STAR says 9 out of 10 homes in the U.S. are under-insulated.
Free help exists: The DOE Weatherization Assistance Program (WAP) provides air sealing and insulation at no cost to eligible households, and DOE reports participating households save an average of $372 or more a year.

Why do drafts cost so much?

Warm air does not stay where you put it. It rises, pushes out through gaps at the top of the house, and pulls cold air in through gaps at the bottom — around doors, windows, pipes, and wires. ENERGY STAR puts it vividly: if you added up all the leaks, holes, and gaps in a typical home’s envelope, it would be the equivalent of having a window open every day of the year.

That is why a drafty house feels uncomfortable even at a temperature that should be warm, and why people keep turning the thermostat up to compensate. You end up paying twice: once for heat that escapes, and again for the higher setting you chose because the room still felt cold. Sealing breaks that cycle at the source, so the settings from Part 1 can actually do their job.

Step 1: Find the leaks in 20 minutes

You do not need special equipment to find the biggest leaks. On a cold, windy day, walk slowly around the inside of your home and hold the back of your hand — or a thin strip of tissue — near the places air usually moves.

Check these spots first:

Exterior doors: the sides, the top, and especially the bottom edge
Windows: around the frame and where the sash meets the frame
Where pipes, cables, and vents pass through walls, floors, and ceilings
Electrical outlets and switch plates on exterior walls
Attic hatches, recessed lights, and the opening around a whole-house fan
Fireplace dampers and the baseboards along exterior walls

Why it works: leaks are not evenly spread. A handful of large, easy gaps — a worn door seal, an unsealed attic hatch — usually account for a large share of the air escaping. Finding them first means your time and money go to the gaps that matter, not to sealing a house that is already tight in the places you happen to look.

If you want a more thorough check, a professional home energy assessment can include a blower-door test that measures overall leakage. That is worth considering before a big insulation job, but it is not required for the fixes below.

Step 2: Caulk the gaps that do not move

Caulk is for stationary joints. The DOE guidance is to use caulk for cracks, gaps, or joints less than a quarter-inch wide between parts that do not move — for example, where a window frame meets the wall, or where a pipe passes through a floor.

How to do it well:

Clean old, loose caulk and dirt away first, so the new bead actually sticks.
Apply in dry weather above 45°F when you can, which helps the caulk set and adhere.
Use about half a cartridge per window or door as a rough buying guide, and cut the tip for a bead that matches the gap — too wide wastes material and looks messy, too narrow leaves a gap.
Smooth the bead, let it cure as the product directs, and re-check after the first cold night.

Why it works: caulk creates a continuous, flexible seal that moves slightly with the house through the seasons. A hairline crack looks harmless, but dozens of them around frames and penetrations add up to a permanent, invisible opening to the outside.

Safety note: do not caulk around flues, chimneys, or other high-heat surfaces with ordinary caulk, and never seal a home so tightly without thinking about ventilation if you have fuel-burning appliances. If you are planning whole-house sealing, a professional assessment of ventilation and combustion safety is the responsible step.

Caption: Caulk belongs on gaps that do not move — frames, joints, and places where pipes pass through. (Symbolic generated image)

Step 3: Weatherstrip the parts that do move

Weatherstripping is for doors and windows that open and close. When the strip is worn, flattened, or missing, cold air pours in every time the wind pushes against that side of the house.

Start with exterior doors, because they are large, used daily, and often the worst leak in the house:

Replace cracked or compressed weatherstripping around the door frame. Measure the full perimeter and add 5 to 10 percent extra for waste and mistakes, as DOE buying guidance suggests.
Add or replace a door sweep at the bottom. You should not see daylight under a closed exterior door.
Fix the door first if it does not close properly — tighten loose hinges and check the strike plate — because no strip can seal a door that hangs crooked.
Apply weatherstripping to clean, dry surfaces above 20°F so the adhesive holds.

For windows, add weatherstripping where the sash moves, and consider a temporary interior window kit or heavy curtains for the coldest, least-used windows in winter. Curtains work best hung close to the glass and closed at night; they do not replace sealing, but they reduce the cold feeling near the window that makes people raise the thermostat.

Why it works: a door is a large moving panel in your wall. Sealing its edges is the closest thing to closing that open window ENERGY STAR describes — and unlike a window replacement, it costs a few dollars and takes under an hour for most doors.

Step 4: Do not forget ducts, outlets, and the attic hatch

Three often-missed spots deserve a look before you spend on anything bigger.

First, ducts. In a typical house with forced-air heating, a significant share of the air moving through ducts can be lost to leaks, holes, and poor connections — ENERGY STAR guidance commonly puts duct losses in the 20 to 30 percent range. Sealing accessible duct joints in a basement or attic with mastic or foil tape made for ducts (not ordinary cloth duct tape, which fails quickly) keeps more warm air reaching the rooms it was meant for.

Second, outlets and switch plates on exterior walls. A foam gasket behind the cover plate costs very little and stops a small but constant draft. Turn off power to that outlet before removing the plate, and never work inside the electrical box itself.

Third, the attic hatch or pull-down stairs. Warm air rises straight to this opening. Weatherstrip its edges and add a rigid insulation panel or an attic-stair cover on the attic side if you can do so safely. It is an unglamorous fix with an outsized effect because it sits at the very top of the house, where pressure pushing warm air out is strongest.

Step 5: Add insulation where it pays first — usually the attic

Insulation slows heat movement; air sealing stops air movement. You need both, and sealing should generally come first, because insulation laid over open gaps still lets air stream through.

ENERGY STAR’s priority order is practical: attics first, then floors over crawl spaces, and accessible basement rim joists. That is the package behind its estimate of an average of 15% on heating and cooling costs. Attics come first because heat rises, attic insulation is usually the easiest to see and to top up, and many attics were built with far less than current recommendations.

A simple check anyone can do: look across your attic. If the insulation is level with or below the floor joists, you likely need more. If it sits well above the joists and covers them evenly, your attic may already be in reasonable shape, and your money is better spent on sealing and on the next area. Recommended levels vary by climate zone, so check ENERGY STAR’s insulation guidance for your zone before buying, and do not compress insulation to fit — compression reduces how well it works.

Why it works: insulation does not generate heat, it keeps the heat you bought inside for longer. That means your heating system runs in shorter, less frequent cycles, rooms stay at a steadier temperature, and the cold-ceiling effect that makes a room feel drafty even without a leak gets smaller.

Renters are not left out. You usually cannot add attic insulation, but you can weatherstrip a door (with your landlord’s permission), use removable window kits, add door sweeps that do not damage the frame, and report a door that does not close or a window that will not latch as a maintenance issue — a landlord is generally responsible for a door or window that does not function, even if energy saving is your motivation for asking.

Caption: Attic insulation is usually the first place extra insulation pays — after the gaps underneath it are sealed. (Symbolic generated image)

Step 6: Get free or low-cost help if you qualify

If your income is limited, you may not have to pay for this work at all.

The DOE Weatherization Assistance Program (WAP) is the nation’s long-running program for exactly this package of work: an energy audit, air sealing, insulation, and heating-system checks, provided at no cost to eligible households through state and local agencies. DOE reports that households save an average of $372 or more a year after weatherization. Eligibility is generally at or below 200% of the federal poverty guidelines, though states administer the program and set application routes locally, so the practical step is to find your state’s WAP office through the DOE how-to-apply page and ask — do not rule yourself out from a national headline number alone.

Pair that with LIHEAP, covered in Part 1, which helps with the bill itself. WAP lowers how much energy your home needs in the first place; LIHEAP helps pay for the energy you still use. Many households qualify for one or both, and local community action agencies often handle both programs, so one phone call can start both applications.

Even if you do not qualify for WAP, ask your utility company about home energy assessments, insulation rebates, and free weatherization kits. Programs vary widely by state and utility and change over time, so check your own utility’s current page rather than relying on a national list.

Frequently asked question: Should I replace my windows to save on heating?

For most households, not first. New windows are one of the most expensive ways to chase heating savings, while sealing, weatherstripping, and attic insulation usually cost far less and address larger losses — that is why ENERGY STAR’s savings estimate is built around sealing and insulation, not window replacement. If a window is broken, rotting, or will not close, repair or replacement is a home-maintenance need on its own. But if your windows are sound and simply feel cold, seal around them, weatherstrip them, and use curtains or an interior kit this winter, then judge the result before budgeting for replacement.

Sources

ENERGY STAR (U.S. EPA) — Why Seal and Insulate? EPA estimates an average of 15% on heating and cooling costs (or 11% on total energy costs) from air sealing and adding insulation in attics, floors over crawl spaces and basements; 9 out of 10 homes are under-insulated: https://www.energystar.gov/saveathome/seal_insulate/why-seal-and-insulate
ENERGY STAR (U.S. EPA) — Seal and Insulate with ENERGY STAR: sealing and insulating can provide up to 10% savings on annual energy bills; simple fixes include weatherstripping doors and caulking windows: https://www.energystar.gov/saveathome/seal_insulate
U.S. Department of Energy, Energy Saver — Air Sealing Your Home, Caulking and Weatherstripping guidance (caulk for stationary cracks under a quarter-inch; weatherstripping for moving parts such as doors and operable windows): https://www.energy.gov/energysaver/air-sealing-your-home
U.S. Department of Energy — Weatherization Assistance Program (WAP): eligibility generally at or below 200% of federal poverty guidelines; average household savings of $372 or more per year: https://www.energy.gov/scep/wap/weatherization-assistance-program

Checked on November 10, 2026. Savings figures are the agencies’ published average or “up to” estimates, not guarantees — your result will depend on your climate, home, and heating system. This post is general information, not financial advice.

이 블로그 검색

Daily Vitamin & Health Guide