How much can insulation lower your energy bill?
ENERGY STAR estimates homeowners save an average of 15 percent on heating and cooling costs by sealing air leaks and adding insulation. Older Louisville homes with empty walls often see more, since they start with so little. Because heating and cooling are the biggest part of most home energy bills, those savings repeat every season.If you are looking up how to lower your LG&E bill, start with the bill itself. It already tells you a lot about where your money goes, and for most Louisville homes the biggest line items rise and fall with the weather outside. That is exactly the part insulation and air sealing work on.
Fall is a good time to look. The AC is winding down, the furnace is about to take over, and a full summer of numbers is sitting in your usage history.
How do you read your bill to see what heating and cooling cost?
Many Louisville homes get one bill that covers both natural gas and electric service. When you look past the total, you will usually find two separate usage numbers, one for each. Those two numbers tell different seasonal stories.
- Gas usage climbs in winter. If your home has a natural gas furnace, most of your winter gas use is heating. Water heating and a gas range use some gas year-round, but they stay fairly steady from month to month.
- Electric usage climbs in summer. Your central AC runs on electricity, so the summer jump in electric use is mostly cooling. Lights, appliances, and electronics make up a steadier baseline.
- Spring and fall show your baseline. In mild months like October or April, when neither the furnace nor the AC works hard, your usage drops close to what the house uses for everything else.
To size up your heating and cooling share, compare a mild month to your coldest and hottest months. The gap is roughly what the weather costs you. In a leaky house, that gap is wide.
Look at usage, not just the dollar amount. Dollar totals move with rates and fees you don't control. Usage shows what your house actually consumed.
Does insulation lower energy bills?
Yes. Insulation slows the flow of heat through your walls, attic, and floors, and air sealing stops conditioned air from leaking out. Together, they reduce how long your furnace and AC have to run to hold the temperature you set.
ENERGY STAR estimates homeowners save an average of 15% on heating and cooling costs by sealing air leaks and adding insulation (energystar.gov). That is an average across many homes. A house that starts with empty walls and a thin attic has more room to improve than one that was insulated well to begin with. Every home is different, so we won't promise a specific amount.
What are the biggest reasons Louisville bills run high in older homes?
Many of Louisville's older homes were built long before anyone thought much about insulation. Here is what we see most often.
Empty exterior walls. Brick homes in the Highlands and Crescent Hill, older frame homes in Okolona, and the shotgun houses found across the city's older neighborhoods often have little or nothing inside the walls. Plaster walls in these homes look solid, but the cavity behind them can be empty air. USA Insulation estimates about 35% of a home's heat loss happens through the walls, which makes them the single largest path.
Leaky, thin attics. Attic insulation settles over the decades, and older attics were often built with just a few inches to begin with. Add gaps around light fixtures, pipes, chimneys, and the attic hatch, and warm air escapes upward all winter. USA Insulation estimates about 25% of heat loss happens through the attic.
River-valley humidity. Louisville sits in the Ohio River Valley, and summer air here is heavy with moisture. When muggy air leaks in, your AC has to remove the water as well as the heat, so it runs longer and your summer electric usage climbs. (We covered this in more detail in our post on why your Louisville home still feels stuffy and humid.)
Floors over basements and crawl spaces. Cold air from below chills floors and pulls heat out of the rooms above. USA Insulation estimates about 15% of heat loss happens through the basement or floor, with another 10% through windows.
These problems aren't limited to the city's oldest streets. Plenty of mid-century homes in St. Matthews and Jeffersontown, and across the river in New Albany and Jeffersonville, were built with far less insulation than today's recommendations.
How to lower your LG&E bill: which fixes matter most?
Some steps are free and quick. Others take a project but keep paying off for years.
Step |
What it does |
Effect on heating and cooling use |
|---|---|---|
Filling empty walls with injection foam |
Fills the largest heat-loss path in older homes |
Large, lasting |
Adding blown-in attic insulation |
Brings the attic up toward the ENERGY STAR recommendation |
Large, lasting |
Air sealing the attic floor and hatch |
Stops warm or muggy air from moving through gaps |
Large, lasting |
Setting the thermostat back at night or while you're away |
Shortens run time during hours you don't need full comfort |
Modest, depends on your habits |
Changing HVAC filters on schedule |
Keeps air moving freely so the system isn't straining |
Modest |
Closing curtains at night in winter and on sunny afternoons in summer |
Slows heat moving through window glass |
Small |
The habits at the bottom are worth keeping, but they work around the house you have. The top three change the house itself, which is why they move the needle most.
For attics in Kentucky, which is climate zone 4, ENERGY STAR recommends R-60 for an uninsulated attic and R-49 when adding to 3 to 4 inches of existing insulation. For walls, our injection foam goes in from the outside. On sided homes, we remove a strip of siding, drill small holes, inject the foam, plug the holes, and put the siding back. On brick homes, the holes go in the mortar joints and are patched afterward. Your interior walls aren't touched, the foam hardens within minutes, and most installs finish in less than a day.
How can you track your savings yourself?
Your usage history already has everything you need. Here is a simple method:
- Save your "before" numbers. Write down your gas and electric usage for each month of the past year, or download the history if your online account offers it.
- Note the date of the work. Mark the month your insulation and air sealing were completed.
- Compare the same months year over year. Put this January next to last January, and this July next to last July. Comparing month to month doesn't work, because the seasons change.
- Watch the heating and cooling months. Your mild-month baseline shouldn't change much. The drop should show up in winter gas use and summer electric use.
- Judge by the season. One unusually cold or hot month can skew a comparison, so give it a full heating season and a full cooling season.
Is now a good time to insulate?
Early fall is a smart time. The work is quick, and you get the benefit before the first hard cold snap sends your gas usage climbing. If cost is a question, we explain what drives how much insulation costs in Louisville, and insulation financing is available through our lending partners.
The bottom line for Louisville homeowners
The best way to lower a high LG&E bill is to shrink the part of it that heating and cooling drive. In older Louisville homes, that usually means filling empty walls, topping up the attic, and sealing the leaks.
USA Insulation has been insulating homes since 1985, has served more than 150,000 homeowners, and is locally owned by a family and veterans. We serve Louisville, nearby Kentucky communities, and Southern Indiana. We'll look at your home, show you where the heat is going, and walk you through what the savings could look like.
FAQ
How much can insulation lower your energy bill?
ENERGY STAR estimates homeowners save an average of 15 percent on heating and cooling costs by sealing air leaks and adding insulation. Older Louisville homes with empty walls often see more, since they start with so little. Because heating and cooling are the biggest part of most home energy bills, those savings repeat every season.How do I lower my LG&E bill this winter?
Focus on heating, since that drives most winter gas use. Seal air leaks around the attic hatch and fixtures, add attic insulation, and fill empty exterior walls. Set the thermostat back at night and change your furnace filter on schedule.How can I tell how much of my bill is heating and cooling?
Compare your usage in a mild month like October with your coldest and hottest months. The difference is roughly your heating and cooling share. Look at usage, not dollar totals, since rates and fees change.How do I know if insulation is lowering my bill?
Compare the same months year over year, such as this January against last January. Look at a full heating and cooling season, and keep in mind that an unusually cold or hot month can skew a single comparison.Can you insulate the walls of an older brick home?
Yes. On brick homes, small holes are drilled in the mortar joints, the wall cavity is filled with injection foam, and the holes are patched. Interior walls are not touched, and most installs finish in less than a day.Do you serve Southern Indiana?
Yes. USA Insulation of Louisville serves Louisville and nearby Kentucky communities, plus Jeffersonville, New Albany, Clarksville, Charlestown, and Lanesville in Southern Indiana.Get a free estimate and savings walkthrough
We'll inspect your walls and attic, show you where your home is losing the most heat, and walk you through where you're likely to see savings, with a clear written estimate and no pressure. Financing is available through our lending partners.Call 502-358-3626 or request your free estimate.
