You found droppings on the attic insulation, or a section of flex duct chewed open above the bedroom ceiling. What this costs depends on how long the rodents were up there before anyone noticed, and most figures published online are marketing copy rather than measurement.

It often comes to light in late summer, when someone finally goes up into a hot attic and finds the damage has been building for a while.

Quick answer: Rodents in a Houston attic go after three things: flex ductwork, blown-in insulation, and wiring. ENERGY STAR puts ordinary duct leakage at 20 to 30 percent of the air moving through the system, so chewed duct adds to a system that already leaks. Texas homeowners policies generally exclude rodent chewing, which leaves most of the repair cost with you.

Texas A&M AgriLife Extension reports that roof rats are found in east Texas and throughout the south, and that one can get into a home through a gap under a door as narrow as half an inch, or a hole the size of a quarter [1]. House mice need less: Rodent IPM guidance from the same service puts them through a dime-sized hole or a quarter-inch crack [2]. Sealing that leaves a half-inch gap anywhere along the roof line has not sealed the house.

What rodents actually chew in a Houston attic

• Flex duct. Opened near a boot or a connection where the duct sags onto the attic floor, which is already a rodent walkway.
• Blown-in insulation. Tunneled through, flattened into runways, and contaminated with urine and droppings.
• Wiring. Gnawed jacket on branch circuits crossing the joists, plus thermostat wire and the control wiring at the air handler.

Texas A&M's attic guidance flags chewing on wires inside the structure [1]. Homeowners notice the duct and insulation first, because those show up as comfort and bill problems, while wiring damage stays hidden.

Why damaged ductwork shows up on your electricity bill

ENERGY STAR's duct sealing page states that "about 20 to 30 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts" [3]. That figure describes a system with no rodent problem. Chewed duct sits on a baseline that already leaks, which is why the complaint arrives as "it runs all afternoon and the back bedroom never gets cold."

ENERGY STAR lists the symptoms homeowners notice, including high summer utility bills and rooms that are difficult to heat and cool, and flags ducts located in an attic as a risk factor by itself [3]. Nearly every Houston house with an attic air handler ticks that box.

The US Energy Information Administration reports that space heating and air conditioning together accounted for 52 percent of a household's annual energy consumption in 2020 [4]. A duct problem takes a percentage off the largest single item in your bill, every hour the system runs.

What happens to attic insulation, and why square footage sets the price

The Department of Energy is direct about the physics: compressed insulation "will not provide its full rated R-value" [5]. Rodent runways compress it, so the attic loses performance along the paths the animals use.

Contamination is the bigger cost driver. Insulation used as a latrine typically comes out instead of being cleaned in place, and removal is often measured across the whole attic. Ask which square footage the removal line covers before you compare two quotes, because a problem that looked like ten square feet can come back priced as a whole-attic job.

CDC rodent cleanup guidance says not to vacuum or sweep rodent urine, droppings, or nesting materials. Disturbing the material dry can put tiny droplets containing viruses into the air. The published method starts with ventilating the space for 30 minutes before anyone goes in to clean. The droppings and nesting material are then soaked for five minutes in a solution of 1.5 cups of household bleach per gallon of water and wiped up with paper towels by someone wearing gloves [8]. That works for a small area, and it is not a realistic plan across 1,800 square feet of blown-in fiberglass.

Chewed wiring and fire risk: what the data actually supports

The US Fire Administration's report on residential building electrical fires for 2014 to 2016 estimates 24,000 such fires a year, causing 310 deaths, 850 injuries, and $871 million in property loss [6]. The attic or crawl space above the top story was the second leading area of fire origin at 13.0 percent, and electrical wire or cable insulation was the item first ignited in 30.9 percent of cases [6].

That report contains no rodent cause category at all. A percentage tying rodents to undetermined-cause house fires circulates widely in pest control trade press, always without a study attached to it, and nothing resembling it appears in the federal data. Treat that figure as unsourced wherever it turns up, and have a licensed electrician look at any chewed jacket anyway.

What drives the repair bill, and why no honest number exists online

We could not find a public dataset of rodent-related attic repair costs for Houston. The dollar ranges on contractor lead pages come with no sample size and usually no date or region, so they cannot be checked. Here is what a contractor is actually pricing:

• Ductwork. How many runs are damaged and whether the plenum or air handler connections are involved, with attic access setting how long the work takes. Replacing two runs differs from replacing a whole system's flex.
• Insulation. Attic square footage rather than damaged area. Vacuum-out removal is a separate line from blow-in replacement, and the target R-value sets the material volume.
• Electrical. Whether the damage sits in open attic space or inside a wall cavity. Splicing an accessible run in a junction box is far smaller than re-pulling a circuit through finished walls.
• Cleanup. Driven by contaminated area, and reduced if insulation is coming out.
• Exclusion. Linear feet of roof line, entry points, and materials.

Ask for those as separate line items. A lump sum cannot be compared against another estimate.

What Texas homeowners insurance will not pay for

The Texas Department of Insurance is blunt: "If rodents and insects chew on your house, your policy won't pay for the repairs" [7]. TDI also lists gradual damage as excluded, using rotted boards and worn roofs as examples [7]. Attic rodent damage found after weeks or months lands in that second category as well as the first.

An ensuing sudden loss can be a separate question, since policies differ on a fire that follows damaged wiring. Ask your agent before you file.

Why exclusion beats another round of trapping

The EPA's rodent guidance makes the mechanical point plainly: "Rodents released outside may find their way back into the house unless you have sealed the entry points into the house" [9]. Trapping reduces the population in your attic today and does nothing about the gap that let them in.

Texas A&M's extension material covers the exclusion materials that hold up:

• cement and low-expansion foam for gaps in masonry and framing
• brass or stainless steel wool, which does not rust out
• hardware cloth, and Xcluder fill fabric [2]

The same guidance sums the approach up as "stuff it, seal it, and check it often" [2]. Checking matters as much as sealing, because flashing lifts and a house sealed in October is not still sealed in August. Trap without sealing and you are likely to pay for the same duct and insulation work twice.

The written scope to ask for before you sign anything

1. An entry-point map giving a location and the sealing material used for each gap.
2. Separate lines for exclusion, cleanup, insulation removal, insulation replacement, duct repair, and electrical work.
3. Attic square footage and target R-value written down as numbers.
4. Photographs before and after, including each sealed entry point.
5. A re-inspection date, plus what happens if activity returns.
6. Confirmation that electrical repair is done by a licensed electrician.

Without the entry-point map in writing, you cannot tell later whether sealing was done or whether you paid for trapping with a warranty.

How Natran approaches rodent work

Until someone has walked the roof line and been through the attic, nobody can say how many duct runs are open or where the animals are getting in.

Natran Green Pest Control starts rodent work with that inspection and maps every entry point it turns up along the roof line and inside the attic, which is the entry-point map the written scope above tells you to ask any provider for. Sealing follows, then monitoring, so you can tell whether the activity actually stopped. That order is integrated pest management applied to a rodent job. Closing the route in is the part that decides whether the duct runs and insulation you just paid for come back as another estimate next summer.

Homeowners often begin the search for a company with the words eco-friendly or green pest control, when what they need to compare is what each company will do in the attic. Ask any provider you are considering, Natran included, for their Texas structural pest control license before work starts.

What to do next

What you pay depends on how long the rodents were up there and how hard the damage is to reach. Chewed duct wastes cooled air on top of a system that already leaks, and contaminated insulation is often priced across the whole attic rather than the damaged patch. TDI says in writing that rodent chewing is excluded. Get the entry points sealed and documented, then hold the scope to written line items with a re-inspection date before you pay anyone.

Frequently asked questions

Does homeowners insurance in Texas cover rodent damage to ductwork?

Generally no. The Texas Department of Insurance states plainly that if rodents and insects chew on your house, your policy will not pay for the repairs [7]. TDI also lists damage that happens gradually over time as excluded, which is where most attic rodent damage falls once it has gone unnoticed for weeks or months. An ensuing sudden loss, such as a fire that follows damaged wiring, may be handled differently depending on your policy wording. Read the policy and call your agent before filing anything.

How small a gap can a rat or mouse use to get into a Houston attic?

Texas A&M AgriLife Extension reports that a roof rat can enter through a gap under a door as narrow as half an inch, or a hole the size of a quarter [1]. House mice need less, roughly a dime-sized hole or a quarter-inch crack [2]. Common entry points include the garage door surround, roof venting, and flashing [1]. Use the quarter-inch figure as your sealing standard, because anything a roof rat fits through a mouse fits easily. Inspect the garage door corners and the roof line close up, since half an inch reads as nothing from the ground. What to seal those gaps with is listed further up, and note that the wool has to be brass or stainless steel, which does not rust out [2].

Do I need to replace all the attic insulation after rodents?

Not always, though partial replacement is less common than homeowners expect. Insulation used as a latrine is normally removed instead of cleaned in place, and removal is often measured across the full attic square footage. The Department of Energy notes that compressed insulation will not deliver its full rated R-value [5], so rodent runways cut performance even where nothing was taken out. Ask the contractor to state the square footage being removed and the target R-value going back in, as two separate lines.

Can chewed wiring in the attic start a fire?

Damaged wire insulation in an attic is worth taking seriously. The US Fire Administration estimated 24,000 residential building electrical fires a year across 2014 to 2016, and found that electrical wire or cable insulation was the item first ignited in 30.9 percent of them, with attics the second leading area of origin at 13.0 percent [6]. That report contains no rodent cause category, so the commonly repeated rodent-fire percentage is not supported by it. Have a licensed electrician inspect any damaged run.

Will trapping alone stop roof rats from coming back?

Trapping is only half the job. The EPA notes that rodents may find their way back into a house unless the entry points have been sealed [9]. Texas A&M's extension guidance treats checking the seal as an ongoing task rather than a one-time visit, because new gaps open as a roof ages [2]. Ask what the exclusion work covers before you agree to a trapping-only warranty.

Reference sources

1. Texas A&M AgriLife Extension, Insects in the City, "Rodents in attics." https://citybugs.tamu.edu/2016/01/05/rodents-in-attics/
2. Texas A&M AgriLife Extension Entomology, "Rodent IPM" (2021). https://extensionentomology.tamu.edu/wp-content/uploads/sites/6/2022/04/Rodent-IPM-2021.pdf
3. ENERGY STAR, "Duct Sealing." https://www.energystar.gov/saveathome/heating-cooling/duct-sealing
4. US Energy Information Administration, "Use of energy in homes" (2020 data). https://www.eia.gov/energyexplained/use-of-energy/homes.php
5. US Department of Energy, Energy Saver, "Insulation." https://www.energy.gov/energysaver/insulation
6. US Fire Administration, "Residential Building Electrical Fires (2014-2016)," Topical Fire Report Series. https://www.usfa.fema.gov/downloads/pdf/statistics/v19i8.pdf
7. Texas Department of Insurance, "What your home policy won't cover." https://www.tdi.texas.gov/tips/what-your-home-policy-wont-cover.html
8. Centers for Disease Control and Prevention, "How to Clean Up After Rodents." https://www.cdc.gov/healthy-pets/rodent-control/clean-up.html
9. US Environmental Protection Agency, "Options for Dealing with Rodent Infestations." https://www.epa.gov/rodenticides/options-dealing-rodent-infestations