Heat Treatment for Termite Control
Heat treatment is a chemical-free termite control method that kills termite colonies by raising the internal temperature of infested wood and structural voids to lethal thresholds. This page covers the mechanism of thermal pest elimination, the structural and infestation scenarios where it applies, and how it compares to alternative approaches such as fumigation (tenting) and liquid termiticide treatments. Understanding the operational boundaries of heat treatment helps property owners and pest control professionals match the method to the infestation type and building conditions.
Definition and scope
Heat treatment for termites — also called thermal remediation — is the deliberate application of controlled high-temperature air to a structure or structural section to eliminate termite infestations without the use of registered chemical fumigants. The method targets the thermal death point of termites, which the University of California Cooperative Extension and independent entomological research have established at sustained exposure to temperatures above 120°F (49°C) at the wood core.
Heat treatment is classified as a non-chemical structural pest control method and falls under the oversight of state structural pest control boards. Licensing requirements vary by state; termite control licensing requirements in the US are administered through individual state pest control regulatory agencies rather than a single federal body. The U.S. Environmental Protection Agency does not register heat as a pesticide, but EPA-registered monitoring equipment and the treatment process itself are subject to occupational safety standards enforced by the Occupational Safety and Health Administration (OSHA) under 29 CFR Part 1910 (General Industry Standards) and applicable state-plan equivalents.
Heat treatment is most commonly applied to drywood termite infestations, which live entirely within wood members and do not require soil contact. It is not a standard treatment for subterranean termite colonies, which nest in soil and return to ground-level moisture sources.
How it works
The thermal remediation process relies on convective heat transfer from propane-fired or electric heating units that force heated air through a structure. Technicians place temperature probes — typically 12 to 30 probes depending on structure size — throughout the building to confirm uniform heat distribution and verify that wood-core temperatures reach the lethal threshold.
The kill mechanism is protein denaturation: at sustained temperatures above 120°F (49°C), termite cellular proteins denature irreversibly, causing death at all life stages including eggs, nymphs, workers, soldiers, and reproductives. Research published through the USDA Forest Service indicates that a 35-minute exposure at 120°F produces 100% mortality in drywood termite test populations, though field protocols commonly target a higher threshold of 130–140°F at the wood core to account for heat-sink variance in dense lumber and wall assemblies.
A standard whole-structure heat treatment proceeds in these stages:
- Pre-treatment preparation — Removal or protection of heat-sensitive items: wax candles, vinyl records, aerosol cans, certain pharmaceuticals, and living plants. Technicians seal or vent refrigerants per manufacturer specifications.
- Structure sealing — Exterior openings are sealed with tarps or foam to contain heat.
- Heating phase — Propane heaters or electric blower units raise ambient air temperature; the phase typically spans 1–2 hours.
- Soak phase — Structure is held at target temperature for a minimum of 30–60 minutes beyond probe confirmation of lethal wood-core temperature.
- Cooling and re-entry — Heating equipment is removed, structure is ventilated, and technicians confirm safe re-entry air temperatures before occupants return — typically the same day, often within 4–8 hours of treatment start.
No residual chemical barrier is left in the structure. Heat treatment provides no ongoing protection against future reinfestation, a distinction addressed further in the decision boundaries section.
Common scenarios
Heat treatment is applied across four primary infestation and structural scenarios:
Localized drywood termite infestations in accessible wood members — When a termite inspection identifies a contained infestation in a single room, attic, or crawl space with identifiable frass deposits and limited gallery spread, spot or room-section heat treatment can be targeted precisely.
Whole-structure treatment for pervasive drywood infestations — When infestation is distributed across multiple structural sections or confirmed through termite damage assessment to affect load-bearing members, whole-structure heat treatment competes directly with fumigation/tenting as the primary elimination option.
Historic and sensitive structures — Termite control for historic structures presents constraints on chemical application. Heat treatment is used when fumigant exposure would risk irreversible damage to finishes, adhesives, or archival materials, and when building fabric cannot support the physical weight and attachment requirements of a tarpaulin tent.
Structures with occupant chemical sensitivities — Properties housing individuals with documented sensitivities to sulfuryl fluoride or methyl bromide residues, or facilities with food-handling or pharmaceutical storage constraints, may use heat treatment to avoid chemical contact entirely.
Decision boundaries
Heat treatment versus fumigation is the central comparison pest control professionals apply when whole-structure elimination is required for drywood termites. The table below summarizes the primary differentiators:
| Factor | Heat Treatment | Fumigation (Tenting) |
|---|---|---|
| Active agent | Thermal energy | Sulfuryl fluoride (registered pesticide) |
| Re-entry time | Same day (4–8 hours typical) | 24–72 hours minimum |
| Residual protection | None | None |
| Heat-sensitive contents | Must be removed or protected | Aeration typically sufficient |
| Structural access requirements | Interior access for probes and heaters | Full exterior tenting |
| Soil-nesting termite efficacy | Not effective | Kills above-ground populations only |
| Regulatory oversight | State pest control board + OSHA | EPA registration + state board + OSHA |
Heat treatment does not eliminate subterranean or Formosan termite colonies because colony cores in soil are outside the treatment envelope. For mixed infestations or properties in high-risk soil-contact zones, termite bait station systems or liquid soil treatments are required as complementary measures.
Because heat treatment leaves no chemical residual, reinfestation risk begins immediately after cooling. Property owners should review termite warranty and protection plans and termite monitoring programs as post-treatment continuity measures. The termite treatment methods comparison page provides a broader framework for evaluating heat treatment within the full range of available options.
References
- U.S. Environmental Protection Agency — Termite Prevention and Control Overview
- USDA Forest Service — Wood Handbook, Chapter 14: Wood Preservation
- OSHA 29 CFR Part 1910 — General Industry Standards (Occupational Safety)
- University of California Agriculture and Natural Resources — Pest Notes: Drywood Termites (Publication 7440)
- EPA — Sulfuryl Fluoride Pesticide Registration and Tolerance Information