Yes – unfortunately, vermin can sometimes get inside an air source heat pump (ASHP). The unit is outdoors, draws in air, and has plenty of warm sheltered spaces that can attract small animals. Typical issues include:
- Rodents (mice/rats): Can squeeze through surprisingly small gaps and may chew on insulation, wiring, or pipe lagging.
- Birds: Sometimes attempt to nest inside the casing, especially if there are gaps or grills they can squeeze through.
- Insects: Wasps or bees may build nests in sheltered corners.
- Slugs/snails: Can crawl inside and occasionally cause short circuits on electrical boards.
Risks
- Chewed wiring / insulation damage → may cause faults or even fire risk.
- Blocked airflow → reduces efficiency or causes the unit to trip.
- Contamination → droppings or nesting material can damage components.
Prevention
- Check and seal gaps: Ensure any entry holes in casing, ducts, or pipe penetrations are sealed with mesh or rodent-proof filler.
- Protect insulation: Use rodent-resistant lagging or cover external insulation with conduit.
- Keep area clear: Avoid stacking wood, compost, or vegetation near the ASHP, which attracts vermin.
- Install mesh guards: Fine stainless-steel mesh over air intakes (without restricting airflow) can help.
- Regular inspection: Check for droppings, gnaw marks, nests, or damage.
👉 If vermin are already inside, don’t run the ASHP until it’s been checked – call your installer or service engineer, as chewed wires can be a serious hazard.
