How to Keep Flies Out of Your Home During A Heatwave
- Aug 4
- 5 min read
When temperatures rise, fly problems can escalate remarkably quickly. During the current spell of unusually hot UK weather, we have received numerous calls from households dealing with flies, particularly bluebottles during this heatwave.
One recent client told us that their kitchen appeared to fill with bluebottles within minutes of putting down food for their dog.
The dog food had not created an infestation in those few minutes. Its smell had probably attracted flies that were already inside the property or nearby. When large numbers of bluebottles appear suddenly, it can indicate that flies have developed in a concealed breeding source and are now emerging as adults.
So, where are they coming from, and what should you do?
Why hot weather brings more flies
Warm conditions accelerate the fly life cycle. According to the British Pest Control Association, a single bluebottle can lay hundreds of eggs. In warm weather, those eggs may hatch in under 48 hours, with the larvae developing rapidly.
Bluebottles are particularly attracted to:
Meat, fish and other protein-rich food
Wet cat and dog food
Food residue on packaging
Kitchen and outdoor bins
Animal waste
Decomposing organic material
Dead birds, rodents or other animals
Open doors and windows also make it easier for adult flies to enter as households try to keep cool.
Bluebottles should not simply be regarded as a noisy nuisance. They visit refuse and decomposing material before landing on food, bowls and kitchen surfaces, potentially carrying contamination on their bodies.
How to prevent flies entering your home
Do not leave pet food standing During hot weather, put down only as much food as your pet is likely to eat promptly. Remove unfinished wet food, wash the bowl and wipe the surrounding floor once your pet has finished. Do not leave wet pet food uncovered between meals. Store unopened and leftover pet food in sealed containers and dispose of used pouches, trays and tins promptly. Rinse the packaging first where appropriate.
Keep human food covered Keep fruit, baked goods and prepared food covered or refrigerated. Clear away plates, crumbs and spillages promptly, particularly anything containing meat, fish, dairy products or sugary liquids. Avoid leaving food uncovered while doors or windows are open.
Pay close attention to bins Use a bin with a properly fitting lid and empty the kitchen bin regularly rather than waiting for it to become full. Tie food waste securely. Meat, fish, bones, pet waste and particularly smelly material may need to be double-bagged in accordance with your council’s waste guidance. Clean food residue from the inside, outside and rim of the bin. Keep outdoor bins closed and, where practical, position them in the shade and away from kitchen doors and windows. Warm-weather waste guidance from UK councils consistently recommends keeping bin lids shut, securely wrapping food waste and cleaning bins after collection.
Fit fly screens Fine-mesh screens allow you to ventilate the house without giving flies an open route indoors. Prioritise kitchen windows, utility rooms and doors that remain open for long periods. Check screens regularly for gaps and damage. Door curtains may help, but a properly fitted mesh screen provides a more dependable barrier.
Remove breeding opportunities Flies can breed in surprisingly small amounts of decomposing material. Check: Under and behind kitchen appliances Beneath freestanding cupboards Food caddies and recycling containers Pet-feeding areas Cat litter trays
Drains and cleaning equipment
Compost containers
Barbecues and outdoor eating areas
Outdoor bins and bin stores
Clean up pet waste from gardens promptly.
What to do if a room suddenly fills with bluebottles
Seeing dozens of bluebottles at once can be alarming. Work through the problem calmly and systematically.
Remove exposed food
Take away pet food immediately. Cover or refrigerate human food and move clean utensils out of the affected area.
Food on which flies have landed may have been contaminated. If you are uncertain whether it is safe, the sensible option is to discard it.
Contain the problem
Close internal doors to stop flies spreading through the house. If possible, open one screened or suitable external window in the affected room and reduce other light sources; flies will often move towards the daylight.
A vacuum cleaner can be an effective way of removing a large number of adult flies without dispersing insecticide around a kitchen. Empty the vacuum outside into a sealed bag afterwards.
Clean affected surfaces
Clean and disinfect food-preparation surfaces, tables and pet-feeding areas. Wash pet bowls and any exposed utensils before reusing them.
Look for the source
Adult flies are the visible part of the problem. Killing them will not solve an infestation if larvae or pupae remain nearby.
Inspect bins, food waste, forgotten food, pet-food packaging and concealed spillages. Also note whether flies appear concentrated around:
A particular window
A loft hatch
A fireplace or chimney
An extractor fan
Ceiling lights
A wall or ceiling void
An unused room or outbuilding
A sudden concentration of bluebottles can sometimes indicate a dead bird or rodent in a loft, chimney, wall void or other inaccessible space. An unpleasant smell may be present, but not always.
Do not dismantle parts of the building or enter an unsafe loft in an attempt to find it.
Be cautious with fly sprays
Non-chemical measures and removal of the breeding source should come first.
If you use a household insecticide, make sure it is authorised for the intended use and follow the label exactly. Protect food, preparation surfaces, children, pets, fish tanks and other animals as directed. Never assume that applying more product will make it work better.
The Health and Safety Executive advises householders to consider non-chemical controls first and to follow all product-label instructions carefully.
When should you call a pest control professional?
Consider obtaining professional help when:
Large numbers of flies continue to appear after cleaning
Flies return daily
You find maggots but cannot identify the source
Activity appears to be coming from a loft, chimney or wall void
You suspect a dead animal is present
The affected area cannot be reached safely
The infestation is affecting a vulnerable person or a food-handling environment
An experienced pest controller can identify the fly species, locate likely breeding areas and recommend a targeted treatment. Correct identification matters: bluebottles, houseflies, cluster flies, drain flies and fruit flies do not all originate from the same places.
The most important step: find the source
Aerosols, traps and vacuuming can reduce the adult flies you see, but lasting control depends on finding and removing whatever is attracting or producing them.
During very hot weather, act as soon as fly numbers begin to rise. Prompt attention to pet food, food waste, bins and entry points can prevent a few visiting flies from becoming a much larger, and much less pleasant, problem.
If bluebottles or other flies are appearing in large numbers and you cannot locate the source, Stratton Pest Control can help identify the cause and recommend an appropriate solution.
We serve homes and businesses across Hertfordshire, Bedfordshire, Buckinghamshire, Essex, Cambridgeshire, North London, Oxfordshire, Northamptonshire, Norfolk and Suffolk.
