The year around a Denver home

Season
Fall
What is active
Mice moving indoors as nights cool
Where odor tends to appear
Exterior walls, kitchens, behind appliances
Season
Winter
What is active
Rodents settled in; squirrels in attics
Where odor tends to appear
Attics, crawl spaces, ducts when heat runs
Season
Spring
What is active
Birds nesting; raccoons and squirrels with young
Where odor tends to appear
Vents, chimneys, eaves, attics
Season
Summer
What is active
Heat intensifies any carcass odor
Where odor tends to appear
Attics and exterior walls on hot afternoons

In fall, a smell in a kitchen or along an exterior wall is most often a mouse that came in for warmth. In spring, a smell at a bath fan, dryer vent or fireplace often means a bird nest gone wrong. Summer brings the strongest odors because heat speeds decomposition and warms attics and walls, while winter heating can push odor from a crawl space or duct into every room.

Denver's dry climate helps small carcasses dry out, so a mouse smell in winter may fade within a couple of weeks, while the same mouse in a warm attic in July can be overwhelming for longer.

Seasonal prevention

A yearly walk-around

Two quick walks around the outside of the house each year catch most problems before they cause odor. In late summer, look low: foundation gaps, burrows, vents near the ground and garage door seals, before mice move indoors. In late winter, look high: chewed fascia, soffit gaps, chimney caps and vent flaps, before squirrels and birds start nesting. Note anything you find and fix small gaps right away.

Common questions

Is a smell in spring always a bird?

No, but birds and young animals in vents, chimneys and attics are common causes in spring. Rodents are possible year-round.

Which season is worst for odor?

Summer usually produces the strongest smells because of heat, while fall brings the most rodent carcasses in walls.

Does snow cover hide entry points?

Snow can hide ground-level gaps, which is why a late-summer walk around the foundation is the better time to look low.

General information for Sloan's Lake, not a quote or professional advice. In an emergency, call 911.