Correcting Room Humidity for Neonatal Puppies

As winter approaches, it is a good idea to consider the relationship the humidity of your whelping area has with the health of your neonatal puppies.

If you reflect on your breeder or rescue experience, and realize that it is more challenging to save puppies or keep puppies healthy during the winter months—please continue reading.

While this article will also benefit breeders and rescues located in a low humidity region year-round, most breeders and rescue customers will see seasonal fluctuations in humidity levels in the whelping area. These are often northern climates where temperatures fall regularly below freezing levels. The cold air outside holds little moisture. Furnaces also reduce moisture as they heat and circulate air.

The ideal humidity range for puppies is 40-60%. Most puppies will thrive in this range. If you have a dehydrated puppy, humidity levels of 55-70% could help in their recovery, in addition to subcutaneous fluids. It is a good idea to consult a veterinarian regarding dehydrated puppies.

Helping a dehydrated puppy can be challenging, but best practices to prevent dehydration can be easy and cost-effective. To help you understand preventative measures better, we will first answer a couple of commonly asked questions.

How does low humidity affect the health of a puppy?

The two primary ways low room humidity (below 30%) can affect a neonatal puppy's health are dehydration and dryness of the respiratory system.

We often think of hydration as the intake of fluids. While intake of fluids is critical, take a moment to think about the number of breaths a puppy will take in a day. On average, a neonatal puppy takes 20 breaths per minute. That is 1200 breaths an hour 28,800 breaths per day. In a dry room, the puppy will breathe out moist air (readily absorbed by the dry room) and breathe in dry air. Each breath of dry air is a micro-dehydration event. 1200 breaths per hour, a dry room, when combined with other normal bodily functions, can remove hydration at a rate faster than a puppy can replace it.

Similar to the above, a puppy’s respiratory system can dry out fast in a low-humidity room. Lungs and airways operate best when moist, and when dry, they are more susceptible to airborne viruses and bacteria.

Signs a neonatal puppy could be dehydrated include:

• Skin that is slow to return to its original position when pulled up slightly (tented skin)
• Darker yellow, orange, or brown urine (more concentrated, less water in the urine)
• Mouth and gums feel sticky (not moist)

While you may see other issues related to low humidity, such as dry or flakey skin, dehydration, and a vulnerable respiratory system, it is dangerous—but highly preventable.

Prevention early beats heroics late

The best way to combat dehydration is prevention.

Before discussing preventative measures, we will briefly discuss the concept of a microenvironment. Whether it be an incubator or a warmed whelping box, you are creating a microenvironment or a microhabitat. A microenvironment is a specific area distinguished from its immediate larger surroundings (the room) by factors such as temperature, humidity, oxygen, protection, and light. Microenvironments depend on the larger immediate environment. At Puppywarmer, we say, “The room is part of the system.”

If you want your humidity in the microenvironment to be correct, the room must be at an acceptable range of humidity. Generally, this is 30-45%. Our 18×18 Incubator is 3.375 cubic feet. A 12’x12’x8’ room has 341 times the volume of our 18×18 incubator. If the room has 20% humidity, the sheer volume of dry air will draw the humidity out of the incubator. The differences in relative humidity and volume are too significant. Attempts to keep an incubator at proper humidity levels in an arid room can lead to issues such as locally chilling a puppy and excessive condensation.

The room is the root cause. Thankfully, mass-produced, affordable products such as Ultrasonic Room Humidifiers can correct room humidity. Ultrasonic room humidifiers differ from older-style evaporative humidifiers. Ultrasonic Humidifiers employ an electronic process and shoot a plume of fine mist into the air. Evaporative humidifiers have a wicking material that a fan blows air across. Older wicking media have the risk of forming bacteria and mildew. Ultrasonic humidifiers do not carry the same risk.

The above photo shows an example of a large ultrasonic room humidifier. These humidifiers could hold 16 liters (about 4 gallons) of water. This humidifier is a good choice for larger rooms and very dry houses. Smaller room ultrasonic humidifiers hold 6-7 liters (less than two gallons). While often effective, they require more frequent refilling. You want an ultrasonic room humidifier that allows you to select the target room humidity. Correcting room humidity with an ultrasonic room humidifier is good for the health of the puppies inside and outside of the incubator, the mother dog, and the humans who spend time in the room.

Puppywarmer does not sell ultrasonic room humidifiers. Ultrasonic room humidifiers are available on Amazon, home improvement-oriented stores, and websites like Home Depot, Lowes, and Menards. Capable brands include Levoit, Holmes, and Elechomes. Ultrasonic humidifiers are often rated for a room size. Seven-liter models usually have to be refilled just once a day. Purchase a unit that can be set for a specific room humidity. You do not need a “warm mist option.” When in doubt, go one size up. An ultrasonic room humidifier for a small room is often $115-$135 (though more options are now available, and highly functional ultrasonic room humidifiers are available for less than $100. Larger room models, often holding more than 10L of water, can be $175-$225 at the time of this blog article in 2025.

Correcting room humidity to 35% has many benefits:

• The incubator will be better able to provide the proper microenvironment for your at-risk puppies
• Healthy puppies in the whelping box are less susceptible to respiratory illness and dehydration
• The mother dog is also more comfortable and less susceptible to respiratory illness
• The humans in the room are also less susceptible to respiratory illness.

If you suspect your puppy is dehydrated, these preventative steps also benefit that puppy. If you suspect dehydration, please consult with your veterinarian. Better yet, plan ahead this winter and start your litter off with a properly humidified room. Planners save puppies.