Heating & Cooling

How Heat Pumps Control Indoor Humidity in Your Home

hygrometer min

High humidity can be a problem in any home. Homes with high humidity problems can cause condensation problems, mold growth, and poor indoor air quality.

So, can a heat pump remove humidity from the air? Yes, one of the benefits of a heat pump is its ability to remove humidity from the air inside a home. During the cooling cycle, heat pumps remove excess moisture in the air via condensation. This lowers indoor humidity levels and improves indoor air quality.

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According to HVAC.com, the ideal relative humidity level inside a home is 40%. Indoor humidity can often fluctuate between 30%-50%. You’ll need a hygrometer to measure humidity inside your home.  

How Can Humidity At Home Be More Than A Nuisance

Humidity has a big effect on the quality of living in your home. It has a direct impact on your heating and cooling, and how people perceive them. Warm air holds moisture far longer than cold, so it makes a home feel “stuffy.” It’s hard to feel cooler on warmer days if your home has high humidity. 1

High humidity also makes it much harder to cool a home. Water vapor is excellent at retaining heat or cold, especially heat. Because heat makes the air rise, high humidity makes it very hard to keep indoors cool. It also makes cooling systems work twice as hard as it needs to handle much hotter heat index. 2

In cooler days where you want a warmer home, humidity also plays a role. Cooler air has lower humidity by default, so it’s harder to warm a home with unstable humidity. By using a way to create efficient humidity control, you get a warmer or cooler home when you want to.

Some telltale signs that your home lacks the proper countermeasures to humidity include:

  • Hot, sticky indoor environment
  • Heavy condensation on the windows
  • Strong, musty odors
  • Mold and mildew growth, especially in kitchens and bathrooms
  • Heavy moisture damage, usually in ceilings
  • Bad allergic reactions
  • High utility bills

Poor indoor humidity control opens up a whole host of problems that many homes have. High relative humidity can have extreme effects on your health and your home.

The Destructive Effects Of Excess Humidity

For starters, a humid home can start to peel off wallpapers. Bubbles will start to form and can remove the wallpaper in its entirety. This is not aesthetic at all, and if you like a beautiful home, it’s quite the pain to resolve.

Another problem is the formation of molds and spores. There’s a big chance that you have a wooden wall or drywall. Humidity can precipitate into the wood, making them swell, and eventually have spores and mold grow into it.

Mold can be a health and safety hazard. Exposure to mold can cause throat irritation, a stuffy nose, irritation to the eye, and skin irritation. Mold caused by humidity can also create a heightened sensitivity to different allergens, which can cause further respiratory problems.

Mold growth in a humid home can cause irreparable damage. It will slowly destroy the wood fibers, converting cellulose to mycelium. By destroying the structure of the wood and turning it into rot, it will fall down in no time.

The best level of humidity should be somewhere between 35 to 45 percent. This level will give you enough humidity to feel a neutral temperature. It will lack moisture that can damage your home while maintaining enough to feel good staying indoors.

With less humidity, you cool your home a few degrees better than it should. Expect the efficiency of your cooling systems to shoot up. You’ll also see your energy costs go down over time, as you need less energy to cool your home.

How Does A Heat Pump Remove Humidity From The Air

The heat pump is an effective cooling system, and much of its function comes from its inner workings. Your average heat pump relies on a concept of heating and cooling we call refrigeration.

Inside your heat pump, there is a large device called a condenser coil. This coil has a gas refrigerant that goes under forced pressure pumping. Once pumped, it sublimates into a liquid and loses all the heat it carries with it.

Once the gas cools down, moisture in the surrounding air radiates its heat into the coil. Moisture sublimates too, becoming liquid in the process. This entire process of efficient cooling and removal is what we know as dehumidification.

Heat pumps recycle indoor air only by design. This air recycling allows for a more stable temperature, unaffected by external temperature changes. Something like a cold, moist window or a hot surface won’t swing your humidity too much.

The heat pump has at least two modes: cooling mode and drying mode. Both modes offer different benefits to a home and how it answers any issues with humidity.

Insiders Tip: If your heat pump is not removing enough humidity from the air, check your thermostat to be sure the fan is set to “AUTO” and not “ON”. The Auto thermostat setting is provides the temperature drop across the evaporator coil needed to properly remove humidity in the air.

The Different Modes Of A Heat Pump

When in cooling mode, the compressor pushes refrigerant through the evaporator coils. Evaporator coils are indoors and air will start blowing across the coils. Refrigerants are effective at absorbing the ambient heat that it touches up. Once it absorbs enough latent heat, it will move through the condenser coil outdoors.

Together with the heat, moisture sets in and becomes liquid too. This process is the same that air conditioning follows, but with extra steps that make it more efficient. It provides exceptional cooling and comfort, but can also give you warmth in colder seasons.

The second mode is what we call drying mode, which is exactly what it says on the tin. What the heat pump does in this mode is to pump both heat and cold out. Rather than cool a space, it tries to keep the relative humidity to the setting you desire. It neither cools down or heats up a space, but instead maintains the humidity of the room.

Anyone inside the home who experiences a heat pump’s work will notice its effects first hand. Temperatures will be more stable and closer to what you want. You will also see a drop in perceived temperature as the pump cuts down on the humidity.

Getting More Benefits From Your Heat Pump

One of the simplest advantages of a heat pump is the lower operational cost. Heat pumps tend to be at least 4 to 5 times more efficient than other heating systems. While the upfront investment can be a bit of a challenge, it makes up for it in long-term savings.

Heat pumps are a good long-term cooling and heating solution, able to produce savings in 5 years. As the average lifespan of a heat pump is at least 10 – 15 years, you can expect good savings. Sure, heat pumps are quite the investment to have, but if you have the money to finance it, you’re doing yourself a favor.

Thanks to the lower humidity, you won’t need to set a thermostat to do the work for you. Pushing your thermostat to higher heating or cooling doesn’t solve any humidity issue. It only adjusts the temperature, not the humidity of an indoor space.

With a heat pump, you will also start seeing decent energy savings on your monthly bill. Because you won’t need to heat or cool an entire room consistently, you don’t need to heat or cool all the time. The temperature will feel neutral, or closer to the setting you did on the pump.

Most homeowners who use a heat pump see a savings of 30 to 40 percent once they install. Energy-Star approved heat pumps will have a higher level of efficiency and savings. More savings means a better, more efficient home temperature control system.

Heat pumps are also far easier to use than many complicated cooling solutions. They’re simple machines, relying on coils to do their job. This means there are far fewer electronics that can stop working in a short amount of time.

The maintenance cost for a heat pump is also far lower when you compare it to a dehumidifier. Most dehumidifiers have substantial costs because of the systems in place to make it work. It has a lot of small parts that help it work like clockwork. A heat pump doesn’t need a lot of expertise to maintain.

One of the best advantages of a heat pump is its lower carbon emission. When you combine it with efficient insulation in your home, you’re making sure that your home has a working internal shield. This shield will protect it from sudden temperature changes while keeping humidity down.

Newer homes are built airtight with foam insulation sealing cracks that would provide natural ventilation. If you are still having humidity problems with your heat pump, you may need to install a whole-house dehumidifier and a fresh air exchanger with your heat pump system. We discuss fresh air exchangers in our article Do You Need an Air Exchanger with a Heat Pump? Consult with a licensed HVAC contractor in your area.


Will a heat pump remove humidity from the air? Yes, a heat pump can regulate indoor humidity to push it to normal levels. By having the right indoor humidity, you get proper cooling and heating without excessive temperature changes. You also get peripheral benefits that you won’t get anywhere else.

A heat pump is an effective dehumidifier. Combining it with efficient insulation at home can help you create a proper indoor ecosystem. A sealed off indoor helps trap heat and cold inside, giving your home the right temperature regardless of the season outside.

Are you looking to invest in a heat pump? Its dehumidifying abilities are more than enough to make people invest in it. Together with the long-term savings, it affords you, you can expect to get a lot out from this wonderful installation.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.