How much does it cost to install a central humidifier?

Reviewed by Adam Graham remodeling expert. Written by Fixr.com.

If you have dry air in your home, or you’re worried about your air quality, installing a central humidifier in the ductwork of your existing HVAC system can help. Central humidifiers work by increasing the relative humidity in your home consistently, making it more comfortable. They come in several different types, sizes, and installation styles, which can impact the cost of the project.

The national average cost to install a central humidifier is between $400 and $1,200. Most homeowners spend around $650 on the professional installation of a flow-through humidifier with a bypass duct for a 2,000 sq.ft. home. At the lowest end of the price range, you can expect to pay around $225 on a basic drum humidifier for a 1,000 sq.ft. home installed. At the highest end, you can expect to pay $2,200 for a steam humidifier for a 3,000 sq.ft. home with an automatic digital humidifier control installed.

Central Humidifier Installation Cost

Central Humidifier Cost by Type

Depending on the type of central humidifier you install, your costs can range between $150 and $1,500. They come in three basic types: drum, flow through, and steam. Each of these types has its own positive and negative attributes and costs to consider. All three can help increase the relative humidity in your home, but they do so in different ways. Your contractor may recommend the best type of unit based on the severity of the dry air problem. Here are the average costs for each type:

Drum Humidifiers

Drum systems have an average price of $150 to $250 and can be bypass or fan-powered. They are the easiest to install and frequently the least expensive, which is why they are the most installed models. They use rotating evaporator pads to lift water from their reservoirs into the air stream, where it evaporates. This is effective, but very high maintenance, as it can cause mold growth. You need to clean the drum and change the pads regularly.

Flow Through Humidifier

A flow-through system is much lower in maintenance needs and costs $200 to $300 on average without installation. This unit can also be bypass and fan-powered and works with your furnace to distribute the moisture in the air. It may use electricity to work, but many do not require it, and while it needs constant water, it has a much lower risk of mold. Water flows through an evaporator pad, where it collects until it evaporates.

Steam Humidifier

Steam systems are the priciest to purchase and install, with materials costing between $300 and $1,500. They are the most effective, giving you better humidity control, with lower maintenance and lower mold risks compared to other types. Steam units can operate independently from your furnace as they use their own heat source to turn water into steam, which is then released into the air. Because of this, they will require an electrical power source and a water source, which will increase the utility costs. However, as a trade-off, they don’t have mold issues.

There are three types of steam units based on how they operate and release the moist air: warm mist (or steam vaporizers) and cool mist systems. Warm mist units boil the water with an internal heating body which gets blown by the fan into the room in the form of steam. On the other hand, cool mist humidifiers operate by using an internal wick filter that absorbs water while a fan blows the air through the filter. Because the water is not heated, this results in a cool mist that gets released into the air. Cool mist units can either use ultrasonic vibrations to disperse cool mist or a submerged disk in the machine that turns rapidly and releases cool mist into the air. Both warm mist and cool mist models are effective in humidifying the air, and the air is the same temperature once it gets to your lungs, regardless of how it was released.

Central Humidifier Cost by Capacity

Based on the capacity of the unit, your costs can range between $150 and $1,500. Just like your furnace, your unit should be sized according to your home’s needs. A unit that was too small would struggle to add enough moisture to the air, while one that was too large could increase your mold risks. Keep in mind that your home’s size is not the only factor that will determine your needs; how well insulated your home is, and whether or not you have a vapor barrier will play a role. The “tighter” your home is, the smaller the capacity you need. While there is some overlap between sizes, a general guide to finding the right one for your home is as follows:

Central Humidifier Cost by Power Source

When looking at the power source, you can expect the price of humidifying systems to be $150 to $1,500 for the unit only. Central humidifiers can either be powered, meaning that they use electricity, or bypass, meaning that they run off of your furnace with no added power. In general, any system that uses electricity will be more costly than a bypass, but both do have a range of costs. Below is a table with how much you can expect to spend for each type of unit:

Bypass Humidifier

The price of bypass systems ranges between $150 and $250 for the unit only. These are usually the easiest and least expensive models to install. Both drum and flow-through units may be bypass. These are also known as furnace and evaporative units. They use the hot air from your furnace to heat a pad/water tray that causes the hot air to evaporate. The humid air is then released into the home through a bypass duct. Bypass units still need a water source to function, but with no electrical hook-up, which is why they cost less to purchase, install, and operate.

Powered Humidifiers

Because any system may be powered, they can have costs ranging from $150 to $1,500 for the unit only. Powered units work similarly to bypass ones but use electricity to boil water and push it through a water tray with a fan to increase moisture. They don’t have to rely on a system to dispense the humid air throughout the home. Any unit may be powered, including drum and flow-through. Steam units, however, are always powered, which is why this group of humidifiers may be referred to as steam humidifiers instead of powered. This is because it takes a certain amount of energy to generate the heat needed to turn the water to steam.

Central Humidifier Cost by Brand

Based on the brand, whole-house humidifiers are priced at $150 to $1,500. Like all appliances, there are several manufacturers of quality central units that are known on the market. Some of the more popular names are Honeywell, Aprilaire, Lennox, and Emmerson. Each has its own types of humidifiers they sell with different specifications, quality, and costs to consider. The installation cost may be provided by the company in some cases. Below are some of the costs related to the popular brands:

Aprilaire Whole House Humidifier

Depending on the unit you get, the Aprilaire central unit price is between $150 and $1,200. Aprilaire is one of the most popular brands of indoor air quality systems and products. Whole house units were the first line of products. Today, they make a wide selection of central humidifier types with different costs, including steam units. Aprilaire consistently gets good reviews from users who like the built-in humidistats and automatic shut offs.

Lennox Central Humidifier

Whole-house humidifiers produced by Lennox can cost between $160 and $1,200, depending on the type you choose. Lennox is a recognizable brand of furnaces, but they also sell some whole house units. They are less common in households than other brands. You will have fewer humidity control options. However, they produce high-quality products that come with a warranty of 5 years for all their models.

Honeywell Central Humidifier

The Honeywell whole house unit costs $170 to $1,500, depending on the size and type. Honeywell is well-known for their thermostats and other home heating and cooling appliances. They have a range of different systems as well, including both drum and flow-through models. They do need to have professional installation to avoid voiding the warranty. They aren’t as sensitive to changing humidity in the air as other brands, so may take some experimentation to determine good levels, but can provide a good source of humidity without needing to bypass ducts.

Emerson Central Humidifiers

The Emerson centralized system price is between $250 and $1,250, depending on size. If you want a top-of-the-line steam model that will take up little space and work consistently, then you’re looking at Emerson. They don’t make as many variations in models as some of the other brands, but they do make high quality steam units that include humidistats and auto shut off. Because they specialize in this industry, their products tend to be higher quality in general.

Cost to Install a Whole House Humidifier

The central humidifier installation price by HVAC professionals is typically $75 to $150 per hour in a standard home. The installation of a flow-through unit typically takes around three hours in most homes. This makes an average total price of $650 for a flow-through model break down into labor costing roughly $300, parts and connections to the pipe making up $100, and the unit itself costing around $250.

The exact installation process and the total price of installation will vary widely, depending specifically on the unit you choose and the setup of your ducts. Most units install at the stack of the furnace, adding moisture to the air just as it leaves the furnace, but some will install in a return duct where it will humidify the air before it gets heated. Regardless, it must be installed where it can be connected to your cold water supply, as the unit will need continuous access to moisture.

Powered units may also need to be wired into your home’s electrical system, or, if there is a GFCI outlet nearby, you may be able to simply plug it in. In most cases, a template comes with the unit, and this is used to indicate where on the ducts to cut. The ducts are cut to accommodate the unit, it is connected to its water and/or power source, and attached to the duct. The entire process takes just under 2 to 5 hours on average, but can take less time for a simple drum unit, and more time for a complex steam system.

Cost of Adding Humidifier to Furnace

The cost to install a humidifier on a furnace for a flow-through unit is around $900. This is made up of $300 in labor, $100 for parts and connections to the pipe, and the unit itself costing roughly $500. The cost of adding a humidifier to a furnace with a bypass setup rather than powered is pretty much identical, with the exception that you do not need to have a power source nearby. You will need to have a template, cut a hole in the duct as it attaches to the furnace, and install the system.

Central Humidifier Pros and Cons

Installing a humidifier comes with a lot of benefits. One of the main ones is that they are very simple to install, especially powered units. Once installed, these units control the air moisture automatically, which means you won’t have to manually press a machine or unit to adjust the humidity level in your home. This also improves the air quality of the home, which has a whole range of benefits for the health. Maintaining the air humidity at an ideal level reduces allergies and other respiratory issues, sore throats, dry skins, irritations, and chapped lips. Most central humidifiers are also very low maintenance, requiring only a yearly change of the evaporator panel (filter) and a simple wipe down to get rid of any debris stuck to it.

Aside from the range of benefits, there are also some downsides to whole-house units. Obviously, they are priced more than portable units, especially if you hire a competent contractor for the installation. A potential risk of using evaporative central units is the appearance of mold and mildew. Because of the way they operate, the moist air that evaporates in the ducts may cause moisture, which, combined with dust, can result in mold growth. To prevent this, you need to properly maintain and regularly clean the HVAC system, producing other costs. Finally, they can cause air leaks and temperature issues in a home. If you notice the temperature shifting in your home or have leaky ducts, consider air sealing your home.

Ideal Home Humidity

For most homes, the ideal humidity level is going to be around 30% to 50%. In the winter months, it’s common for indoor humidity levels to naturally drop due to the lower amount of moisture in cold air, making the air too dry. This is why a central unit can be beneficial. Both low humidity and high humidity can lead to health problems, however, which is why aiming for a balance of 50% is ideal.

Problems with Low Humidity

Low humidity causes the air to be dryer, which in turn can cause several potential health issues, as well as potential problems with your home and comfort level. These can include a higher risk of illness, as many viruses thrive in lower humidity, aggravation of issues such as asthma and allergies, and difficulty keeping warm at lower temperatures. Dry air can also contribute to static electricity and can cause damage to wood floors, windows, plaster, and paint. These materials may shrink or crack if the moisture level in the air gets too low.

Problems with High Humidity

Humidity that is too high can also lead to problems, which is why you should not use your central unit during the summer months when the air is naturally more humid. High humidity can cause issues that include mold, mildew, and bacteria growth that can cause health problems, as well as dust mite infestations and musty odors. Wood can absorb water, so wood floors and window frames can warp. Condensation and water stains can occur, as can peeling paint. Finally, high humidity can lead to a muggy or sticky feeling, as well as potentially labored breathing.

Humidistat vs Thermostat

The price of a humidistat ranges between $30 and $150, while thermostats are priced $20 to $400, depending on the model. If you install a central humidifier, you may find that it comes with a built-in humidistat. This is a gadget that controls how much moisture the unit is putting out and lets you see at a glance what the current and desired levels are. It functions similarly in its reading, control, and output to a thermostat, but a thermostat controls your heating and cooling system, and not the humidity levels in your home. The humidistat controls only the humidity levels and not your heating and cooling system.

Humidistat vs Humidity Gauge

A stand-alone humidity gauge is a good accessory to have that you can purchase for $10 to $50, while a humidistat will cost $30 to $150. It’s important to keep humidity levels in check, not only for comfort, also but because having too much humidity in the home can lead to mold growth. For this reason, you will want to have a way to measure the relative humidity in the air to determine when to use the humidifier and when to turn it off. There are two basic devices for doing this–a humidistat (or hydrostat) and a humidity gauge, sometimes called a hygrometer. Both will tell you what the humidity in your home is, but they work in different ways.

A humidity gauge is a stand-alone device that you can use to determine the humidity in a room of your home. You can either install it on a wall or move it from room to room. It’s only going to tell you what the humidity is, and it won’t control your system. A humidistat is used on the unit itself. It will also read the humidity, but it helps you control it with a programmable unit allowing you to set a specific humidity, so the unit will turn itself on and off when those levels are reached.

Humidistats can give you better control over your system, while humidity gauges can help you determine manually whether one room needs more humidity than another. Humidity gauges will also help you take a look at the humidity from the weather. Most central humidifiers come with a humidistat built in. There are some very basic units that don’t have them, and they tend to cost a little less, but it’s very common for most of the popular name brands to have one.

Enhancement and Improvement Costs

Bypass Gate

Most higher-end units come with a bypass gate installed, which costs about $70 to $150 more. Humidifiers should ideally only be used in winter when the air is dry; in the summer, humidity levels are usually already high enough. A bypass gate allows the unit to be shut off during the summer months when the air conditioning is on. The air from an air conditioner would flow around the unit, rather than through it, so you aren’t adding moisture to air that doesn’t need it.

Automatic Digital Humidifier Control

A unit with an automatic digital humidifier control feature increases the costs by roughly $100. A humidistat measures the humidity and temperature in the house and adjusts it to the level of humidity you’ve set it to manually. An automatic digital control unit, on the other hand, measures both the inside and the outside temperature and automatically determines if additional humidity is needed in the home. This gives you greater control over the humidity in your home and helps you maintain an optimal level by getting automatic readings and adjustments. Most models can be used both manually and automatically. To use the model in automatic mode, you would need a sensor installed on the outside and measures the outdoor temperature to determine the level of humidity needed indoors.

Additional Considerations and Costs

• Humidifier maintenance. Your humidifier will need regular maintenance to keep running properly. This includes regular cleaning and making sure it has water, but you can also have it professionally maintained about once a year. HVAC maintenance visits are priced around $100 to $150.
• Humid climate. Homes in climates that are naturally humid may not require a central humidifier. In fact, adding a humidifier in these climates may put your home at greater risk of mold development.
• Weatherstripping. You can reduce the size of the unit you need with good weatherstripping to seal gaps around doors and windows. Many houses lose large amounts of humidity this way. In some cases, weatherstripping alone may be all that is necessary, eliminating the need for a humidifier. It has an average price of $200 to $600.
• Energy bill savings. Installing a central humidifier can help your home feel warmer and more comfortable, even when it’s cold outside. Therefore, when running your system, you may be able to lower your thermostat and save money on your energy bills.