When you think of humidity what comes to mind.Mist ,fog,dew,wetness.Well all these conventional picture of humidity tells that it is related to amount of moisture in the air.But our comfort level is not just related to moisture present in the air.A more important and useful term is relative humidity and temperature that affects our level of comfort inside our house or outside.When accessing IAQ(Indoor air quality) both these factor must be taken into account.
So what is relative humidity(RH)?
Well in simple terms it is the amount of moisture present per cubic meter of air.Now while the volume of given air remains fixed the number of molecules of air,in other words how dense the air is depends on the temperature of the air.Now obviously dense air which is colder can hold less moisture than hot air because as air expands when heated there is more space between molecules in hot air to accommodate water molecules than in colder air.
So if we take air of fixed amount of moisture content in it and heat it its RH will decrease and if we cool it RH will increase.You can test it by measuring RH at inlet and outlet of your furnace or AC respectively.
But there is a paradoxical effect seen in weather conditions.
You may have seen that hotter seasons are high in humidity while colder seasons are dry.This is because it generally rains or water evaporates faster in hot season so no of water molecules per cubic meter of air is higher than is in winter.
While in winter the air saturates and the water condenses to form droplets or ice.But we don’t see droplets forming on window panes in summer.
We know that AC coil takes up the latent heat from water vapor molecules and removes moisture and but it increases RH. It is only when this cool air mixes with indoor hot air that the RH of supply air decreases while of whole house increases.
Note-While AC is moderately effective in removing humidity than a dehumidifier it can work as a natural dehumidifier especially by using over cool feature of thermostats.
Similarly a furnace makes the air less dense so reduces RH of supply air but when it mixes with the colder air of whole house the RH of supply increases while of whole house decreases.
How humidity affects us.
High humidity levels in the home creates allows for growth of for mold ,dust mites,powerful allergens and irritants which is not good especially for people with asthma.
On the other hand if humidity is below 30%,
- It causes irritation of the mucous membranes in nose and throat, leading to breathing difficulties.
- Dry air is adds to discomfort to people with skin or eye conditions.
- It is also dry wood made items them too much creating cracks in them.
HVAC components that control your indoor humidity.
Whole house Humidifier-Used in winter season. Introduces water molecules into the draft air by intake from a solenoid valve and pouring it on a meshed plate. The water evaporates and is then taken away by the air draft on the duct it is installed.
Dehumidifier-Can be used in extension to AC.Work almost like AC but do not cool the air but help in making you cool since it removes the stickiness and mugginess from air so your sweat evaporates faster and make you feel cool.
Dehumidity-stat–
It is a simple device that operates and control the dehumidifier or AC But it is more used for energy saving device when you are gone for extended period of time or vacation rather than humidity control and prevent growth of mold or mildew inside your home.
The setting of the nob is like follows.
In summer
When Away-Set the Knob(Used for dehumidification) to 60 % and temperature to your desired cooling temperature Ex-80 degree F and set your fan switch to auto. When away your thermostat wont work if humidity is less than 60% but dehumidifier would.
When Home-Set the Knob to about 100% and operate the thermostat normally.
In winter
This humiditistat comes with the company making your whole house humidifier.In winter when humidity is low Set the humidistat knob to 55 % which in summer would have been in off position.Also you need to adjust the humidity level according to the temperature outside to prevent formation of dew on windows etc and dry the house furniture or wood work beyond acceptable limits.However people generally forget to change it from time to to time.
An alternative to all this could be a humidity controlling thermostat which can control both humidifier or dehumidifier according to the weather and RH present outside.Below we have listed some good wifi thermostat with humidity control feature that is easy to set and forget type.
1.)Honeywell YTHX9421R5101WW/U Prestige IAQ Kit with Redlink technology
Although this thermostat is not programmable it is a full on solution for your indoor air quality including temperature and humidity.It comes with multiple temperature and humidity wireless sensor that you can install inside or outside home and based on inside and outside reading it will smartly adjust your AC or dehumidifier or Humidifier.It says DIY type but it is recommended to install it through professionals.
Check out Honeywell prestige IAQ kit on Amazon.
Other than that it uses red link technology by Honeywell which is secure and reliable in terms of communication between devices.Here is a video explaining Red link technology.
2.)Aprilaire 8620W WiFi Thermostat
Aprilaire is an HVAC manufcacturer that makes humidifiers,dehumidifiers air purifiers,home automation using zoned temperature control and of course thermostats.The above model of Aprilaire thermostat can control both your humidifier and your dehumidifier from the thermostat itself.Along with humidity it also has event based air cleaning and ventilation controls. It has an auto mode which allows you to control humidity hands free.
Temperature we feel is also a affected by humidity so if you can control that with other parameter other than heating and cooling it can lower your energy cost. At least that is what the company claims.In all it is a decent thermostat that allows auto humidity control.
Thermostat can be configured for humidifier or dehumidifier through installer setup and then humidity or dehumidity set point can be set by pressing the humidity control icon or main screen. In auto mode of humidity control you can set it to Off Low,Normal or High and the thermostat will automatically adjust the setpoint according to temperature. In manual mode it will give suggestion of setpoint according to outside temperature and you can directly give the RH set point.
In case of dehumidification it will give current % level of dehumidification. Raise it to make air less dry and lower it to make it more dry. If AC is used for dehumidification it can lower the temperature by upto 3 degree to dehumidify.
Check out more reviews price and ratings of Aprilaire 8620W WiFi Thermostat on amazon.
3.)Venstar T7850 Programmable WiFi Thermostat
Venstar is a US based company which exclusively makes thermostats for residential and commercial use and energy management system for small businesses. The above model is T7900 which is only residential model with humidity control humidifier and dehumidifier. It has color touch screen which also allows you to set wallpapers and sd card into the Thermostat.You can add voice control by connecting Alexa device.(only).You set the humidity set point and it will humidify using humidifiers or dehumidify using cooling mode.It also auto adjust recovery time using changing seasonal trend.It calls it smart recovery.Overall its a little pricey but good addition to add to your comfort level.
Click here for more rating reviews and price of Ventar T7850 wifi thermostat on Amazon.
4.)Honeywell TH8321WF1001 vision pro 8000 thermostat
This thermostat also has the ability to control but humidifier or dehumidifier or AC. It uses seperate set point for humidifier and dehumidifier. Although when used in common mode ie Off mode(Niether heat or cool mode) the thermostat may maintain 15 % difference in two set points.
For humidify or dehumidify setpoint-
Touch MENU and select Humidification or Dehumidification
Touch Auto.
Touch up or down key to change set point
Touch Done to save.
To prevent frost or condensation on windows when using humidifier on cooler climate Goto MENU, then select Window Protection. It is son a scale of 1 to 10 with lower number used for lower humidity levels.
NOTE: Window (frost) Protection is only available if thermostat can get outdoor temperature data either from an outdoor installed air sensor or local outdoor weather data through internet connectivity via wifi.
If AC is used to dehumidify it can lower the set point(Over cool) to upto 3 degree to reach the desired temperature.
In commercial use to maintain humidity the AC may
• Over cool from 1° to 5° F below set point.
• Run AC or cooling for the minimum “on” time.
• Run both cooling and heating together dehumidity without lowering the temperature.
It is compatible with upto 3 heat and 2 Cool stages heat pumps with auxiliary heat and 2 heat 2 cool stages most conventional oil, gas, electric steam or gravity boilers even with duel fuel feature.
Additionally The VisionPRO 8000 WiFi Programmable Thermostat features a large touchscreen display for easy control of your home comfort. You can program a schedule for each day or adjust the temperature remotely using the Total Connect Comfort app. It also offers Adaptive Intelligent Recovery and energy-saving scheduling options.
5.)Ecobee3 4 and 5 smart thermostat
Ecobee 3 4 and 5 all have humidity control feature but Ecobee 4 is the middle ground in the whole range of ecobee smart thermostat in terms of price and features.But it has what you need. Note- Ecobee 3 lite do not have this feature. That is ability to control humidifier or dehumidifier It uses its ACC+/ACC- terminals to control any other accessory other than heating or cooling like humidifiers. To dehumidify you can use AC. In summer month you can adjust humidity by setting the humidity set point and also AC over cool max setting so you don’t over run Ac to lower the humidity.
For winter moths it has a frost control which lowers humidity set point as the outside temperature falls.This prevent frost on windows and save them from damage.
Check out more reviews ratings and price of Ecobee 4 smart thermostat in Amazon.
Here is a video how to set humidity in summer. Setting in winter will go along the similar process and or you can refer your manual.
6.)Nest smart thermostat-When it comes to thermostats we know nest is the market leader. It comes with almost all feature you need in a thermostat. Only drawback is that it is not cheap and maybe not for everybody if you dont need most of its other feature like geofencing etc basically what makes it a smart thermostat.
To connect to humidifier Nest uses single wire from humidifier that connects to the star terminal The other wire from humidifier connect toC terminal of HVAC system.
In Nest controlling humidity after wiring is just as simple as setting the humidity set point and over.You will be done. It will start controlling your AC dehumidifier or humidifier according to your humidity set point.See in this video.
Check out more reviews,price and rating of nest smart thermostat on amazon.
7.)Cielo Breez Plus, Smart Air Conditioner Remote Controller
This probably a new entrant into thermostat market is meant only for those who suffer from hot and humid climate.Its is cost effective way of controlling Ac to keep temperature as well as humidity into your desired range.Works with most of the AC brands and models and is also compatible with Alexa and Google assistant. It also has Geofencing. However if you want to control your Furnace or humidifier in winter as well this is totally not the thermostat you need. Other than that it has overall good customer feedback and ratings.
Check out more reviews price ratings of Cielo Breez Plus, Smart Ac thermostat on Amazon.
8.)Honeywell T10 thermostat
Elevate your temperature and humidity control in the most important areas using the T10 or T10+ Pro Smart Thermostat. Gain precise control over your preferred rooms by incorporating Smart Room Sensors and establishing a personalized schedule, or let the sensors adapt to your lifestyle automatically.
Experience the convenience of Auto Home and Away Mode, allowing you to adjust your thermostat from anywhere using your mobile device or enabling your home to respond automatically based on your schedule with geofencing.
Achieve optimal comfort by focusing on multiple rooms with the addition of Smart Room Sensors (sold separately), ensuring temperature regulation precisely where it matters to you.
There is option to control humidity level by using humidifier like steam in colder months or dehumidifier like AC in summer month. There id also a provision of window protection to control frost in the window by selecting a scale ranging from 1 to 10 that indicated how well the windows are insulated.
In using AC as dehumidifier there is a setting to select the over cooling range of temperature from 1 to 5 degree so the temperature can drop from current cool setpoint untill the desired humidity level is reached.
The relative humidity level ranges from 25 % minimum to 80 %. Prior to 2019 models had minimum 40 % but it updatea automatically to 25 % when connected to wifi and registered in Resideo App.
When you use humidifier and dehumidifier in common mode ie neither heatinh or cooling but off mode the the theremostat automatically add 15 dead band to its humidifier and dehumidifier set point and automatically select humidifier or dehumidifier to control humidity.
When AC is used to control humidity the temperature may fall to 3 degree below set point before desired humidity is reached.
Check out more reviews price ratings of Honeywell T10 thermostat on Amazon.
9.) Emerson Sensi wifi/ smart thermostats
There are four models of sensi that are compatible with humidifier and dehumidifiers in your home. They are
- 1F87U-42WF (Classic) series
- ST55 (Smart) all series
- ST75 (Touch) all series
- ST76 (Touch 2) all series
To connect the thermostat with humidifiers they have Y2 * that can be used to connect to two stage cooling or humidifier. Similarly to connect to dehumidifier they have W2* that can be used to connect to two stage cooling or dehumidifiers.
It can also dehumidify systems that do not have dehumidifier by using the AC. It can do so by running the AC past your set point by 3 degree to lower the humidity if required.
To set up a the humidity settinggo to Advanced Set Up menu select set up HVAC equipment and press add additional accessories and press yes on wired humidifier or dehumidifier. If you can’t press yes you have configured to two stage heating/ cool g Go back and change it it 1 stage Heating/ cCooling.
In advance settings
Humidify and
Dehumidify feature controls are also available.
For Humidification
Press Humidifiy.
Toggle the feature on or off. Adjust the set percentage
to using the up/down arrows.
Similarly for dehumidification use press Dehumidify and proceed as above.
Check out more reviews price ratings of Emerson Sensi wifi/ smart thermostats on Amazon
10.)Emerson 1F95-1291 7-Day Touchscreen Thermostat with Humidity Control
It has two terminal Hm connected to humidifier that energies on call for heat if humidity is less than set point to humidify. It also has Dhm that it uses with compatible system with required connection on control module or have a relay installed that can lower the fan speed to dehumidify on call for dehumidification.
Auto Humidity Reduction (HR) – This feature automatically lowers humidity setting when the outside temperature drops to prevent the interior windows/walls from reaching the dew point preventing water to condense on surfaces.
Automatic Humidification (AH) – This feature if enabled, will energize the humidifier and circulator blower independent of call for heat if the actual humidity is below the set point.
It also has features like cycle humidifier that cycle the humidifier for 10 minutes On to 10 minutes off while the blower and/or furnace is continuously running to lower water usage by 50 %.
It also has prgrammable Dehumidification Optimal Comfort
Mode (OC) or Optimal Dehumidification (Od) mode. In OC mode it lowers humidity when it is above setpoint by 2% but only when call for cooling is required so uses less energy.
While Od mode is same as OC except it does not wait for call for cooing so consumes more energy. It can also over col by 30 degrees.
Other Features of the product include:
- Spacious 12-inch touchscreen display, providing a large and user-friendly interface.
- A programmable thermostat with a 7-day capability, enabling you to customize unique schedules for each day of the week.
- Wide-ranging compatibility with various heating, cooling, and heat-pump systems, ensuring it works seamlessly with most setups.
- Keypad lockout feature for enhanced security and control, preventing unauthorized access and changes.
Check out more reviews price ratings of Emerson 1F95-1291 7-Day Touchscreen Thermostat on Amazon
11.) Bosch bcc100 smart thermostat
This thermostat has an option to connect to one accessory either humidifier or dehumidifier.
To do that connect the control wire of accessory to the H/DH terminal of wall plate.
You can configure the thermostat to auto humidity control if you correctly wire the humidifier or dehumidifier and configure it in initial setup. Based on that the thermostat will turn on humidifier on heating and dehumidifier on cooling. You can also configure it it work as humidistat which works independent of heating or cooling call.
If the external accessory connected is humidifier you can configure the thermostat to “Cool to dehumidify” so that the cooling device over cool within permissible degree below setpoint or “Hot gas reheat” mode to dehumidify the air and yet maintain temperature.
Note- The HVAC equipment must include this feature for the thermostat to work.
The new updates in model enable it to use for evaporation and steam type external humidifiers.
It supports Conventional (Gas, Oil, Electric) and up to 4 Heat / 2 Cool heat Pump including duel fuel systems.
It is compatible with Amazon Alexa voice commands but not with other home automation system. it also does not have IFTT or geofencing.
It has 5 inch sleek design and touch screen options ans is programmable using phone App.
Check out more reviews price ratings of Bosch bcc100 smart thermostat on Amazon
12.)Wyze smart thermostat
This wifi thermostat comes also has humidity control. It is quite popular smart thermostat because of its affordability and smart features like geofencing 3 in 1 smart remote sensors that monitors temperature, humidity and motion and AI learning capabilities though to give energy saving tips. It can interact with Wyze devices like Wyze Cam V3, Wyze Lock, Wyze Plug and Wyze Cam Floodlight.So it makes a perfect choice if you already have these devices installed.
It has ACC+/ACC terminals to connect a humidifier or dehumidifier.
Thermostat can be configured to one of the four accessories Humidifier, Dehumidifier, Ventilator and Emergency heat by turning the dial and pressing the button to make choices in initial set up.
To configure dehumidifier:
Select
1.Cooling: For Dehumidifier to run only when the cooling stage is active and humidity is above the desired range.
2.Fan:To Run the Fan when humidifier is On.
3.Energize:Active on or Active off.
To configure humidifier:
Select
1.Fan: To runs the fan when the humidifier is On
2.Heating: To run Humidifier only when the heating stage is active and the humidity is below the desired level.
To set humidity set point go to Settings>Humidity preference and set desired level of humidity.
Check out more reviews price ratings of Wyze smart thermostat on Amazon