What is the proper humidifier setting in extremely cold weather?

I received this question from one of our readers.  She thought her windows had too much condensation on them.  Here’s what I advised her.


During cold winters, your heating system can make the air in your home too dry, making it uncomfortable for you. To improve the air quality, you can add a humidifier to those areas where you spend the most time, or you can install a whole house humidifier to your heating system.  To better monitor the humidity levels in your home, consider purchasing a hygrometer. A hygrometer is a small instrument with a display that shows what the relative humidity level is in the room where it is located. Inexpensive and user-friendly, this handy item can help you to monitor the air so you can adjust your humidity level when required.

Keeping in mind that every home is different, humidity levels can be affected by many factors. The number of people living in the home, the number of showers taken, the amount of laundry done and even a wood burning fireplace contributes to humidity levels if you keep firewood inside to dry out. The number of times a day an exterior door is opened and even cooking all affect your comfort level.


Keeping the correct humidity level in your home is important. Humidity levels below 25% are associated with increased discomfort, static electricity and dry skin, which can lead to chapping and irritation. High humidity levels can result in condensation within the home and on interior surfaces such as windows.

And remember, the colder it becomes outside, the easier it becomes for moisture to appear on your windows.


Warm air is drawn to cold air. The colder it is outside, the easier the warm air will migrate to a cold surface like your windows, and form condensation. So you most likely will have to turn the humidity level down. Monitoring the amount of condensation on your windows is as good a way as any to gauge and adjust the humidity level in your home.


The recommended average relative humidity level is between 35% and 45%. This range will provide the best comfort for your family, while helping to protect wooden furniture and floors and many other belongings or materials in your home.

Hope this helps,


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62 Responses to “What is the proper humidifier setting in extremely cold weather?”

  1. Muyiwa says:

    Hi Dave,

    Thanks for your article. Great comments and very helpful. Just a quick question – if there is condensation on the window, your recommendation is turn the humidity level down. Does this apply even if the humidity level is already below 35%?



    • Dave says:

      Yes, it does. You can turn it down to a point where there is a very minor amount of condensation on the windows. There could be other factors at play that cause condensation (showers, lack of bathroom ventilation, no range hood) that you might want to look for as well.

      • nicole says:

        Hi Dave,
        I have a question. The tube that leads from outside to inside, not sure if this one is bringing air in or out. Anyway the instillation inside the tube is wet. Why is this happening and how can i make it stop? Do i have to replace the tube all together?
        thanks, Nicole

        • Dave says:

          Hi Nicole,

          Sorry this took so long. I needed to discuss this with some of our experts. Here is what they said.

          Air exchangers have a core (heat exchanger) built into the unit. Yes the exchangers can remove some (not all ) of the humidity from the home. The exchanger has a defrost cycle so in cold temperatures as the heat is extracted from the home’s outgoing moist air (to warm the incoming fresh air), the temperature of the outgoing air drops to the point where moisture/frost can form on the surfaces of the heat-exchange core. A build-up of frost can block airflow through the HRV.

          Yes a humidifier would assist in humidifying the home.

          The air exchanger should be checked to see if the system is balanced to ensure that there are equal amounts of air exiting the building versus entering the building via the air exchanger.
          On most air exchanger models there is a dehumidistat dial/setting that can be set to control moisture levels in the home. The manufacturers literature should be consulted to find the comfort setting.

          I hope this helps. If you need someone to come out and take a look you can reach us at 1-800-266-3939.


  2. Maureen Bax says:

    I have a room humidifier in the area of my home we spend most of our time. I have been wondering about many of the questions mentioned. I now know how to solve the problems related to heat, humidity settings, dry skin and static electricity. Very much appreciated. Thank you for sharing.

  3. Jim Galloway says:

    Would like to know more about air exchangers. Do they control humidity? What recommended setting should they be set at during winter months?

    • Dave says:

      Hi Jim,

      An air exchanger brings fresh air into your home and it would affect humidity depending on the time of year. In the winter when it’s really cold, it would bring in dry air that would need humidity added. So to answer your question, it doesn’t control humidity. You would need a humidifier as well.


      • Mike says:

        We have an HRV that is used on occasion to bring in cold, dry air in the winter to decrease high levels of humidity in our newer, well sealed house. I track the humidity level with a Hygrometer and documentation on the CMHC website suggests decreasing relative humidity as the outdoor temp decreases to reduce condensation and mold build-up. Does this seem like a reasonable approach? I don’t think a humidify is needed.

        • Dave says:

          Hi Mike,
          A certain amount of humidity is a good idea, not just for the personal and health benefits, but for your home. Things like hardwood floors benefit from a proper humidity level. It is advisable to monitor your humidity level and change it according to the outdoor temperature. A colleague of mine has a small, ten dollar, hygrometer on his second floor and uses that to determine what setting he puts his humidifier on.

  4. Gillian Ber says:

    I am a home owner and I found this information very helpful. We have a humidifier on our furnace and it seemed strange to me that the colder it was outside, the more we should turn the humidifier DOWN.

    I was thinking that if it was very cold outside, the furnace would be on more often, therefore the humidifier should be turned higher to combat the dryness in the house. Who knew it would be the opposite!

    Can you also send me information on how to clean my humidifier? Also I would like to know how I can tell when it needs cleaning. Also, can you tell me when I should clean the filter, or when I should just throw it out and get a new one. And – how do I know that it is operating correctly – what do I look for? My humidifier looks a lot like the one shown in this article. Thank you.

    • Dave says:

      Using a humidifier allows you to turn the thermostat down one or two degrees while still maintaining a comfortable feeling in your home, potentially lowering your heating bills. Why? Warm air holds more moisture than cold air and so the home’s temperature can be lower, but still feel comfortable.
      Maintaining your humidifier just once a year, helps to ensure it operates at maximum efficiency in order to provide you and your family the utmost comfort during cold, dry winters.
      Direct Energy offers a Humidifier Maintenance for $84.95 that will ensure your humidifier does continue to operate as efficiently as possible. Getting it maintained once a year, ideally before the cold weather hits in autumn or, right after the winter so the unit doesn’t sit dirty all summer and gum up or calcify.

  5. Joe says:

    Very useful advise regarding to keep correct humidity level. Where can I buy Hygrometer? Please advise.

  6. Harold says:

    I want to know the difference between humidifiers, hot and cold, and which is better.

  7. param says:

    Hi I have had a Honeywell steam Humidifier that was never installed right it has never worked from day one………
    And I am unable to find someone reliable to have it fixed and working do you offer that service for this model please ??

  8. Falcon says:

    I have humidifier added to the furnace outlet. It has different setting based on the temperature. Since temperature varied daily and it is cumbersome to adjust humidifier everyday, should it be ok to leave at lowest temperature during winter? So far that is what I have been doing.

    • Dave says:

      Hello. There should be a “comfort” range on your humidifier and typically you’ll get the best results when it’s set within this range. You can also invest in a hygrometer – it will tell you what the relative humidity is in your home – and set your humidifier based on the humidity level and your personal preference.

  9. Mal says:

    Do you supply and install home humidifiers?

  10. Van says:

    Does Direct Energy install furnace humidifier?

  11. Barry says:

    How much does it cost to get a humidifier put on a gas furnace? I have 3 portable humidifiers by Honeywell….they do a great job but need to be refilled with water frequently. Can i control the humidity level with a furnace one…..I have a few wood guitars in the house and need to keep the level up so they don’t crack.

    • Dave says:

      Hi Barry,
      The cost depends on the type and model, but on average you’re looking at $400 for a mid-range humidifier. You control the humidity with a furnace mounted unit and there is very little maintenance required. I would consider adding one if you have guitars and other wood products in your home.

  12. Frank. says:

    I just skimmed over the article quickly and I have to mention that if you run humidity at 25 to 35 percent when it is very cold, you will get too much condensation on your windows. This will not harm your windows but some of the humidity will make its way into the walls where it will cause damage. As a rule of thumb, I adjust my humidifier on my furnace down in percentage points of humidity as it get colder. When we get that extreme cold like -25 and lower, my humidistat is no higher than 15 to 20 percent. Just look at your windows. You should have no more than about a half inch of condensation around the bottom edge. Any more that that and you are running a risk of doing damage inside your wall.

  13. Joanne says:

    Thanks for the information Dave, I had to turn mine off as I had the same issues. If I lowered the Level, it would still be too strong and still creates too much consendation. I now have turned it back on and have no issues although when it gets very cold like it did last weekend, the condensation started again.

  14. willie says:

    Dave ,I had a flow through installed about two months ago ,the installer set it at 45%,my old drum type went on the blink unknown to me ,and now mpst of my floors squeek,he told me to turn it up full for a couple of days ,then when the furnace ckicks in turn it till the soloniod clicks ,what do you think ,,Willie,,

    • Dave says:

      Hi Willie,
      I would go with his recommendation, but, I wouldn’t leave it running at full humidity if you were away for a long period. When you’re home, turn it up and monitor it, you should also notice the humidity in the home increasing substantially, especially if it’s dry and cold outside,

  15. jean smart says:

    how do I know if I have this on my furnace,
    my windows seldom have moisture but then
    my old windows must be drafty JS

  16. Ron Percy says:

    Hi Dave,

    Thanks for posting very useful information.
    We are having a modular home built roughly 1400 sq. ft., well insulated and sealed. Electric baseboard heaters and a gas fireplace will be installed. For two adults living in this home, what humidifier system would you recommend? Winters get to below -30 degrees.


    • Dave says:

      Hi Ron,
      During cold winters like the one we just endured, your home’s heating can make the air in your home too dry, making it uncomfortable for you. Because you don’t have a forced air duct system to move warm heated air from a furnace throughout your home, you are limited to using a stand-alone humidifier in those areas where you spend the most time.

      I don’t make recommendations on makes or models of humidifiers to purchase however I can provide you with some information on how to best choose a humidifier.

      There are several types of humidifiers in the market, which are not only different in the way they operate, but also give different results and have different maintenance requirements.

      The common types of humidifiers are:
      • Evaporative humidifier – Basic and affordable, needs regular wick replacement
      • Cool mist humidifier – Popular and affordable, many choices available, look for permanent filter
      • Warm mist humidifier – Better for health, but may be hot to touch.
      • Ultrasonic humidifier – Usually more expensive but with quieter operation.

      After you choose the type of humidifier you think would work best, you have to measure your room size in order to buy the humidifier that has the right capacity to work in that room. If you need to humidify the whole home, get a “whole house humidifier” instead of purchasing several separate humidifiers. This will save you on cost. For a small to medium room, a humidifier with roughly 2-gallon-per-day capacity is fine. If the room is large, you can get a console humidifier with about 9-gallon capacity.

      There are also numerous and varied features on a humidifier that you might want to consider:
      • Does it have an auto shut-off feature?
      • Does it provide quiet operation?
      • Are the controls easy to operate and understand?
      • Is the tank well designed? Meaning how easy is it to fill?
      • What kind of filters? Permanent or inexpensive replaceable filters. Are they easily accessible on the unit and are they easy to find at a retailer?
      • What is the warranty and where do you return the unit if you have a problem?

      To better monitor the humidity levels in your home, consider purchasing a hygrometer. A hygrometer is a small instrument with a display that shows what the relative humidity level is in the room where it is located. Inexpensive and user-friendly, this handy item can help you to monitor the air so you can adjust your humidity level when required.

      Keeping the correct humidity level in your home is important. Humidity levels below 25% are associated with increased discomfort, static electricity and dry skin, which can lead to chapping and irritation. High humidity levels can result in condensation within the home and on interior surfaces such as windows. In most Canadian cities, ideal indoor relative humidity levels are between 30% and 50% in the winter.

      The recommended average relative humidity level is between 35% and 45%. This range will provide the best comfort for your family, while helping to protect wooden furniture and floors and many other belongings or materials in your home.

  17. Anne says:

    Hello Dave,
    Enjoyed reading your article on humidity. We have always had a problem with moisture on windows in the winter. Therefore, I just turned the modifier on Off. And, we still have moisture on the windows. When it was so cold this winter frost would form have way up. Should we get a de-humidifier?
    Our friend had the same problem….he then installed triple glazed windows and that was the end of moisture on his windows. Would you recommend we do that as well?
    Looking forward to your reply. Thank you.

    • Dave says:

      Hi Anne,
      The colder it becomes outside, the easier it is for moisture to appear on your windows. Warm moist air is drawn to cold dry air. The colder it is outside, the easier the warm moist air will migrate to a cold surface like your windows, and form condensation. Monitoring the amount of condensation on your windows is as good a way as any to gauge and adjust the humidity level in your home. In your case, it sounds like your humidity levels are too high, even without a humidifier on. However, it is also very uncommon to employ a de-humidifier in the winter. Your window condensation problem, I suspect, is being caused by your environment.
      Keeping in mind that every home is different, humidity levels can be affected by many factors. The number of people living in the home, the number of showers taken each day, the amount of laundry done and even a wood burning fireplace contributes to humidity levels (if you keep firewood inside to dry out). The number of times a day an exterior door is opened and even cooking can all affect the humidity in your home and your comfort level. Do you have a tap dripping? A shower dripping? Does your dryer vent properly to the outside? Does your bathroom vent actually vent to the outside? Do you have a dirt floor crawl space? Something is causing the condensation on the windows to form half way up.
      To better monitor the humidity levels in your home, consider purchasing a hygrometer. A hygrometer is a small instrument with a display that shows what the relative humidity level is in the room where it is located. Try setting it up in various rooms in the house (for a few days at a time) to see if you get varying degrees of humidity in the different rooms. If one or two rooms clearly have higher readings, consider some of the factors I mention above to isolate the problem and, effectively solve whatever issue might exist.
      The recommended average relative humidity level is between 35% and 45%. This range will provide the best comfort for your family, while helping to protect wooden furniture and floors and many other belongings or materials in your home.
      Regarding your friend who replaced his windows. Certainly a great upgrade for any home however, it is quite possible that replacing the windows in your home before you solve your high humidity problem could actually cause more humidity on your windows. Newer windows are sealed tighter than old windows and effectively keep the warm air from exiting the home. If the warm moist air has nowhere to go, you could end up with more condensation.
      Having said that, it is certainly a really good idea to seal up any air leakage you might have in your home. Caulking, weather stripping and insulating air leaks can decrease the warm air escaping and that will save you money on your energy bills.
      Good luck with solving your humidity issue.

  18. Carolyn says:

    Hi Dave: We just had a new furnace/AC unit installed in our home.

    We also had the humidifier installed on the furnace.

    I note that the tube that runs from the humidifier to the drain(?) did have water in it at one point (trickling – not alot) and now it’s dry.

    We have it set to the “comfort” level and for the past several days there has been no water in the tube. Is this telling us that the house is humid enough? I worry because of the lack of water in the tube – wondering if it’s working properly.

    We were also told to keep the fan on the furnace running at all times (24/7). This new furnace is noisy – is it necessary to have the fan on continually – and for what purpose – better circulation?

    Many thanks!

    • Dave says:

      Hi Carolyn,

      The easiest way to check to see if you are getting the humidity you need is getting a hygrometer. You can pick one up at a hardware store around $10. You can move it around the house to measure the humidity. At the moment the air in your home is probably pretty dry. We’ve had a fairly dry fall so that could be why you aren’t seeing any water.

      You don’t need to leave your fan on 24/7 if you don’t want to. Having the fan on all the time keeps the air moving in your house continuously which means the air gets cleaned and humidity added more often. However, that may or may not impact your comfort. I would suggest turning it off and seeing if it makes much of a difference.

      You said the new furnace is noisy – is the furnace itself making lots of noise or is it just the rush of air making the noise? If it’s the furnace itself that’s making lots of noise you should have the company you installed it take a look at it. If it was Direct Energy, you can call us at 1-800-266-3939 and we will be happy to send someone out to take a look at it.


      • Carolyn says:

        Thanks Dave.

        Yes, it was Direct Energy that installed it, and yes, it is the “rush of air” that is making the noise

        If the house is dry, shouldn’t the humidifier be working to humidify the air? What does the water in the tube signify – I took it to mean if there was water in the tube it was humidifying the air. Perhaps I’m mistaken.

        I will invest in a hygrometer – tomorrow.

        • Dave says:

          Hi Carolyn,

          I’ve sent your details to our call centre and someone will be contacting you. We want to make sure you are happy with your investment.


  19. NEWTON JAM. says:

    yes thanks,a hygrometer is a great idea,CAN GET ONE AT A HARDWARE STORE hOME dEPO ETC

  20. Andrew says:

    Hi Dave,

    Which specific hygrometer do you recommend from places like Home Depot, Walmart, Home Hardware, etc. that gives reasonably accurate relative humidity readings?



    • Dave says:

      Hi Andrew,

      I don’t have a specific brand or type that I’d recommend. They are pretty simple units. The retailer you purchase from may have some suggestions.

      Thanks for your question.


  21. Karen says:

    Hi Dave;

    Could excess humidity cause what may appear as a roof leak?

    I’ve had problems with water on the floor, near the baseboard, in one of the bedrooms in my house, every winter. I thought that it was an ice-damming problem, since it only happens in winter, and have been dealing with the roofing company but they aren’t much help.

    It happened again this year, but there’s no ice or snow on the roof and the windows were wet also. The humidifier was set at 30%, so I turned the humidifier down to 20%.

    • Dave says:

      Hi Karen,

      I need to ask you some more questions to see if we can figure this out. 1. How is your home heated? Natural gas furnace, boiler, etc? 2. Does the water show up in the same spots every year? 3. Does the water appear below windows only? 4. How much water is it – small puddles, large puddles? 5. Does the water show up only near outside walls? 6. How old is your home and do you know how well your attic is insulated? Did the roofers look in your attic? 7. Do your neighbours have snow on their roofs?

      I’m not sure what the problem is yet but answers to these questions should help.


      • Karen says:

        Thanks Dave.

        Since I posted this I had the roofer and an Insulation expert check out the problem and found out what caused water to puddle on the floor under the baseboard on an windowless outside wall in an upstairs bedroom.

        First, it was determined that the attic and roof were fine. No water, no leaks, dry as a bone.

        After inspecting the bedroom and the basement utility room below, turns out that the culprit was a) the house was too humid, and b) an exposed gas pipe in the basement utility room directly below the bedroom was allowing cold, moist air to travel up the wall and then condense upstairs, creating a puddle of water on the floor at the baseboard.

        The humidity was set at 30%, but it was too high because the windows were wet and runny. I’ve since turned it down to 25% and the windows are fine and I’ve not seen the water since. The insulation company is coming in a few days to blow some insulation around the gas pipe and joist headers to make sure that the area is sealed up.

        The other interesting thing about this situation was that it started after I upgraded the windows and doors in the house, as well as installing a new roof. The house was no longer as drafty, which created a condensation problem with that exposed pipe opening.

        So it has a happy ending with a comparatively inexpensive fix–$400 bucks vs thousands to tear apart a roof or re-insulate an attic!

        • Dave says:

          Hi Karen,

          So glad to hear you found a solution and it wasn’t too expensive. Would we be able to highlight your comment in an upcoming newsletter? I’m sure it would be helpful to other home owners out there.

          All the best,

  22. Cindy says:

    Hi Dave,
    We find it dry in my house, our hair, skin, we have colds, and sometimes get shocks!
    The heating company told me to crank up my humidistat on furnace to 50-60.. Watch for condensation on windown to know if I need to turn it down. Well, we have no condensation on windows and I still think its dry!.. Help!
    Ps.. Town house size ,
    Thanks:) Cindy

    • Dave says:

      Hi Cindy,

      I would suggest starting with getting a hygrometer to get a better measurement of the humidity in your home. You can pick them up at hardware stores and they are inexpensive but so helpful. If the hygrometer is showing low humidity then there may be a problem with your humidifier.


  23. Daniel says:

    Hi Dave,

    How long does it take to see a difference in the relative humidity once you’ve turned on the furnace humidifier? Throughout January 2015, relative humidity in my home was around 32% with the humidifier off. I’ve turned on the humidifier for about a week and set it to the middle of the comfort range and the relative humidity has only increased to 33%. I’ve inspected the humidifier and water does flow through when the heat is turned on. Would you consider this to be “normal” operation or something wrong? We have the furnace fan on 24/7 and our house is about 3000 square feet.


    • Dave says:

      Hi Daniel,

      Each home is different so I can’t really say. However I would suggest that you get a hygrometer to help you measure the humidity. Since it’s separate from your humidifier it should help you find the true humidity in each room of your home.


  24. Bern says:

    HI Dave,

    My parents accidentally left their house humidifier on high for about 2 weeks. My husband noticed the hardwood was damp, cupboards and doors had already formed ice (it is winter at the moment).
    He has already turned down the humidifier and put the heat up to try drying the house. What else do you recommend we do to prevent anymore damage to the house??


  25. Barb says:

    I have ice chunks in the corner of my windows as well as condensation on the bottom… We had a very cold night last night… Is because there is still too much moisture inside my house? I already turned my humidifer on my furnace down to 20 last night … I now turned it down to 12 ….is this right? I have a lot of wood in my home .. Don’t want it too dry … Tell me what more I should do!!!!!

    • Dave says:

      Hi Barb,

      Warm air is always looking for an exit and cold windows are very appealing. Ice is forming because the moist air is warm and the window is so cold. Are your windows old? Are there any drafts coming from the window?

      I would leave your humidifier setting where you normally have it because you actually need the moisture now more than ever unless you were seeing moisture gather on your windows before it got so cold. Your furnace is working really hard in this cold to keep you warm but when that happens it will dry out the air more because it’s on more.

      I hope this helps. Stay warm and let’s hope this frigid weather breaks soon.


      • March 3, 2015

        Hello Dave:

        It would be quite helpful if you would indicate the ACTUAL humidifier setting in your reply above rather than using the generic response “I would leave your humidifier setting where you normally have it, etc;”

        With the extreme cold causing some of my front windows to frost up (at the start the frost was melting each sunny afternoon causing the resultant water to puddle on the interior window ledge-good grief!) and, yes, there are significant draughts with these poorly installed & poorly insulated windows :-( In any event, I turned my humidifier down to 15% and the frosting up problem was resolved. I check the windows throughout my house on a daily basis to make sure everything stays OK whilst this extreme weather continues. At the appropriate time, ie: when the frost no longer occurs, I will increase the humidifier setting.

        By the way, my windows are 17 years old-do you consider these to be OLD and needing replacement? The draughts are quite significant, therefore, I was also wondering if perhaps using a good sealant around each would be sufficiently beneficial or, indeed, even the correct thing to do. If it is OK can you recommend a top notch brand of sealant to me please.

        Cordially, Ms Jan Donnithorne

  26. Darlene says:

    Hi with extremely cold temps we get a lot of moisture and ice buildup on our windows. Our furnace is set at 72 and currently we do not have our humidifier on. It seems that is counter productive…. Is this true? Or should we have it on and at what setting?

  27. Harsh says:

    Hi Dave. I have the humidifier on my furnace in 2500 sq feet new 2 years old home.i have HRV unit installed too. I have bought 2 different Hygrometer .one in basement and one in main floor ..I’m not able to maintain the humidity above 35-40%..some

    • Dave says:

      Hi Harsh,

      This has been a tricky winter for sure when it comes to maintaining the proper humidity levels in the home. It is a delicate balance between satisfying what is right for the occupants, interior finishes and furnishes, and what is right for the windows and other parts of the building envelope (ceilings, walls etc.). These issues are a result of the extreme cold temperatures that we have been experiencing since mid January. These temperatures are causing the interior surfaces of our walls, windows, and ceilings to be lower than normal which is causing condensation to occur more frequently.

      Window and Ceiling Condensation – typically we like to keep indoor relative humidity at about 45- 55% for premium comfort, but this is difficult to accomplish when the temperatures are so low outside so we may have to sacrifice a little and go to the low end of the scale and possibly slightly lower however it will still be difficult and almost impossible to eliminate the condensation on windows completely. There are some things we can do to minimize though –

      1. keep the air moving in the home
      2. have the furnace fan in the “on” position instead of “auto”
      3. ensure that heat supply vents are not blocked by drapes, furniture etc, especially the ones that are located below windows
      4. if ceiling fans are installed in bedrooms turn them on low, especially at night when sleeping. A lot of moisture is added to the room from our bodies and breathing


  28. Harsh says:

    …someone has advised to run the humidifier on full to maintain humidity and put the HRV running continuously for 1 hour everyday setting instead of running at regular interval,still not much change ..what’s the best humidity level which helps inside the house health wise and for wood.How can I attain humidity at 45-50%

  29. Ed says:

    Hi Dave,

    I have dry problems in the house in the winter. I have a Carrier Infinity controller than controls the furnace and the humidifier. Humidity level is set on the Infinity controller not to a specific %level but to a number of bars of humidity. The controller does indicate the actual % level in the house but one cannot set to a specific %level.

    I also have an HRV that has it’s own humidity setting that we adjust based on outside temperature.

    So, it’s possible at times that the humidifier is adding humidity and the HRV is removing it just due to the lack of the same setpoints. That’s a separate issue. Over the past 2 years we’ve tried to maintain the humidity level at 30% minimum but once it gets real cold (-20 C) we are not able to maintain that level without condensation on the windows. The HRV runs 24/7 on low speed for air exchange. The windows are brand new double pane vinyl casement windows.

    We are not sure if the low level of humidity at that temperature is caused by the amount of dry air that is being brought in by the HRV, caused by the humidifier not being able to replenish the lost moisture taken out by the HRV, a combination of small humidifier and too much air exchange or the fact that no matter what we try to do we are always gonna get condensation at -20 C at levels above 35% humidity in the house.

    Any thoughts or suggestions?

    • Dave says:

      Hi Ed,

      Thanks for your question.

      The unfortunate reality of living in Canada is that we will encounter some truly chilling weather extremes. We can do our best to mitigate the effects of these extremes on our home, but it can be a challenge and sometimes we may not be able to accomplish this 100%. That’s not to say that all is lost. From your note, it seems like you have some great equipment in your home to help you deal with these issues.
      Firstly, the ideal relative humidity range for a home and its occupants is in the 45-55% range. However during extreme cold (typically once it reaches -15) even the low end of that scale is hard to achieve without making our windows look like it has been raining inside. By trying to achieve 35% you are heading in the right direction for temperatures below -15.

      If your home is dry during the cold days of winter it is typically best to turn off the HRV as you will be removing what little moist air you have in the home and replacing it with even drier air. Ideally an HRV performs best during the “shoulder” months of the heating season when the average temperature outside are very close to the temperature set points within the home.

      An alternative to the HRV is the ERV. The difference between the units is that the ERV is able to perform some moisture recovery and/or moisture prevention. The ERV is designed to run for the majority of the year. During the summer months, it will transfer the moisture from the incoming humid air to the outgoing air minimizing the effects of adding humidity to a home that is likely be cooled by an air conditioner. In the winter time that process will reverse; the unit will recover some of the moisture from the outgoing air and transfer it to the incoming air minimizing the drying effect of that colder, drier air coming in.

      I will email you the owner’s manual for the Carrier Infinity controller as a reference. This controller comes with a great feature called window protection to help prevent moisture on windows during the heating season. Have a look at pages 6-11 for information on this feature as well as setting up comfort profiles when incorporating humidifiers and air exchange systems with your heating and cooling systems.

      In summary I would suggest at the very least, turning off your HRV during the majority of the winter when temperatures are below -5 and trying to find that “sweet spot” on the humidity control that will provide enough moisture in the air without sacrificing the surface and sills of the windows.

      I hope this helps!


      • Ed says:

        Hi Dave,

        Thanks for the manual but it is for the new carrier controller and I have and older version SYSTXCCUID01-A. From what I can tell, my controller does not have the capability to control the HRV which I would love for it to do. The new version obviously would do a better job but can’t justify the upgrade for just the winter cold spells or about 4 weeks max per year.

        Yes the ERV would have been a better purchase but when I got the HRV, 15 years ago, they were not recommending an ERV for our area. Don’t really want to upgrade until I have too. HRV works fine otherwise.

        A better humidity control would be ideal but there is not many that seem to work with the Venmar Constructo 1.5. Venmar does have a manual switch version that allows for intermittent use (33% of one time each hour). That might be better in that I would still get some fresh air in the house.

        thanks again,


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