[Alfisti]

I have obviously googled this as best i can but thought i would run it by the folks here who seem to know a thing or two about housing and construction issues.

House is 3200 sq feet plus basement, windows installed near 16 years ago during a major rebuild/reno, we bought the house 11 years ago. Windows are wood from a high end manufacturer in Toronto (Marvin Windows), double hung. They are not great windows though, if it wasn't $60K to replace them I would.

Now, the problem is getting progressively worse on really cold days. So say below 0 celcius, as the furnace kicks in, condensation begins to appear on the sills, being double hung there are two sills per window so it is a 20 minute job to remove the condensation each morning. if i do not remove it, i get mold.

Right now it is minus 12 celcius, furnace is set to 70 and condensation was enough to partially soak a bath towel once i was done.

We do have a humidifier, I set it as low as i can possibly set it, any lower and it is so dry in here that we zap each other.

My suspicion, as a guy who knows little about these things, is a) the windows are not great and are contributing to the problem, but i suspect there is also jut not enough airflow in the house either.

Any thoughts here? It is really chronic and needs to be addressed. Thanks in advance.

[Frostynorth]

The humidity could still be a bit high. There are charts for what should be the range depending on outdoor temperature as it changes. If you're closing blinds for privacy, there needs to be enough room for airflow.

You could wrap the windows in that clear plastic to help keep the moisture off the glass and greatly keep heat in.

Leaving the furnace fan run constantly will help with airflow.

[BMWGUYinCO]

Originally Posted by Alfisti

We do have a humidifier, I set it as low as i can possibly set it, any lower and it is so dry in here that we zap each other.

We had the same problem when I installed an Aprilaire Model 800 Steam Humidifier (FYI this thing is fantastic). But no matter how low I set it, I had this condensation, even on brand new windows.

The trick for me was, I installed a relay device around the furnace (not the fan) power line, so that whenever the furnace kicks on (again, - not the fan), it closes the line loop and runs the humidifier. This bypasses the control unit for the humidifier altogether.
FYI my wife loves the cold, so at night the temp is set to 65, and during the day it changes to 68.

Hope this helps.

[Th3Walrus]

Hello fellow Southern Ontarian. It was really cold yesterday and last night. You either have the humidity too high still (although you said you get zaps), or the windows are shit.

I have my humidity set to 34% right now, and I need to lower it a little as I too am getting too much condensation and drips at the bottom of most windows.

[Alfisti]

Originally Posted by BMWGUYinCO

We had the same problem when I installed an Aprilaire Model 800 Steam Humidifier (FYI this thing is fantastic). But no matter how low I set it, I had this condensation, even on brand new windows.

The trick for me was, I installed a relay device around the furnace (not the fan) power line, so that whenever the furnace kicks on (again, - not the fan), it closes the line loop and runs the humidifier. This bypasses the control unit for the humidifier altogether.
FYI my wife loves the cold, so at night the temp is set to 65, and during the day it changes to 68.

Hope this helps.

Ok I had the Aprailaire 700 installed 3 years ago and the problem did increase substantially though it was always there. I just checked and it was at 18%, i can't go lower or we frizz each other.

TBH I don't understand your relay device and what it does exactly but will take onboard once i speak with a HVAC expert.

Wife HATES cold and refuses to set any lower than 70, should would have it at 75 if i let her.

[Th3Walrus]

I think what he's saying is, the humidifier now only runs when the thermostat calls for heat, instead of running until it hits a humidity setpoint.

[BMWGUYinCO]

Originally Posted by Alfisti

TBH I don't understand your relay device and what it does exactly but will take onboard once i speak with a HVAC expert.

Sorry, let me explain it this way. The Aprilaire is normally controlled by a humidity sensor that is installed and measures moisture in the HVAC vents. However, this is kind of flawed because the vents can trap moisture, therefore the sensor thinks there is humidity present and won't run the main unit...Like you, we tried to set it lower in order to reduce condensation but then it ran too little (because of aforementioned problem) and we started getting static electricity shocks like when touching a light switch or even when kissing each other LOL.

So, I installed a device that looks like a metal ring that sits around the "live" wire that runs the furnace. Whenever electricity comes on to power the furnace via that wire, that metal ring (the relay) senses it and then runs the humidifier. So, the humidifier only runs when the actual furnace is running - bypassing the humidity sensor that normally controls the unit.

Hope that made sense.

This:

Originally Posted by Th3Walrus

I think what he's saying is, the humidifier now only runs when the thermostat calls for heat, instead of running until it hits a humidity setpoint.

[Alfisti]

Walrus I had assumed that was already happening? Ok will need to clarify that.

What about running the fan 24/7? So keep the air moving?

EDIT: Just saw BMW's response. OK so then you get less condensation because the humidifier is only on when air is circulating?

[BMWGUYinCO]

Originally Posted by Alfisti

Walrus I had assumed that was already happening? Ok will need to clarify that.

What about running the fan 24/7? So keep the air moving?

EDIT: Just saw BMW's response. OK so then you get less condensation because the humidifier is only on when air is circulating?

Well to be specific, in fact we have a two stage HVAC fan, which is set to constantly run 24/7 (so normal operation is at the lower, stage 1). When either the air conditioner or furnace comes on, the fan increases in strength (to stage 2). This ensures air circulation and more even air temps on all 3 levels of the home year round. This setting was also suggested by our HVAC installer as they claim this lowers how often the unit has to run in either air conditioning or heating mode.

But the humidifier running is independent of the fan - that only runs when the furnace comes on, and pushes out the humidified air at the stage 2 fan. Clear as mud?

[Alfisti]

YeAH i AM WORKING SO NOT ABSORBING ALL THIS BUT i ....urrrrgh stupid caps. Anyways, yes it does make sense, i suspect i am not running the fan enough based on what you are saying, too much still air contributing.

I will get through this winter cos we don't have strangers in our house with the Rona, but i need this sorted before next winter.

[M_Six]

I have four of these scattered around the house.

https://www.amazon.com/gp/product/B08LKC4K15/

They're pretty accurate and consistent. Wifey has a huuuuge book collection and recently we found some light mold on some books, so now she's like a hawk looking for humidity. We have these on bookshelves and if we see one go above 50%, we roll in the dehumidifier and fire it up for a while. You might try one of these near your windows to see what the humidity level is right there.

Our bedroom has heavy blackout drapes, so we have to keep them open during the day to keep condensation from building up on the windows. We also have a whole house humidifier built into the furnace, but it's off now due to the aforementioned mold issue. Hasn't been uncomfortably dry this year anyway, so we don't really need it.

[mrjimyjohn]

From a building design perspective the change you must make is either:

A. Reduce absolute humidity of air at the window, or

B. Increase inner surface temperature of the window

Since you don’t want to lower the R.H. of your humidifier you can also achieve A by lowering the thermostat. This will reduce the absolute humidity for the same R.H.

B. can be achieved by either replacing windows with better performance or by locally heating the air at the window with something like a baseboard heater or film insulation as suggested above.

It sounds like you have a central furnace with forced air distribution. Do you have diffusers near these windows? If so you could play with the balancing dampers to provide more airflow here.

Cycling your fan on more often or constantly might help with A. by averaging your house R.H. more evenly, or it might make it worse depending on where your humidistat is and the unit’s control logic

[M_Six]

Originally Posted by mrjimyjohn

From a building design perspective the change you must make is either:

A. Reduce absolute humidity of air at the window, or

B. Increase inner surface temperature of the window

The small hygrometers I linked to will sit right on a window sill. Would be a good way to check the air temp right at the windows. If the dew point (not relative humidity) at the window is 50F (pretty dry) and the temp on the inside of the window is 40F, you're going to get condensation unless you have air flowing over the window. Just as when you take a cold can of beer out of the fridge and let it sit on the counter. Condensation will happen.

[o_g]

Do you have any window coverings? I find window coverings encourage condensation due to stagnant air. If you can open the window coverings a little bit to allow some circulation, then that will help.

[lakefront]

Originally Posted by BMWGUYinCO

Well to be specific, in fact we have a two stage HVAC fan, which is set to constantly run 24/7 (so normal operation is at the lower, stage 1). When either the air conditioner or furnace comes on, the fan increases in strength (to stage 2). This ensures air circulation and more even air temps on all 3 levels of the home year round. This setting was also suggested by our HVAC installer as they claim this lowers how often the unit has to run in either air conditioning or heating mode.

But the humidifier running is independent of the fan - that only runs when the furnace comes on, and pushes out the humidified air at the stage 2 fan. Clear as mud?

Sounds like you installed a current sensing relay on one of the fan wires. This insures the humidifier is only powered when the fan is running. Once the fan starts, the humidistat senses whether to open the water valve on the humidifier. As long as you have the relay on the "heating" speed, this should work fine. You don't want it running when the fan is on "circ" mode (what you are calling Stage 1). Only when the furnace is running.

[Alfisti]

OK I keep seeing you guys refer to a circ mode, to be clear, when the furnace is not engaged I do not hear anything running, no humidifier (does it make noise??) and no fan.

Also re the diffuser question above, the issue is primarily on the second floor which is considerably colder than the ground floor. Airflow to the second level is weak, both in summer and winter but especially summer.

[DETRoadster]

Your house is a system, not a collection of individual parts. You have BOTH a humidity problem and a window problem that presents itself when you have an outdoor air temp problem. The lack of insulation in and around the windows is allowing them to conduct the old form the outside to the inside and when you get below the dewpoint, given the humidity in the room, condensation forms.

We have aluminum framed windows in our house that love to conduct cold from the outside. In the winter we have to leave the shades open to get enough airflow in there to avoid condensation. We have one particularly troublesome window where we place an electric radiant heater under it when it get really cold out. Just to bump the temp up that extra little bot to ward off the condensation.

[DETRoadster]

Originally Posted by Alfisti

OK I keep seeing you guys refer to a circ mode, to be clear, when the furnace is not engaged I do not hear anything running, no humidifier (does it make noise??) and no fan.

Some furnaces have a "fan only" setting. Mine is actually a physical switch down on the furnace itself. Yours may not have this.

[BMWGUYinCO]

Originally Posted by lakefront

Sounds like you installed a current sensing relay on one of the fan wires. This insures the humidifier is only powered when the fan is running. Once the fan starts, the humidistat senses whether to open the water valve on the humidifier. As long as you have the relay on the "heating" speed, this should work fine. You don't want it running when the fan is on "circ" mode (what you are calling Stage 1). Only when the furnace is running.

Not quite. I installed a current sensing relay on the furnace live wire, not the fan live wire (those are two separate things).

This ensures the humidifier is only running when the furnace is on.

The fan operates 24/7/365 in stage 1 (low level speed), ensuring air circulation and more balanced temps across all 3 finished levels of our home.

When the furnace kicks on, then so does the humidifier and the fan then kicks into stage 2 (higher fan speed). When furnace shuts off, so does the humidifier, and the fan returns to stage 1 low level fan speed, but it is running continuously. So the fan, regardless of stage 1 or 2, runs independently of the humidifier.

[Alfisti]

OK I have a fan setting, so you guys leave it going 24/7? I assume that is the fan in the furnace not the aircon fan right? So if I set my thermostat to fan ON instead of AUTO the fan will run 24/7 and help circulation but won't it pump in cold air and force the furnace on more?

[BMWGUYinCO]

Originally Posted by Alfisti

OK I have a fan setting, so you guys leave it going 24/7? I assume that is the fan in the furnace not the aircon fan right? So if I set my thermostat to fan ON instead of AUTO the fan will run 24/7 and help circulation but won't it pump in cold air and force the furnace on more?

That is correct, because you probably also have a setting for either "Heat" or "AC" mode.

By your posts regarding current outside temps, I'm making a safe bet you are running in Heat mode, so that means that even if the fan is running 24/7 your AC will not kick on.

[Alfisti]

Yeah there is COLD or HEAT OR OFF then there is fan ON or AUTO or OFF. I default leave it is AUTO for fan and I flick it to HEAT in winter, COOL in summer.

So I have no circulation other than when the heater (furnace) kicks into gear. So from what you blokes are saying, I should set the fan to ON.

Will that circulate the internal air or pump from outside? Cos outside is fucking cold, minus 23 right now.