NF - Cant get this humidity thing right

[atvaholic]

Hoping someone has been through this problem before. Seems there is alot of good "non-fishing" info on here..

 

We have had a number of problems with humidity in our home, to the extent that in the winter, our windows are constantly dripping water. Running multiple dehumidifiers helps, but there is still moisture, causing mould on the windows. Humidity in the house was about 57-58%.

Our doctor was concerned about the air quality in our house, and suggested we do something about it as the kids allergies were really acting up.

 

After discussing with many people, we decided to get an HRV installed. About $1800 later we were in business. The problem is, the way they set up the HRV, it runs 24/7, including the furnace fans. This dried up the windows good, but now the house feels way too dry! (RH was measured @50%). We turned off the HRV and called the installer. They suggested we get a hygrometer that works with the HRV to keep the humidity at the preffered level. Another $100 and it was done.

 

So I set the humidity around 55%, and it seems to keep it stable. However then when we had a cold night I noticed the windows full of water again. So I turned it down to 52%. Seems to be drying the windows again. Then last night my wife wakes up in the middle of the night with a nosebleed...I turn up a little but the house still feels dry.

 

I did some reading and its suggested to keep your house between 35 - 50%. If we keep the house any lower we will shrivel up! Anyone have ideas...im out of them..

[danc]

You're on the right track. Your house humidity will have to be adjusted accordingly with the outdoor temps to maintain a healthy living environment and also to a level that is benificial to your house. There's no magic numbers here. Keep playing with it until you find the best settings for both.

[Roy]

I'm no HVAC guy but I suspect your house is sealed tight and with no proper air circulation, you'll always have condensation in the windows.

[atvaholic]

I'm no HVAC guy but I suspect your house is sealed tight and with no proper air circulation, you'll always have condensation in the windows.

Hey Roy, yes it is sealed tight. The HRV is designed to exchange the outside/inside air.....thought it would fix this problem..

[Rod Caster]

It sounds like your trapping moisture inside the house. It's always a fine line between holding heat and controling moisture.

 

Are your evacuating fans properly suited to your habits? Ie: is the kitchen fan on and effective when you boil water? Does your bathroom fan actually evacuate after a shower? Are these fans actually removing the air or are they weak or simply displacing the moist air?

My kitchen fan is LOUD, so I don't use it when I'm cooking...this creates condensation inside my tightly sealed condo. I will be replacing it soon with a quiet, RH sensitive fan. (around $400 for a good one).

 

Take a look at your evacuating fans. A lot of moisture/mold/condensation issues are the result of bad ventilation.

 

Keeping your house at a constant temperature will also reduce the creation of condensation.... do you turn your heat off during the day, back on in the evenings?

[danc]

You shouldn't need, or use evacuating fans if you have an hrv in your house. If you are, you are affecting the air balancing of your hrv, which is very important. To be most efficient, your hrv should be exhausting the same amount of air as it is bringing back into the house. Using any other means of exhaust will throw this balance way off.

 

Do you know if your hrv has been properly balanced atvaholic?

[atvaholic]

RodCaster: We do use the fans when showering, cooking, etc. They vent to the outside if thats what you are asking. We lower the temp 1 degree for sleeping, thats it.

 

Dan: Im not sure if it was balanced. I know they went through each vent in the house and checked/adjusted the airflow. Is this what you mean?

Edited March 8, 2012 by atvaholic

[danc]

RodCaster: We do use the fans when showering, cooking, etc. They vent to the outside if thats what you are asking. We lower the temp 1 degree for sleeping, thats it.

 

Dan: Im not sure if it was balanced. I know they went through each vent in the house and checked/adjusted the airflow. Is this what you mean?

 

Most important is that the cold air end of your HRV has been balanced. That is the exhaust to outside and the fresh air in from outside. Your existing exhaust fans should have been decomissioned after your HRV was installed. Using traditional exhaust fans in a house that has an HRV kinda defeats the purpose and throws the efficiency of your fancy and expensive HRV out of whack. Your HRV replaced your outdated exhaust fans.

[Rod Caster]

Most important is that the cold air end of your HRV has been balanced. That is the exhaust to outside and the fresh air in from outside. Your existing exhaust fans should have been decomissioned after your HRV was installed. Using traditional exhaust fans in a house that has an HRV kinda defeats the purpose and throws the efficiency of your fancy and expensive HRV out of whack. Your HRV replaced your outdated exhaust fans.

 

Yep, I had "condo" in mind, not a house with an HRV.

 

Maybe the HRV vents are not properly located, making the moisture-control system less efficient.

If the HRV installer tied into your old ventilation system ... then maybe the original ventilation system should be looked at. I'm thinking you may need more breathers for your HRV so it's more consistent throughout the house. If the vents are concentrated at certain locations, you would get "hot spots", some super-dry and others not.

Edited March 8, 2012 by Rod Caster