Dry house from Baseboard heat

JDF

I have baseboard heat from a gas-fired furnace throughout my house. I just moved in about 2 months ago, and prior to closing, my home inspector checked out the system and gave it the thumbs up. However, for some reason, my house is very dry (approx. 24% humidity) I thought the water/steam going through the pipes to my baseboard heaters would create a more moist heat. Why isn't this happening and how can I fix this problem? I have central air conditioning - can I humidify the house through the duct work in this system? Thanks.

Mike T., Swampeast MO

Water systems are sealed, so there's no way for water in the system to make it to the air. When working properly, steam systems vent only air--not steam. The air they vent may be fairly humid, but it's not going to be enough to make any real difference.

Relative humidity naturally drops in a house when it's heated by any method. Cold air holds less water vapor, so when it's heated, the relative level of the humidty drops even though it still contains the same amount of vapor.

Your A/C system might be able to be used--probably with a steam humidifier. Steam humidifiers are reliable but expensive to operate. You might want to consider self-contained, free-standing humidifiers. They do require regular attention but are inexpensive to operate. Don't add too much humidity--if you do the warm, moist air escaping the heated shell of the house will begin to condense in cold spaces like wall cavities and attics. BAD NEWS when that happens!

Lots of charts are available on the web for recommended indoor humidity levels at various outdoor temps--as it gets colder, you want to reduce the indoor humidity level. (That's why many humidistats controlling the appliance are marked in outdoor temps--not relative humidity level.)

michael_15

The water is still in the pipes

If it's a hot water system, it's a closed system, so water doesn't leave. It's no better than forced air in that sense -- any increase in temperature results in a decrease in the relative humidity, regardless of the source of the temperature increase.

Forced air tends to feel drier, though in theory it wouldn't be. There are probably good reasons for this, such as speeding up the stack effect (hence bringing in colder drier air from outside) or increased airflow over your skin or something.

Steam heat doesn't really give out moist heat either (unless you take the air vent off or something silly like that); it's a closed system not designed to lose water. It's actually a little bit less dry (though I'd guess not noticeably so) since the air forced out of the vents is often at closer to 100% relative humidity for the original temperature. (100% relative humidity at 60 degrees and subsequently heated to 70 degrees is around 70% relative humidity.)

-Michael

Joe Brix

You might be able

to add a humidifer to the AC system and add a hydro-air hot watr coil to the air handler so the air moved around will be warmed and hold more of the humidifier's moister.
As said, are the ducts well insulated and there's the added cost of running th air handler blower.

A free standing humidifier would be a better solution. The humidity will want to mix throughout the house. The humifier will use less electric then running the blower and it will be accessable for maintenace. Aprilaire makes an in-wall unit that would mount inside a closet with a water line to pump moisture into the room for the whole house.

JDF

Thanks/ Aprilaire

Thanks for all of your responses. Looks like we need a humidifier. Joe, that Aprilaire you mentioned sounds interesting. How are they for quality/service, etc? Are there any other brands I should consider? Thanks.

jerry scharf_3

why it's dry

John,

People did a great job explaining why the heating system won't help the dry air.

The serious thing to look at is why the air is so dry. In a sealed house, the moisture would climb rather than fall, because we exhale moisture, cook, take showers... So this says that you are exchanging outside air for inside air at a high enough rate to drop your humidity quite low.

You could drop a humidifier in and pay the money to run it. Or you could seal up where the air is leaking and save money. I would do a general pass looking at the building envelope, then come up with a plan for how to seal it up. It should include a blower door test after the main stuff is done.

jerry

Joe Brix

Aprilaire

Is probably the best known. Checkout the www.aprilaire.com
site. The Model 350/360 is what you want.

JDF

Interesting

I don't doubt that my house is not perfect at keeping the heat in. I'm a complete layman with this stuff - how do I make my house more efficient? Where should I look first to places that might be leaking air? The windows in the house are all 2 year old Andersons, so I'm assuming those are OK. Thanks for your response, I think you're definitely on to the problem.

JDF

Thank you - nm

nm

jerry scharf_3

a couple thoughts

John,

About the windows, they could be perfect and the frame they were installed in might still leak like a seive.

If you want to get into this for yourself, I would start at www.buildingscience.com, lots of information about what works and what doesn't when it comes to insulation. given the house is all done there are fewer options, but still enough to make your head spin.

If you want someone else to lead the project, look around at local companies who do blower door testing, they should be able to plan out a cost effective strategy for your building. Even if you go this route, it's good to get enough understanding to be able to select the best contractor.

Often your local utility will help with this and possibly help with the costs. It's really a sub that they recommend, so you need to treat them like anyone else offering to work for you.

jerry

JDF

thanks

Thanks a lot - great insight. This is a great board here, I really appreciate the help!

BillW@honeywell

Another possibility...

Add a "reheat" like the poster above said, but just be cautious that it won't provide much warm air to the space, just enough to take the chill off. Consder a steam humidifier rather than an evaporative type. They are more expensive upfront, and require diligent maintenance, but will provide humidity control independent of a call for heat, and are more effective and accurate. Also look at sealing your house up as the other poster suggested. Windows, doors, housewrap etc...some are basic DIY projetcs, others require a pro. Check out our humidifier options at www.honeywell.com/yourhome.