which dries your throat more? hot air or baseboard?

ken_6

and why?

Unknown

Hot air

(gas fired or oil fired) drys the throat more than hot water heating. The heat exchanger gets very hot and as the return aair passes thru the heat exchanger the air is dried out. Hot air heat typically heats the leaving air to about 135 degrees. That air is blown thru the building. The warm dry forced circulating air pulls moisture out of the wood floors, furniture and the human body.

If you install good humidfier and add moisture into the building you feel more comffortable.

Base board convectors or radiators heat the surronding air a bit more than 80 degrees. The air air rises and circulates by covective currents. The circulation is very slow. Take a room about 10 by 10 and has an air change of 1.5 per hour 20 cubic feet a minute of air is in circulation. You do not feel the air move at all.

The same room with forced air circulation (minimum 1 CFM per sq.ft.)will haave an air movement of 100 cubic feet per minute.

The fast moving air will evaporate more water from the room than steam heat or water heating.

Jake

John Mills_3

Seems to me

that humidity level in the house would be similar between the 2. The reason for low humidity in the house is infiltration. Cold outside air, even at high relative humidity, leaks in and is heated up by whatever means. That air warms up to 70 or so and ends up with a very low relative humidity. You can see this if you can read a psychrometric chart. How dry the house is depends upon how tight it is. My house now is extremely tight and even with scorched air, needs no humidity. The family home was built in the teens and was very leaky. 2 console humidifiers barely made a dent in the low humidity. It was heated with a converted gravity system so the radiators weren't that hot.

One area where air might be a factor is in drying out the skin but there really isn't that much air moving. A ceiling fan will do much more in that respect.

Steamhead

Having lived with both

I'd say scorched air is definitely worse. The moving air dries your skin.

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Tom M.

surface area vs. surface temp

The key is the surface area. Your baseboard fins dont get very hot but there are thousands of them throughout the house. Hot air furnace heat exchangers don't have much surface area and therefore must have a hotter surface temperature which will dry out the air. This is a selling point for air handlers with hydro-air coils. They don't dry the air out as much.

Firedragon_4

I totally agree with you John,

and I live in an oil-fired hydronic home that uses c/i radiators, copper fin-tube baseboard and unit heaters in the 5 zones and like it very much.
BUT, I would not stay in this house without my humidifiers, FACT!

I have two, really need a third and it makes for a lot more comfortable home, a wetter throat and nose and oh yeah, I was also sick of the static shocks.

I've had the house for 32 years and the humididfiers for only 15 and would not go back to just the heat!

In my seminars I teach 'total comfort' and you can't do that for most without humidifiers and in some cases IAQ equipment too! Working on a new seminar about IAQ now for installers, we're missing the boat in a lot of cases.

John Mills_3

IF

baseboard fins & heat exchangers DRY the air, where is the condensate going to?

Mark Hunt

John is right


moisture is removed from a home by convective heat loss or Stack effect.

Warm air picks up the moisture and will rise and leave the structure at the top. The cold/dry air enters the structure at the bottom and the process repeats itself.

The greater the stack effect, the greater the effect on humidity.

Mark H

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ken_6

bottom line?

would radiant vs baseboard be different?

would sealed combustion vs natural draft be different?

would basboard with reset be different than 180 all the time

would hydro air at different water temps (reset) be different?


thanks

John Mills_3

I just don't see

how the type of heating greatly affects humidity. Less infiltration, higher humidity. That's in black & white on the psychrometric chart. How you heat that air doesn't matter. What temp it ends up at does. A heating system doesn't dry the air - if it did it would need a condensate drain like an evaporator coil. The amount of moisture in the air is the same, just the relative humidity is drastically lower as the air is warmed up.

Getting out the psychrometric chart, if it is 35F out and 80% humidity and that air infiltrates and is warmed to 70F, the RH is now about 22%. The chart doesn't care how it is heated, just that it is.

In Ken's question, the only thing I see as having an effect on the homes RH is the 2nd item. Fuel appliances consume great amounts of air to assist in the combustion process and provide dilution air for proper exhausting of the fumes. If my old memory serves me right, between combustion & dilution air, it takes nearly 30 cu ft of air to burn 1 cu ft of natural gas. Run a 100,000 BTU appliance an hour with inside combustion, that is A LOT of air. Using a draft induced appliance greatly reduces that. Using a sealed combustion appliance eliminates that.

Mark Hunt

radiant vs. baseboard


Radiant heat produces almost no convective air movement. I say almost because there will be some convection created with joist heating. When plumbers, electricians and cable guys drill through the wall cavities to bring stuff into the basement they make chimneys.

ALL homes will have convective heat loss regardless of how they are heated. A radiant system will not contribute as much loss as a completely convective system, but there will be convection in the home. Every home has a refigerator and a stove and they make convection. People make convection. When you run a clothes dryer you depressurize the house as you would when running any exhaust fan. Recessed lighting is another good source of convection.

Sealed combustion units will also help reduce the amount of depressurization and that will lower the stack effect.

Running a reset system would not necessarily lower the stack effect because you are still trying to maintain a certain air temp. The higher the air temp, the greater the convective loss. This is also why radiant systems should cost less to operate. You should be able to run the system at lower air temps than a convective system.

A good way to solve dry air in your home during the colder months is to have a blower door test performed to quantify and locate the areas of leakage in the home and then seal it up. IMPORTANT to remember that once this is done you may need a mechanical ventilation system otherwise you will have the opposite problem not to mention the mold issues!!!!

A qualified shell specialist should own a blower door kit and monitor the percentage of leak reduction as they go.

Hope this helps!!

Mark H

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