Does hydronic heat feel warmer than forced air?

kensheets2

Hello
I have finally got my hydronic system operational using old cast iron rads on a second property.
Question is, does hydronic heat feel warmer than forced air?  The thermostat was at 65 and it felt warmer than my house with forced air at 70.  Am I imagining this or is hot water heating naturally warmer.
Both are 1920 era un insulated homes.

Thanks
Ken

Big Ed_4

Yes, radiators with deliver more comfort . Radiant heat is the better heat which heat the objects in the room. Those cast iron radiators produced 40% radiant heat .. Warm air or scorched air dries out the air though infiltration or heat loss ... Comfort is the balance between temperature and humidity .. A good humidifier will help ..

Canucker

It could be a couple of things that I can think of. If a duct system isn't sized or balanced properly, it can depressurize rooms, which could cause more infiltration of outdoor air. Secondly, there is a radiant output to those big old cast iron rads that is probably making you feel warmer, even though the air temp is still 65. The last thing I can think of is the room itself. You can get the air temp to 65 fairly quickly but all the objects and the structure itself would still be below that temp for awhile until it balanced out. You would feel a little colder in the house while that evening out was happening because you'd be losing some body heat to those objects/rooms too

Jamie Hall

The short answer is yes -- and it's because, as @Big Ed_4 said, of the radiation from the radiators. It's very like a sunny day outside -- if you stand in the sun with no breeze, even a rather chilly day by the thermometer can seem nice and warm. Same day, move into the shade, and you're cooler.

Ironman

There’s a recent article posted on here by Dan Holohan titled “Your Body is a Radiator” that explains this very well.

As mentioned, radiant heats objects, not the air, they in turn heat the air. This is the proper way to do it. Forced error does just the opposite: it heats the air which in turn then attempts to heat the objects - including your body.

kensheets2

Very good, glad it wasn't my imagination,  I thought the old school CI Rad system would work better than forced air on an old un insulated block/stucco home in Central PA.
Thanks for the input 👍

Ironman

You definitely don't wanna use forced air on that. You'll feel like it's 65* when the air is actually 75* because your body will be heating the walls instead of the walls heating you.

EBEBRATT-Ed

They call it "cold 70" the air may be 70 degrees with with uninsulated walls the walls are like an ice cube. Hot water or steam does a better job of heating the walls.....better comfort

EdTheHeaterMan

kensheets2 said:

Does hydronic heat feel warmer than forced air?

Not really, It only feels that way!

I think there is a scientific term for it but I can't think of it. It has to do with infrared radiation. But you don't need SPF 50 lotion.

Just know that you may be going crazy but it has nothing to do with the temperature.

I'm sure this was no help, but it was interesting.

kensheets2

Ed the heater man, I already know I'm crazy, just wasn't sure about hydronic heating, haha!

jimna01

You will never take my hydronic heat out of cold dead hands. Yes it feels warmer. I love the slow radiation from the walls.

MaxMercy

I've lived in many homes, and my current home has a hydro-air setup. Not only is it comfortable, but it responds much **faster to the set back thermostat than any baseboard system I've lived in. I've never had a hot air furnace though, and my understanding is that the required air flow is much higher than the hydro-air needs. I image the high air flow could make it feel drafty.

**I remember the time we were without power for three days during the winter. Fortunately, the outside temp was in the high 30s and our inside temp was mid-high 40s when the power came back. 10 minutes after the lights came on, we were getting hot air out of all zones. The house was in the 60s in about 30 minutes.

Tim_D

This all has to do with Mean Radiant Temperature. A typical room has controlled and uncontrolled surfaces. MRT is roughly the area weighted average. A forced air system has very little controlled surface area vs the comparatively large area of a cast iron radiation system. A forced air system is almost entirely convective heating whereas a cast iron hydronic system provides both convective and radiant heating. If we take a typical corner room over an unheated basement and with an unheated attic above the MRT could be in the 50's on a cold day. All of those cold surfaces draw our btu's away. Hot must go to cold. The convection provided by a warm air system can not easily overcome this radiant exchange. Insert a few square feet of 180 degree cast iron and the MRT will increase significantly and the room will feel more comfortable, often at a lower temperature setpoint.