Hot Water Heating System Versus Hot Air System.

[Hudson]

I'm in a technical highschool learning plumbing and heating.

Missed a day of school and he gave me a project on the title above. Problem is he never taught me anything about a hot air system so I'm clueless on how it works and what have you. Hot water makes perfect sense. Tried googling but it sounds super inconclusive and sounds like someone just made it all up in about 10 seconds.

I have to compare and contrast the difference between the two assuming all things are constants (size of house, type of fuel, etc etc) with the only difference being the heating system.

Could someone please fill me in and educate me on the pros and cons of a hot air system?

Thanks a million!

 

[havasu]

Are you referring to a forced air heating unit?

 

[Hudson]

Are you referring to a forced air heating unit?

I would assume so.

Here's his exact wording, "compare and contrast the differences between a hot h20 heating system and a hot air system".

 

[havasu]

That's what is also sounds like to me. You should be able to research forced air units to provide him an adequate answer.

 

[stevemachine]

Cheaper install or initial cost
Air movement throughout home

Cons
You have to heat all the air in the room before you feel warm
Air becomes very dry

 

[stevemachine]

Hot water heating

Pros
Zoning out your heating system (multiple t stats)
Radiant in floor heats objects instead of air Objects will not rob heat off your body as with forced air objects are not heated only the air is heated

Cons
Expensive install and alot more labour

Those are just some general ones of the top of my head

 

[stevemachine]

Another con for hot water heating is you will need some sort of air movement with that system (at least in commercial applications, recommended for residential) Your air can become stagnant because there are no fans moving it like in a forced air system

 

[Hudson]

Thank you!

So on a forced hot air system the furnace heats air, and sends it throughout ducts to the entire house (only 1 T-stat) and blows air throughout the room via ducts?

 

[stevemachine]

Correct. It's heated via convection currents in the room, but pushed through duct work from the blower motor

 

[LiQuId]

with forced air the heat ends up at celing level first ( where yioure not hanging out ) then works its way down to where the T stat is. Humans generally are most comfortablle at 72' but with forced air you have a more difficult time achieving perfect heat as the heating curve of FA does not Match the heating Curve of the human body, with H20 it is almost identical.

Forced air uses convection as mentioned.
Hot water uses Radiant heat.

When you have air changes 4 complete air changes every 24 hours if memory serves ( Code ) FA loses much of the heat caus e the air gets dispelled. in H20 systems radiant heat ( heating object and not the air between ) does not lose its energy when air changes occur. it also brings the heat down to a level where you feel it more ( our bodys heating curve is close to water heating curve because we are mostly water, not air This is why commercial Car washes and such use Radient heat systems, otherwise they would lose all their heat when someone opens the bay door.

FA cheaper
h20 more expensive

And the above mentioned things. you are on a good site to learn much, stay on here and let us know how you do..

Interesting note. there is something called the "cold 70's " this occurs when you are near a cold surface ( imagine drinking a coffee ner a large window on a winter day ) the chill you experience is because you are losing heat to the windowpane. remember these 2 things

1. there Is NO SUCH THING AS COLD, only an absence of heat.
2. heat must move towards or occupy a colder space.

and just for complete randomness of info. The human body releases 400 btus of heat ( 1, 680 joules ) at rest every hour.