Should forced air Fan be ran with radiant heat?

tommygags

Hi all, first off thanks for all the continued help! Really appreciate it. 

Is it recommended to run the fan at all - if so, how often/long throughout the day? Ever since I installed radiant heat I've never turned on the fan. 

Other info:
I have radiant heat on my first floor and forced air on the second floor. The second floor heat is only on at nighttime and there is about a 6-8 degree difference in the floors. By the staircase you can feel almost like a faint cool air is blowing on you. I'm assuming that's because the hot air is rising and the cold air from upstairs is coming down.   Maybe I should run the upstairs fan?

Thanks!

ethicalpaul

I can't tell-- is the upstairs colder than you want it? What is the discomfort here you are trying to solve (if any)?

tommygags

ethicalpaul said:

I can't tell-- is the upstairs colder than you want it? What is the discomfort here you are trying to solve (if any)?

1) no discomfort, just seeing if it's recommend to use the fan with radiant heat

2) would running the fan upstairs or downstairs be beneficial

ethicalpaul

I'll look forward to seeing what the radiant experts say about this (I just have self-installed supplemental radiant), but my opinion is this:

1. All running the fan would do would be to additionally circulate air causing the upstairs to be colder by increasing circulation against cold surfaces like walls and especially windows. I guess it would also depend on where the "return" air is coming from. If it's ducted to return air from the upstairs and deliver it to the upstairs I can't think of any possible benefit other than to give the dust a fun ride. I don't think it would do much to change the circulation with the downstairs. And if it were ducted to take air from the downstairs and deliver it upstairs, that is going to "steal" additional heat from downstairs for no known benefit.

2. If there's no discomfort presently, what does "beneficial" mean? (this is a philosophical question admittedly)

TAG

Is there interconnected ductwork between the two floors?

I find there is a benefit in two of my situations. The ducted system balances things out. Mine are zoned --so that helps.

STEVEusaPA

I say no. Radiant on the first floor is heating objects, FHA on the second floor is heating the air. Assuming none of the duct work on the second floor is connected to the first floor, turning on the second floor fan is only going to circulate the air on the second floor, which will be cooler.
And if the ductwork, specifically the return ducts are properly sized, you'll actually de-pressurize the house and pull in colder outside air (or cold attic air) resulting in less comfort, feeling colder upstairs.

bburd

Aside from the minimal to zero benefit of running the fan, and the likely creation of cool drafts that may make the house feel uncomfortable, ducted fans use a surprisingly large amount of electricity.

tommygags

Thanks everyone! Just what I needed to hear.