Running air handler in winter

262markm

good evening

I have a hydronic hot water boiler as primary heat for my home. For central air I have a 2 ton system with the air handler in the attic. The attic is not conditioned I have 8 6” insulated ducts around the home which is a single story ranch

The central was added a few years ago

my question is

Would it be better to run the fan on the air handler constantly through out the winter or close all of the ducts and don’t run it at all

I had tried briefly and had a lot of condensation in the ducts. I didn’t run it long enough to dissipate any of it to see if it would clear

just looking for what is the best practice

Located WI

thank you

EdTheHeaterMan

Blowing cold air in the air conditioning ducts in the winter will cause your heating system to burn more fuel. think about it this way. if the attic is cold and you use the ductwork and the air handler as a heat exchanger to move heated air from your home into the cold attic so the heat can be exchanged in the attic and cooled down to put colder air back in the rooms, then the heater will need to operate more to replace that heat the was transferred to the attic.

Remember Insulation does not stop the flow of heat transfer, it just slows it down. Your attic duct may have only 1" or 1.5" of insulation wrapped around those ducts. The floor of the attic has 6" to 8" of insulation in the ceiling of the top floor. 6" insulation beats 1.5" any day! The air handler may have only 3/4" to 1" of insulation inside that metal outer cover. 6" beats 1" every day.

Do Not run the fan in the winter.

Kaos

You can reduce seating of the ducts by air sealing. The less air from your house escapes through the ducting, the less moisture will make it up there. Find sombody with a duct blaster and get the ducting sealed up. Besides the energy improvement, well sealed ducts also means you are not pumping attic air into the house in the summer when cooling.