DuctWork and High CeilingsDuctwork and High Ceilings - I did not see any reference to my question and would appreciate a response as soon as possible, as due to a medical situation, have to make a decision soon. We own an OLD house with 13′ ceilings in a large part of the home and 11″ ceilings in the LV/DR and BR. We are oscillating on where to place the ducts…Floor or ceiling. It appears to be counterproductive to me to put the ductwork in the ceiling since it will have so far to go.

We are looking for the most cost-effective, not upfront cost but operating cost, solution. In addition, we are considering DF heat pumps. The house will need 2 or 3 to be zoned correctly. Please let me know about the duct placement and thank you for your help?


Ductwork and High Ceilings | Answer

Thanks for visiting High Performance HVAC and asking a good question. There is not a good answer to your inquiry as the best to place ductwork is usually cost-prohibitive. Before I cover the ductwork issue, I want to address the subject of the high ceilings. It is best to reduce the height of ceilings that are too high if it doesn’t change or affect the overall look of your home. Lowering those ceilings will reduce the square footage you need to condition with your air conditioner or heating system whether it is a heat pump, gas furnace, boiler system, or electric heat. It will save you money in the long run by lowering those ceilings.

Ductwork is essential to your heat pump system, and the ductwork must have airtight integrity, so it delivers 100% of the conditioned air produced by the heat pump and delivers it into the space that needs conditioning. That is number one whether the ductwork supply diffusers come from the floor or the ceiling. The next most important thing about the ductwork is that it is insulated properly, especially around the boots. Without proper insulation, these boots can sweat in the summer and cause moisture damage.

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It is normally cost-prohibitive to do the ductwork for optimal performance because it will require double the ductwork. For cooling, you want the ductwork diffusers in the ceiling because cool air falls, and for heating, you want the ductwork diffusers in the floor because warm air rises. That is the most practical way of doing, but it is cost-prohibitive because it requires double the ductwork and additional controls between the heating mode and cooling mode.

What typically happens when ductwork is installed in a new home is the installer chooses the easiest and most practical way to install the ductwork. In a two-story home, the ductwork supply diffusers upstairs will be in the ceiling while downstairs, the ductwork supply diffusers will be on the floor where the home has installed in the crawl space. If the home is on a slab, then the ductwork is most likely in the ceiling downstairs also as the installer installed the ductwork before the final wall and ceiling finish was completed.

DuctWork and High Ceilings

In your case, I would determine what runs more…..the air conditioning or the heat. You can run your air conditioner 3 to 5 months of the year while the heat can run for six months of the year, so it would probably be best to install the ductwork in the floor instead of the ceiling. That is if you run the heat more than the air conditioner. Good luck and I hope everything works out for you.

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DuctWork and High Ceilings