High velocity air conditioning?

Michael_12

I'm buying a 1920's house with hot water radiator heat. I want to install central air. How do I know if I'd be better served by a high velocity system versus traditional forced air A/C?

Mark J Strawcutter

room for ductwork

If you've got room for properly designed and sized ductwork for a conventional system it will be less expensive. I've had both, and in my opinion the only reason for high-V is space for ductwork.

Mark

Bud_14

If you have the room for traditional ductwork…Go with an Air handler. 95% of the time there is room for a normal system. Find a contractor that will take the time to look at different options for getting supplies and returns to different areas of the home. This could take some time if it is not an attic job and if I see that it can be too involved (some have taken three hours) I do charge for this. Not all contractors are created equally! Some just don’t have the foresight to see other options. Many times the opportunity is there right in front of them and they miss it. And I have a small problem designing it for other contractors that don’t know what to look for… the customer then loses. Unless of course they are existing customers, we do want to keep themJ
Hi Velocity can be a bit tricky. The only advantage is that they can be stuck into little spaces. However, I’ve seen these installed wrong, from to long of runs to design problems, like aiming the high steam of air over the dinning room table or on top the bed…so design, design, design is important! You have to live with it for the next twenty plus years

Good luck with your project, hope all goes well

Bud

www.thesheetmetalshop.com

Dan M

I had a complete unico system installed last summer. My house is a 1910 two story that has hot water heat with radiators. The high velocity system was installed in about three days . The system cools my finished attic, second floor and first floor. The small vents hide well with most in the ceiling and some on the floors ( even have oak covers for my hardwood floors) The system cooled the house very well. If duct work can be installed with out alot of hassel it is usually cheaper to go with a traditional system. High velocity systems cost more than normal system but can be installed all most anywhere. moral of the story ....If I could have used a traditional sytem i would have but because I could not I used a high velocity system and I am very happy with it

Dan M

I had a complete unico system installed last summer. My house is a 1910 two story that has hot water heat with radiators. The high velocity system was installed in about three days . The system cools my finished attic, second floor and first floor. The small vents hide well with most in the ceiling and some on the floors ( even have oak covers for my hardwood floors) The system cooled the house very well. If duct work can be installed with out alot of hassel it is usually cheaper to go with a traditional system. High velocity systems cost more than normal system but can be installed all most anywhere. If installed inproperly The systems can be noisey. The pipes prefer long sweeps rather than sharp bends or tight corners ( Make sure your insaller has done theses before) Recklessly cramming the pipe in difficult spots can produce noise. moral of the story. ....If I could have used a traditional system I would have but because I could not I used a high velocity system and I am very happy with it and the installer

jerry scharf

High velocity vs standard

Michael,

I'm not a pro, but I have a passion for energy efficiency and have gotten hooked on the wall. My view is that you use an HV system if there isn't the space to run regular ducts (3 inches vs 8.) The standard systems are more efficient (should really say can be), cheaper and more contractors can deal with them.

There is some claims that because you have to seal the ducts on an HV system, it leaks less that a standard system. Just make sure your contractor seals and insulates your ducting well whichever way you go.

good luck,
jerry

Mike T., Swampeast MO

One consideration beyond price and "installability" is humidity removal. Hi-velocity units EXCEL at removing humidity.

Such though comes at a price--it somewhat reduces the efficiency of the condensing unit and for that reason they will suggest that the most efficient (and more expensive) condensing units be used in high-velocity systems.

I'm in an extremely warm humid summer climate. Around here A/C contractors recommend against using the highest efficiency condensing units in traditional ducted systems because they are not as effective at removing humidity.

Having felt a number of both, I tend to agree. With the same thermostat setting on a high-velocity system and an extremely high efficiency standard system you can feel downright "chilly" with the HI-V system and "muggy" with the traditional. Around here you can increase the setting of the HI-V system around 5° for the same level of comfort.

John Mills_3

For the price...

of the Unico or Space Pak air handler, you could get a variable speed air handler from any brand and couple it with a dehumidistat for super humidity control.

The HV air handler usually reduces capacity and drops SEER about 2 points. Take a 3 ton 12 SEER outdoor unit, you're ARI rating often is 30,000-32,000 BTU and 10 SEER. Put the same outdoor unit on a VS air handler, you'll get the full capacity and INCREASE your SEER as much as 1 point or more.