Application Possibilities for JUCAs

There are a LOT of possibilities about how to use a JUCA to distribute heat in your house. We will use the popular Model B-3B as an example, but all JUCAs (except the Fireplace Inserts) can use similar ideas. First, let's look at a front and side view of the free-standing B-3B.


Not Using Ducts

The simplest installation would not involve using any ducting. The 8 by 16 outlet at the top of the back of the unit is blocked off with a Main Distribution Duct End Cap. The warm air is ejected out both sides of the unit, through individually adjustable outlets. Since the warm air is thrown downward and outward at good velocity, the warm air is able to travel across quite large rooms. If a house has reasonably open construction, it may even be possible to heat the entire house in this way.

Applications - Just in room

This type of application can use the STANDARD, MEDIUM or MID blower. Obviously, the Standard is the least expensive, and, unless one or more of the following are true, it makes sense to use it. It is NOT a wimpy standard blower! Actually, its 465 cfm airflow rating is nearly EIGHT TIMES the airflow of many competing products' 60 cfm blowers!

If you expect to some day feed warm air into house ducting, it might make sense to get the Medium or Mid now, even though you won't currently use the ducting capability of the JUCA unit.

Another possible reason for using the Medium or the Mid blower in an unducted application is if it is installed in a room that is longer than 30 or 40 feet. The Standard blower should still get decent heat to the far corners of such a room, but those corners might be a couple degrees cooler than the room nearer the JUCA. The stronger blower should make it so all parts of the room are the same temperature.

Finally, a third reason could possibly apply for using the Medium or the Mid for an unducted application. The Standard blower rotates at about 1500 rpm to move its 465 cfm of air. If, instead, a Medium blower was used with a Variable Speed Control which was set so it moved about 465 cfm of air, that larger blower would only need to rotate at about 700 rpm. The significance of this is that it is considerably quieter. We don't think the standard blower is horribly noisy, but it does make some sound. This arrangement makes quite a bit less. If you insist on even less sound, see the REMOTE option mentioned below.

Using Ducts

More commonly, though, it is necessary to send at least some of the heat through warm air ducts to be able to heat distant parts of the house. If the JUCA is near a conventional warm air furnace, it may be possible to feed the JUCAs warm air into the existing duct system of that furnace. There are actually a variety of ways to join such a system, depending on a number of variables. For all the possibilities suggested from here on, you should probably look at our Ducting page, and get guidance from a local heating contractor or building inspector.

Applications - And into ducts

Nearly every way of doing this involves using one of the optional blowers. As to which of the optional blowers to choose, we suggest that you do the Questionnaire that does an approximate heat loss analysis of your home to then recommend the best choice of optional blower.

If you are intending to use the air moving capability of the blower in an existing conventional furnace, you STILL need to use a blower on the JUCA, but in this one specific case, it MAY be possible to use the Standard blower for a ducted application. That pretty much depends on how far apart the two furnaces are.

If the JUCA is installed in a basement location, it is often desirable to elbow the duct upward, to be able to join an existing ducting system (or to feed its own ducts) that are up near the ceiling.

Applications - Overhead ducts

The Questionnaire's guidance on blower choice will probably be fine.

Another common situation is where the JUCA is installed UPSTAIRS, but the existing ducting system is DOWNSTAIRS. In this case, the JUCAs warm air duct could be elbowed downward, so the duct passes down through the floor and then is able to join the existing duct system (again considering the safety concerns described in our Ducting page). Since warm air naturally wants to rise, it is important that one of the optional larger, stronger blowers is used for such an application. This sort of installation could not be accomplished with virtually any competing product.

Applications - Ducts under floor

Since warm air wants to naturally rise, and you're going to force it downward, if there is a possibility of two different blowers, it is probably best to opt for the larger one of the two. Do the Questionnaire mentioned above for guidance.

If the REMOTE option is chosen, the blower may be mounted in a remote location. There are a couple of good reasons for considering this. If the warm air duct goes downward through the floor, it would have to pass behind the blower, as shown above. Since the optional blowers extend 13 or 15 or more inches out the back of the JUCA, adding the 8 inch thickness of the warm air duct could make the unit sit a good distance out from the wall. Having the duct there instead of the blower can reduce this distance several inches.

Applications - Remote blower

Another reason for having the blower REMOTEly located is related to sound. Our optional blowers are conventionally used as the blowers in gas and oil furnaces. They're not HORRIBLY noisy, but moving that much air is bound to make a certain amount of noise. By having the blower located REMOTEly, say downstairs (inside of an air box), the environment around the JUCA itself can be virtually absolutely silent.

If the blower to JUCA distance is over about 15 feet, you might consider going up one size in blower choice, over what is recommended in the Questionnaire program.

Another common situation is where it is expected that the downward and outward flow of the JUCAs warm air will heat MOST of the house, but there is a distant bedroom or bathroom that will certainly need some extra heat. In this case, it may not be necessary to have a full-blown duct system installed. It may be possible to run just one or two small (round) (inexpensive) ducts to those rooms.

Applications - And one small duct

Usually the Medium or Mid blower is most appropriate for such situations. The Standard blower is not strong enough to push much air through the duct, so don't choose that.

In any case, the JUCA is the same for these various possibilities (except for the REMOTE option). Sometimes, people block off the duct connection for the first winter, and see just how much of the house the JUCA could heat without using any ducts. If the house is heated fully and evenly enough to please the occupants no further work would be called for. If, instead, some parts of the house weren't getting the heat needed there, a limited or full duct system could be installed at that later date. A LOT of flexibility!

Applications - Always into room

In ALL cases, please note that warm air can come out the JUCAs side outlets, whether or not air is also fed into a duct system.

Once the JUCA has sent its warm air out the large trunk line duct, there are a bunch of additional possibilities available:
  • The warm air may be able to go into the WARM air ducts of the house.

  • The warm air may be able to go into the COLD air return of the house.

  • The warm air could go into a SEPARATE air duct system.

  • A single small warm air duct may be able carry heat to one distant room or bathroom, as described above.

  • The warm air could dump into a ADJACENT rooms. A conventional furnace with a duct system could pick it up from that room by a cold air return for that furnace.

  • The warm air could just be dumped into a basement area, knowing that the heat will rise, warming the floor of the rooms above.

  • The warm air could be directed into a solar heat storage system, for use later.

The links above are all part of our DUCTING Page. You may want to read all of it because it a LOT of useful ideas in it.

The JUCA Home Page is at:

E-mail to: