Woodburning Furnace

High-Efficiency Fireplace - JUCA Super-Fireplaces

Click to Enlarge Pix of a JUCA F-9A with Brass Doors and Mantel
Wood and Gas Burning Fireplaces
JUCA has produced high quality, high-efficiency, clean-burning wood- and gas-burning fireplaces for over 35 years. Over 100,000 Americans live in homes being entirely heated with JUCA products. People LOVE them!

JUCA Fireplaces can feed warm air into house warm air ducts to supply heat to the entire house. The popular Model F-9A (shown here) is rated at 140,000 Btu/hr output (about like a normal gas house furnace.) An F-9A can heat the WHOLE HOUSE and looks EXACTLY like a normal fireplace! A strong 465-cfm blower is included as standard, with several options up to 2,550-cfm (3/4 HP) for VERY large houses. Beautiful Brass Doors are included! And the F-9A is only about $1,900!

The JUCA F-9A Built-In Fireplace Furnace can have any of over 4,000 different appearances! (Including Arch-Tops!) No matter what decor you're going for, a JUCA F-9A with appropriate door choice will enhance it!

A JUCA F-9A can use wood OR gas (OR both!) to entirely heat your home. JUCA makes a wide variety of wood- and gas-burning models, including:

Click to Enlarge Pix of a JUCA F-9A

JUCA Super-Fireplace - Operation to find out:
How Does A JUCA Work???
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(Arch-Top Fireplace shown here) All of these models are individually CUSTOM MADE so a customer can request special features or special-size dimensions, for a special application or situation. In addition, JUCA often makes exotic and unusual units to order, such as a 5-glass-sided unit (for a 5-sided room) and wedge-shaped units for hyper-modern motifs. JUCA's efficient operation keeps prices very reasonable

JUCA products all include extremely sophisticated high-efficiency heat- exchangers. A computer was extensively used in CAD to maximize performance. That's why JUCAs stand alone in entirely heating whole houses! Several are GUARANTEED to be able to entirely heat ANY home in the U.S. This is true whether burning wood OR gas! With wood, 8-12 hour burn times are normal, while burning cleanly! That's why JUCA was featured on the TODAY Show, in NEWSWEEK, in the New York Times, in Mother Earth News and elsewhere.

JUCA Super-Fireplace Info Sheet Index
Solar Heating??
FREE Air Conditioning??
JUCAs are entirely manufactured in the U.S.

By the way: It is not NECESSARY to get huge heat output from a JUCA. On mild days, you can use it to just "take the chill off."

Many owners have found that their house values increased more than the cost of the JUCA!

JUCA products are so advanced that sometimes it may not be obvious to a prospective customer just all the choices and options available for a particular house. JUCA has created hundreds of web-page presentations to help supply answers to questions and solutions to unique installation situations. Many background subject discussions on fireplaces, woodstoves, wood burning, etc., are included in its 2,900 screens. Of course, substantial information is also included on the many JUCA models, their various options, and a multitude of suggestions on how best to plan, install and enjoy a JUCA. All prices of all products are included, even all the hundreds of options available to you.

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.

The web-site includes pictures which help one know the distinction between mantels, lintels and hearths in a regular fireplace; discussions on modern house-air purity considerations; hundreds of suggestions on getting maximum performance and enjoyment from your fireplace/woodstove. An Inter-Active 'Questionnaire' asks some questions about the house and then does an approximate heat-loss analysis of the house. It then suggests the best JUCA and best blower for that specific house and even calculates the amount of wood to cut to heat it completely for a whole winter!

Hundreds of other presentations address specific subjects. There's a chart that describes the burning characteristics of about 35 species of wood. A sub-program helps select among over 4,000 different brass-door appearances available for the Model F-9A! A LOT of useful stuff!

For technical jocks, the web-site includes some really hairy stuff, such as the quintuple Integral Calculus equations used to design the JUCA heat exchangers for maximum performance. Theory, physics, chemistry, thermodynamics and aerodynamics discussions are included in the TECHNICAL section. (NORMAL people don't have to be subjected to this sort of abuse!)

For NON-Technical people, there are visual mini-movies, charts, graphs and such to present the JUCA concepts for most people.

JUCA Model F-9A, showing features The rotating JUCA Model F-9A at left shows some of its features.

On the front is the large opening of the huge firebox (brass doors removed for clarity). The (included) door assembly has a draft control for air for the fire.

On one side of the body is the (Standard) blower; on the opposite side is the 8" by 16" warm air outlet (to feed into ducts and/or to warm air registers in the room). An automatic blower control has a temperature probe in the warm air chamber there.

Notice the offset of the door assembly to the main body (we call it the "snout") that allows space for full thickness facebrick everywhere on the facing. Also note the heat baffle and air chambers below the firebox.

The entire firebox is surrounded by heat exchange chambers, to capture radiant heat from the fire inside. Not visible are the tubular heat exchangers bridging across inside above the fire, to capture convective heat from the smoke.

Clean-Burning Non-Airtight Operation

JUCA products are all designed to work on a NON-airtight principle of operation. This is a VERY important (and unique) characteristic of all JUCA products. ALL other (competing) woodstoves and efficient fireplaces operate on an air-suffocation (or air-tight) principle of operation. That approach NECESSARILY causes major changes in how the fire burns and how the fireplace/woodstove operates, from how it would have worked as a ":normal" fireplace. These effects require those products to have designs which have small fireboxes, small doors and small glass areas, limited heat exchange areas, and a sealed fire chamber. They also require SERIOUS design attention to the fact that suffocation designs tend to burn poorly, and therefore tend to create creosote and pollution.

JUCA uses a totally different approach. Our NON-air-tight design allows the woodstove/fireplace to operate very similarly to how a fireplace traditionally operated, VERY cleanly. (You could even roast marshmallows or make popcorn in it, which you cannot do with ANY competing product! Competing products cannot be operated with the door open because the design theory doesn't allow it.) Our computer-designed heat exchange structure up above captures most of the heat that would have been lost up the chimney, we have a huge firebox size, a very large glass viewing area, a large door for feeding wood, and a blower that is MUCH stronger than any competitor.

All these characteristics combine to capture the most heat possible from the fire's output, while not messing up the fire's original operation. That original operation always included very clean burning, which the JUCA's design maintains. JUCAs do NOT share the air-tight products' problems of huge creosote and pollution creation. JUCA's non-air-tight design allows capturing all that heat while burning so cleanly that no "catalytic combustor" or "secondary burn" is even necessary or desirable!

This difference between the JUCA's non-airtight design and ALL competing products (which are ALL airtight) has some other implications. Because those airtight products developed a bad reputation in the 1980s for creating a lot of pollution and creosote (because of the suffocation of the airtight operation), the EPA and other government agencies passed stringent laws applying to them. Commonly, the chimney must be re-lined ($$$).

A JUCA woodburner does not require all that, and the EPA and other agencies agree. The JUCA unit actually operates as a traditional old fireplace did with the only major difference being that the JUCA captures most of the heat that would have gone up the chimney. Building fires is the same as in a conventional fireplace, and the fire behaves as you expect a fireplace fire to behave. That is definitely NOT true of airtight woodstoves and fireplaces, which operate VERY differently!

Why are JUCAs different from all competing Woodburners?

The answer to that is pretty complex, and it's why we have hundreds of informational pages in our web-site. A capsule version:
Back in the 1970s, only Potbelly stoves, Franklin stoves and barrel stoves existed. They all produced huge amounts of heat, but TOO MUCH, and for only an hour or two. Great temperature variations in the room were common. So the problems were: too much heat and too short a burning period.

Two solutions arose. The Airtight design and the JUCA design.

  • The airtight approach was to severely restrict the amount of air available to the fire. With less air, less burning (which is actually chemical oxidation of the fuel) could occur, which means less excessive heat production, which is good. Since the wood did not get consumed as rapidly, it lasted longer, giving longer burn times, which is also good.

    With MODERATE restriction of the air supply, this represented a great improvement over previous woodburners. During the 1970s, people tended to use them in such an appropriate way.

    When energy awareness became dominant about 1980, people started to try to use such products in extreme ways. They SERIOUSLY restricted the air supply, to make them operate even more efficiently. That happened, but an unexpected consequence was extremely poor burning. Under some conditions, fully 1/3 of the energy in the wood was going up the chimney as creosote and pollution! Which also reduced intrinsic efficiency, but no one noticed.

    In the early 1980s, a lot of houses burned down, because massive unseen creosote accumulations in chimneys would catch fire and burn at over 5000°F, and no chimney could handle that. A lot of pollution was also getting put in the air.

  • The JUCA approach was very different. It involved a larger firebox, normal non-airtight burning, MUCH thicker pieces of wood, and a sophisticated heat capture system. In principle, the fire would be allowed to burn as rapidly as it wished, but the thick pieces of wood (logs) NATURALLY only burn at a moderate rate, because burning can only occur at the SURFACE of a piece of wood. (Thicker logs actually burn more slowly!)

    Thicker logs ALSO naturally burn more EVENLY (for reasonably constant heat output) and for a much longer time.

    The JUCA design accomplishes the goals of evenness of heating and long burn times, in a VERY different way than airtight designs do. In a far more natural way. The burning is extremely complete and efficient and clean. Virtually NO creosote or pollution is created in the fire, as fireplaces have operated for hundreds of years!

    The flaw in the logic so far is that thick logs burn so slowly that they create rather small amounts of heat. This is why the sophisticated heat capture and heat exchanger system in a JUCA is so important. It captures MOST of the heat actually produced, and sends it out into the room and does not allow it to go up the chimney.

    As a footnote, airtight products CAN NOT safely use extensive heat exchangers to improve their efficiency. Since they naturally produce so much creosote in their smoke, and creosote condenses out at about 350°F, they must NOT be extremely efficient. Otherwise, they would cause massive creosote accumulation in their chimney systems. Some products like that were briefly sold around 1980, but they proved to be very dangerous products for this reason. Since JUCAs are non-airtight, the fire burns very cleanly, so there's little very creosote in the smoke, so we can capture the daylights out of the heat in the smoke! An optimally efficient JUCA can have smoke temperatures of 250°F. We are thus able to capture more than an extra hundred degrees of heat from the smoke before it goes up the chimney! Voile! Very high efficiency!

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.

JUCA Varieties

Click to Enlarge Pix of a JUCA F-9A with Brass Doors and Mantel

JUCA Built-In Fireplace Models

Other companies' 'Zero-clearance' fireplaces all have unusual appearance, which give away the fact that they are not actually massive masonry fireplaces. Not so with the JUCA F-9A series. The JUCA facing appearance is exactly like a conventional fireplace with a set of brass doors on it. There are no ugly black metal panels with air holes around the door opening. (All the "performance parts" are hidden inside the wall). 'Brass' may be too specific a term here since JUCA offers Antique Brass, Polished Brass, Satin Brass, Black, Copper, Chrome, Pewter, Nickel, Swedish Metal, Enamel, and all manner of combinations of these. In recent years, Arch-Top appearances have become fairly common on the JUCA F-9A. Over-size dimensions (or dimensions to suit a specific space) and many custom options are commonly included as part of an F-9A. JUCA offers over 4,000 different "standard" appearances! If this incredible choice isn't enough, even gold-plated and platinum-plated optional facings have occasionally been requested and supplied!

All JUCAs use conventional large or small house ducting and normal warm air grille outlets to get the heat out into the room (and house). The air intakes and outlets DO NOT have to detract from the appearance of the fireplace They can be on other walls or even in other rooms!

No matter WHAT decor and "mood" you want to create, a JUCA F-9A can help achieve it.

Performance to heat the ENTIRE HOME combined with beautiful conventional fireplace appearance and operation. Wow!

About $1,900 up (plus shipping) Details, Options
For a better view of the JUCA F-9A

JUCA Built-In Fireplace Model Types

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Varieties

Click to Enlarge Pix of a JUCA F-9A

Built-In Traditional Fireplaces

Most people tend to select a conventional rectangular fireplace appearance on their JUCA Fireplace. The standard size of the F-9A is the so-called 36(w) by 28(h), the most popular size fireplace in the U.S., but JUCA has made units as wide as 78 inches! About 1300 different "standard" appearances are available in rectangular shape, to fit in with ANY room decor. This includes a variety of finishes, frame widths, and door appearances and opening modes.

All this at VERY REASONABLE prices and relatively quickly.

About $1,900 (plus shipping) Details, Options

For a better view of the JUCA F-9A
JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Built-In Fireplace Model Types

Click to Enlarge Pix of a JUCA F-9A

Arch-Top Built-In Fireplaces

Some artistic design applications involve room decors that need an arch-top fireplace to blend in properly. Both Flat-Arch and Full-Arch varieties are available on the JUCA F-9A (about 700 different Arch-Top appearances available.) The famous JUCA performance is still there, with the ability to heat the whole house, but perfectly hidden from view.

All this is at VERY REASONABLE prices and relatively quickly.

About $2,100 up (plus shipping) Details, Options

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
For a better view of this JUCA F-9A Arch-Top
JUCA Built-In Fireplace Model Types

Double-Sided Built-In Fireplaces

Some applications need a through-the-wall fireplace for aesthetics reasons. The JUCA F-9AX model handles these situations. Even for unusual situations when one side needs to be an Arch-Top fireplace and the other side needs to be conventional rectangular, the F-9AX is the unit to get. Competing double-sided fireplaces require identical appearance (usually with black metal areas) on both sides. The JUCA F-9AX could have Polished brass Traditional Bi-Fold doors on one side in a Great Room (for a regal feeling); and Black Clear-View Twin doors on the Family Room side (for a cozy feeling). And, as always with a JUCA, the unit has ability to heat the whole house!

All this at VERY REASONABLE prices and relatively quickly.

About $2,300 (plus shipping) Details, Options

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Built-In Fireplace Model Types

Custom-Sized Built-In Fireplaces

JUCAs 'standard' custom-built units include many thousands of possible combinations. They're all also available with customer-specified dimensions. Taller, wider, deeper, shallower, shorter, ... No Problem!

All this at VERY REASONABLE prices and relatively quickly.

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Built-In Fireplace Model Types

Unique Custom Built-In Fireplaces

Pix of an unusual Porthole Fireplace Pix of a Wedge-Shaped Fireplace
Need a circular-shaped or wedge-shaped door appearance? We build the firebox/heat-exchanger to customer- or builder-specified plans and include appropriate shaped doors (again in many possible finishes.)

Pix of a Scalloped Arch Fireplace Pix of a Gothic-Arch Fireplace
How about a Scalloped arch appearance? Or a Gothic-Arch Fireplace?

Pix of an Art-Deco Fireplace
Or an Art-Deco motif? Or a Bay Window feel? JUCA does it, still maintaining the whole-house heating capability!

All this at VERY REASONABLE prices and relatively quickly.

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Built-In Fireplace Model Types

Other Unique JUCAs for Specific Applications

JUCA loves to create unique custom-designed fireplaces, woodstoves, and wood burning furnaces for specific situations. Many very unusual appearing JUCAs now heat homes. In addition, JUCAs heat greenhouses, warehouses, factories, pig brooders, barns, garages, pole barns, etc., etc.

Considering what JUCA calls 'standard,' these are usually 'cake!'

All this at VERY REASONABLE prices and relatively quickly.

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
JUCA Varieties

Click to Enlarge Pix of a JUCA F-9A

JUCA Gas-Burning Units

All of the normal JUCA units are built very sturdy, in order to be able to burn wood safely. However, all can be combined with a normal gas-log set to make it a gas-burning unit, too! In this way, double benefit is gained. If the user feels industrious, the gas logs are removed and wood is burned; at other times, the gas logs are burned. In both cases, the romance of the fire is present, as well as the JUCA performance to heat the whole house! The changeover usually only takes a couple of minutes.

JUCA's gas-burning units can have manual control, wall control, remote control, or even wall-thermostat control. This last choice can allow the JUCA unit to act as the automatic central heating source for the house!

The gas-burning capability of a JUCA can be delayed until later. The unit can be used as wood-only for now, and then later gas can be used. As long as the unit is built with the gas-line stub pipe installed, the gas log-set could be installed years later, using wood now! Great flexibility!

The opposite approach can also be used. As long as gas is reasonably priced (AND AVAILABLE), why not burn gas in the fireplace, heating the entire home in the process? If something silly happens again in the Mid-East (and it will), where conventional fuel sources are interrupted, then take the two minutes to remove the log set and start burning wood. The best of both worlds! See any of the JUCA models listed above. All can be wood-, gas-, or both.

Roughly $1,900 (depending on model)

JUCA Built-In Fireplace Furnaces for more info on these models.
JUCA Super-Fireplace Info Sheet Index for an Index of Many More Subjects.
For a better view of the JUCA Gas-Burning F-9A
JUCA Varieties

E-mail: JUCA at JUCA e-mail


Totally Heating a Home with Solar Heat??

We have a sister company in Solar Heating that has just as much technology and expertise as we do! If you have interest in really high performance in a Solar Heating system, you might want to visit the NorthWarm Totally Solar Heated House - Version 1 web site. Most of the Solar systems are based on a patented system.

Even better, the Version 1 System includes a sub-system that is also a way of entirely Air Conditioning virtually any existing house in the United States nearly for FREE! In a spirit of hoping to assist California homeowners from enormous summer electric bills (and power outages), this sub-system is being made available, for FREE, at Free Home Air Conditioning We hope that, if enough California homeowners would install the simple system, maybe the power companies and the energy grid could keep up with the Summer high demand for electricity. Since we're giving this information away, you could probably help some of those California homeowners to tremendously reduce their summer electric bills and maybe help avert blackouts out there, so let any of your California friends know about that possibility available to them!

We are also involved with a variety of other projects that are meant to give benefit to society in one way or another. Some are social or intellectual presentations, meant to help find solutions to things in our lives. Others are products or services that also are meant to somehow improve our lives. If you have curiosity about this, you might want to visit a directory page we set up for these Public Services Home Page. If you are civic-minded or otherwise motivated, a number of those projects could benefit from the participation of additional people.

Energy-Related presentations in this Domain:

Becoming Self-Sufficient A thorough presentation
Physics of Global Warming. (June 2004, June 2008)
The Physics of Global Warming and Climate Change (June 2004, Feb. 2007)
Alternative GREEN Water Heater HeatGreen - A Simple and Non-Fossil-Fueled Water Heater, HG3a (biodecomposition) (March 2007)
Alternative GREEN Furnace with no Fire HeatGreen - A Simple, Non-Fossil-Fueled Home Heating Furnace, HG3a (biodecomposition) (March 2007)
Low-Tech Active Solar Heating Low-tech, low cost approach (April 2007)
Heat and Cool a House Naturally, without a Furnace or Air Conditioner (1977, Nov. 2000)
World Energy Supplies Coal, Oil, Natural Gas, Uranium supplies and consumption (May 2010 Report)
Black Asphalt Pavement and Sunlight Environmental Effects of Asphalt Pavements, Roofs, and Parking Lots (August 2007)
Perfect Energy Source From the Earth's Spinning (1990, Nov. 2002)
Perfect Energy Source From the Earth's Spinning (1990, Dec. 2009)
The Physics of Tornadoes The Physics of Tornadoes, including How they Form. A potential energy source (Feb. 2000, May 2009)
Survival Ark, Sixty-Acre Floating Communities for Survival For Sealevel Rising (July 2008)
Climate Effects of Electric Power Plants
Global Warming Effects of Carbon Dioxide
Hydrogen. Hydrogen as a Fuel for Automobiles and Other Vehicles (August 2003)
Solar Heated House NorthWarm Totally 100% Solar Heated House - Version 1 (1979)
Solar Cells Photovoltaic Cells, PV, Electricity from Sunlight (Jan 2002)
High-Speed Transportation 200 mile per hour TRANS Super-Efficient Transportation System (invented in 1989)
Electric Cars, Hybrid Cars Battery-Powered, Hybrid Cars and Hydrogen-Powered Vehicles (April 2006)
Windmills Practical Wind-Generated Electricity (Residential, some Watts) (1975 and April 1998)
Tower Windmills and Electricity Practical Large-Scale Wind-Generated Electricity, 1200 KiloWatts (Community, a thousand homes) (a million construction jobs and 12,000 MegaWatts of electricity Nationally) (June 2007)
Earth Energy Flow Rates due to Precessional Effects (63,000 MegaWatts of Energy) (Sept 2006)
Productive Usage of Nuclear Power Plant Wastes Productive Disposal of Nuclear Power Plant Wastes (1980s, Sept 2005)
Conserving Energy
Storing Energy Various Methods
How Much Solar Energy
How the Sun Works in Creating Light and Heat
Energy Inventions Related to Energy Crises
Generating Electricity from Solar Energy From solar, wind or other sources nearly 24 Hours a Day (2001, tested 2003)
Generating Electricity from Solar Energy, Improved A Unique Method of Using Solar Energy to Generate Electricity (late 2010)
Alaska Pipeline Alyeska pipeline Local Climate Effects (August 2005)
Home Air Conditioning Natural, GREEN and FREE! (1978, December 2000)
A Better Hybrid Vehicle An Entirely Different Approach to a Hybrid Vehicle (1992, May 2008)
Woodburning Furnace Fireplace, Woodstove - JUCA Super-Fireplaces (designed 1972, manufactured 1973 on, still not matched)
Burning Wood for Heating The Physics of Burning Wood as a Heating Fuel (published 1978)
North Pole Heating Faster than anywhere else
Global Warming Solutions
How Airplanes Fly Aerodynamic Lift, Bernoulli Effect, Reaction Lift (April 2003)
Efficient Flight - TURCAN Greatly Reducing Turbulence and Drag for Aircraft and Airfoils, TURCAN (summer 1998)
Construction School My Concept of a GREEN Campus (1990, Dec 2008)
Conservation of Angular Momentum A Violation of the Conservation of Angular Momentum (Sept 2006)
The Physics of Hurricanes A Credible Approach to Hurricane Reduction (Feb 2001)
Enhanced Automotive Engine Significant Improvement (2001)
The Politics of Global Warming Why No Leaders Seem to See Urgency in Global Warming
Source of Energy - the Moon (Artificial Tides) (1998, 2010)
Source of Energy - the Moon 2 (Energy Harvesting) (1975, 2010)
Making Electricity from Solar, Wind, Water, More Make All Your Own GREEN Electricity (2001, 2003, 2010)
Woodstove Energy Production from a Radiant Woodstove (published 1979)
Firewood Ratings Firewood Info Chart.