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FAQs with REAL and TRUE Answers

FAQs with REAL and TRUE Answers

If you want to find TRUE answers to your questions about outdoor wood burning furnaces and water boilers, you’ve come to the right place. We won’t tell you that your wood will burn for 92 hours or that you can put your furnace 500 feet away!

Do I have a choice of colors?

Yes, you can choose from a wide variety of colors for our NCB-80, 175, 250 & 325G boilers!

Retail prices listed include the standard colors of Evergreen or Charcoal. All other colors are an additional $100.00.
The NCB120 & GT-6000 are available in only their respective standard colors.

Also, color selections are close representations but are not guaranteed exact due to differences in computer displays.

Do these furnaces need to be near the house? How far an outdoor furnace be?

We recommend that the Nature’s Comfort Outdoor Furnace be within 2-300 feet of the house – but no less than 30 feet, to avoid downdraft problems. We recommend that you check with your insurance to determine how close or far you are able to put the outdoor furnace from your house.
Claims in product brochures and manufacturer’s websites that these units can be 500 ft from the house are hard to believe without ridiculous amounts of heat loss and wasted wood. We do have a customer that is 325 feet from his home, heating 4880 sq. ft. and he’s real happy!
It is hard to see much heat energy being left after a run of 500 ft. even with underground temperatures of 50-60 degrees below the frost line – let alone at 12-18″ in frozen ground, where most people say to put the lines..

The furnace can be 10 feet from the house. 2 feet? Don’t believe it unless you don’t have windows or you have a 20-30 foot smoke stack.

Can boilers explode?

The Nature’s Comfort Outdoor Furnace is a non-pressurized systems which totally eliminates this possibility.

Does the furnace come fully assembled?

Yes. Like most major appliances the unit is delivered to you ready to install.

How often do I have to fill it up?

We put wood in our furnace at 8 AM and 8 PM in the dead of winter, with plenty of wood still left over. So 2 times a day max. Some people do it just once a day. Don’t believe exaggerated claims of 72-96 hours! This just isn’t possible – except in the summer, heating only water and a pool, hot tub or spa.
The size of your house, outdoor temperatures and the size of the house will determine how much wood you use and how often you fill the furnace along with whether you heat hot water.

Can I use an outdoor wood furnace if I live in town?

Wood may not be the best fuel choice in densely populated urban areas where automobile exhaust and other pollution already puts excessive strains on air quality. Smoke can also overwhelm your neighbors if the wind blows the wrong way.
However, in suburban, small town, and rural areas, wood makes good sense. If you choose to install your Nature’s Comfort furnace in a densely populated area the stack height should exceed the rooflines of existing homes.
As for using a wood furnace in town, you would have to check with your municipality to see if an outdoor wood furnace is permitted.

Can I heat more than one building?

One of the many advantages of the Nature’s Comfort Outdoor Furnace is the ability to heat multiple buildings (up to 4) from one location. Simply add a pump and Pex lines to your location and you will have an additional heated area or building.

Can the Nature’s Comfort heat my pool and/or spa?

Yes, many Nature’s Comfort Outdoor Furnace customers heat their pool and/or spa. You can put wood in the furnace every 3 days or more in the summer. I guess this is where many manufacturers get the outlandish claims of 72 – 96 hours burn time!
Remember that smoke output will be greater in the summer due to the smoldering fire and plan accordingly.

Should I consider radiant heat?

Radiant heat installed under new or existing floors can be a great way to heat your home. Radiant floor heat is the most efficient way to transfer heat, however, it is important that you design the system correctly. Many people with electric baseboard heaters opt for this method.
It isn’t drafty or noise and gives you clean and comfortable heat down low, where you need it!

Can I connect the Nature’s Comfort to a pressurized heating system?

by the use of a water-to-water heat exchanger the heat can be transferred from one system to the other.
Connecting it directly to the existing system and depressurizing it is a big no-no and will cause you problems with air pockets, etc.

Can I heat my domestic water with the Nature’s Comfort?

Yes, our system circulates potable hot water in a closed system, between the boiler and the hot water heater. This keeps the hot water refreshed, hot and ready to go at all times.
Most people find they also save between $30 and $60 a month (OR MORE!) heating their water with a wood outdoor furnace – boiler.

With our system there is no change of getting scalding water out of your tap – like with other systems!

I only have baseboard electric heat, how can I use the Nature’s Comfort?

Many people with electric baseboards elect to install non-drafty, even-heating and comfortable radiant floor heat between the floor joists or water baseboard heaters.

Can I connect the Nature’s Comfort to a forced air heating system?

Yes, more than 90% of all installations are connected to existing forced air heating systems. This is one of the easiest to install; almost as easy as Hydronic units and free-hanging units in a garage or shop.

Is there a lot of heat loss when the unit is outside and its below 32° F?

The units are highly insulated to avoid heat loss. In fact icicles form on the outside in the winter. That means that heat is being kept inside.

Is this furnace (boiler) pressurized or non-pressurized?

The Nature’s Comfort Outdoor Furnaces are safer, non-pressurized units. Technically they are atmospheric vented, which means they are totally safe and never build pressure.

Antifreeze for outdoor furnace as a rust inhibitor?

Unscrupulous dealers will tell you that the sole purpose of antifreeze is to keep the furnace from freezing up. Not true; the main reason is rust prevention. Rust is the no/no word in the outdoor furnace business.
Antifreeze is generally not needed as it takes a long time to freeze 170 gallons of water and there is plenty of expansion room in the top of the tank anyway.

There are several other alternatives to prevent freezing and at far less cost. An in-line electric heater can be installed on the return line and set at just above the freezing mark as an extra safeguard.

Even better, you can also simply leave the pump running if you go on vacation and it will extract heat from the furnace keeping the water warm. The pump uses about the same power as a 80W light bulb.

Antifreeze is an excellent rust inhibitor but it does have a disadvantage. It is designed to keep engines cooler. When used in an outdoor furnace, it has been stated that it takes 18 percent more firewood to heat the system water/antifreeze mixture than to just heat water.

Do not use regular automobile antifreeze. The best glycol additive is Dowfrost from the Dow Chemical company. It is environmentally friendly, allows higher operating temperatures, has excellent anti-corrosion features and has a longer life expectancy than other glycols.

We have also heard that Beet Juice is an excellent and inexpensive antifreeze! Beet Juice has a neutral Ph just like water.

Won’t the fire box burn out eventually?

The Nature’s Comfort Outdoor Furnaces are made with a high quality mild steel and will not rust out with proper maintenance and treatment.
What about stress cracks? Since water surrounds the firebox, the metal can only get so hot since it’s being continually cooled by the water. The extreme quality of the metal we use helps avoid stress cracks as well.

How heavy is your furnace?

Our NCB-175 wood weighs in at a hefty 1733 lb dry, which is a testimony as to how much steel is really in the furnace. To see the weights of all of our other furnaces, go check out a specific model for all of the specifications by going to the Nature’s Comfort tab at the top of the page.

Why is the water jacket so big? 175 gallons is a lot more than others!

Many stoves do not have enough water capacity and tend to cycle too often. You load the stove with wood and fire it. With a small water capacity, the water reaches set point temperature and the stove shuts down.
On cold days the heat is quickly drained from the water an now you have cold water trying to heat your house – until it warms up again.
More water also means more capacity (available BTUs) but at the same time the water doesn’t have to be heated as much, over and over again, either.

The Nature’s Comfort Outdoor Furnace has a large water tank capacity, so you can burn the total load of wood with good draft, burn and efficiency.

What can I expect to pay for an outdoor wood furnace?

Total prices will vary depending on the shipping location but our prices start at a low, low $3,480 for the NCB-80 model.

How long is the warranty?

We have a 20-YEAR limited warranty. There is also a 5 year ON-SITE warranty including parts and labor on the entire structure. This excludes the electrical parts such as the pump and the blower which have a one year manufacturer’s warranty.
We don’t have you ship the furnace back, like some companies. What good is a warranty if it’s going to cost you a thousand dollars for shipping?

What about Stainless Steel Wood Furnaces?

Stainless steel may not last longer than mild steel in an outdoor furnace, because all stainless is a “forever” product. There are many grades and some of them are subject to rusting and corrosion. Automobile exhaust systems are made from one of the lower grades; they resist high temperatures but totally corrode.
Stainless is expensive so the fireboxes are made very thin. Stainless gets stress cracks in it which get bigger and bigger until you have a BIG leak!



We have replaced leaking stainless steel furnaces only 5 and 6 years old!

Most outdoor furnace manufacturers went to stainless steel to get in on the stainless quality image, but since it’s expensive many of them went to a low-cost, cheap-grade stainless – which is still subject to rust and corrosion! During the manufacturing and welding process for stainless steel, IF the proper quantity and blend of corrosion-resistant and stabilizing elements are used, then it does indeed become a “forever” product. This is not normally done and post-weld annealing is needed to restore ductility, formability, toughness and corrosion resistance.

If you do purchase one of the lower grade stainless steel furnaces, be sure that exact model has has a proven track record of corrosion resistance. The furnace design is every bit as important as the material that it’s made from.

How long will the furnace last?

We have a 20-YEAR WARRANTY with an exclusive 5-year ON-SITE parts AND labor warranty on the furnace. This excludes the electrical parts such as the pump and the blower which have a one year manufacturer’s warranty.
The life of your furnace depends upon proper maintenance. With proper maintenance your furnace will give you many years of dependable service.
If you have any other specific warranty questions, be sure to call Randy at (608) 519-4664!

Is burning wood bad for the environment?

A wood heating system is the right choice for the increasing number of consumers who are concerned about our environment. Wood is a totally renewable resource, which, when burned, results in no net carbon dioxide increase. Carbon dioxide is a part of the natural plant-growth cycle and occurs naturally when trees are allowed to rot on the forest floor.
Burning wood gives off no more carbon than a rotting tree!
On the other hand, fossil fuels release carbon dioxide when burned which otherwise would stay trapped in the earth. This causes a net increase in carbon dioxide, which is believed to be responsible for the heat-trapping “greenhouse effect.” So when heating with wood versus fossil fuels, you actually achieve a net reduction in greenhouse gas emissions.

In addition, harvesting firewood has a pruning effect on forests, which allows net growth to flourish. The wood you burn likely comes from your local area — it’s not imported and not subject to price increases due to events outside your control, as is the case with oil.

Many times the owners have land with fallen trees spread throughout abundantly – which means FREE WOOD!

What is the BTU rating of your furnace?

The NCB-175 wood is rated at 220,000 BTU storage capacity. To check the BTU capacity of our other furnaces, click on a model to get all of the specs.

Don’t believe the outlandish claims of 300,000 BTU from a 100 or 120 gallon furnace! They simply aren’t true. I just read about one that said it was 400,000 BTU with a 95 gallon tank. Preposterous! Where did these people go to school?

The water would have to be well over 500 degrees to do this. And at what temperature does water boil? 212º F of course. And we don’t want the water boiling! This is just a cheap sales tactic.

A BTU is the amount of heat needed to raise the temperature of 1 pound of water by 1 degree Fahrenheit.

That means that if the normal water temperature is 60 degrees F and it needs to be raised to 180 degrees, that it will take 163,200 BTU to do this. Remember that a pound of water is about 16 ounces. A gallon of water is approx 8 lb.

(170 gal. x 8) = 1360 lb.

Temperature change = 120 degrees

1360 x 120 = approx. 163,200 BTU

Find out how many BTUs you need HERE or check the label on your current furnace.

What do experts say?

According to the University of Nebraska, “Wood burning stoves may not only save people money on their heating bills this winter, but also are a clean alternative to electric or gas furnaces,” Adams said.
Scott Josiah, state forester with the Nebraska Forest Service at UNL, said “There also are environmental benefits to using wood heat. Wood heat produces little pollution and is environmentally friendly, especially when wood is used in a high-efficiency wood burning stove and where firewood is a readily available resource.”

What are the advantages of the Nature’s Comfort Wood Furnace?

The chance of carbon monoxide build-up in your home is eliminated.
The change of a gas explosion from your furnace in your home is eliminated.
Indoor pollutants of harmful gases and fumes are eliminated.
Asthma and other breathing difficulties are greatly helped by eliminating the dry air, fumes and gases.
Eliminated the chance of chimney and flu fires from your furnace.
The NC furnace removes the fire hazard from your home or building because all of the burning and stoking takes place outside. Insurance companies love theses furnaces. Often lower rates of higher coverage can be had by changing from a fireplace or indoor wood stove to an outside wood furnace.
An outdoor wood furnace also helps your indoor air quality and can alleviate respiratory and allergy problems caused by burning wood indoors. No more dark sooty walls and bus either! thermostatic control provides your home with even, steady heat.
The house will be less drafty as well, when heating with the outside boiler, because ther is no combustion device operating inside drawing in cold outside air to replace that used in combustion.
Current owners of the Nature’s Comfort Furnace are also using up to 25 to 50 percent less wood compared to other heating alternatives. Since the Nature’s Comfort can burn larger pieces of wood it will dramatically reduce time spent preparing the wood.
The Nature’s Comfort Wood Furnace means easy maintenance and few parts requiring service. You don’t need costly electrical gadgets and features to cause problems down the road. This is a proven design!

How can the Nature’s Comfort heat my home and water?

The heated water is pumped to the home or building through insulated underground pipes (Pex pipe). A water-to-air heat exchanger or water-to-water heat exchanger, conveys the heat into the home’s forced-air furnace, boiler, or radiant floor heating system. We use a direct hookup to the hot water heater.

It can also supply potable hot water to the water heater to provide domestic hot water.

Why Use Boiler Plate for an Outdoor Firebox?

Boiler Plate has a higher tensile strength than mild or regular steel and so it is less prone to rupturing. That is needed in a pressurized unit, like actual boilers and old steam engines.

The industry has thrown the name around (boiler plate) as if it was needed when it is absolutely not needed. It is of no use in a non-pressurized unit. Our 1/4″ high quality mild steel fireboxes probably have more tensile strength than the others with their “boiler plate” fireboxes that are the same thickness and thinner!

What is the Shaver Outdoor Wood Fired Furnace?

It is a safe and efficient way to heat your home with wood. The Shaver furnace is designed to look like an attractive storage building and is installed outside, away from the home or building being heated.Having an outdoor furnace eliminates smoke,  pollution and wood debris within the house. A water jacket surrounds the huge furnace firebox and the heat is transferred from the wood fire to the water. The water is then piped at 130 F to 180 F (adjustable), to the house. It then goes through a heat exchanger, which is a lot like a radiator. Air blows over the heat exchanger (in your furnace’s plenum or ductwork), extracting heat for your home.

Heating systems other than forced air (such as boilers or radiant floor heating systems) can be hooked up very simply. In fact a boiler is the easiest system to hook up!

What is the Nature’s Comfort Outdoor Wood Furnace?

It is a safe and efficient way to heat your home with wood. The Nature’s Comfort furnace is designed to look like an attractive storage building and is installed outside, away from the home or building being heated.

Having an outdoor furnace eliminates smoke, pollution and wood debris within the house. A 3/16″ water jacket surrounds the huge furnace firebox and the heat is transferred from the wood or coal fire to the water. The water is then transferred through pex piping at 180 F (preset), to the house. It then goes through a heat exchanger, which is a lot like a radiator. Air blows over the heat exchanger (in your furnace’s plenum), extracting heat throughout your home.

Heating systems other than forced air (such as baseboard or radiant floor heating systems) can be hooked up very simply.