Camping Wood Burner With Chimney: A Complete Hot Tent Setup Guide

A camping wood burner with chimney can turn a cold-weather campsite into a warm, comfortable shelter while also providing a practical way to cook, boil water, and dry damp gear. But a tent stove is not simply a smaller version of a household wood stove. The stove, chimney, stove jack, ventilation, tent material, and clearances all need to work together as one system.

For winter camping, the biggest advantage is straightforward: wood is widely available, the stove produces strong radiant heat, and the chimney removes smoke and combustion gases from the shelter. The trade-off is that you are managing an active fire inside a fabric shelter, so setup and operating discipline matter.

This guide explains how to choose, install, and use a camping wood burner with chimney safely, including stove sizing, chimney design, stove-jack installation, fuel selection, ventilation, overnight operation, and maintenance.

What Is a Camping Wood Burner With Chimney

A camping wood burner with chimney is a compact wood-burning stove designed specifically for use in a compatible hot tent, canvas shelter, wall tent, teepee, or other purpose-built shelter.

Unlike an open campfire, the fire is contained inside a metal firebox. A connected chimney pipe carries smoke and combustion gases outside the shelter while the stove body radiates heat into the living area.

A typical system includes:

• Wood-burning stove body
• Firebox and stove door
• Adjustable air intake
• Stovepipe or chimney sections
• Damper, depending on the stove design
• Spark arrestor
• Stove jack
• Heat-resistant floor or stove mat
• Fireproof gloves
• Chimney support or guy lines
• Ash pan or removable grate on some models

The important point is that the chimney is part of the heating system, not merely an accessory. Chimney height, diameter, joints, draft, and placement can significantly affect combustion and safety.

Why Use a Wood Burner for Cold Weather Camping

A properly designed hot-tent stove provides several advantages that are difficult to reproduce with ordinary camping heaters.

1. Strong radiant heat

Metal stove surfaces become hot quickly and radiate heat directly toward people and equipment. This can make a cold shelter feel considerably more comfortable even before the entire tent reaches an even temperature.

2. Fuel can be locally sourced

Wood is often available around established camping areas where collecting firewood is permitted. This can reduce the amount of liquid or compressed fuel that needs to be transported.

However, never assume you can collect firewood anywhere. Follow local land-management rules, campground regulations, fire restrictions, and seasonal closures.

3. Cooking capability

Many camping wood burners have a flat top that can be used for:

• Boiling water
• Heating soup
• Cooking simple meals
• Melting snow for water
• Warming cookware

The stove therefore serves two functions without requiring a separate cooking appliance.

4. Drying wet equipment

A controlled wood stove can help dry damp gloves, socks, and clothing.

But drying gear around a stove requires caution. Never place clothing, sleeping bags, towels, or synthetic materials directly on the stove or close enough to contact hot metal or sparks.

5. Better winter-camping comfort

A hot tent allows campers to escape wind, cold rain, and snow while maintaining a warm central living space.

For long winter trips, this can be a major improvement over relying entirely on sleeping bags and insulated clothing.

Camping Wood Burner With Chimney vs Traditional Campfire

A wood stove does not eliminate the risks associated with fire. It changes how those risks are managed.

The chimney is the major difference.

A correctly installed chimney creates a path for hot gases to leave the shelter. If the chimney system is poorly assembled, blocked, damaged, or leaking, the risk of smoke and carbon monoxide entering the shelter increases substantially.

The Most Important Requirement Is the Tent

Before buying a camping wood burner with chimney, make sure the tent is designed or approved for wood-stove use.

Do not assume that a regular camping tent can safely accommodate a wood stove simply because you can cut a hole in the fabric.

Look for a Proper Stove Jack

A stove jack is a heat-resistant opening designed to allow the chimney to pass through the tent wall or roof.

A quality stove jack should:

• Be securely integrated into the tent
• Use heat-resistant material
• Fit the chimney diameter appropriately
• Have enough surrounding material to maintain safe clearances
• Be installed according to the tent manufacturer's instructions

The stove jack is one of the most critical components in the entire system because the chimney can become extremely hot during operation.

Choose Appropriate Tent Materials

Traditional hot tents commonly use canvas or polycotton fabrics, although some modern shelters use specialized stove-compatible synthetic materials.

Do not rely on the appearance or thickness of a fabric to determine whether it is stove compatible.

A lightweight nylon or polyester backpacking tent may soften, melt, deform, or ignite when exposed to the temperatures associated with a wood-stove chimney.

Only use a wood burner in a shelter specifically designed or approved for that purpose.

How to Choose the Right Camping Wood Burner

The best camping wood burner is not necessarily the largest or lightest model.

You need to balance:

1. Tent volume
2. Stove output
3. Firebox size
4. Weight
5. Chimney length
6. Fuel availability
7. Cooking requirements
8. Trip duration
9. Weather conditions
10. Packability

Match the Stove to Tent Volume

Tent volume is often a better starting point than floor area.

A simple calculation is:

Tent volume = length × width × average interior height

For example, a shelter measuring approximately 8 × 8 feet with an average usable height of 5 feet has about:

8 × 8 × 5 = 320 cubic feet

That does not automatically tell you which stove to buy, but it gives you a better basis for comparison than floor dimensions alone.

Why Oversizing Can Be a Problem

A stove that is too large can create excessive heat.

You may end up:

• Overheating the shelter
• Running the stove inefficiently
• Opening doors and vents unnecessarily
• Consuming wood quickly
• Increasing the risk of overheating nearby materials

Why Undersizing Can Also Be a Problem

A tiny stove in a large winter shelter may require constant refueling.

You may have to:

• Process very small pieces of wood
• Add fuel frequently
• Burn the stove harder
• Spend more time managing the fire
• Struggle to maintain useful temperatures during severe weather

For backpacking, however, a smaller stove can make sense because weight may be more important than maximum heat output.

Titanium vs Stainless Steel Camping Wood Burners

Material choice affects both portability and durability.

Titanium

Titanium camping stoves are popular with backpackers because they can be extremely lightweight.

Advantages include:

• Low weight
• Good corrosion resistance
• Excellent strength-to-weight ratio
• Fast setup for many folding designs
• Compact rollable chimney systems

The main disadvantage is that thin titanium components can be easier to deform if handled roughly or overheated.

Stainless Steel

Stainless steel stoves are generally heavier but can be attractive for:

• Base camping
• Wall tents
• Car camping
• Frequent winter use
• Larger shelters
• Users who prioritize durability

A stainless stove may also retain heat differently depending on its construction and thickness.

Which Material Is Better

Choose titanium when pack weight and compactness are priorities.

Choose stainless steel when durability, stability, and repeated base-camp use matter more.

There is no universally superior material. The right choice depends on how you camp.

Understanding the Camping Wood Burner Chimney

The chimney is responsible for moving smoke and combustion gases away from the shelter.

A typical tent-stove chimney consists of multiple pipe sections that connect to the stove and extend through a stove jack.

Chimney Diameter

The chimney diameter must match the stove manufacturer's specification.

Do not assume that a larger pipe is automatically better.

A chimney that is incorrectly sized can affect:

• Draft
• Combustion
• Smoke production
• Stove efficiency
• Fire control

Always follow the stove manufacturer's recommended chimney diameter.

Chimney Length

The chimney needs enough length to extend safely through the stove jack and outside the shelter.

The exact required length depends on:

• Tent height
• Stove location
• Stove-jack position
• Chimney design
• Manufacturer requirements
• Local conditions

A chimney that is too short may not provide adequate clearance above the shelter and can interfere with draft.

A chimney that is unnecessarily long can create transport and setup problems.

Chimney Sections

Collapsible or nesting chimney sections are popular because they pack efficiently.

Before each trip, inspect every section for:

• Cracks
• Warping
• Corrosion
• Loose joints
• Missing fasteners
• Excessive soot or creosote
• Deformation around connection points

A chimney is not something to install once and forget.

Why a Spark Arrestor Matters

A spark arrestor is typically installed near the top of the chimney.

Its job is to reduce the chance that burning embers will leave the chimney and land on:

• Tent fabric
• Dry vegetation
• Sleeping equipment
• Nearby shelters
• Forest litter

A spark arrestor does not make a wood stove fireproof.

It is only one layer of protection.

You still need to:

• Burn appropriate dry wood
• Avoid excessive overfiring
• Inspect the chimney regularly
• Maintain safe clearances
• Keep the stove stable
• Monitor changing wind conditions

A heavily restricted or clogged spark arrestor can also affect draft, so it should be kept clean.

How to Set Up a Camping Wood Burner With Chimney

A careful setup is more important than getting the fire started quickly.

Step 1: Choose the Stove Location

Place the stove on a stable, non-combustible or manufacturer-approved protective surface.

Keep it away from:

• Sleeping bags
• Clothing
• Backpacks
• Tent walls
• Plastic gear
• Synthetic fabrics
• Low-hanging equipment

The exact clearance should come from the stove and tent manufacturers rather than a generic internet rule.

Step 2: Stabilize the Stove

Open the stove legs completely and verify that the stove sits level.

A small stove can become surprisingly unstable when loaded with wood.

Make sure:

• All legs are locked
• The floor is firm
• The stove cannot rock easily
• The door opens without hitting equipment
• The chimney connection is aligned

Step 3: Assemble the Chimney

Connect the chimney sections according to the manufacturer's instructions.

Check each connection carefully.

A good chimney should be:

• Properly seated
• Structurally stable
• Free of visible gaps
• Correctly aligned
• Supported where necessary

Do not improvise chimney components that are not designed to work together.

Step 4: Pass the Chimney Through the Stove Jack

Feed the chimney through the designated stove jack.

Never force a hot chimney through ordinary tent fabric.

The chimney should not press directly against unprotected fabric.

If your stove system requires a heat shield or specialized chimney shield, install it exactly as directed.

Step 5: Secure the Chimney

Wind can move a tent and chimney independently.

Use the appropriate support system, guy lines, brackets, or other manufacturer-approved method.

A chimney that moves excessively can:

• Damage the stove jack
• Stress chimney joints
• Pull on the stove
• Bring hot metal closer to tent fabric
• Increase the chance of tipping

Step 6: Check Ventilation

A wood fire consumes oxygen.

Your tent must have adequate ventilation while the stove is burning.

Do not seal a hot tent completely in an attempt to conserve heat.

Fresh-air ventilation is particularly important because carbon monoxide is colorless and odorless.

A carbon monoxide detector designed for the environment, where appropriate and permitted by the manufacturer, provides another layer of protection but does not replace proper chimney installation and ventilation.

Step 7: Start With a Small Fire

Do not begin with a firebox packed completely with wood.

Start small.

A controlled first fire allows you to check:

• Draft
• Smoke movement
• Chimney joints
• Stove-jack clearance
• Door seals
• Air control
• Spark-arrestor behavior

If smoke enters the shelter, stop and correct the problem before continuing.

How to Get Better Draft From a Tent Stove Chimney

Draft is the pressure difference that helps pull combustion gases through the chimney.

Hot gases rise because they are less dense than cooler surrounding air.

A simplified way to think about it is:

Hotter chimney + sufficient height + unobstructed airflow = stronger draft

Several factors influence draft.

Chimney Temperature

A cold chimney may draft poorly when the fire is first started.

This is why a small, clean-burning fire is often useful for warming the chimney before adding larger pieces of fuel.

Chimney Height

A taller chimney can generally provide stronger draft than a very short chimney, although the correct height depends on the stove and shelter design.

Do not simply add unlimited pipe length.

Follow the manufacturer's chimney specifications.

Chimney Blockages

Ash, soot, creosote, ice, snow, and debris can interfere with airflow.

Inspect the chimney before every trip and clean it when necessary.

Wind

Wind can either help or disrupt chimney performance depending on its direction and speed.

A properly secured chimney is particularly important during exposed winter camping.

What Firewood Works Best in a Camping Wood Burner

The best firewood is generally dry, seasoned wood that fits comfortably inside the stove's firebox.

Avoid relying on large wet logs simply because they burn longer.

Wet wood can produce:

• More smoke
• Poorer combustion
• More soot
• More creosote
• Less usable heat

Small pieces are often easier to control in a compact tent stove.

A Practical Firewood Strategy

For a small stove:

1. Start with dry tinder
2. Add thin kindling
3. Build a small flame
4. Add progressively larger pieces
5. Allow the stove to establish a stable draft
6. Adjust airflow gradually

Avoid choking the stove down immediately after lighting.

A smoky, smoldering fire is generally less desirable than a hot, clean-burning fire.

How Much Firewood Should You Bring

Fuel consumption varies significantly with:

• Stove size
• Tent volume
• Outdoor temperature
• Wind
• Wood moisture
• Stove design
• Insulation
• Desired indoor temperature
• How frequently the stove is fed

Instead of relying on a universal number, test your stove before a remote winter trip.

For example, during a backyard test, measure how much properly dried wood the stove consumes over two or three hours at your normal operating setting.

Then repeat the test under colder conditions if possible.

This gives you a much more useful estimate than an advertised burn time.

How to Control Heat With a Tent Wood Stove

Temperature control comes primarily from fuel load and airflow.

Too Much Wood

Adding too much wood at once can create excessive heat.

Signs may include:

• Very intense flames
• Extremely hot stove surfaces
• Excessive chimney temperature
• Difficulty controlling the fire
• Unusual glowing of metal components

If your stove appears to be overheating, follow the manufacturer's emergency operating instructions and reduce the fire safely.

Too Little Wood

A very small fire may not maintain useful heat in severe conditions.

The goal is not maximum flame size.

The goal is a stable, controlled burn appropriate for the stove.

Never Use a Tent Stove as a Sleeping Appliance

One of the most important hot-tent lessons is this:

Do not treat a wood stove as an unattended overnight heater unless the specific stove, shelter, installation, and manufacturer's instructions explicitly allow it.

A wood fire can:

• Burn through fuel
• Produce carbon monoxide
• Throw sparks
• Overheat components
• Cause chimney problems
• Shift as the fire burns
• Create unexpected hazards

Many experienced winter campers let the fire go out before sleeping and rely on an appropriate sleeping system for overnight warmth.

Your sleeping bag, sleeping pad, clothing system, and shelter insulation should be capable of keeping you safe without depending on an unattended fire.

Carbon Monoxide Safety in a Hot Tent

Carbon monoxide is one of the most serious risks associated with combustion inside an enclosed shelter.

It is especially dangerous because you cannot reliably detect it with your senses.

A wood stove can produce carbon monoxide when combustion is incomplete, particularly when:

• The fire is smoldering
• The chimney is blocked
• Chimney joints leak
• Draft is inadequate
• Ventilation is insufficient
• The stove is operated incorrectly

Reduce Carbon Monoxide Risk

Always:

• Use a purpose-built stove and chimney
• Keep the chimney unobstructed
• Check pipe connections
• Maintain ventilation
• Never operate a damaged stove
• Never ignore smoke entering the shelter
• Follow the stove manufacturer's instructions
• Use a suitable carbon monoxide alarm when appropriate

If anyone experiences symptoms such as headache, dizziness, nausea, confusion, unusual fatigue, or weakness while a combustion appliance is operating, move into fresh air immediately and treat the situation as an emergency.

Common Camping Wood Burner Setup Mistakes

Even experienced campers can make avoidable mistakes.

Mistake 1: Using a Regular Tent

A standard backpacking tent is not automatically compatible with a wood stove.

Fix: Use a purpose-built hot tent or another shelter explicitly designed for stove use.

Mistake 2: Ignoring the Stove Jack

A stove jack is not just a convenient hole.

Fix: Make sure the chimney passes through the correct heat-resistant installation and maintains the manufacturer's required clearances.

Mistake 3: Using Wet Firewood

Wet wood can create smoke and deposits while producing less useful heat.

Fix: Carry properly seasoned firewood or use dry wood that is legal to collect locally.

Mistake 4: Running the Stove Too Hard

More flame does not always mean better heating.

Fix: Learn the stove's normal operating range through controlled testing.

Mistake 5: Forgetting Ventilation

Closing every opening can trap combustion gases.

Fix: Maintain appropriate fresh-air ventilation while the stove is operating.

Mistake 6: Neglecting the Chimney

A chimney may look fine from the outside while accumulating soot internally.

Fix: Inspect and clean it regularly.

Mistake 7: Putting Gear Too Close to the Stove

A sleeping bag can ignite or melt long before you realize how much radiant heat it is receiving.

Fix: Maintain the manufacturer's required clearance and use appropriate protective barriers.

Mistake 8: Failing to Secure the Chimney

Strong wind can move the pipe and shelter.

Fix: Use appropriate guying and support systems.

Camping Wood Burner With Chimney Safety Checklist

Before lighting your stove, run through this quick inspection:

• Tent is specifically compatible with wood-stove use
• Stove jack is undamaged
• Stove sits on a stable protective surface
• Required clearances are maintained
• Chimney sections are correctly connected
• Chimney has no obvious cracks or deformation
• Spark arrestor is installed and clean
• Chimney is properly supported
• Tent has adequate ventilation
• Firewood is dry and appropriately sized
• Fire-starting equipment is ready
• Heat-resistant gloves are available
• Water or another appropriate emergency fire-control method is accessible
• Carbon monoxide detection is available where appropriate
• Weather and local fire restrictions have been checked

This takes only a few minutes and can prevent a serious problem later.

How to Maintain a Camping Wood Burner

A camping wood burner requires regular maintenance just like any other combustion appliance.

After Each Trip

Allow the stove to cool completely before handling it.

Then:

1. Remove cold ash
2. Inspect the firebox
3. Check the door and seals
4. Inspect chimney sections
5. Clean the spark arrestor
6. Look for soot or creosote
7. Check folding legs and hinges
8. Dry all components
9. Store the stove somewhere dry

Pay Special Attention to Creosote

Creosote is a combustible deposit associated with wood combustion, especially when fires burn poorly or chimney surfaces remain relatively cool.

Heavy buildup can reduce chimney performance and increase fire risk.

Regular inspection and cleaning are therefore essential.

A Simple Pre-Trip Test for Your Hot Tent Stove

If you have never used your camping wood burner with chimney before, do not make your first test in a snowstorm miles from the trailhead.

Perform a controlled test at home or another legal location.

Test Procedure

1. Assemble the tent and stove exactly as you plan to use them.
2. Install the chimney and stove jack.
3. Verify clearances.
4. Start a small fire.
5. Observe smoke behavior.
6. Check chimney connections.
7. Monitor the stove's heat output.
8. Practice adding wood while wearing gloves.
9. Practice adjusting airflow.
10. Allow the stove to cool completely.
11. Inspect the equipment afterward.

This exercise teaches you something that product specifications cannot: how your specific stove behaves inside your specific shelter.

How to Pack a Camping Wood Burner for Backpacking

For backpacking trips, packability can be as important as heating performance.

Look for:

• Folding legs
• Removable chimney
• Nesting components
• Rollable titanium pipe
• Compact firebox
• Low overall weight
• Integrated storage solutions

A lightweight stove may weigh only a fraction of a traditional steel stove, but remember that the complete system weight matters.

Calculate:

Stove + chimney + spark arrestor + stove jack accessories + floor protection + tools + gloves

A stove that looks extremely light in a product listing may become much heavier once the entire system is packed.

What to Look for in a Camping Wood Burner With Chimney

If you are comparing models, prioritize these features.

Essential Features

• Purpose-built tent-stove design
• Compatible chimney system
• Secure stove legs
• Reliable door closure
• Adjustable airflow
• Appropriate chimney diameter
• Spark arrestor
• Replacement parts availability
• Clear operating instructions

Useful Features

• Glass viewing window
• Flat cooking surface
• Removable ash pan
• Folding shelves
• Damper
• Heat shield
• Carry bag
• Rollable chimney
• Adjustable legs

Features That Matter Less Than You Think

Do not choose a stove solely because it has:

• The largest glass window
• The highest advertised heat output
• The longest claimed burn time
• The cheapest price
• The lightest empty stove weight

A stove is a system.

Reliability, safe operation, appropriate sizing, chimney compatibility, and replacement-part availability are usually more valuable than impressive marketing numbers.

Best Camping Wood Burner Setup by Camping Style

Backpacking and Winter Trekking

Prioritize:

• Titanium construction
• Compact folding design
• Lightweight chimney
• Small firebox
• Efficient packing

The trade-off is more frequent refueling and potentially less cooking space.

Car Camping

A heavier stainless steel stove may be preferable.

You can carry:

• Larger firewood
• Larger stove
• Longer chimney
• Heavier heat protection
• More cooking equipment

Weight becomes less important when the vehicle carries most of the equipment.

Base Camp and Wall Tent Camping

A larger stove can make sense when the shelter is spacious and the stay lasts several days.

Look for:

• Larger firebox
• Durable steel construction
• Stable legs
• Longer-lasting components
• Larger cooking surface
• Easy cleaning

Can You Cook on a Camping Wood Burner

Yes, if the stove is designed for cooking.

A flat stove top can work well for:

• Boiling water
• Heating coffee
• Simmering soup
• Frying simple foods
• Heating a cast-iron pan

Cooking also changes the stove's heat-management requirements.

When cooking, monitor the fire closely and avoid placing excessive cookware on a small stove.

Always follow the manufacturer's instructions regarding whether cooking and space heating can be performed simultaneously.

How to Make a Hot Tent Warmer Without Burning More Wood

A bigger fire is not always the best solution.

Improve the entire shelter system first.

Improve Ground Insulation

Cold ground can pull heat from your body continuously.

Use an insulated sleeping pad with an appropriate cold-weather rating.

Reduce Unnecessary Air Leakage

Seal excessive drafts while maintaining the ventilation required for safe stove operation.

Use the Correct Tent Size

A stove does not need to heat a huge unused volume.

For solo or two-person winter trips, an appropriately sized shelter can make heat management much easier.

Organize the Interior

Keep sleeping equipment away from the stove while maintaining a practical warm zone around the living area.

Dry Clothing Carefully

Dry wet gear gradually and at a safe distance rather than placing it directly against hot surfaces.

Camping Wood Burner With Chimney: A Practical Winter Setup

For a typical cold-weather hot-tent trip, a well-balanced system might include:

• Stove-compatible canvas or specialized hot tent
• Compact wood-burning stove
• Correct chimney system
• Spark arrestor
• Stove jack
• Heat-resistant floor protection
• Fire-resistant gloves
• Dry firewood
• Fire-starting kit
• Carbon monoxide detector where appropriate
• Suitable sleeping bag
• High-R-value sleeping pad
• Warm clothing
• Emergency communication equipment

The stove is only one part of the winter-camping system.

A warm shelter cannot compensate for inadequate sleeping insulation, poor clothing, or unsafe fire management.

Frequently Asked Questions

Can you use a wood burner in any camping tent

No. Only use a wood burner in a shelter specifically designed or approved for wood-stove use, with the appropriate stove jack and clearances.

Does a camping wood burner need a chimney

A wood burner used inside a compatible enclosed shelter requires a properly designed flue system to exhaust combustion gases outside. Never operate a tent wood stove without its complete chimney system.

How long should a camping stove chimney be

There is no universal chimney length. It depends on the stove, tent, stove-jack location, chimney diameter, and manufacturer specifications. Use the chimney configuration recommended for your stove.

Can you leave a wood stove burning while sleeping

Do not assume that you can safely leave a wood stove burning unattended overnight. Follow the manufacturer's instructions and your shelter's guidance. For many camping situations, allowing the fire to go out before sleeping is the safer approach.

Can you use a wood burner in a nylon tent

Do not use a wood stove in a nylon shelter unless the manufacturer specifically states that the tent is designed and approved for that application. Many conventional synthetic tents are not suitable for hot-tent stove use.

Is titanium or stainless steel better for a camping wood burner

Titanium is usually attractive for lightweight backpacking, while stainless steel is often better suited to heavier base-camp use. The best material depends on your priorities for weight, durability, cost, and frequency of use.

How often should a tent stove chimney be cleaned

Inspect the chimney frequently during use and clean it whenever soot or creosote accumulates. Heavy or unusual buildup is a reason to stop using the system until it has been properly cleaned and inspected.

Can you burn any wood in a camping wood stove

Use dry, suitable firewood that complies with local regulations. Avoid wet, chemically treated, painted, or contaminated wood.

Final Thoughts on Camping Wood Burners With Chimneys

A camping wood burner with chimney is one of the most useful pieces of equipment for serious hot-tent and winter camping. It can provide heat, cooking capability, and a dry place to recover from cold weather.

But the best setup is not simply the stove with the highest heat output.

It is a complete system in which:

the tent is compatible, the stove is correctly sized, the chimney is properly installed, ventilation is maintained, clearances are respected, and the fire is actively managed.

If you are new to hot-tent camping, start with a simple setup and practice it before taking it into severe winter conditions. Learn how quickly your stove heats the shelter, how much wood it consumes, how the chimney drafts, and how the tent behaves in changing wind.

Once those skills become routine, a properly installed camping wood burner can make cold-weather camping dramatically more comfortable while still allowing you to travel light and spend more time outdoors.