Portage and Main 34 44 versus

Heatmaster MF 7000 

They Are both Shaker grate models.

They Are both pretty equal capacity models.

They both have a multi-pass heat exchanger.

One of the difference is that the Portage & Main has a fully water cooled heat exchanger. Every square inch is water cooled.

Heatmaster MF 7000 has just got a steel bypass plate.

we want to see if that water cooled heat exchanger – which is ALSO more costly to make, is it really more effective at the end of the day ???

Boiler showdown

PortageandMain 34 44 versus Heatmaster MF 7000 

Making an Informed Choice.

We Measured How Much Wood You Would Save

in this ‘9 Hour Case Study’ Featuring a Side-by-side Comparison of both boilers   

Are you exploring ways to heat your home more efficiently ? Let us guide you through the benefits of outdoor boilers, a heating solution you might not have considered yet. Our team has conducted extensive tests comparing different outdoor boilers to demonstrate their effectiveness.

We’ve meticulously prepared both boilers and stayed with them for 9 hours, ensuring they start at the same temperature and use equal amounts of wood with the same moisture content. This precise setup allows us to accurately assess their performance.

For nearly 50 years, we’ve been crafting the Portage and Main boilers, renowned for their multi-pass heat exchanger that significantly reduce wood consumption. In contrast, Heatmaster boilers, are often reported to require a lot more wood. Many of our customers have switched from Heatmaster to Portage and Main, noticing up to a 50-60% reduction in wood usage!

It simply means LESS wood burnt = MORE savings 💲 💲 💲 and

LESS time spent loading & operating the boiler = MORE time with your family and farm friends ⏰ ⏰ ⏰

Our goal today is to validate these claims. We believe that even a 20-25% reduction in wood usage is a substantial benefit. We’ve gathered data, and the results are in. So read on …

📝Part 1 of 3 : Introduction

In this three-part case study, we embark on a detailed examination of two outdoor boiler systems: The time tested – Portage and Main Boiler and Heatmaster. Our primary focus is to assess their performance under specific conditions, using Tamarack wood with a moisture content of 15-30%.

This report, being the first installment, sets the stage for an in-depth analysis, aimed at providing valuable insights for both consumers and industry professionals.


The Importance of Moisture Content in Wood Burning Explanation of how moisture content impacts combustion, efficiency, and emissions. Relevance of testing boilers with wood in the 15-30% moisture range.


Selection of Wood Criteria for choosing Tamarack wood, including its properties and common usage in boilers. Process of ensuring the wood’s moisture content was consistently within the 15-30% range.

📝Test Conditions

Description of the controlled environment where the tests were conducted. Detailed explanation of how the wood was weighed and prepared for each boiler. Key Performance Indicators for Boiler Efficiency Analysis

🔥 Fuel Consumption: Maximizing Efficiency and Minimizing Costs -Importance of Wood Conservation: Emphasizing the significance of saving wood, which directly correlates to reduced time spent in collecting firewood. Economic Impact: Highlighting the monetary savings achieved by using less wood, a crucial factor for our audience’s budget considerations.

🔥 Water Temperature: Ensuring Optimal Heat Transfer and Comfort -Temperature Consistency: Evaluating how effectively each boiler maintains a stable water temperature, essential for consistent heating performance. -Efficiency in Heating: Analyzing the ability of the boilers to reach and sustain desired water temperatures with minimal energy expenditure.

🔥 Stack Temperature: A Gauge for Combustion Efficiency -Measurement of Emissions: Stack temperature as an indicator of how cleanly and efficiently the wood is being burnt.

Below, you’ll find detailed charts and observations that will help you make an informed decision before purchasing an outdoor boiler. Discover how you can heat your home more effectively and efficiently!



📝Part 2 of 3: Introduction

In Part 2, this detailed account provides a comprehensive comparison between two outdoor boiler systems, Portage and Main and Heatmaster, focusing on their performance under specific testing conditions using Tamarack wood with a moisture content of 15-30%. Here’s a structured summary highlighting key user pain points and findings:

📝 Methodology

The wood’s moisture content was meticulously maintained within the 15-30% range to ensure consistent testing conditions. – The tests were conducted in a controlled environment, with careful preparation of the wood for each boiler.

📝Key Findings Portage and Main Boilers

🔥 Refractory Brick Advantage: The use of refractory bricks around the firebox enhances combustion, leading to more complete burns and finer ashes. This design helps maintain higher temperatures essential for efficient combustion, aligning with the fire triangle principles (fuel, oxygen, temperature).

🔥 Stable Performance: The boiler demonstrated consistent performance with less need for user intervention, like knocking down wood to prevent bridging. The design allows for even burning and efficient heat transfer, minimizing smoke and emissions.

🔥 Efficient Heat Transfer: The boiler effectively maintains water temperature, ensuring optimal heat transfer and comfort. It cycled on and off every 15 minutes or less, showing superior temperature regulation and efficiency.

📝Key Findings Heatmaster

🔥 Bridging Issues: The boiler experienced repeated bridging, where logs would not fall properly, leading to uneven combustion and reduced efficiency. This issue necessitated manual intervention to knock down the logs, which is impractical, especially during the night.

🔥 Inadequate Combustion: The design, which lacks refractory bricks and relies solely on air from underneath, resulted in incomplete combustion. This led to lower temperatures and inefficient operation, as evidenced by the boiler’s struggle to maintain set temperatures and longer cycle times.

🔥 Heat Loss Concerns: Observations indicated potential heat loss areas around the boiler, affecting its overall efficiency since it doesn’t follow the “Fire Triangle” for optimum combustion.


The comparative analysis highlights significant differences in performance, efficiency, and user convenience between the two boilers. The Portage and Main boiler, with its refractory brick design and efficient combustion, outperforms the Heatmaster boiler, which faces challenges with bridging and heat retention. These findings are crucial for consumers and industry professionals looking for reliable and efficient outdoor boiler systems.

Frequently Asked Questions

1. What is the cost of shipping an outdoor coal/wood-fired boiler?

The cost of shipping an outdoor coal/wood-fired boiler varies depending on the size of the boiler and the shipping distance. It is recommended to check with the manufacturer or supplier for an accurate shipping cost.

2. Are outdoor coal/wood-fired boilers environmentally friendly?

Outdoor coal/wood-fired boilers can be environmentally friendly if they are used responsibly and if the wood is sourced sustainably.

3. What is the typical installation cost for an outdoor coal/wood-fired boiler?

The installation cost for an outdoor coal/wood-fired boiler varies depending on the location, complexity of the installation, and the installer. It is recommended to get a quote from a qualified installer before purchasing a boiler.

4. What kind of warranty comes with an outdoor coal/wood-fired boiler?

The warranty for an outdoor coal/wood-fired boiler varies depending on the manufacturer or supplier. It typically ranges from 1 year to 20 years, and may cover different components or parts of the boiler.

5. Is customer support available for outdoor coal/wood-fired boilers?

Yes, customer support is typically available for outdoor coal/wood-fired boilers. It is recommended to check with the manufacturer or supplier for information on the type of support that is available, such as phone or email support, technical support, or service and repair support.

6. How long does it take for an outdoor coal/wood-fired boiler to heat up?

The time it takes for an outdoor coal/wood-fired boiler to heat up depends on the size of the boiler and the amount of wood that is used.

7. How do I know what size outdoor coal/wood-fired boiler I need for my home?

The size of an outdoor coal/wood-fired boiler needed for a home depends on the square footage of the home, the climate in the area, and the heat loss of the building. It is recommended to consult with a professional installer or the manufacturer for guidance on selecting the right size boiler.

8. Are there any government incentives for installing an outdoor coal/wood-fired boiler?

Government incentives for installing an outdoor coal/wood-fired boiler vary depending on the location and jurisdiction. It is recommended to check with local and state agencies to see if there are any incentives available.

9. Can an outdoor coal/wood-fired boiler be used for commercial or industrial applications?

Yes, outdoor coal/wood-fired boilers can be used for commercial or industrial applications, but the size and type of boiler needed will vary depending on the specific requirements of the application.

10. How long does an outdoor coal/wood-fired boiler last?

An outdoor coal/wood-fired boiler can last for up to 25 years with proper maintenance.

BL 25X34 | 28X40 | 34X44 | 40X44

THE ULTIMIZER COAL/WOOD SERIES helps you heat from under 2,000 sq ft to 12,000 sq ft, producing up to 500,000 BTUs

3 Reasons to choose Portage & Main boilers 


Efficient | Save Money

Portage and Main Boilers are known for RELIABILITY & high efficiency, achieved through a unique design MAXIMIZNG heat transfer and MINIMIZING heat loss. High-quality materials like stainless steel, help withstand harsh Canadian climate. With a boiler efficiency rating of up to 99%, they can help homeowners SAVE MONEY on their heating bills and reduce their environmental impact


Optimum burn | Save Time

Advanced technology to ensure CLEAN & LONG burn times, optimal performance, EASE of USE & maintenance. A simple digital control panel to adjust temperature and monitor performance. Save time and stop researching , as our R&D team designed a conventional/gasifier boiler with REFRACTORY CEMENT and FIRE BRICK lining for CORROSION PREVENTION


Easy Financing |  Flexibility

We focus on services you need, but also make sure you get what you need at the RIGHT TIME.  We understand how important it is to keep your family and dear ones warm. The Portage and Main Boilers team provides you with a flexible way to pay & offers you more purchasing power for you. Talk to us and we could help you bring home the most efficient outdoor boiler

Portage & Main Ultimizer

Unique Features & Benefits


1st : First pass
2nd : Second pass
3rd : Third pass
4th : Fourth pass
A. Refractory brick lining & dry base design
B. Air from above & below
C. Full length quad-pass heat exchanger and upper baffle
D. Water – cooled rear baffle
E. Sectional, easy to repair design

A. Refractory Brick Lining

The Portage & Main Ultimizer is a refractory lined, dry base boiler. In the industry it has become known as an “updraft gasifier” because of its efficient burn. The Ultimizer is simple to use, easy to maintain and not fussy about the fuel it burns. It is very important to understand the “fire triangle” in order to fully appreciate the advantages of the Ultimizer design, and how it will save you fuel, money and time. To achieve a clean, efficient burn with complete combustion, an optimal balance of OXYGEN, HEAT & FUEL is required. The Portage & Main Ultimizer has been specifically designed to achieve this optimal balance.

Dry base design, zero ash line corrosion & no bridging 
The heat stored in the refractory lining helps ensure that a more complete combustion process occurs. I.e. fuel is reduced to charcoal in a 3-stage process.

STAGE 1: The fuel is heated to evaporate and drive out moisture. This starts at 212 degrees F

STAGE 2: It starts to break down on a chemical level at 500 degrees F. Volatile matter is vaporized. These vapors contain 50% to 60% of the heat value of the fuel, making it imperative for them to be burnt properly at a temperature in the range 1100 degrees F for maximum combustion efficiency. When all the volatile gases have been released, the remaining material is charcoal

STAGE 3: Charcoal burns at temperatures in excess of 1100 degrees F. Latent heat also helps in the re-ignition of the fire at the start of the next burn cycle. It also helps to dissipate moisture that is a result of the combustion process. The dry base boiler design gives a very hot burn. The water jacket sits above the brick line so it isn’t up against the fire, taking away the heat prematurely. This eliminates ash line corrosion and the fuel is completely burnt, resulting in considerably less ash.

B. Air from above & below

Exhaust gases make their 1st and 2nd pass at the top of the firebox where they move under and around a water-cooled baffle and into the heat exchanger. Gases then travel to the front of the boiler in a 3rd pass, make a 180 degree turn and move in a 4th pass to the back of the heat exchanger. In this way, all available heat is taken from exhaust gases before they exit the chimney. It gives up to 50% more heat transfer compared to other non water-cooled, non brick lined designs.

C. Full length quad-pass heat exchanger and upper baffle

The Ultimizer heat exchanger runs the full length of the boiler. It is completely surrounded by water which gives maximum heat transfer.

D. Water-cooled rear baffle

The water-cooled baffle at the rear of the Ultimizer fire pot absorbs heat and traps combustion vapors. Turbulence is created when air is introduced from below and above the fire. This turbulence provides an optimal burning environment for the vapors, leading to a hotter and more efficient burn. Also, by trapping the vapors, they are thoroughly burnt before entering the high efficiency heat exchanger. This heat exchanger is totally surrounded by water for maximum heat transfer.

E. Sectional, easy to repair design

Not a throwaway design like other brands are. The Ultimizer weighs substantially more than other brand boilers. That’s due to the heavy weight, long lasting, quality materials that go into our design. It provides a long-term, sustainable solution to your heating needs. At the end of its long life, the water jacket can be replaced. Just remove the top half of the boiler and bolt on a new top section, no welding required and your trusty boiler is good to go again. This means a very sustainable warranty, resulting in savings for the customer of several thousand dollars by rebuilding rather than replacing the entire boiler.

Portage & Main Ultimizer Boiler Features



📝Portage & Main Ultimizer Features


🔥 1. Refractory Lined Firebox

The Portage & Main Ultimizer is a refractory lined, dry-based boiler. A 2-1/2″ thick refractory lining surrounds the fire pot. This absorbs heat, facilitating a hot, efficient burn. The refractory also serves to evaporate moisture and eliminate caustic ash line corrosion. The Ultimizer has become known in the industry as the “updraft gasifier” due to the efficiency of its burn. The Ultimizer is simple to use, easy to maintain, and not fussy about the fuel it burns.

🔥 2. High-Efficiency Quad Pass Heat Exchanger

The heat exchanger runs the full length of the furnace and is completely surrounded by water. This means that combustion gases are kept in the boiler for longer and that the heat is fully extracted. Exhaust gases make their 1st and 2nd pass at the top of the fire pot where they move under and around a water-cooled baffle and into the heat exchanger. Gases then travel to the front of the boiler in a 3rd pass, make a 180-degree turn, and in the 4th pass move towards the rear of the heat exchanger. In this way, all available heat is taken from the gases before they exit the chimney. This design gives up to 50% more heat transfer compared to other non-water-cooled brick-lined designs.

🔥 3. Water Cooled Baffle

The water-cooled fire pot baffle absorbs heat and traps combustion gases. Turbulence is created when air is introduced from below and above the fire. This turbulence provides an optimal burning environment for the gases and leads to a hotter, more efficient burn. The trapped gasses are thoroughly burnt before entering the high-efficiency fully water-cooled heat exchanger.

🔥 4. Water Jacket Above The Brick Line

The Ultimizer water jacket sits above the brick line – not against the fire. This eliminates ash line corrosion and means that fuel is completely burnt. There is considerably less ash. Other brands of water jackets sit against the fire and this takes away valuable heat prematurely, and bridging of fuel becomes a problem.

🔥 5. Shaker Grates

Make cleaning out ash easy. Just rock the grates with the handle. The shaker plates are manufactured from North American 3/4” plate steel – not poorer quality imported cast iron which doesn’t last.

🔥 6. Forced Air

Self-modulated air is introduced both under and over the fire, resulting in a fully efficient burn. No extra controls are required, controlled with a weighted flapper.

🔥 7. Fire Pot Loading Door

Multi-layer insulated fire door with a heavy-duty adjustable handle and superior, high-density silicone-enhanced gaskets

🔥 8. Ash Pan Or Scoop

Makes removing ash easy. Also gives an entry point for the under-fire air

🔥 9. Heat Exchanger Cleanout Door

Allows easy access to the fully water-cooled quad-pass heat exchanger.
Only minimal cleaning is necessary due to the refractory lining and high-temperature burn. Most of the smoke has already been burnt, so creosote build-up is greatly reduced

🔥10. The Front Door

Acts like a storm door on a house. Helps reduce moisture buildup and corrosion. This additional outer door combines with a multi-layer insulated inner fire door. Truly reduces heat loss

🔥 11. Back Door

Housing for the boiler hookups, aquastats, and other components. Dry, fully lockable, and secure. All insulation is covered with galvanized steel for a safer, cleaner finish

🔥 12. Aquastat

Made by Johnson Controls. Time-tested, off-the-shelf, reliable. Easy to source, easy to set, and simple to operate.

🔥 13. Water Indicator Float

The water level indicator gauge is well-placed for easy viewing and is designed to reduce evaporation.

🔥 14. Sectional Design

The Last Boiler You Need to Buy. Not a throw-away design as so many products are these days.
The heavy-duty refractory brick, which gives the Ultimizer the ability to burn hot and clean, also safeguards against ash line corrosion. This in turn means that just the top half of the boiler can be easily replaced at a fraction of the cost of a complete boiler. If you ever need to rebuild, the entire fire pot and water jacket can be removed by simply unbolting the top section from the bottom section just above the bricks. The new top section then bolts into place. In less than half a day, with no welding required, you can have a fully rebuilt boiler.


Confidently Recommended By Family & Friends

Read on ..


Clean, green wood heat from an outdoor furnace

Green, sustainable, inexpensive space heating and domestic hot water is what I wanted for my house and workshop.


It was early 2010 when I began researching outdoor wood furnaces as an option for making this happen. A week before this past Christmas, I lit the first oak and maple fire in the unit I installed, and my hints at this project in my columns over the last few months have got people asking me for more specifics.

Outdoor wood furnaces have been around for decades, but it’s only in the last few years that new combustion technology means these systems now burn clean enough to be considered truly green.

All outdoor wood furnaces look pretty much the same from a distance. Imagine a small, metal building, like a half-size garden shed. There’s a door at one end that opens into a firebox. Energy from burning wood heats water to about 82C (180F) in an insulated tank within the building, where this water is available to be circulated to and from structures to be heated via underground pipes. The hot water can be used in radiators, in-floor heating pipes, or to warm air used in forced air heating systems.

Outdoor furnaces move the fire, ash and danger of heating with wood outside. They also have large fireboxes that handle big wood that’s easier to cut and split than smaller stuff. These are the two main advantages that got me thinking about outdoor wood furnaces in the first place. But as I soon discovered, there are two technical issues when it comes to assessing the quality of any particular unit. First, what percentage of heat energy from the wood actually makes it to the water in the storage tank? And second, how cleanly does the unit burn?

When the guy who works at the little country hardware store where I buy my stuff heard I was installing an outdoor furnace, he wondered why. “Don’t those outdoor furnaces burn a rainforest worth of wood each year?” Well yes, they do. Or at least some models do. The difference between efficient and inefficient outdoor furnaces means burning either 15 cords of wood a year or 30, and as I discovered, something called a fire-tube boiler is key to frugal operation.

The outdoor furnace I bought is made by a Canadian company called Portage and Main, and their fire-tube boiler design is one reason I chose them. Multiple hollow steel tubes run through the boiler tank itself, surrounded by water. Exhaust gases are directed through these tubes where they transfer huge amounts of heat to the water before heading up the chimney.

This fire-tube design originated in 1804, and was an enduring feature of marine and locomotive boilers in their time. Fire tubes are even used in modern industrial boilers today.


MORE Client TestimoniaLS


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About Portage & Main

Our head office is located in Prince Albert, Saskatchewan, Canada. Our dealer network spans North America and we would be glad to put you in touch with one of our knowledgeable agents. Our staff oversees the development of new products, monitors production, designs heating systems, and offers tech support for installers. All our wood furnaces are designed for installation outdoors and deliver wood heat indoors.






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