2023 Reviews — Best Gas Garage Heaters for Homeowners

Big Maxx is one of the leading brands, known for overall quality and manufacturing some of the best gas garage heaters for the money. This 50,000 BTU model (MHU50NG) is a popular size, capable of heating a 3-car garage, or up to about 1250 sq.ft. Out of the box it’s ready for natural gas (NG) but if you need it to run on propane (LP) it includes a conversion kit so can convert it from NG to LP. This heater is also perfect for heating up a workshop. We do a full review of this model later in the article, so for now, let’s take a look at more excellent gas heaters.

NOTE: If you want a propane version of the Big Maxx you see above, then you can skip the conversion process and just buy the propane model MHU50LP — it’s also 50,000 BTU.

— Tis’ the Season to Need Heating…

Usually around late October people start looking for the best gas garage heater for their home, and/or workshop, barn even small industrial spaces. The versatility is quite vast for these garage heaters. Basically, if you need to heat large open spaces then you probably need a gas heater to keep it warm. It’s that simple

In this buying guide we review a wide-range of gas garage heaters that we feel are worth your money. Plus, we discuss other important things you should know like garage heater safety and choosing the right size gas garage heater for your space.

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Best for Workshop & Garage: Overhead Radiant Heater / Natural Gas

Heatstar By Enerco F125444/ MH25NG — 25K BTU

This NG heater is ideal for workshops and garages, especially where ceilings are low, between 7 to 9-feet. Radiant heaters emit infrared which quickly warm up people. These work just like infrared sauna’s, and if you’ve used one you know that it warms you up from the inside out. Great intense gas heater.

What’s the Best Gas Garage Heater?

Every year, around this time, we review a lot of garage heaters. As the cold weather starts setting in, people realize the need to install or upgrade their garage or small shop heaters. Usually, we look at a selection of both gas and electric garage heaters. This time, I’m going to focus the review entirely on the best gas garage heaters. The models will include natural gas, this is piped gas that is supplied to your home by a utility company, as well as propane, gas that you buy in bottles or tanks.

In total, there are nine different gas heaters for the garage included in this review. That’s a lot of specifications to work through, and they aren’t always that different. To help you find the best gas garage heater, I’ll provide a comprehensive buyer’s guide after reviewing the products. I’ll discuss the pros and cons of gas garage heaters vs electric. I’ll also help you determine what size garage heater your need based on the size of your garage or shop. I’ll even provide installation and safety tips for a gas garage heater.

VIDEO | Installing A Gas Garage Heater

Choosing the best gas garage heater for your needs

When deciding which is going to be your best choice of the gas garage heaters available to you, there are two main factors to consider. Deciding, before you read the review, which is going to be your best option, will save quite a bit of time. You can skim through until you find those heaters that meet your criteria.

Choosing between natural gas and propane is fairly basic. If you have access to a natural gas supply in your area, this should be your obvious choice. With natural gas supplied via a pipe leading to your home, you never need to worry about propane tanks running empty and all the hassles associated with transporting, replacing or refilling your propane tanks. Natural gas from a utility company can be much cheaper than propane and, most of the time, cheaper than using an electric gas heater. Though this will depend on your local suppliers and surcharges that may apply. If you don’t have the advantage of natural gas, then propane is obviously going to be your only option, other than electric. I’ll discuss the two types of gas used for garage heaters in the buyer’s guide.

Size is important. The larger the gas heater, the more expensive it’s going to be. No one wants to spend extra money if they don’t need to. So you want the size of your garage heater to perfectly match your needs. If you’re not sure which size gas garage heater is best for you, you’ll get the all the information that you need lower down the page.

Best Gas Heater for Large Workshop or Garage

Mr. Heater MHU125 — 125K BTU

Ultra-fast heating. Turn it on and your garage or shop will be toasty warm within an hour. Install this in a smaller garage or workshop and you’ll heat up your space even quicker. Most people wait until their indoor space is unbearably cold before installing a gas heater, but you can save yourself the frustration and discomfort by preparing before the cold wave arrives. It always does. Stay Ready!

Basically, you should buy a gas garage heater that is one size up from the calculated BTU requirement for your garage. So, if you calculate your heating requirement to be 38,000 BTU, a 40,000 BTU gas heater is going to be your best option. Under sizing your gas heater may save a bit today, when you buy the garage heater, but you’ll get something that is never going to do the job properly. So you want to go for the size that is the most economical, but still able to provide the heating needed to keep your garage or shop snug all winter long.

Like I said, I’ll go into all the facts and tips regarding gas garage heaters later in the article. For now, let’s take a look at what’s on offer. Our review of the best gas garage heaters. To make your life easier, I’ll be dividing the review into two sub-headings: Best Natural Gas Garage Heaters and Best Propane Gas garage Heaters. Many of the natural gas garage heaters have adapter kits that will allow them to be used with propane.

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VIDEO — How to Install a Big Maxx Gas Heater

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Best Gas Garage Heaters / 2023

Modine HD45AS0111: 45,000 BTU Gas Heater

One of the best gas garage heaters for the money that consistently gets rave reviews from customers. Ideal for

Features:

Overview / HD45AS0111

Commonly known as the Hot Dawg garage heater, the Modine 45,000 BTU gas garage heater is extremely popular. There are several good reasons why people are so endeared to this product. A big reason for this is the brand’s reputation. With well over a century of experience behind them, Modine is a highly respected manufacturer of heating equipment for the home, garage, and industrial or commercial applications.

The Modine HD45AS0111 is designed as one of the best gas heaters for a garage, in that it’s compact, easy to install and operate, as well as being highly efficient. While the Modine Hot Dawg is primarily intended as a natural gas heater, it comes with a propane adapter kit. You can use this gas garage heater with the most convenient gas type for your situation. The heater also comes supplied with a high-altitude kit.

VIDEO | History of Modine

With a heating capacity of 45,000 BTU, the Modine HD45AS0111 is one of the smaller gas garage heaters in this review. It’s more compact than most, measuring 26” X 12” X 16.5”. It weighs a fairly hefty 60-pounds, but that is quite within the normal range for a quality, 45,000 BTU gas garage heater. With side ventilation, it can be mounted quite close to the ceiling, so it won’t be in the way. It has electric ignition, using standard 115V power. The total amperage requirement for the ignition system and the circulation fan is 3.7A. This makes it a very efficient heater as far as electric consumption goes. The gas burner efficiency is rated at 80%, it’s not going to use as much gas as most similar sized forced ventilation gas garage heaters.

Installation is simplified by the use of dual piping positions, you can connect your pipes to either the left or right of the heater. The standard power exhaust allows for small diameter vent pipes and roof or side wall exhaust. The unit mounts easily, using ceiling brackets for DIY installation. Though it’s best to use a certified gas installer who knows your local regulations for gas pipes and connections. Incorrect installation can result in a fine from local authorities or, even worse, your insurance company may refuse to pay out for any kind of fire damage to your home if you have a gas installation that has not been installed by certified technician.

Even if your garage heater is not the cause of a fire, it may provide a reason for some insurance companies not to honor your claim. It’s better to play it safe and I’ll discuss the matter of gas heater installation, as well as safety considerations later in the article. This gas heater is designed for ceiling mounting, it’s not suitable for wall mounting.

The Modine Hot Dawg is one of the more expensive gas garage heaters that you can get. But that also means it’s one of the best in terms of safety, quality and ease of use. If you’re not looking for the cheapest gas garage heater, but rather one of the best, this could be the one for you. That is if you’re looking for a small to mid-sized garage or workshop heater.

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Mr. Heater Big Maxx MHU80NG (F260560)

80,000 BTU: Best gas garage or workshop heater

Applications : Residential Garages, Metal Buildings, Warehouses, Agricultural Building, Storage Buildings

Features :

• 80,000 BTU per hour
• For use with natural gas
• Heats up to 2,000 sq. ft.
• Spark ignition features self-diagnostic control module
• Includes 2 angle brackets for ceiling mount
• Low Profile Design – Can be installed in low-ceiling buildings
• Minimum 8 ft clearance from floor to base of heater required
• 1/2″ gas connection
• Category 1 vertical, category 3 horizontal venting
• Natural Gas to Liquid Propane conversion kit included
• Thermostat sold separately
• Size : Length : 29.33 / Width : 15.50 / Height : 26.37
• 3 year Limited on parts and burner, 10 year limited on heat exchanger

✓ View or download the MANUAL for the Mr. Heater Big Maxx MHU80NG.

Overview

One of the biggest attractions to the Mr. Heater Big Maxx range is the wonderfully cheap price. If you consider that this 80,000 BTU gas heater is a good deal cheaper than the 45,000 BTU Hot Dawg (reviewed above), it is difficult to ignore. Does the fact that it’s so much cheaper make the Mr. Big garage heater an inferior product? I suppose that depends on how you look at it. Going by the customer reviews, it appears that the more expensive Modine has had fewer complaints. This certainly points to better quality control at the factory.

INSTALLATION VIDEO | Indepth Installation & Operation

In many respects, the Mr. Heater Big Maxx isn’t as user friendly, or as easy to install. It really comes down to that old saying: you get what you pay for. By all accounts, the Mr. Heater appears to be a well-made, durable product. The issues raised have mostly been about faulty components and not really the general quality of the materials used or the actual design of the heater. By all accounts, the guys at Mr. Heater are very helpful and eager when dealing with customer complaints. They provide a good warranty. So, if you’re one of those unlucky few that do get a defective component in your gas heater, they will probably sort it out for you quite quickly. This may be a bit of an inconvenience but, in the end, you’re going to get a gas heater that does the job and should work well for quite a few years.

Judging by the weight, there’s a lot of metal in this heater. The Mr. Heater 80,000 BTU Big Maxx weighs an incredible 95-pounds and measures 30.31” X 27.55” X 22.04”. This is a bulky, heavy gas heater, which is going to present a few challenges when it comes to installation. Then again, it’s a very powerful heater and that will always mean that you’re getting a larger unit.

Once you’ve taken the weight and size of this heater into account, your installation is as easy as the best of them. So it has power ventilation with pipe connections for side wall or ceiling vents and a kit to adapt the Mr. Heater for propane use. The heater has electronic ignition with self-diagnosis and a low oxygen safety shutoff.

With a 3-year warranty on all parts and burners, along with 10-years for the heat exchange, I wouldn’t be too worried about buying such a cheap gas garage heater. They’re obviously quite confident about the quality of this product to offer such a generous warranty period. This warranty is quite necessary when we consider that there have been a few issues with some components leaving the factory floor with defects. At least you know you’re covered and the guys at Mr. Heater appear to be more than willing to assist their customers with friendly after sales service. If you want a cheap gas heater for your garage, this is certainly one of your best options in the 80,000 BTU range.

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Mr. Heater Big Maxx MHU50NG (F260550)

50,000 BTU : One of the best gas garage heater for large work spaces up to 1250 sq.ft.

Features:

Overview

As part of the Mr. Heater Big Maxx series, the MHU50NG is basically the same as the 80,000 BTU model that we’ve just looked at. It’s obviously a little smaller and lighter than the larger model. But, for the rest it looks and functions like the other Big Max gas garage heaters. So it has vertical and horizontal vent pipe options (for ceiling or wall vent pipes) and all the other features are the same. I’ll only concentrate on the differences that apply to this product.

The Mr. Heater Big Maxx 50,000 BTU gas garage heater weighs a much more manageable 63-pounds and is more compact, measuring 25” X 18.5” X 17”. You need a minimum 8’ clearance from the base of the heater to the floor. This model also includes the propane conversion kit.

True to form, the Big Maxx 50,000 BTU gas garage heater is one of the cheapest in its class and has the same fantastic 3-year warranty on the critical components, along with a 10-year warranty on the heat exchange.

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Good Cheap Gas Heater if You Have High Ceilings

Mr. Heater MH40NG (F272800) / 1000 sq.ft

40,000 BTU : Transfers almost all of the fuel it burns directly into clean safe radiant heat. Ideal to be used in buildings with 12 to 15 ft ceilings.

Features:

• 40,000 BTU per hour
• For use with natural gas
• Heats up to 1000 sq. ft.
• For use in buildings with 12 to 15 ft ceilings
• Efficient infrared heat that directly heats people and objects which in turn heats surrounding air to desired temperature
• Includes adjustable thermostat for individually controlled warmth and all necessary brackets and hardware
• No electricity required
• Easy to install
• No moving parts to service
• Quiet, clean, odor-free operation
• Non-corrosive materials used throughout construction

✓ View or download the MANUAL for the Mr. Heater MH40NG.

Applications : Loading Docks, Warehouses, Factory Production and Assembly Areas, Animal Pens and Stalls, Automotive Repair Shops, Sporting Arenas, Public Entrance-ways

Overview

The Mr. Heater MH40NG, 40,000 BTU gas garage heater is departure from the Big Maxx heater range. Unlike the other Mr. Heater products in this review, this one is an infrared gas heater. It doesn’t use a forced ventilation, circulation fan. Instead, the Mr. Heater HH40NG is a radiant gas heater, using infrared ceramic panels that glow red hot. The main advantage to using this infrared heater is the simplified installation. It doesn’t require ventilation pipes or an electrical connection. In this category of gas garage heaters, the MH40NG is very reasonably priced. When using the heater continuously for long periods, infrared gas heaters are generally more economical to run. I’ll provide the details regarding gas heater economy in the buyer’s guide.

This is a very compact, lightweight gas heater and is, therefore, one of the easiest to install. It weighs only 28.2-pounds and measures 35.5” X 12.5” X 21”. You need to be aware that, as this is an infrared heater, you need greater clearances around the heater. You need to allow for 36” between the top of the heater and the ceiling, 30” to the sides and back, 68” from the base of the heater to the floor. This means you need a fairly high ceiling (12-15 ft.).

Compared to most gas garage heaters, installing the Mr. Heater MH40NG is a cinch. You need to have a gas line installed to the heater position, it will be plain sailing from here on. The heater has a bracket that allows for it to tilt up and down. This bracket can me mounted to a wall or attached to ceiling brackets. Once installed, you just need to connect the gas line to the heater and install the thermostat in a convenient place. The thermostat doesn’t require an electric connection. This means it’s perfectly simple and nothing can go wrong. The heater uses a pilot flame, so there’s no electronic ignition. Because it doesn’t use a fan, there’s no additional electric running costs.

This heater can only be connected to a natural gas supply and is not suitable for propane use. A propane version of the same heater is available. This is a separate model and cannot simply be converted with a propane kit. I’ll be reviewing the Mr. Heater 40,000 BTU propane infrared equivalent, under the heading Best Propane Gas Garage Heaters.

Customer response to this heater has been very positive. This is always a delight to see when a product is on cheaper end of the scale. It’s a real money saver as it requires basically no maintenance, uses no electricity and, in most cases, will use less gas than fan assisted gas garage heaters.

As far as your budget goes, this should be an amazing solution to your garage heating needs. Though in colder climates, it may be slightly lacking. You can read more about this in the buyer’s guide, if you’re not sure whether a smaller infrared heater is going to be your best option.

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Heatstar by Enerco F160560 (HSU80NG)

80,000 BTU : Can heat up to 2000 sq.ft. garages, warehouses, workshops or other large spaces where you need to keep warm when its cold outside.

Features:

• 80,000 BTU per hour
• For use with natural gas
• Heats up to 2000 sq.ft.
• Spark ignition features self-diagnostic control module
• Includes 2 angle brackets for ceiling mount
• Low Profile Design – Can be installed in low-ceiling buildings
• Minimum 8ft clearance from floor to base of heater required
• 1/2″ gas connection
• Category 1 vertical, category 3 horizontal venting
• Natural Gas to Liquid Propane conversion kit included

✓ View or download the MANUAL for the Heatstar by Enerco HSU80NG.

Overview / F160560

Continuing along the theme of more affordable, large gas heaters for your garage, the Heatstar 80,000 BTU model cannot be ignored. Priced between the really cheap Mr. Heater and the more expensive Modine equivalents, this natural gas garage heater (with propane kit) combines affordability with a pretty high quality standard.

At 78.85 LBS, this is not a heavy heater for its size and class. This is a forced convection gas heater with a circulation fan and vent pipes. Their website does not give any dimensions for the product, but it looks to be very much the same size as most other gas heaters that share this design, maybe a bit more compact with a better height clearance. It mounts an inch from the ceiling (minimum clearance) and is rated for a ceiling height of 8 – 12 ft. This should work for most garages.

Specifications are pretty similar to all the best heaters in this class. The 4” vent pipes can be installed for either side wall or ceiling ventilation. It has electronic ignition and this, along with the fan use standard 110V power. It has an angled ceiling mount bracket which allows you to mount it to a variety of ceiling types – you don’t need to have a flat ceiling.

An optional thermostat is available and the heater can be adapted for use with propane. The propane kit is included with your purchase.

A reasonably affordable, efficient, and well-made gas heater, the Heatstar is the ideal solution for a large garage or mid-sized shop. With a 3-year warranty on the major components (10-years for the aluminum heat exchange), you can be assured that manufacturing standards and materials are up there with the best of them.

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Heatstar by Enerco F160550 (HSU50NG)

50,000 BTU : Best gas garage heater

Features:

• 50,000 BTU per hour
• For use with natural gas
• Heats up to 1,250 sq.ft.
• Combustible Clearance : Above 1″; Behind 18″; Sides 1″
• Spark ignition features self-diagnostic control module
• Includes 2 angle brackets for ceiling mount
• Low Profile Design – Can be installed in low-ceiling buildings
• Minimum 8ft clearance from floor to base of heater required
• 1/2″ gas connection
• Natural Gas to Liquid Propane conversion kit included
• Gas Inlet Pressure : Min 3.5″ WC
• Gas Inlet Pressure : Max 14″ WC
• Mounting Height Range : 8ft – 10ft

✓ View or download the MANUAL for the Heatstar by Enerco HSU50NG.

Overview

Apart from its more compact size, there’s no telling the difference between the Heatstar F160550, 50,000 BTU gas heater and its larger 80,000 BTU brother. This too is a forced convection gas garage heater with a boxy design. Though with its smaller dimensions, will fit into a smaller area.

The features and installation requirements are the same as the larger model. It weighs a little less (63-pounds) and requires the same minimum ground clearance of 8 ft. The angled mounting bracket offers the same convenient ceiling mounting and this model also allows for side wall or ceiling ventilation. You also get a propane kit with this model.

If you’re impressed by the 80,000 BTU Heatstar but are looking for something a bit smaller (and cheaper), this is the gas garage heater for you. Quality and warranty match that of the larger 80,000 BTU model.

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Heatstar by Enerco MH25NG (F125444)

25,000 BTU : Excellent overhead garage heater for the money. Great buy.

Features:

• 25,000 BTU per hour
• For use with Natural Gas
• Heats up to 500-600 sqft
• For use in buildings with 7 to 8ft ceilings
• Efficient infrared heat that directly heats people and objects which in turn heats surrounding air to desired temperature
• Includes adjustable thermostat for individually controlled warmth and all necessary brackets and hardware
• No electricity required
• Easy to install
• No moving parts to service
• Quiet, clean, odor-free operation
• Non-corrosive materials used throughout construction

✓ View or download the MANUAL for the Heatstar by Enerco MH25NG (F125444).

Overview

Like the Mr. Heater MH40NG, this also an infrared, radiant heater. They are similar in price, but the Heatstar only produces 25,000 BTU per hour, whereas the Mr. Heater is rated at 40,000 BTU. In reality, this is a more expensive heater when you take the size difference into account. This is something I’d expect as Heatstar by Enerco is the more expensive brand. With this, one would expect a better level of quality and a more efficient design. By my observations, this certainly seems to be the case.

With a 99% efficiency rating, this little infrared gas garage heater is going to keep your gas bills low. This, alone, makes it a worthy investment. Spend a little extra on a quality gas garage heater and then save money on gas for the rest of its lifetime. The convenient wall mount bracket allows for overhead heating in an area with limited ceiling height. Your minimum clearance for this heater is only 7 – 8 feet. The minimum clearances make it a very versatile heater: 14” to the ceiling; 16” for the sides; 12” back and 48” below. It requires no electric installation or ventilation pipes and is probably one of the easiest gas garage heaters to install. An optional millivolt thermostat is available and, this too, requires no electric wiring.

The reflective frame, surrounding the 3 ceramic gas burners increases the heating ability of this, already very efficient gas heater. The specs on Amazon can be a little confusing, by including the words “40 LB propane capacity”. I’m not too sure what they mean by this. The Heatstar MH25NG is a natural gas heater and I see no indication (anywhere) that this heater can be used with propane.

I really like the practical and versatile design of this gas garage heater.  All round, the quality seems to be of a very high standard. Along with its great efficiency, I think that the Heatstar 25,000 BTU radiant heater is worth the price. There’s a 1-year warranty on the gas control and 3-years for the burners.

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Best Propane Gas Garage Heaters

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Unlike the most natural gas heaters, those designed to run exclusively on propane, cannot be adapted. So the two gas heaters in this section of the review are only to be used with propane tanks.

Mr. Heater MH40LP (F272700) | Not available.

40,000 BTU : Best overhead propane garage heater if you have high a high ceiling.

Features:

• 40,000 BTU per hour
• For use with propane gas
• Heats up to 1000 sq. ft.
• For use in buildings with 12 to 15 ft ceilings
• Efficient infrared heat that directly heats people and objects which in turn heats surrounding air to desired temperature
• Includes adjustable thermostat for individually controlled warmth and all necessary brackets and hardware
• No electricity required
• Easy to install
• No moving parts to service
• Quiet, clean, odor-free operation
• Non-corrosive materials used throughout construction

Overview

I’ve already reviewed the Mr. Heater MH40NG natural gas infrared heater. This model, the Mr. Heater MH40LP, is the same heater that’s been designed for propane use. If haven’t read the review of the MH40NG, I’ll run through the specs again.

As with any radiant infrared heater, the Mr. Heater MH40LP is compact and very easy to install. It requires no electrical installation. You just need a propane tank and the required pipes and fittings. The thermostat, that’s supplied with the heater also requires no electric connection. This heater requires a minimum #40 propane tank.

While its size is good (35.5” height and 12.5” width), it requires substantial clearance for safe use – 30” to the sides and back, 68” from the base of the heater to the floor. This means you need a fairly high ceiling (12-15 ft.). The weight and wall bracket make for a hassle-free installation. The Mr. Heater MH40LP weighs only 28.2-pounds.

With its 99% efficiency rating and a very reasonable purchase price, the Mr. Heater MH40LP is very economical gas heater for any garage or shop up to a size of about 1000 sq. ft. The limited warranty of only 1-year isn’t as good as the other gas heaters in this review. Though I don’t believe this reflects on the quality of the product. For a propane gas heater at this price, this is a one of the best.

Do you have any questions about Mr. Heater heaters? Well, visit the Mr. Heater University page to learn more about their heaters.

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Mr. Heater MH60QFAV (F271370)

60,000 BTU Forced air Propane heater

Features:

• 60,000 BTU per hour
• For use with propane gas
• Heats approximately 1500 sq ft
• Runs up to 14 hrs on 20lb tank (low setting)
• High temperature limit switch
• Continuous ignition
• QBT Technology – 50% Quieter than a standard propane heater
• 10ft hose and regulator included

Overview

The biggest attraction to this powerful propane heater, has to be its portability. It can be used as garage heater whenever the need arises, but is just as useful on a jobsite, to dry out your basement or when trying to dry masonry and paintwork in damp conditions. You can even use it as an outdoor heater when entertaining. So, in terms of versatility, this is a fantastic propane heater, with any number of uses. Buying the Mr. Heater brand means you’re paying very little for a good level of quality.

Weighing only 13-pounds, with dimensions of 16” X 8.8” X 13.5”, the Mr. Heater MH60QFAV is a truly portable gas heater. It has a carrying handle to facilitate easier moving. Although compact and light, this heater delivers the goods as far as heating goes. Using any of the variable settings, it will provide 30,000 to 60,000 BTU, using a fan to provide forced convection rapid heating. At the lowest setting, you can expect up to 14-hours from a 20 LBS propane tank. By using QBT (Quiet Burner Technology), the MH60QFAV is much quieter than most conventional propane heaters – they claim up to 50% noise reduction.

Safety is fully taken care of. It has high-temperature limit switch is CSA certified. This heater has continuous ignition and requires 115V electric supply for the electronic ignition system.

Powerful enough to fulfill most heating requirements, the wonderfully cheap Mr. Heater MH60QFAV is big hit amongst homeowners and contractors alike. The versatility of having a portable garage heater speaks for itself.

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Buying Guide: Garage & Shop Gas Heater

I’m now going to discuss all the details regarding garage heaters. I’ll start off by looking at the pros and cons of gas garage heaters vs electric. Is a gas garage heater really your best choice? I’ll look at the various types of gas: what is the difference between natural gas and propane? How do you install a gas garage heater and what are the important safety considerations? This buyer’s guide is going cover all of this in a detailed and easy to understand manner.

Gas Garage Heater vs Electric Garage Heater

Gas is the most efficient way of heating. Whether it’s for cooking, heating your home, or your garage, gas is usually going to be the most economical way of doing things. It’s for this reason that gas garage heaters are the most popular.

An electric heater is usually cheaper to buy, but is likely to cost a lot more to run. However, in some areas, an electric heater may cost less to use. If you live in an area where natural (piped) gas is not available, you’ll be forced to use propane gas in tanks. This can be expensive, but not always. It’s a good idea to compare the cost of your gas options vs electric supply in the area that you live. Generally, you’ll find that natural gas is going to work out as the cheapest.

One should also consider the proximity of your garage in relation to your electrical or gas supply. If your garage is far from the house, propane may be the easiest and, possibly the cheapest of your options. At least, when it comes to your initial installation. Though you must balance this against your long term running costs.

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Types of Gas Garage Heaters

There are two types of gas heaters that you can use to warm your garage or shop. These being forced air gas heaters that use a fan to circulate the heat, and infrared gas heaters that radiate the heat from the heater.

Although they are generally less efficient, forced air (or forced convection) gas heaters tend to be more popular. This is mostly because there are fewer safety concerns and they heat the area more rapidly. Forced air gas heaters have ventilation pipes that ensure that there is no risk of low oxygen levels in the area. This simplifies your safety, but complicates the installation. You need to install ventilation pipes to the outside of the building. Because of the circulation fan, your garage will heat up much quicker than it would if you were using a radiant, infrared heater. Though the continuously running fan and the exhaust vents mean that the heat dissipates more rapidly. This means that it consumes more gas than a radiant gas heater.

When comparing efficiency, the best forced air gas heaters are about 80% efficient, whereas the best infrared gas heaters are almost 100% efficient (often rated at 99% efficiency). In addition to the gas used, forced air heaters use a certain amount of electricity, so you’re paying for both gas and electricity.

Infrared gas garage heaters don’t require a vent pipe, making them easier and cheaper to install. Though this poses a risk because there is no circulation of fresh air into the garage. Some users opt to install additional ventilation for safety reasons. DIY enthusiasts who work with wood or spray paint often prefer a radiant heater as there’s no fan to stir up dust in garage.

These heaters radiate the heat from ceramic panels and don’t use a fan to circulate the heat. This means that heat is absorbed by solid objects and people in the garage and is then radiated into the surrounding air. While this takes more time to heat the area, there is virtually no heat loss. Once the garage is heated, it requires less gas to keep the temperature stable. If you use the area for long periods of time, a radiant heater is going to save quite a bit.

Because these heaters don’t use a circulation fan, there is an additional safety concern. The heat will always be greatest around the heater because the air is not blown away by a fan. This means that flammable objects close to a radiant heater run the risk of igniting. For this reason, the safety clearance distances around an infrared heater will always be greater than that of a forced air heater.

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What’s the difference between natural gas and propane?

Propane or Liquefied Petroleum Gas (LPG) and natural gas (Methane) are the most popular fuel sources used for heating. While they are used for the same applications, the type of gas differs and cannot always be used for the same heating equipment.

Natural gas, or methane (CH₄) occurs naturally and is piped from under the earth’s surface or under the oceans. This gas is abundant and has very low emission levels. It is, therefore, considered to be an environmentally friendly fuel. It has a lower calorific value when compared to propane (38.7MJ/m³ vs 93.27MJ/m³).

Propane (C₃H₈) can be compressed into a liquid state (LPG) and stored in tanks, making it a portable form of gas that can be used anywhere. Because of its higher calorific value, propane requires a greater ratio of air to gas in order to combust. Propane needs a ratio of 25:1, compared to 10:1 for natural gas. This is the reason why you can’t interchange the one gas type for another without making some changes. Basically, the jets (or nozzles) that supply the gas to the burners need to be to provide the correct ratio of air to gas.

With a flame burner (like those used in a forced air heater), this is a simple procedure. However, infrared red heaters that use a ceramic panels don’t use an open flame and the entire panel needs to be replaced for the type of gas that is being used. You can usually get an adapter that allows your forced air gas heater to use either natural gas or propane. The same cannot be said for infrared (radiant) gas heaters.

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Gas Garage Heater Installation and Safety

Before you install a gas heater to your garage, I strongly recommend making sure that you have the best insulation possible, in both your ceiling and walls. A drafty, badly insulated garage is simply going to let all the heat escape and this is going to drive up your running costs astronomically.

VIDEO | How to Install A Garage Gas Heater

If you’re a capable DIY guy, it should be quite simple to do most of the installation yourself. Though it’s important to use a certified gas technician for the installation of the gas pipes and fittings. Adhering to local codes and regulations is mandatory. This is as much for your own safety as it is for remaining in compliance with the law. An uncertified gas installation will probably affect your insurance claims in the future.

Because forced air gas heaters are usually heavy and bulky, you’ll probably want an extra hand to help you. Deciding where to install your gas garage heater is going to be the first step. Most people install their gas garage heaters close to the garage door. This is where the cold air enters the area. So it’s a good idea to heat the cold air before it circulates through the garage. You’ll need to consider the height requirements as recommended by the manufacturer. This may mean compromising on the best location for your heater.

If the ceiling is too low close to the garage door, you’ll obviously have to install the heater where the ceiling is at an appropriate height for the minimum ground clearance. You will also need to observe the distance between the ceiling and your heater, as well as the clearance from the walls. All this information will be available in your owner’s manual. Clearance specifications will vary, so there really isn’t a one-size-fits-all way to calculate this. You have to follow the manufacturer specifications. Installing the ventilation pipes should also be done in accordance with the manufacturer specifications.

Once you’ve marked out the area where you intend installing your gas garage heater, cut the holes for your ventilation pipes and install them before installing the heater. Your gas heater will usually come with an installation kit that includes mounting brackets. Some may be for both ceiling and wall mounting, while others may be for just one or the other. Ceiling mounting brackets are often designed exclusively for flat ceilings and will need some modifications for a pitched ceiling. Using threaded rod is the best way to adjust to the height differences in your ceiling. You cut the rod to fit the highest part of the ceiling, allowing you to bolt the standard bracket at the same height as the lower part.

If you’ve followed the manufacturer’s installation procedures and adhered to the local gas/electrical codes, you should have a perfectly safe gas heater installation. When using the heater, there are a few safety aspects that you should consider.

There are usually a lot of flammable materials in your garage. These could be anything from gas cans, paint and other chemicals, as well as fabric, cardboard or wood. All flammable materials need to be stored and used a safe distance from the gas garage heater. For a forced air gas heater, it is recommended that don’t store or use flammable materials within a distance of 3-feet from the heater. For an infrared gas heater, the clearance is twice the distance, at least 6-feet. I don’t recommend using a spray gun when you have a gas garage heater in operation, the fumes emitted are highly flammable and travel over a large distance undetected. Installing a low-oxygen and fire warning system in your garage will be a good idea.

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How many BTUs does your garage heater need?

Heating any area is based on the natural phenomenon of obtaining equilibrium or balance. Basically this means that whenever there’s imbalance (one area that has more energy than another), energy will be transferred from the area where it’s highest to the area where it’s lowest. Hence the term heat transfer. To quantify the rate of heat transfer, we use the British Thermal Unit (BTU). One BTU (British thermal unit) is measured as the amount of energy (joules) needed to heat 1-pound of water, by 1°F at sea level. We can view a BTU as package of heat that is passed from one particle to another.

When we’re talking about garage heaters, your garage is a micro-environment. It is separated from the general environment by the walls and ceilings. Better insulation in your garage will make heating this environment more effective. To calculate the BTUs needed to heat your garage, we need to consider three factors: the volume of your garage, the temperature difference between your desired temperature and the ambient temperature, and the level of insulation in your garage.

Garage Size

Most manufacturers of garage heaters give you an estimated area in square-feet or they may simply say that it’s good for a 2, or 3 car garage. This is a rough estimate and will usually be based on a standard ceiling height of about 8’, with the assumption that your garage has good insulation. To improve this figure, they will usually rate their product for a mild climate where the difference between your ambient temperature and your desired temperature isn’t too great. Manufacturers always try give you the best case scenario. This is seldom the case and you will usually need a larger garage heater than what is advertised.

If you want a more accurate measure of your BTU requirement, it will mean doing the math. If all of this sounds like hard work, you can work on a basic estimate of 5,000 BTU for every 100-150F². You’ll need to account for local climatic conditions and the insulation in your garage. A cold climate and low insulation will require the highest BTU. Conversely, a mild climate and a garage with good insulation will require a lower BTU heater.

You want to know the exact volume of your garage in cubic-feet. This means first calculating the area by multiplying the length of your garage by the width. To get the volume, you multiply the area by the height of your ceiling. If you have a flat ceiling, this is simple. A pitched, or sloping ceiling is more complicated, you need to calculate the area of the triangle formed between the lowest and highest point of your ceiling. I find that it’s just as good to simply take the ceiling height at the center-point of your garage, and multiply this by your area.

Temperature Requirement

By taking the average winter temperature in your area (add about 10% to account for very cold days) and subtracting this from your desired temperature, you get the temperature difference for your BTU calculation. So if your average winter temperature is 50°F, and the desired temperature for your garage is 75°F, your temperature difference is going to be 25°.

Insulation

There’s no exact measure for insulation. We distinguish between good, average and poor insulation. Good insulation being modern energy-efficiency standards. Average insulation would be a decent level of insulation in your walls, but probably no additional ceiling insulation. Poor insulation is no additional insulation to your walls or ceiling. You can only estimate your BTU adjustment to account for insulation. If you have average insulation, add 10% to your BTU requirement for good insulation, add 20% for poor insulation.

Calculating you BTU heating requirement

For this example, I’ll use a garage that’s 18’ X 20’, with an 8’ ceiling. Our volume is, therefore 18 X 25 X 8 = 2,880F³. I’ll be assuming that the garage has good insulation.

I’ll be taking the average temperature for New York in January (27°F) and a desired garage temperature for the garage of 65°F. Our temperature difference is 65 – 27 = 38°F

We multiply the area by the temperature difference, then multiply our answer by 0.3, to get our BTU requirement. 2,880 X 38 X 0.25 = 27,360 BTU. From this calculation, we can deduce that a 30,000 BTU garage heater will be adequate for a well-insulated garage. For an average or poorly insulated garage, you’ll need at least 35,000 BTU. This would be for cold climate, like New York. In a warm climate, your BTU requirement could be half this.