Nobody likes unreliable heat, but that's exactly what happens when you buy one of the many low-quality heaters circling around the marketplace. Space heaters are particularly infamous for poor heating ability and are prone to starting fires.
That's why I recommend unit heaters for garages, barns, and other large spaces where it might not be feasible to install a furnace or ductless mini split. Unit heaters are safer, more effective, and hassle-free than portable space heaters.

Below, I've used my decades of professional HVAC experience to recommend the best heaters for various applications. Please spend some time reading through each of our categories, selections, and criteria for picking the best heaters. Remember to click on each pick to view the product page filled with more features, specs, reviews, and other great resources.

 

The Best Unit Heaters

 

Best Garage Heater	Best Large Room Heater	Best Heater for Basement	Best Heater for Greenhouse	Best Workshop Heater	Best Heater for Warehouse
Modine Hotdawg HD	Reznor UDX	Williams Forsaire Wall Furnace	Modine Effinity93	Berko HUHTA	Modine PDP

 

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How We Picked the Best Unit Heaters

When recommending unit heaters, we take five features into account.

 

Ease-of-Installation/Service

The best heaters are easy for professionals to mount, install, and service. They should require minimal mounting brackets and, ideally, will have those brackets included in the package for installation convenience. Some units include electric wiring knockouts and field wiring connections, which make it easier and faster for your installer to get the heater running on day one. Easy access to features and components makes maintenance a breeze. We look for these and other characteristics that'll make setup and service seamless. NOTE: Do not attempt to install a unit heater without a licensed, insured, and bonded professional, as it could void your warranty and pose a physical risk.

 

Features

Although unit heaters are fairly straightforward, and that's a good thing, some do include practical features that'll help you in the long term. Power venting is one feature that's important for ensuring that exhaust gases are quickly and efficiently removed from the heater. Another neat feature some units have is an external status light that blinks if there's a problem, making it faster to identify and address maintenance issues. We'll call out any feature we believe will improve a heater's performance and lifespan. 

 

Profile

Once installed, heaters should be out of sight and mind. Nobody wants a giant eyesore. That's why we look for heaters with a low mounting clearance because they rest closer to the ceiling and away from view. I also like heaters with a low vertical height for the same reason. External paint is another important factor for keeping a low profile and should be an unobtrusive, neutral color. Besides the visual aspect, you also want a unit heater that is quiet, so it doesn't interrupt whatever you're doing, whether hosting a garage party or concentrating on a task. 

 

Warranty

Although unit heaters are extremely reliable, and I've rarely seen any issues, I still place great importance on warranty no matter the purchase. After all, you want to know that you're protected if something goes awry. If two heaters seem identical in every other way, that extra year of coverage could be the deciding factor in choosing the best one.

 

Overall Value

Depending on the model, output, and capabilities, unit heaters are generally priced very fairly. Although, as I always say, value isn't all about price. A low-price unit that fails after a couple of winters isn't an advantage to anyone. When evaluating value, we look at the quality of the unit and what you're getting before weighing that against the price. In that sense, all the other criteria come into play here.

 

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Best Garage Heater: Modine Hotdawg HD 

If you spend significant time in your garage, whether working or entertaining, the Modine Hotdawg HD will keep you warm all winter without getting in the way. It's designed to keep a low profile, with a height of only 12.2 inches and the ability to mount one inch away from the ceiling on only two angle brackets. Beyond this, the Modine HD has a neutral color. It's baked on with polyester paint that not only blends the heater into your garage but offers corrosion resistance in case you use acidic products. Not only will it be out of sight, but its quiet operation means it won't interrupt whatever you're doing.

Your installer will be pleased with the Modine HD too. It comes with field wiring connections and electrical knockouts for easier installation and maintenance. Plus, certain models include the required mounting brackets in the package, so you don't have to purchase them separately. 

A power venting system quickly and efficiently removes exhaust, while the permanently lubricated motor reduces wear and tear and contributes to that quiet performance. All of this is backed by Modine's quality reputation and a two-year part, 10-year heat exchanger warranty. I would call this the go-to for any garage application and promise you won't be disappointed. 

 

Spec	Details	Rating
Ease-of-Installation/Service	Electric wiring knockouts & field wiring connections; Mounting brackets included on select models
Features	Aluminized steel heat exchanger; Permanently lubricated motor; Power venting system
Profile	Only 12.2 inches high; Can be mounted with 1-inch clearance from ceiling; Only 2 brackets required; Very quiet operation
Warranty	2-year parts; 10-year heat exchanger
Overall Value	Great price for a powerful heater that won't get in the way.

 

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Best Large Room Heater: Reznor UDX

For those looking to provide heat for a pole barn, reception hall, or other large, open indoor space, I recommend the Reznor UDX unit heater. Available in 14 sizes ranging from 30,000 to 400,000 BTUH, you'll find the perfect UDX heater for your space. When installed, the heater blends in with its two-tone black and white powder-coated, scratch-resistant paint job. Clean-rounded corners and edges offer a modern look, and there are no visible screws or fasteners. 

Speaking of installation, the Reznor UDX is easily suspended from either two or four suspension points and comes with a low-voltage terminal strip on the outside of the cabinet for easy wiring connections. There is also a status LED on the front panel that will alert you if something is ever wrong, so you can have it addressed right away. A removable front face simplifies maintenance.

Wherever you install the UDX, it will be quiet thanks to its vibration-isolated fan and venter motors that are designed for low-noise operation. With a 5-year part and 10-year heat exchanger warranty, you'll enjoy great heat for years to come with this unit.

 

Specs	Details	Rating
Ease-of-Installation/Service	Can be suspended from 2 or 4 suspension points; Includes exterior low-voltage terminal strip for simpler wiring
Features	Wide range of BTUH; Aluminized steel heat exchanger; External status indicating LED; Very quiet operation; Multi-try direct spark ignition
Profile	Vibration/noise isolation for quiet performance; Two-tone black & white color; Clean-rounded corners & edges; No visible screws or fasteners
Warranty	5-year parts; 10-year heat exchanger
Overall Value	Powerful, discreet unit heater at a fair price.

 

Who It's For:

 

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Best Heater for Basement: Williams Forsaire™ Electric Wall Furnace

Basements aren't ideal locations for venting. That's why the Williams Forsaire electric wall furnace is the perfect solution for adding warmth down there. It's particularly great for finished basements because it requires less than a foot of floor space and can be recessed into the wall or mounted right against the surface. Furthermore, the clean-looking, soft-white powder-coated finish helps the furnace discreetly blend into your décor. 

Performance is top-notch. The Forsaire's counterflow blower system improves heat distribution by moving air from the ceiling to the floor. Gone will be the days of the cold, clammy basement. What I find really neat is that you can heat two rooms with one installation by using the rear outlet register accessory (sold separately). This register allows the furnace to heat rooms on either side. Electrical operation means not having to mess with natural gas or propane, although a professional installation is still necessary.

Overall, this is a nifty little heater with a contemporary look that promises to keep your basement warmer than ever. The price point is great, and you get a one-year limited warranty. You can't go wrong. 

 

Specs	Details	Rating
Ease-of-Installation/Service	One furnace can be easily set up to heat two different rooms
Features	Counterflow blower system redirects air from ceiling to floor; Blower equipped with a self-cleaning air scoop design
Profile	Can be recessed into the wall or surface mounted; Requires less than 1 foot of floor space; Has a soft-white powder-coated finish to blend into surroundings
Warranty	1-year limited warranty
Overall Value	Compact wall furnace with a sleek, modern look at a good price.

 

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Best Heater for Greenhouse: Modine Effinity93  

If you have a greenhouse, especially one with single-pane glass, it can be difficult to control the temperature. Since most greenhouses are built inefficiently, you need an extremely efficient heater to compensate. Enter the first-of-its-kind Modine Effinity93 condensing unit heater. Its condensing technology is the same used on high-efficiency furnaces and boilers and gives this unit heater a whopping thermal efficiency rating of 93 percent! That's the type of efficiency you can count on to keep your greenhouse warm without breaking the bank.

The Effinity93 also allows for an efficient installation. It includes electric wiring knockouts and field wiring connections for streamlined electrical work. Plus, it has external thermostat connections, an easily accessible disconnect, and can be vented using PVC or CPVC. This heater does produce condensate and includes an external plug for a condensate pump. We also recommend a neutralizing system (sold and installed separately) that allows you to repurpose the condensate water for your greenhouse plants.

Overall, this condensing unit heater is revolutionary. Although it comes with a cost, you're protected with a 2-year part, 10-year heat exchanger warranty. The Effinity93 should also last for years, largely thanks to its unique anti-corrosion technology. I recommend getting the model with the stainless steel heat exchanger so it better handles the moisture inside a greenhouse. It's a solid option.

 

Specs	Details	Rating
Ease-of-Installation/Service	Electric wiring knockouts & field wiring connections; External thermostat connections; Accessible disconnect; Can be vented using PVC or CPVC
Features	Condensing technology allows 93% efficiency; Anti-corrosion technology; Permanently lubricated motor; Power venting system; Stainless steel heat exchanger
Profile	25.8 inches high, 42.5 inches wide, 33.8 inches deep
Warranty	2-year parts; 10-year heat exchanger
Overall Value	Groundbreaking efficiency that is well worth the higher price tag for greenhouse applications.

 

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Best Workshop Heater: Berko HUHTA

Many of us have workshops in the basement, shed, garage, or other space that we use year-round. To avoid needing to layer up during winter, I recommend the Berko HUHTA as the best workshop heater. For one, since it runs on electricity, you won't have any concerns about it taking in dusty air like you would with a gas unit. Besides this, it's small. With a height of only 12.5 inches, width of 14 inches, and depth of 11.75 inches, it'll take up minimal real estate. Plus, dynamically balanced fan blades keep it quiet.

That doesn't mean the Berco won't pack a punch. The built-in thermostat offers a temperature range of 45°F to 135°F. You can direct this heat horizontally or vertically, depending on how you mount the unit. Adjustable louvers offer even more control. Another great feature is the automatic fan delay. The fans wait until the heating element is warm to start moving, preventing cold air blasts.

Installation and servicing are simple. Just remove one screw, and the bottom control box swings open. Note that you will still need a professional installer to validate the one-year limited warranty. Costing less than $500, this little heater will serve you well for years with minimal investment. 

 

Specs	Details	Rating
Ease-of-Installation/Service	Removing just one screw opens the bottom control box for servicing; Can be easily positioned horizontally or vertically
Features	Built-in thermostat with a temperature range of 45°F to 135°F; Adjustable louvers; Automatic fan delay
Profile	Only 12.5 inches high, 14 inches wide, 11.75 inches deep; Quiet operation
Warranty	1-year limited warranty
Overall Value	Compact, inexpensive heater perfect for your typical workshop.

 

Who It's For:

 

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Best Heater for Warehouse: Modine PDP

 

Warehouses require serious heating power due to their size, which is why I recommend the Modine PDP unit heater. Available in heating capacities up to 400 BTUH, the Modine PDP has no problem forcing warm air across long distances with a maximum air throw of 69 feet. What's more, it uses a propeller for air movement that helps minimize the unit's depth and allows for more installation flexibility. Electric wiring knockouts and field wiring connections further reduce the time and effort spent on installation and maintenance.

Another capability I like on the Modine PDP is the power venting system that quickly ejects exhaust and minimizes installation costs related to ventilation. The unit's permanently lubricated motor reduces the required maintenance and helps increase lifespan. It also includes an ignition controller that helps prevent false starts of the unit. Finally, if you take pride in your warehouse's aesthetic, the Modine PDP is painted in a neutral polyester color that provides corrosion resistance and durability. 

The overall value is great, especially since the Modine PDP is priced hundreds of dollars less than comparable warehouse unit heaters. You won't be disappointed by the amazing heating power this compact unit provides.

 

Specs	Details	Rating
Ease-of-Installation/Service	Electric wiring knockouts & field wiring connections; Mounting brackets included on select models
Features	Propeller-based air propulsion; Aluminized steel heat exchanger; Permanently lubricated motor; Power Venting System; Ignition controller
Profile	40.25 inches high, 40 inches wide, 38.2 inches deep
Warranty	2-year parts; 10-year heat exchanger
Overall Value	Can't beat the value when it comes to effective warehouse heating.

 

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Heater FAQs 

What is a Unit Heater?

Unit heaters are self-contained heaters that use a fan to blow warm air directly into a space. They are permanently installed on the wall or ceiling and do not require ductwork. Available in a wide range of BTU options, unit heaters are also much more powerful and safer than portable space heaters. Learn more in our unit heater buyer's guide.

 

Are Garage Heaters Safe?

Depending on the type and installation, garage heaters can be perfectly safe, or a fire hazard. The unit heaters we recommend above fall into the safe category, assuming they're professionally installed and properly used. They are usually mounted on a wall or ceiling away from combustible materials and are controlled with a thermostat to avoid overheating.

It's a much different story with portable space heaters. According to the Consumer Product Safety Commission, portable heaters were involved in an estimated average of 1,700 fires per year. Often, this is because they run too long and too hot. They are often mistakenly placed near drapes or furniture that can easily ignite. Although their lower price and portability can be tempting, portable garage heaters often are not worth the risk. That's why you won't find them on our list.

 

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Is a Unit Heater the Same as a Furnace?

Although both provide heat using forced air, furnaces and unit heaters are designed for different applications. While a furnace is typically used as a central heating system for every room in a building, a unit heater is designed to heat one space, be it a garage, basement, or warehouse.

Furnaces and unit heaters both use a blower fan, but a furnace requires ductwork to distribute the warm air around the building. Since a unit heater only heats one open space, the blower throws the warm air across the room. To put it simply, a unit heater can be considered a furnace without ductwork.

 

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How Do I Size a Heater?

Sizing a unit heater is based on many factors, including your local climate, desired temperature, insulation levels, and room size/orientation. That's why we always recommend hiring a professional to do a Manual J Load Calculation to find out exactly how much heat you need for the space, which will help you choose the right-size unit heater.

 

 

About Ken 

Ken DeJong has been a versatile handyman for decades, able to adapt to every home improvement challenge thrown his way. From working on cars in his youth, to installing carpet, and even doing decorative painting, Ken is a determined jack-of-all-trades. He served as a manager at Lowes before joining the Power Equipment Direct team.

 

Ken has amassed a wealth of product knowledge across various categories, especially when it comes to heating and cooling equipment. He has taken roughly 130 hours of professional training hosted by industry vendors and now trains others in his department. He’s particularly fascinated by ductless mini splits and the inverter technology that makes them exceptionally quiet and efficient.

When he's not helping customers choose the right evaporator coil or tankless water heater, Ken puts his creativity to use designing t-shirts and writing royalty-free instrumental music. To sum up, Ken is a professional who is obsessed with acquiring new skills and sharing his knowledge to help others optimize their home living.