Compared: Shelter SF1000E Vs. US Stove Hot Blast HB1520

Thanks to recent New Source Performance Standards (NSPS) from the EPA, homeowners searching for a wood furnace to heat their home now have fewer choices than ever. This fact is a double-edged sword: fewer choice makes it less likely for you to find a furnace that fits your specific needs and preferences. But it also makes it easier to learn about your options.

After the EPA’s new regulations, there are really only four key manufacturers left making residential wood burning forced-air furnaces:

• HY-C (under our Fire Chief and Shelter brand names)
• US Stove
• Drolet
• Lamppa Manufacturing

Even with so few brands and models to choose from, it can be difficult to find the right wood burning furnace for you. That’s why in this guide, we want to compare two popular EPA-approved models: the US Stove Hot Blast HB1520 and the Shelter SF1000E.

We’ll take a head-to-head look at the specifications of each furnace, examine their clearances to combustibles, do a deep dive on their pricing, and much more.

By the time you’re finished here, you should have a much better sense as to which wood furnace is the best choice for you.

Model comparison:

Shelter SF1000E Vs. US Stove Hot Blast HB1520: Specifications

There’s no getting around it — a furnace’s specs are a huge driver in the decision-making process for most buyers. Both furnaces are relatively close to one another in their capabilities, but there are some key differences that set them apart.

US Stove maintains that their HB1520 is capable of heating living spaces up to 3,500 square feet. The Shelter SF1000E, on the other hand, is better suited for (relatively) smaller homes around 2,500 square feet in size.

When it comes to delivering heat, the SF1000E is powered by a distribution blower rated for 1,800 cubic feet per minute (CFM) capable of delivering up to 143,500 BTUs per hour. By contrast, the Hot Blast HB1520 utilizes two distribution blowers rated for 500 CFM each. These twin blowers combine to deliver up to 180,000 BTUs per hour.

Finally, there’s efficiency — the percentage of the furnace’s maximum peak input that ends up being delivered into the living space as heat. US Stove’s Hot Blast 1520 features an efficiency rating of 75%, while Shelter’s SF1000E has an efficiency rating of 79%.

Now, let’s dive a little deeper to learn more about how these furnaces stack up — specifically with regard to their clearances to combustibles.

Shelter SF1000E Vs. US Stove Hot Blast HB1520: Clearances to Combustibles

Clearances to combustibles are important safety specifications that need to be followed when installing a wood furnace. Here’s how they’re defined:

Clearances to combustibles are the distances from which a specific side of a wood burning furnace must be kept from flammable material (like paper, wood, or drywall) to ensure their safe operation.

After all, a wood furnace is essentially just a metal box with a fire inside. And even despite the steel walls that enclose the fire, the unit still needs to be kept a certain distance away from combustible materials on all sides. Here’s what that looks like in practice:

The Hot Blast HB1520 unit itself measures 23-½” in width and 31” in depth. To ensure safe operation, it requires 26 inches of clearance behind the unit, 16 inches on either side, and 48 inches on the front.

Taking all of these measurements into consideration, the HB1520 requires about 40-½ square feet of space for proper installation — about 5 square feet for the unit itself, and about 35-½ square feet around the unit to meet clearance-to-combustible requirements.

The Shelter SF1000E, on the other hand, measures 25-½” in width and 28-⅜” in depth. Its clearances to combustibles are 12” behind the unit, 6 inches on either side, and 48 inches in front. This results in a required installation area of approximately 23 square feet — about 5 for the unit itself and an additional 18 around the unit.

All of this means that the US Stove Hot Blast HB1520 requires a good deal of space around it to ensure safe installation. If you want one of these units, it’s imperative to ensure you have enough room to install it.

If your space is limited, a Shelter SF1000E can accommodate tighter installs while still operating within safe clearance-to-combustible limits.

Shelter SF1000E Vs. US Stove Hot Blast HB1520: Firebrick

We’ve talked at length about firebrick before and its importance in the insulation and heat distribution of a wood furnace. When it comes to the types of firebrick that comes preinstalled in the SF1000E and the Hot Blast HB1520 furnaces, there’s a major difference:

• The HB1520 comes with pumice firebrick
• The SF1000E comes with clay firebrick (from Alsey Refractories Co.)

Clay and pumice firebrick differ quite a bit from one another. For one, in terms of structural integrity, firebrick testing reveals that clay firebrick breaks under 28,498 pounds per square inch (psi) of pressure, while pumice brick breaks under 6,044 psi. This means pumice firebrick is very fragile compared to clay brick, and you’ll likely need to buy and replace it more often.

The same firebrick testing reveals that clay firebrick heats through very evenly, while pumice firebrick tends not to transfer heat nearly as efficiently. In simple terms, this indicates that clay firebrick insulates the furnace and disperses heat much better than pumice brick.

Overall, clay firebrick is a lot tougher than pumice brick. It also absorbs and transfers heat more effectively, protecting the interior structure of the furnace while allowing it to distribute heat optimally.

Shelter SF1000E Vs. US Stove Hot Blast HB1520: Price

The MSRP for US Stove’s Hot Blast HB1520 is $2,499. The MSRP for the Shelter SF1000E is $3,250. And while these figures seem pretty cut-and-dry, the reality is a bit more complicated — and the price you pay may vary.

It’s important to remember that MSRP stands for manufacturer’s suggested retail price. Manufacturers produce goods and come up with a recommended price point for retailers, but those retailers are free to charge whatever they want for the products they sell.

For example, at the time of writing, one major retailer sells the Shelter SF1000E for $2,199.99. That same retailer sells the Hot Blast HB1520 for $1,999.99.

Another major retailer sells the SF1000E for $1,999.93, while yet another retailer sells the HB1520 at MSRP for $2,499.99.

MSRPs are a good indicator of what you might expect to pay for a wood furnace, but they’re not the whole story. Be sure to shop around to find the best price for your wallet. Also, try to take advantage of deals and discounts that may be available for either the units themselves or their shipping costs.

Shelter SF1000E Vs. US Stove Hot Blast HB1520: Installation

There’s a lot that goes into installing a wood burning furnace, but the process can essentially be broken down into 4 steps:

1. Getting the furnace to its location
2. Hooking the furnace up to the building’s ductwork
3. Installing a chimney for the furnace
4. Installing the furnaces’ electrical components

Let’s compare the HB1520 and the SF1000E to see how they stack up with each other throughout these four steps.

1. Getting the Furnace to Its Location

Furnaces are heavy. But when it comes to getting one where it needs to go, the SF1000E has a bit of an advantage. At 45-½" x 25" x 42", it’s a bit smaller than the HB1520, which measures 45" x 25-⅜" x 54-¾". It also weighs 150 pounds less, clocking in at 435 pounds to the HB1520’s 585 pounds.

Its lighter weight and smaller frame make maneuvering the SF1000E a bit easier and getting it to its installation location less of a hassle.

2. Hooking the Furnace Up to Ductwork

When it comes to connecting the furnace to ductwork, the SF1000E is a bit more DIY-friendly than the HB1520.

The Shelter unit comes with both a built-in plenum and two ductwork connection points. Hooking it up to the existing HVAC ducts is as easy as cutting a few 8-inch holes in the ductwork and adding some prefabricated ducts to complete the connection.

The HB1520, on the other hand, requires a customized plenum built by a sheet metal fabricator. From there, it’s possible to install the plenum on your own, but making it yourself is a tough task better left to a professional (as is its installation for some homeowners).

3. Installing a Chimney

For both furnaces, the process of installing a chimney will be essentially the same. Both furnaces come with a 6-inch chimney pipe connection on the back. Whichever furnace you buy, building, installing, and connecting the chimney will be a virtually identical process.

4. Installing the Furnaces’ Electrical Components

Similarly to its built-in plenum, the Shelter SF1000E comes with pre-wired electrical components. To install them, all you need to do is attach the blower motor, draft induction blower, and fan limit control to the furnace. From there, all of the electrical components simply plug into the electrical control hub (the same way a lamp plugs into an outlet).

The US Stove Hot Blast HB1520, on the other hand, requires a bit more technical electrical expertise. The components are not pre-wired, and in some cases, you may need to hire an electrician to complete the installation to ensure everything is set up safely.

Which Wood Burning Furnace Should You Get?

This has been a close look at the Shelter SF1000E and US Stove Hot Blast HB1520 wood burning furnaces. It’s a lot of information to take in and understand, and you may be wondering, “Which furnace should I get?”

To answer that question, start by considering the size of the installation area where you want your furnace to go. If you have a lot of room, either furnace will suit your needs nicely. If you're limited on space, the SF1000E may give you a bit more room to work with.

On the specs, the HB1520 has advantages in some areas. It’s rated to heat more square footage and it delivers a bit more heat overall. On the firebrick front, though, the SF1000E’s clay brick outperforms the HB1520’s pumice brick in a number of key aspects.

When it comes to price, the answer is complicated. While the HB1520 has a much lower MSRP, as we’ve seen, MSRP rarely reflects the reality of what retailers charge for these furnaces. In some cases, the Hot Blast is cheaper. In other cases, the SF1000E is cheaper. Be sure to shop around and compare prices to get the best deal.

Finally, when it comes to installation, the answer depends on whether or not you plan to do a self-install or pay a professional. For DIYers, the SF1000E was designed to be as easy to install as possible. If you’re paying someone to do the work, though, the ease or difficulty of installation won’t make much of a difference to you.

Overall, be sure to assess what you want in a wood burning furnace and choose the model that suits your needs best. And if you want more model comparisons, check out how the Fire Chief FC1000E stacks up against the HB1520.