SunFire SF120: heat for buildings that have no flue, and sites that have no power

Almost every heater in a workshop catalogue assumes two things about your building: that it has a chimney route, and that it has a mains circuit where the heat is needed. The SF120 assumes neither. It is a portable radiant heater on wheels, and its electrical requirement can be met by a 12 V pure sine inverter of 800 W or more, or by a generator, as readily as by a 120 V supply at 60 Hz. The electrics run the fan, the pump and the controls — the heat comes from the fuel.

That single design decision is why this unit turns up in places a fixed appliance cannot go: a shell being fitted out, a rented bay where nothing may be installed, a job site, a paddock, a wash bay with the doors open, or a second building that only needs heat six days a year.

Radiant, and why it matters with the door open

A forced-air heater warms air, and warm air leaves through an open bay door about as fast as you can make it. A radiant heater warms surfaces — the floor, the equipment, the vehicle, the people — and those surfaces then hold and re-release the heat. In a building that is sealed, the difference is modest. In a building that is being opened every ten minutes, it is the whole ball game, because the heat you paid for is stored in the concrete rather than sitting at the ceiling waiting to escape.

It also explains why the SF120 is usable indoors at all. It is described as low-noise, smokeless and odorless, and the manufacturer's claim on emissions is precise: zero CO emissions when properly tuned and at steady state temperature. Read that as written — it is a claim about a correctly set-up unit at running temperature, not a blanket statement, and it is not a substitute for the ventilation any combustion appliance needs. Tuning is not optional on this machine; it is the condition attached to the claim.

Moving it, which is the point

Portability on heaters is usually a caster and a hope. This one is specified properly for it.

It weighs 120 lbs dry and 210 lbs with a full tank — a spread worth planning around, because a full unit is a two-person push and an empty one is not. It rides on rubber flat-free wheels, which is the correct answer for a yard covered in swarf, screws and broken glass, and the handle collapses so it can be stored or transported without catching on everything. And it carries a lifting bracket, so it can be picked up by crane, sling or forklift rather than manhandled up onto a truck bed.

Assembled dimensions are 32"L x 28.5"W x 33.75"H, which is a footprint that fits in the back of most work vehicles.

Fuel and run time

Dual fuel: it runs on diesel or kerosene, which matters more than it sounds when you are working somewhere remote and taking whatever the local supplier stocks. Flow rate is listed as .85 GPH on diesel or #2 fuel oil and .78 GPH on kerosene, from a 14 gallon tank, giving approximately 16 hours of running on high — a full working day and the night before it, so the shop can be warm when the first shift arrives without anyone refuelling at 5am.

Output is 120,000 BTUH, rated to heat up to 2,800 sq. ft.

Control and safety

The SF120 accepts any standard mechanical or battery-operated wall thermostat, which converts it from a heater you switch on into one that holds a temperature. One instruction from the specification is worth repeating because getting it wrong will cost you a thermostat: do not use a thermostat that requires 120 V to operate. Mechanical or battery types only.

A tip switch is fitted as standard and shuts the unit down if it is knocked over — a meaningful feature on a portable appliance that lives among moving vehicles and trailing air lines rather than bolted to a wall.

The specification also records the unit as UL listed, and states that it is manufactured in the USA.

Perfect For

• Rented workshops and leased bays where a flue penetration or a fixed appliance is not permitted.
• Construction and site work — run it from a generator or a 12 V inverter where there is no building supply yet.
• Wash bays, detail bays and paint prep areas that are open to the outside for much of the day.
• Agricultural and equipment yards, moving between a shed, a shop and an outdoor work area.
• Any shop with a second building that needs heat occasionally and cannot justify a permanent installation.
• Events, race paddocks and mobile service operations where the heater travels with the crew.

Specifications

Certification, and the limits of it

This unit's specification records it as UL listed, and it is the only heater on this part of our catalogue whose data actually carries that claim, so we are repeating it as recorded rather than assuming it.

What a listing does not do is worth knowing. It is an appliance-level safety assessment; it is not a statement that any particular use is permitted in your building. Portable combustion heaters are subject to local fire code, to landlord and insurer conditions, and in some workplaces to specific rules about running them indoors or unattended. The zero-CO claim above is likewise conditional on the unit being properly tuned and at temperature. Ventilate, follow the manual, and check your local requirements before you rely on it indoors.

Shipping and Delivery

Ships as freight within the lower 48 states, free of charge. Plan the unloading before you order: this arrives crated and getting it off the truck is the customer's responsibility, so you want a forklift, a dock, or an arrangement to collect it from the carrier's terminal. Tell us if the delivery address is residential, because residential delivery is a separate service with a fee attached. When it arrives, inspect the crate before you sign — note any damage on the bill of lading at handover, photograph it, and keep the packaging until you have run the unit. A clean signature is very difficult to unwind later.

Warranty

The manufacturer's warranty applies. We have not restated the terms here because they are not part of the data attached to this listing and an approximate warranty is worse than a pointer to the real one; our warranty claims page explains how to start a claim. And the standing advice for any fuel-burning appliance: leave it assembled until the claim is open. A unit taken apart before anyone has inspected the fault is a claim that has usually already ended.