Description
Product Summary
The Sterling GG105A1NSA11 is a 105,000 BTU/h low profile gas-fired unit heater from the GG Series. It puts out 86,100 BTU/h at 82% thermal efficiency and moves 1,300 CFM through a horizontal discharge with adjustable louvers.
At 23-9/16 inches tall, the GG hangs close to the ceiling in garages, shops and small warehouses where headroom matters. It ships ready for standard or separated combustion venting, and it is ETL certified for commercial use and for residential use as a garage utility heater.
At a glance: 105,000 BTU/h input, 86,100 BTU/h output, 82% thermal efficiency, 1,300 CFM, 115V single-phase, natural gas, standard or separated combustion. Ships in 3-5 business days.
Key Features
- Low profile cabinet that keeps the heater up and out of the way.
- Dual venting: standard combustion, or separated combustion with a Sterling combustion air inlet kit, Category I or III, horizontal or vertical.
- Single-orifice burner in a stainless steel burner box: one burner to service and one orifice to change for an LP conversion.
- Gas conversion kit included with every unit.
- Direct spark ignition with an integrated control board and external LED status light for faster troubleshooting.
- Tubular serpentine heat exchanger with a curved, non-welded design that handles thermal stress well.
- Power vented with a combustion air pressure switch, high limit switch and OSHA fan guard.
Sizing and Coverage
Sterling sizes unit heaters from a building heat loss, not from floor area alone. Its application manual uses a short version of the ASHRAE method:
- Subtract your local outdoor design temperature from the indoor temperature you want to hold.
- Measure the exposed wall, glass, roof and floor areas, counting doors as glass.
- Multiply each area by its heat-transfer coefficient and the temperature difference, then add 10% for walls facing prevailing winds.
- Add infiltration: building volume in cubic feet x 1 to 2 air changes per hour x temperature difference ÷ 55.
- The total is the BTU/h of output the unit heaters need to supply.
For a quick estimate before you run the numbers, an insulated garage or shop usually needs 40 to 60 BTU/h of output per square foot. At 86,100 BTU/h, that is roughly 1,450 to 2,150 sq ft. Uninsulated metal buildings, tall ceilings and busy overhead doors push the need higher.
Place units so warm air blows toward the walls and doors with the most heat loss, and avoid blowing directly on people. In larger buildings, several heaters around the perimeter work better than one big unit.
| Mounting height (floor to bottom of unit) | Approx. heat throw |
|---|---|
| 8 ft | 60 ft |
| 10 ft | 54 ft |
| 12 ft | 44 ft |
Sterling does not recommend mounting this size higher than 12 ft. Throw figures are approximate and assume no discharge nozzle.
Need a different size? The GG low profile series is also available here in 75,000 BTU (GG075A1NSA11C).
Specifications
| Brand | Sterling |
|---|---|
| Model | GG105A1NSA11 |
| Series | GG Low Profile |
| Heating Input | 105,000 BTU/h |
| Heating Output | 86,100 BTU/h |
| Thermal Efficiency | 82% |
| Airflow | 1,300 CFM |
| Air Temperature Rise | 60 °F |
| Fuel | Natural Gas (field convertible to LP) |
| Ignition | Direct Spark (DSI) |
| Heat Exchanger | Aluminized steel tubular (409 stainless optional), single-orifice burner |
| Venting | Standard or separated combustion, power vented, Category I & III |
| Flue Size | 4 in standard / 5 in separated combustion |
| Combustion Air Inlet | 5 in |
| Gas Connection | 1/2 in NPT |
| Fan Motor | 1/10 HP Shaded Pole, 1,050 RPM |
| Electrical | 115V, 60 Hz, 1-Phase |
| Full Load Amps | 6.4 A |
| Min. Circuit Ampacity | 7.5 A |
| Dimensions (W x D x H) | 30 x 26-3/8 x 23-9/16 in |
| Unit Weight | 105 lb |
| Shipping Weight | 115 lb |
| Certification | ETL listed, ANSI Z83.8 (commercial, and residential as a utility heater) |
| Max. Mounting Height | 12 ft to bottom of unit |
| Heat Throw at 8 ft | 60 ft |
| Gas Control | Single stage |
| Altitude Rating | 0–4,999 ft (field derate above 2,000 ft) |
| Motor Enclosure | Open drip proof (ODP) |
| Control Access | Right hand (field convertible to left) |
Installation Requirements
- Clearances: 1 in from the sides, top, bottom and flue collector to combustibles, with 18 in on the fan and control box side for service access.
- Residential garages: mount with at least 18 in between the unit and the floor.
- Repair garages: mount at least 8 ft above the floor and vent as separated combustion; standard combustion is not allowed (NFPA 30A).
- Thermostat: keep the setting at 50°F or higher. Running colder lets flue gas condense in the aluminized heat exchanger and shortens its life. It is not a freeze-protection heater.
- Entering air: 104°F maximum, or the fan motor trips on its thermal overload.
- Location: do not install in corrosive or flammable atmospheres, or where combustion air carries chlorinated or acidic vapors.
- Altitude: rated up to 2,000 ft; above that, derate input 4% per 1,000 ft (U.S.). Maximum altitude is 14,000 ft.
Gas and venting work should be done by a qualified, licensed installer following the National Fuel Gas Code (ANSI Z223.1/NFPA 54) and local codes.
Model Number Breakdown
| Code | Meaning | This unit |
|---|---|---|
| GG | Series | Residential low profile tubular propeller |
| 105 | Capacity | 105,000 BTU/h input |
| A | Furnace type | Right-hand control access |
| 1 | Heat exchanger tubes | Standard aluminized steel |
| N | Gas type | Natural gas |
| S | Altitude | 0–4,999 ft |
| A | Gas control | Single stage |
| 1 | Supply voltage | 115/1/60 |
| 1 | Motor type | Open drip proof (ODP) |
Is This the Right Configuration?
The GG105A1NSA11 is the standard build: aluminized steel heat exchanger, single-stage gas valve and open drip proof motor. Sterling's own selection guide recommends a different build in these cases:
- Humid, coastal or corrosive air, or spaces that sit below 40°F: choose a 409 stainless steel heat exchanger. Moisture and salt corrode aluminized steel over time.
- Occupied spaces where steady comfort matters: two-stage gas control holds temperature more evenly and cycles less. Single stage is the most economical choice for warehouses and storage.
- Dusty spaces (wood shops, textile work): a totally enclosed motor (available on 60,000 BTU and larger GG sizes) resists clogging better than an open drip proof motor.
- Dust, fumes, high humidity or negative pressure: vent it as separated combustion so the burner draws outside air. This unit converts with the combustion air inlet kit below.
If your space falls into one of these cases, contact us before ordering and we will quote the matching Sterling build.
Compatible Sterling Accessories
| Sterling part number | Description |
|---|---|
| X7-5 | Combustion air inlet kit, 5 in, for separated combustion (GG 90–120) |
| VC-4 | Vent cap, 4 in (GG 30–120) |
| X2-090 | 30° downturn nozzle (GG 90–120) |
| X3-090 | 60° downturn nozzle (GG 90–120) |
| X4-090 | 90° downturn nozzle (GG 90–120) |
| G3 | 1-stage thermostat with fan switch |
| G6 | Locking thermostat cover |
| A7 | High pressure gas regulator (supply pressure above 1/2 psi) |
Accessories are special order from Sterling and typically ship in 2–4 weeks. Call or email us to add any of them to your order.
What's Included
- GG105A1NSA11 unit heater with power venter, direct spark ignition controls and OSHA fan guard
- Gas conversion kit for LP
- Flue collar (field installed per the included instructions)
A 24V thermostat, gas piping, vent pipe, hanging hardware and the optional combustion air inlet kit for separated combustion are sold separately; see the accessory list above.
Ideal Applications
- Residential garages and detached workshops
- Auto repair bays and small commercial shops
- Storage rooms and light warehouse spaces with low ceilings
Frequently Asked Questions
How many square feet will the GG105A1NSA11 heat?
Roughly 1,450 to 2,150 sq ft in an insulated building, based on 40 to 60 BTU/h of output per square foot. Confirm with a heat loss calculation, since insulation, climate and door traffic change the answer.
How high can I mount it?
Up to 12 ft to the bottom of the unit. In a residential garage it must sit at least 18 in above the floor; in a repair garage, at least 8 ft.
Is it approved for a home garage?
Yes. The GG is ETL certified under ANSI Z83.8 for residential use as a utility heater in non-living spaces such as attached or detached garages.
Can it run on propane?
Yes. The unit ships for natural gas and includes the gas conversion kit, so a qualified installer can convert it to LP.
What venting does it need?
It has a 4 in standard / 5 in separated combustion flue connection for standard combustion. For separated combustion, run a 5 in combustion air pipe to the inlet using a Sterling combustion air inlet kit.
What power does it need?
115V, 60 Hz, single-phase. Full load amps are 6.4 A and minimum circuit ampacity is 7.5 A.
Does it lose capacity at altitude?
Ratings apply from 0 to 2,000 ft. In the U.S., input is derated 4% for each 1,000 ft above sea level. See the installation manual.
What is the warranty?
Sterling covers the heat exchanger, flue collector and burners for 10 years from the date of manufacture, and the rest of the unit for 1 year from factory shipment (or 18 months from manufacture, whichever comes first).
White Paper
