For consistent garage heating without ductwork, a ductless mini-split heat pump is the most directly relevant option. The Rellytech 11,500-BTU model is best for spaces up to 550 square feet, while the 12,000-BTU and 18,000-BTU models offer larger stated coverage. A wall-mounted 2-in-1 unit is a simpler alternative for small spaces, and the propane heater provides radiant heat but is not ductless. Match the product to the garage’s size, power setup, and ventilation needs.
| Product | Best suited for | Key detail |
|---|---|---|
| Rellytech 11,500 BTU Mini Split | Garages up to 550 sq. ft. | Heating stated down to -4°F |
| Rellytech 12,000 BTU Mini Split | Garages up to 750 sq. ft. | 115V/110V model |
| Rellytech 18,000 BTU Mini Split | Larger garages | Coverage stated up to 1,250 sq. ft. |
| Wall-Mounted 2-in-1 Unit | Small spaces needing heating and cooling | 1800W PTC heating |
| ThermoMate Propane Heater | Spot or temporary heating | Radiant heat; not ductless |
Rellytech 11,500 BTU Mini Split
Best for: A smaller garage or workshop with a stated area of up to 550 square feet. This ductless inverter system provides 11,500 BTU and includes heat, cool, fan, dehumidify, turbo, sleep, and eco modes. The product states that it can heat down to -4°F and includes auto-defrost.
Its listed 29 dB minimum operating noise, 24-hour timer, and screen-off function may suit garages used as offices or hobby spaces. The removable, rinseable filter and one-touch coil-drying function are useful maintenance features. It was selected for its explicit garage use, stated coverage, and low-temperature heating claim.
Limitation: Its stated coverage is limited to 550 square feet, and the listing does not establish that it will suit every garage layout or insulation level.
Rellytech 12,000 BTU Mini Split
Best for: Buyers who want ductless heating and cooling for a garage within the product’s stated 750-square-foot coverage. The system provides 12,500 BTU of heating and 12,000 BTU of cooling, with a listed 115V/110V power specification.
Four operating modes—heat, cool, fan, and dry—support use through different seasons. ECO mode is intended to optimize energy use, and four fan speeds with a 90-degree vertical swing allow airflow adjustments. This model is a useful middle choice when the 550-square-foot model’s stated coverage is too small.
Limitation: The listed temperature range is 61°F to 88°F, and the product details do not specify a low outdoor-temperature heating limit.
Rellytech 18,000 BTU Mini Split
Best for: Larger garages, with coverage listed up to 1,250 square feet. This heat pump provides 18,400 BTU of heating and 18,000 BTU of cooling and uses a 208–230V power supply. It may be a better fit than the 11,500-BTU and 12,000-BTU models when the garage’s area calls for greater stated capacity.
The system has heat, cool, fan, and dry modes, plus an ECO function. Four fan speeds and a 90-degree vertical swing let users adjust airflow. It was selected as the highest-capacity ductless option in this product list.
Limitation: It requires 208–230V according to the listing, so check the garage’s electrical setup before choosing it. Listed coverage alone does not account for insulation, ceiling height, or climate.
Wall-Mounted 2-In-1 Heating And Cooling Unit
Best for: Buyers seeking a compact, windowless unit for a small garage or similar space. The product combines cooling with 1800W PTC ceramic heating, adjustable fan speeds, and remote operation. Its listing describes it as requiring no window installation or complicated ductwork.
Compared with a mini split, this is a simpler-style option for buyers who prioritize a combined heating-and-cooling appliance. It was included because the listing specifically names garages and describes year-round use.
Limitation: The product details do not give a garage-area coverage figure or a heating output in BTU. Avoid choosing it for a large or especially cold garage without confirming that its capacity meets your needs.
ThermoMate 18,000 BTU Propane Heater
Best for: Buyers who need radiant heat for a garage or workshop and are considering a propane alternative. It provides up to 18,000 BTU and lists coverage up to 450 square feet. Features include an oxygen depletion safety system, tip-over protection, and a regulator and hose.
This option may work for targeted or temporary warmth, but it is not a ductless heat pump or an electric mini split. The listing describes operation at no more than 32 dB and states that a 20-pound propane tank can run for up to 69 hours on the low setting.
Limitation: The manufacturer says not to use the heater in tightly enclosed spaces. Follow its ventilation and safety instructions; do not treat this as a sealed, whole-garage heating system.
Buying Guide: Choosing Ductless Garage Heat
How much capacity does the garage need?
Start with the garage’s square footage, then compare it with the product’s stated coverage: 550, 750, or 1,250 square feet for the three mini splits. These figures are product claims, not a guarantee for every building. Insulation, ceiling height, air leakage, and local winter temperatures affect comfort, so seek a professional sizing assessment if conditions are unusual.
Which power setup should you check?
The 12,000-BTU model lists 115V/110V, while the 18,000-BTU model lists 208–230V. Verify the required power and installation details before purchasing. The supplied information does not state the electrical requirements for every other option, so confirm those with the product documentation.
Do you need heating only or year-round comfort?
A mini split can provide both heating and cooling, and the listed Rellytech models also include fan and dry modes. The wall-mounted unit also combines heating and cooling. The propane heater is a heating alternative, not an air-conditioning system.
What matters for a cold or occupied garage?
For colder conditions, the 11,500-BTU model specifically claims heating down to -4°F and auto-defrost. If the garage is used for work or relaxation, compare noise and airflow features, such as the 29 dB claim on that model. Always check the full installation, operating, and maintenance instructions.
Frequently Asked Questions
What is the best type of ductless heater for a garage?
A ductless mini-split heat pump is a strong option when you want dedicated heating without ducts and also value cooling. Choose capacity based on the garage and the system’s stated coverage.
Can a mini split heat a garage in winter?
Yes, the listed mini splits include heating. The 11,500-BTU model specifically states operation down to -4°F; the other supplied listings do not state a minimum outdoor heating temperature.
Is the propane heater a ductless mini split?
No. It is a portable-style propane radiant heater, not a ductless heat pump. Its listing cautions against use in tightly enclosed spaces.
Should I choose the 12,000-BTU or 18,000-BTU model?
Compare the stated coverage and power: the 12,000-BTU model lists up to 750 square feet and 115V/110V, while the 18,000-BTU model lists up to 1,250 square feet and 208–230V.
Can a wall-mounted 1800W unit heat a large garage?
The supplied product details do not provide a coverage area or BTU heating rating. Confirm its capacity for the specific garage before relying on it for larger spaces.