For an 800 sq ft garage, all five options here are 18,000 BTU mini splits, so the choice is less about raw capacity and more about the garage itself, installation, and how much extra coverage a manufacturer claims. My leading picks are the MRCOOL DIY Select for its pre-charged DIY-oriented line set and stated 800-square-foot fit, the DELLA Vario for its higher listed 21 SEER2 efficiency and closer 1,000-square-foot coverage claim, and the Garvee for buyers who want a broad coverage claim and app control.
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The main tradeoff is that a listed square-foot range is only a starting point. A drafty, uninsulated garage with a high ceiling or strong afternoon sun can need more heating or cooling than a finished, insulated space of the same floor area. I rank these by how clearly their stated capacity fits this garage use, what installation demands they place on the buyer, and how much useful evidence the supplied specifications provide. I would still match the final choice to a room-by-room load calculation and local code requirements, rather than treating any advertised coverage figure as a guarantee.
Complete the kit
Key Takeaways
- All five picks provide 18,000 BTU of cooling, making insulation, ceiling height, climate, and door leakage key factors in choosing one for an 800 sq ft garage.
- MRCOOL is the clearest size match in the supplied descriptions: it explicitly lists 800 sq ft and includes a pre-charged Quick Connect line set aimed at DIY installation.
- DELLA is the efficiency standout at a listed 21 SEER2 and claims coverage up to 1,000 sq ft, but it still calls for professional installation and line-set vacuuming.
- Garvee, the 19 SEER2 model, and Rellytech all claim coverage up to 1,250 sq ft; that extra range does not prove they are better sized for every 800 sq ft garage.
- Check your available 208–230V or 230V electrical service and have a qualified installer verify capacity before buying; advertised coverage cannot replace a load calculation.
| MRCOOL DIY Select 18000 BTU Mini Split AC/Heating System, 230V Heat Pump |  | Best Overall for a Direct 800 Sq Ft Match | Cooling capacity: 18,000 BTU | Listed coverage: Up to 800 sq ft | Cooling efficiency: Up to 17.3 SEER2 | VIEW ON AMAZON | See Our Full Breakdown |
| DELLA Vario Series 18,000 BTU Ductless Mini Split Air Conditioner and Heat Pump |  | Best Efficiency-Focused Match | Cooling capacity: 18,000 BTU/h | Heating capacity: 19,000 BTU | Listed coverage: Up to 1,000 sq ft | VIEW ON AMAZON | See Our Full Breakdown |
| Garvee 18,000 BTU Mini Split Air Conditioner with Heat Pump, 19 SEER, 1250 Sq. Ft, Inverter, Remote, Installation Kit, White |  | Best for Buyers Who Want App Control and Broad Coverage Claims | Cooling capacity: 18,000 BTU | Listed coverage: Up to 1,250 sq ft | Efficiency: 19 SEER | VIEW ON AMAZON | See Our Full Breakdown |
| 18000 BTU Mini Split AC/Heating System, 19 SEER2, 230V Inverter Air Conditioner with 1 Ton Heat Pump, Complete Installation Kit Included, Covers Up to 1250 Sq.Ft, White |  | Best for Buyers Comparing a Complete Kit and 19 SEER2 | Cooling capacity: 18,000 BTU | Listed coverage: Up to 1,250 sq ft | Efficiency: 19 SEER2 | VIEW ON AMAZON | See Our Full Breakdown |
| Rellytech Mini Split AC/Heating System, 18000 BTU, 19 SEER2, 208-230V |  | Best for Buyers Who Need a 208–230V Specification | Cooling capacity: 18,000 BTU | Heating capacity: 18,400 BTU | Listed coverage: Up to 1,250 sq ft | VIEW ON AMAZON | See Our Full Breakdown |
| mini split size for garage 800 sq ft | Cooling capacity | Listed coverage | Voltage | Installation |
|---|---|---|---|---|
| MRCOOL DIY Select 18000 BTU Mi | 18,000 BTU | Up to 800 sq ft | 230V | — |
| DELLA Vario Series 18,000 BTU | 18,000 BTU/h | Up to 1,000 sq ft | 208–230V | Professional installation and line-set vacuuming required |
| Garvee 18,000 BTU Mini Split A | 18,000 BTU | Up to 1,250 sq ft | 230V | Installation kit included; professional setup required |
| 18000 BTU Mini Split AC/Heatin | 18,000 BTU | Up to 1,250 sq ft | 230V | Complete installation kit included; professional installation recommended |
| Rellytech Mini Split AC/Heatin | 18,000 BTU | Up to 1,250 sq ft | 208–230V | Professional installation required |
More Details on Our Top Picks
MRCOOL DIY Select 18000 BTU Mini Split AC/Heating System, 230V Heat Pump
For a garage that is genuinely close to 800 sq ft, MRCOOL is the most direct match in this group: its description states that the 18,000 BTU system is suited to spaces up to that size. That is a more relevant starting point than the 1,250-square-foot claims on Garvee, the other 19 SEER2 system, and Rellytech. It does not make the sizing decision for you, though; insulation, local outdoor temperatures, ceiling height, and garage-door leakage still affect the required capacity.
The strongest difference is installation. The included pre-charged Quick Connect line set is described as avoiding the vacuum pump, gauges, brazing, and refrigerant handling needed with conventional setups. That makes it the clearest option for buyers seeking a DIY-oriented product, though electrical work, mounting, code compliance, and the exact permitted installation process still need careful checking. In contrast, DELLA explicitly calls for professional installation and line-set vacuuming.
MRCOOL lists up to 17.3 SEER2, below DELLA’s 21 SEER2 and the 19 SEER2 claims on several competitors. It also supplies a 230V requirement and app and voice control, plus an 18.5 dB(A) silent-mode figure. The tradeoff is a lower stated cooling efficiency than the alternatives with higher SEER2 claims, and the listing does not provide detailed heating capacity or cold-weather operating limits. I would choose it for the installation approach and stated size fit, not assume it has the strongest heating performance.
Pros:- The listing directly identifies spaces up to 800 sq ft.
- Pre-charged Quick Connect line set is described as a no-vacuum DIY installation approach.
- Includes app and voice control options.
- Lists quiet operation down to 18.5 dB(A) in silent mode.
Cons:- Its up-to-17.3 SEER2 claim is lower than the listed ratings for the other efficiency-focused picks.
- The supplied details do not state heating capacity or a low-temperature heating limit.
- Requires 230V service, and the DIY description does not remove the need to check local rules and electrical requirements.
Best for: Garage owners looking for an 18,000 BTU system explicitly described for up to 800 sq ft, especially those interested in its Quick Connect DIY-oriented installation design.
Not ideal for: Buyers prioritizing the highest listed SEER2 rating, or anyone who needs documented heating capacity and low-temperature performance before choosing.
- Cooling capacity:18,000 BTU
- Listed coverage:Up to 800 sq ft
- Cooling efficiency:Up to 17.3 SEER2
- Heating efficiency:Up to 8.5 HSPF2
- Voltage:230V
- Installation feature:Pre-charged Quick Connect line set; no-vacuum DIY approach described
- Controls:App, voice assistant, and remote
- Listed noise:As low as 18.5 dB(A) in silent mode
Our verdict“I would start with MRCOOL when the garage is near 800 sq ft and the Quick Connect installation approach matters more than having the highest listed efficiency.”
DELLA Vario Series 18,000 BTU Ductless Mini Split Air Conditioner and Heat Pump
DELLA is the efficiency pick for a buyer whose 800 sq ft garage is reasonably well sealed and who wants a higher listed cooling-efficiency figure. Its 21 SEER2 rating is the highest stated here, and its coverage claim of up to 1,000 sq ft sits closer to the garage size than the 1,250-square-foot claims from Garvee, the other 19 SEER2 unit, and Rellytech. Its 18,000 BTU cooling capacity remains the same as the others, so the higher rating is about seasonal efficiency, not extra cooling capacity.
Heating information is more developed than in the MRCOOL listing: DELLA specifies 19,000 BTU heating and operation down to -4°F. It also includes Wi-Fi and Alexa support, 4D airflow, a dehumidifier mode, and a remote with room-temperature sensing. Those features can be useful in a garage where airflow and humidity control matter, though the source does not establish how the system will perform in every climate or in an unusually leaky building.
The notable compromise is installation. Unlike MRCOOL’s stated no-vacuum DIY approach, DELLA requires professional installation and line-set vacuuming; changing line-set length may also require refrigerant adjustment. Its 208–230V supply range is flexible compared with a strictly 230V specification, but the installation requirements are less casual. I rank it behind MRCOOL overall because its coverage claim is not as exact a match to 800 sq ft and the installer burden is higher, despite the stronger efficiency claim.
Pros:- Highest listed cooling efficiency in this group at 21 SEER2.
- Lists 19,000 BTU heating and operation down to -4°F.
- Coverage claim of up to 1,000 sq ft is relatively close to the target garage size.
- Includes Wi-Fi, Alexa, dehumidifier mode, 4D airflow, and a room-sensing remote.
Cons:- Professional installation and line-set vacuuming are required.
- Changing line-set length may require refrigerant adjustment.
- Indoor noise is listed at 32 dBA, higher than MRCOOL’s stated silent-mode figure.
Best for: Owners of a relatively well-insulated 800 sq ft garage who value the highest listed SEER2 rating in this lineup and can arrange professional installation.
Not ideal for: DIY-first buyers or owners of a very drafty garage who need a load calculation before relying on a broad coverage claim.
- Cooling capacity:18,000 BTU/h
- Heating capacity:19,000 BTU
- Listed coverage:Up to 1,000 sq ft
- Efficiency:21 SEER2
- Voltage:208–230V
- Refrigerant:R-454B
- Heating operating limit:Down to -4°F (-20°C)
- Installation:Professional installation and line-set vacuuming required
Our verdict“I would pick DELLA over the broader-coverage 19 SEER2 models when efficiency and documented heating details matter more than DIY installation.”
Garvee 18,000 BTU Mini Split Air Conditioner with Heat Pump, 19 SEER, 1250 Sq. Ft, Inverter, Remote, Installation Kit, White
Garvee offers a straightforward feature mix: 18,000 BTU cooling, a heat pump, inverter operation, app control, and a stated 19 SEER rating. The listing claims coverage up to 1,250 sq ft, which gives an 800 sq ft garage apparent headroom on paper. Compared with DELLA’s up-to-1,000-square-foot claim, that broader range may appeal to owners planning to condition an attached work area too, but it does not prove the unit will be correctly sized for a particular garage.
Its listed 28 dB noise level and cooling, heating, dry, auto, and fan modes give buyers useful day-to-day control options. App control is a practical distinction from products whose supplied details focus on a remote, though MRCOOL also lists app access and goes further with voice-assistant control. The 19 SEER rating is below DELLA’s stated 21 SEER2, and the source labels Garvee’s figure SEER rather than SEER2, so I would not treat those values as a direct, like-for-like efficiency comparison.
The main drawback is the installation burden: the listing says professional setup and includes an installation kit, not a clearly described DIY refrigerant connection. That makes it less appealing than MRCOOL for a hands-on installation plan. The supplied information also omits heating capacity and cold-weather limits, so buyers in climates with severe winter conditions should request those details before deciding. Garvee fits shoppers who value convenient controls and a broad stated coverage range more than a precise 800-square-foot fit.
Pros:- Provides 18,000 BTU cooling and heat-pump operation.
- Includes app control and cooling, heating, dry, auto, and fan modes.
- Lists 28 dB noise and inverter technology.
- Installation kit is included for professional setup.
Cons:- The stated coverage reaches 1,250 sq ft, which is a broad claim rather than a specific 800 sq ft sizing match.
- Heating capacity and low-temperature operating details are not supplied.
- Professional installation is required, and its SEER label is not the same wording used for several SEER2 claims here.
Best for: Garage owners who want app control, multiple operating modes, and a stated coverage range that may also suit a connected work area.
Not ideal for: Buyers who need a directly stated 800 sq ft fit, documented cold-weather heating performance, or a clearly DIY installation route.
- Cooling capacity:18,000 BTU
- Listed coverage:Up to 1,250 sq ft
- Efficiency:19 SEER
- Voltage:230V
- Operating modes:Cooling, heating, dry, auto, and fan
- Listed noise:28 dB
- Controls:App and remote
- Installation:Installation kit included; professional setup required
Our verdict“I would choose Garvee if app control and flexible modes lead your checklist, but not on its 1,250-square-foot claim alone.”
18000 BTU Mini Split AC/Heating System, 19 SEER2, 230V Inverter Air Conditioner with 1 Ton Heat Pump, Complete Installation Kit Included, Covers Up to 1250 Sq.Ft, White
This 18,000 BTU system claims coverage up to 1,250 sq ft and lists 19 SEER2, making it a plausible candidate for a garage that shares air with a larger finished area. For a standalone 800 sq ft garage, that coverage claim is less useful than MRCOOL’s explicit 800-square-foot statement or DELLA’s up-to-1,000-square-foot figure. I would base the decision on a load calculation rather than assuming the larger listed range means the unit is a better bargain or more suitable.
The listing includes a complete installation kit, inverter operation, multiple modes, and self-cleaning. It uses R-32 refrigerant and requires 230V power. Compared with Garvee, it supplies a SEER2 rating rather than a SEER label, but the noise figure is listed at 38 dB, higher than Garvee’s 28 dB and MRCOOL’s 18.5 dB(A) silent-mode figure. These figures may use different measurement conditions, so they are helpful context rather than a controlled comparison.
Installation is not as simple as the word “kit” may suggest: the provided details recommend professional installation, and the unit weighs 92.4 pounds. That calls for help with handling and mounting, particularly for overhead or high-wall placement. The specifications also list 210W, but do not explain the measurement conditions or reconcile that figure with the product’s 18,000 BTU capacity; I would ask the seller or installer to verify electrical and performance data. I rank it below Garvee because it offers fewer clearly stated control details and has a higher noise figure, while keeping its own appeal for buyers prioritizing a complete kit and SEER2 disclosure.
Pros:- Lists 19 SEER2 and inverter operation.
- Includes a complete installation kit and multiple operating modes.
- Uses R-32 refrigerant and lists self-cleaning.
- Broad stated coverage may suit some larger connected spaces.
Cons:- Professional installation is recommended, and the unit weighs 92.4 pounds.
- The 38 dB noise figure is higher than the figures listed for Garvee and MRCOOL.
- The 210W listing lacks context and should be verified with the seller or installer.
Best for: Buyers who want an installation kit, an explicitly stated 19 SEER2 rating, and a unit that could serve a larger connected space if a professional confirms the load.
Not ideal for: Anyone looking for a clearly DIY system, a quietest-possible garage unit, or complete confidence in the supplied electrical details without further verification.
- Cooling capacity:18,000 BTU
- Listed coverage:Up to 1,250 sq ft
- Efficiency:19 SEER2
- Voltage:230V
- Refrigerant:R-32
- Listed noise:38 dB
- Weight:92.4 lb
- Installation:Complete installation kit included; professional installation recommended
Our verdict“I would shortlist this model for its kit and 19 SEER2 claim only after an installer confirms the electrical details and its fit for the garage load.”
Rellytech Mini Split AC/Heating System, 18000 BTU, 19 SEER2, 208-230V
Rellytech is a simple 18,000 BTU option for shoppers who want a stated 19 SEER2 rating and a 208–230V supply range. Its cooling capacity matches the other four systems, and its listed coverage extends to 1,250 sq ft. For an 800 sq ft garage, that is a broad manufacturer claim; unlike MRCOOL, it does not directly identify 800 sq ft as its target, and unlike DELLA, it does not list a closer 1,000-square-foot limit.
One useful advantage is that Rellytech supplies both heating and cooling figures: 18,000 BTU cooling and 18,400 BTU heating. It also lists 8.5 HSPF2, which adds a heating-efficiency measure not provided in the supplied details for most of the competing models. The multiple modes and adjustable airflow can help tailor operation to different work routines, but the listing does not provide a noise figure, controls information, or a cold-weather operating limit. Buyers who need those details should obtain them before choosing it over DELLA.
Professional installation is required, so this is not the alternative to MRCOOL for someone hoping to use a DIY-style line set. Compared with Garvee, Rellytech gives more explicit heating-capacity and HSPF2 information, while Garvee provides a noise figure and app control. Its 208–230V range may match more electrical setups than a strict 230V listing, but a qualified electrician or installer still needs to confirm the garage circuit and disconnect requirements. I place it fifth because the core capacity is clear but the supplied information leaves important ownership questions unanswered.
Pros:- Lists 18,000 BTU cooling and 18,400 BTU heating.
- Provides 19 SEER2 and 8.5 HSPF2 figures.
- Specifies a 208–230V supply range.
- Includes multiple modes and adjustable airflow.
Cons:- Coverage claim of up to 1,250 sq ft is broad for an 800 sq ft garage and does not replace load calculations.
- Professional installation is required.
- The supplied specifications omit noise level, control options, and cold-weather heating limits.
Best for: Buyers who want listed heating capacity, HSPF2 information, and a 208–230V specification, with professional installation available.
Not ideal for: DIY installers or shoppers who need stated noise, app-control, or low-temperature heating details before purchase.
- Cooling capacity:18,000 BTU
- Heating capacity:18,400 BTU
- Listed coverage:Up to 1,250 sq ft
- Cooling efficiency:19 SEER2
- Heating efficiency:8.5 HSPF2
- Voltage:208–230V
- Operating modes:Cooling, heating, fan, and dry
- Installation:Professional installation required
Our verdict“I would consider Rellytech when its heating figures and voltage range fit the project, but I would get its missing operating details before committing.”
How We Picked
I compared the five systems against one specific job: heating and cooling an 800 sq ft garage. Since each listing gives an 18,000 BTU cooling capacity, I did not treat small differences in broad coverage claims as proof that one unit will perform better in a particular garage. I gave more weight to whether the listing directly mentions a fit near 800 sq ft, whether it supplies meaningful heating and efficiency information, and what it says about installation.
Installation is a major separator in this group. MRCOOL describes a pre-charged Quick Connect line set and a no-vacuum DIY approach, while DELLA explicitly requires professional installation and line-set vacuuming. Garvee, the third 18,000 BTU system, and Rellytech are also presented as professional-install options or include installation kits without the same clearly stated DIY process. Buyers should check local regulations, warranty terms, and installer requirements before interpreting “kit included” as permission to install the refrigerant system themselves.
I also compared efficiency claims, electrical requirements, noise figures where provided, and the quality of the supplied capacity details. A stated 19 or 21 SEER2 rating can help compare seasonal cooling efficiency, but it does not determine whether a unit can handle a hot, leaky garage. Where the source gives incomplete, inconsistent, or broad claims, I call that out rather than filling in missing performance details. My ranking favors usefulness for this garage scenario, not a claim that one product will suit every building.
| mini split size for garage 800 sq ft | Listed coverage | Installation |
|---|---|---|
| MRCOOL DIY Select 18000 BTU Mi | Up to 800 sq ft | — |
| DELLA Vario Series 18,000 BTU | Up to 1,000 sq ft | Professional installation and line-set vacuuming required |
| Garvee 18,000 BTU Mini Split A | Up to 1,250 sq ft | Installation kit included; professional setup required |
| 18000 BTU Mini Split AC/Heatin | Up to 1,250 sq ft | Complete installation kit included; professional installation recommended |
| Rellytech Mini Split AC/Heatin | Up to 1,250 sq ft | Professional installation required |
Factors to Consider When Choosing Mini Split Size For Garage 800 Sq Ft
For this 800 sq ft garage, I would use the product specifications as a shortlist, then check the building and electrical setup before picking a capacity.Start with the garage, not the coverage claim
Floor area alone does not determine the heating and cooling load. I would note ceiling height, insulation in the walls and roof, air leakage around the overhead door, window area, sun exposure, and how often the door opens. A finished garage with good insulation may have a very different load from an uninsulated metal outbuilding of the same size. The listings in this group give broad coverage figures, but none replaces a professional load calculation based on the actual space and local design temperatures.
All five products list 18,000 BTU cooling, yet the coverage claims range from 800 to 1,250 sq ft. I would not assume that a larger published area means extra capacity or better performance. If the garage is poorly insulated or used as a workshop with heat-producing equipment, have an installer assess the conditions before choosing among these units. If it is well insulated and used intermittently, sizing still needs to account for how quickly you want it to reach a comfortable temperature.
Compare capacity and heating information carefully
Cooling BTUs describe capacity, while SEER2 and SEER describe seasonal cooling efficiency. A higher listed efficiency can indicate less electricity used across a defined cooling season, but it does not add cooling power. DELLA’s 21 SEER2 is the strongest stated efficiency figure in this lineup; the 19 SEER2 claims on the third product and Rellytech follow, while MRCOOL lists up to 17.3 SEER2. Garvee lists 19 SEER, not SEER2, so I would avoid treating that number as directly equivalent without matching test standards.
For winter garage use, compare heating capacity and outdoor operating limits as well as cooling specs. DELLA lists 19,000 BTU of heating and operation down to -4°F; Rellytech lists 18,400 BTU heating and 8.5 HSPF2 but gives no cold-weather limit in the supplied information. MRCOOL states 8.5 HSPF2 without heating capacity or an operating limit. I would ask for the full performance table at your local winter temperatures before relying on any model as the garage’s main heat source.
Confirm electrical and installation requirements
These are ductless split systems with outdoor and indoor components, not plug-in room air conditioners. The stated supply is 230V for MRCOOL, Garvee, and the third system; DELLA and Rellytech list 208–230V. Have an electrician or qualified installer verify the available circuit, breaker, disconnect, wire sizing, and location before ordering. Voltage listed by itself does not confirm that the existing garage electrical panel can support the system.
Installation approach is a substantial difference. MRCOOL describes its pre-charged Quick Connect process as a no-vacuum DIY option. DELLA specifically requires professional installation and line-set vacuuming, while the other listings point toward professional setup or recommend it. I would check local codes, manufacturer warranty terms, and installer requirements rather than assume that an included kit means the refrigerant work is unrestricted. Also plan for condensate drainage, outdoor-unit clearance, wall mounting, and a suitable route for the line set.
Choose useful controls and efficiency features
App access can be convenient when the garage is detached or you want to adjust settings before working in it. MRCOOL lists app and voice controls; Garvee lists app control; DELLA lists Wi-Fi and Alexa compatibility. The supplied details for the third product and Rellytech do not establish app control, so I would not buy them assuming it is included. Features such as dry mode and a dehumidifier setting may help with damp conditions, but they do not replace proper drainage or a plan for moisture in the building.
Noise figures also need context: MRCOOL lists 18.5 dB(A) in silent mode, Garvee lists 28 dB, DELLA gives 32 dBA for the indoor unit, and the third product lists 38 dB. Measurement methods and operating settings may differ, so I treat them as a rough guide rather than a lab comparison. In a garage beside bedrooms or a shared living space, ask which setting the number represents and consider both indoor and outdoor unit noise.
Frequently Asked Questions
Is an 18,000 BTU mini split the right size for an 800 sq ft garage?
It can be a reasonable shortlist capacity, and MRCOOL explicitly describes its 18,000 BTU model for spaces up to 800 sq ft. But the right size depends on insulation, ceiling height, air leakage, climate, solar exposure, and garage-door use. I would ask a qualified HVAC professional to calculate the load before buying, especially for an uninsulated garage or one with high ceilings and frequent door openings.
Does a mini split rated for 1,250 sq ft make it a better choice for an 800 sq ft garage?
Not by itself. Garvee, the third system, and Rellytech list coverage up to 1,250 sq ft, but all three have the same stated 18,000 BTU cooling capacity as the other options. Coverage estimates use assumptions about a space; they do not prove that a unit is a better fit for your garage or that it will cope with a high heat load. Compare a load calculation, efficiency, heating data, installation demands, and electrical requirements instead.
Can I install one of these mini splits myself?
MRCOOL is the only product in this comparison whose supplied description clearly presents a pre-charged Quick Connect line set and a no-vacuum DIY approach. DELLA calls for professional installation and line-set vacuuming, and other listings require or recommend professional setup. Local codes, electrical work, warranty terms, and manufacturer instructions still apply, so I would confirm the permitted installation path before purchasing any system.
What electrical service should I check before ordering?
Check the product’s voltage specification and have an electrician confirm that the garage circuit and panel can support the equipment. MRCOOL, Garvee, and the third model list 230V, while DELLA and Rellytech list 208–230V. Voltage alone does not tell you the required breaker, wire size, or disconnect arrangement, so use the unit’s installation documentation and a qualified professional rather than relying on the existing outlet or panel label.
Which model is best for heating an 800 sq ft garage in winter?
DELLA provides the clearest cold-weather details in the supplied information, with 19,000 BTU heating and operation down to -4°F. Rellytech lists 18,400 BTU heating and 8.5 HSPF2 but no outdoor operating limit, while MRCOOL lists 8.5 HSPF2 without a heating capacity or temperature limit. I would compare each model’s performance table at your local winter design temperature and ask an installer whether supplemental heat is needed.
Conclusion
For the most direct match to an 800 sq ft garage, I would begin with MRCOOL DIY Select: it states that coverage size and has the clearest DIY-oriented line-set description. If your priority is seasonal efficiency and you are prepared to hire an installer, DELLA Vario stands out with its 21 SEER2 rating and more specific heating details. Choose Garvee if app control and multiple modes matter most, but treat its larger coverage claim as a rough guide rather than proof of fit.
The third 19 SEER2 system is worth a closer look if you want a complete kit and can verify its listed electrical information; Rellytech makes sense when its heating figures and 208–230V range fit your project. For any of the five, I would confirm the circuit, installation rules, and load calculation before buying. An 18,000 BTU label is a starting point for comparing these options, not a substitute for checking the actual garage.
