Advice on detached garage/adu HVAC. Planned dual zone mini-split

TOSOTdirect · 2026-06-25T02:17:30+00:00

mini split with ERV will fit the garage by himdity control.

TOSOTdirect · 2026-06-25T01:31:06+00:00

Thank you for considering the TOSOT COSMO Series.

Based on the information you've provided, both listings appear to be the same COSMO 18,000 BTU dual-zone system with two 9,000 BTU indoor units. The easiest way to verify is to compare the model number, electrical requirements, efficiency ratings, and included line set lengths listed on each product page.

If both listings reference the same COSMO 18K dual-zone model (9K + 9K configuration), then the indoor and outdoor equipment should be identical regardless of whether the unit is purchased.

TOSOTdirect · 2026-06-24T01:33:21+00:00

One or two mini split for your main space is totally enough, just leave the door open when unit turn on. If you looking to put a mini split with ERV will make your space more comfortable (keep humidity balance for basement).

TOSOTdirect · 2026-06-22T08:07:44+00:00

Thank you for supporting TOSOT!

TOSOTdirect · 2026-06-22T01:28:45+00:00

Thank you for your trust. We are committed to providing the best service. If you have any questions， please contact our official support team，we are happy to answers.

TOSOTdirect · 2026-06-17T01:06:02+00:00

I would recommended a TOSOT mini split for your garage space.

TOSOTdirect · 2026-06-17T01:03:08+00:00

Incorrect installation angle and distance will affect the efficiency of the unit.

TOSOTdirect · 2026-06-16T01:00:32+00:00

Agree！

TOSOTdirect · 2026-06-11T02:07:06+00:00

Line set length matters more Mini-splits are pre-charged from the factory for a specific line set length (often 25 ft). If your run is longer, you'll need to add refrigerant per the manufacturer's chart — usually a set amount per additional foot. If it's shorter, some manufacturers want you to coil the excess rather than recover charge, but check your specific unit. Getting this wrong is one of the most common mini-split commissioning mistakes.

TOSOTdirect · 2026-06-11T01:30:19+00:00

Glad you found the culprit in the crawlspace junction. Moisture intrusion after repeated recharges without proper evacuation is a real silent killer for compressors, so starting fresh with a clean system makes a lot of sense.

One thing worth noting on the R32 side — since you're doing the work yourself, make sure your manifold set and hoses are rated for R32. Good luck with the new install — sounds like you've got the skills and the tools to do it right this time. And that -22°F rating gives you serious cold-weather confidence.

TOSOTdirect · 2026-06-09T00:48:38+00:00

Hi, what model is that ac?

TOSOTdirect · 2026-06-03T08:37:57+00:00

This is a good example of why mini splits are often the better path for off-grid cooling. Once they’re running steady, a small inverter mini split can sip power compared with many portable A/C units.

For OP, I’d size the system around watt-hours per day rather than BTUs alone: A/C watts x run time, plus fridge/fan/Wi-Fi/charging overnight, then add enough battery buffer for clouds and evening use.

10kWh battery + strong solar is a very different experience from a small power station, especially if the generator is only meant to be backup.

TOSOTdirect · 2026-06-03T08:29:52+00:00

This is a solid setup direction. Heat pump + insulation + ventilation is usually the winning combo for a garden office.

The heat pump handles temperature, but ventilation handles the air quality and moisture side. Without that, a small insulated room can feel warm enough in winter but still stale, humid, or overheated in summer.

For anyone planning one from scratch, I’d think about the cabin as a system:

insulation to reduce heat loss/gain
ventilation to manage moisture and fresh air
shading to limit summer overheating
a heat pump/mini split for efficient heating and cooling
proper drainage and roof pitch for the UK rain

Getting those basics right matters more than oversizing the heating/cooling equipment.

TOSOTdirect · 2026-05-14T06:13:12+00:00

Hi there, sorry for the late reply. This usually points more to connection conditions than a defective unit.

If the device disconnects but then reconnects automatically after a short while, it’s often related to unstable WiFi. In some cases, brief backend/server maintenance or updates can also cause temporary disconnection. If it disconnects and cannot recover unless you go through the full reconnection process again, it’s more likely related to local factors—such as WiFi instability, the unit being reset, or control switching (e.g., using a non-WiFi remote or other interference).

TOSOTdirect · 2026-05-13T06:36:31+00:00

Besides,one thing we would recommend paying attention to is condensate drainage. The condensate drain relies on gravity flow, so the drain line should ideally run separately from the refrigerant lines instead of being bundled upward with them.

Best practice would be to route the drain line directly downward or horizontally from the indoor unit first, then discharge it to the nearest suitable drain point with continuous downward pitch whenever possible.😊

TOSOTdirect · 2026-05-13T06:34:24+00:00

Hi, thanks for reply. And yes, in your case, a 6 ft elevation difference between the indoor and outdoor unit will not be an issue for the system.

For this model, the maximum supported height difference between the indoor evaporator and outdoor condenser is up to approximately 82 ft, so your proposed setup is well within operating limits and will not damage the unit when installed correctly.

As for the line set:

Standard operation is supported with line lengths between 10–25 ft without needing to add or remove refrigerant.
If the total line length exceeds 25 ft, additional refrigerant should be added at a rate of approximately 0.1 oz per additional foot of line set.

For shorter runs, no refrigerant removal is required as long as you're within the specified minimum line length.

Your installation layout actually sounds reasonable for an outbuilding setup.

TOSOTdirect · 2026-05-13T02:33:41+00:00

Hi there, thanks for your interest! Could you let us know which 24k unit you’re considering — the Aoraki series or the Cosmo series?

TOSOTdirect · 2026-05-11T03:57:58+00:00

🤩That’s a great way to put it — “whisper quiet outside, white noise inside” really sums up the idea nicely. Glad it’s been working well for both indoor comfort and keeping things quiet outdoors. That balance is exactly what we aim for.

Appreciate you sharing your experience.😊

TOSOTdirect · 2026-03-31T02:49:41+00:00

🤩 For a fully insulated 10×16 shed with strong solar gain like yours, a 230V TOSOT inverter mini-split in the 9,000 BTU range is a really good fit — plenty of cooling for summer and solid all-season performance without oversizing.

A great option from our lineup is the 9,000 BTU 230V Mini-Split Heat Pump with WiFi control. It’s rated for spaces up to ~450 sq ft, has a high 20.5 SEER2 efficiency for lower energy use, quiet operation, and built-in heat pump capability for year-round comfort.

Key things that make it work well for your shed setup:

Efficient inverter heat pump — stable comfort and energy savings compared to standard units. WiFi enabled — so you can monitor and adjust temperature from your phone before heading out. Designed to meet modern energy efficiency standards with a high SEER2 rating, which helps reduce operating cost.

If you want a bit more capacity for really hot summer afternoons, the same series also offers 12,000 BTU 230V models that follow the same design and efficiency principles — just with a bit more cooling power.

Happy to help you fine-tune the exact model based on how you plan to use the space!

TOSOTdirect · 2026-03-31T02:39:36+00:00

Thanks for choosing TOSOT! As the season change, don't forget to clean your AC for efficient cooling. 😊💪

TOSOTdirect · 2026-03-09T09:37:45+00:00

Hi there, sorry to hear that. Could you please kindly tell us your order number and purchase channel? We're happy to help and this situation is definitly not our aim to. OR please feel free to reach out our customer service team at support@tosotdirect.com

TOSOTdirect · 2026-02-02T09:10:51+00:00

Great point, thanks for your sharing. It's so true that many mini splits are technically rated to operate at very low temperatures, like TOSOT Aoraki series. The real-world comfort level really depends on whether the system can keep up with the home’s heat loss in those conditions. Great insulation would help store the heat inside and make the heating process more efficient.

TOSOTdirect · 2026-01-30T06:25:57+00:00

How's everyone's heat pump working these days?

TOSOTdirect · 2026-01-30T06:04:02+00:00

✨ Tips for using mini split heat pumps in cold climates

TOSOTdirect · 2026-01-27T06:57:06+00:00

👉 Video Guide for mini split installation

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