ACDC18C Solar Air Conditioner Heat Pump

The ACDC18C 18,000BTU solar air conditioner requires no grid connection, no batteries, no inverter, no charge controller – just plug in the solar panels and start saving up to 100% on daytime cooling or heating costs. A grid connection can be added to allow operation at night, and to provide higher daytime capacity & uninterrupted operation during low sunlight. The ACDC18C can heat or cool between 700 to 1,000 sqft.

For a smaller 12,000 BTU unit, check out the ACDC12C

For an AC unit compatible with batteries, check out the DC48


None (2) 100' PV cables with MC4 connectors +$240.00
None IMO 2 Pole, 16 AMP DC Disconnenct +$85.00
None MidNite Solar 300V DC Lightning Arrestor +$130.00


Save Up To 100% on Heating/Cooling Costs!!

Keep the inside of your home or office cool all day for next to nothing in energy costs. Preventing daytime heat build-up also cuts evening cooling costs. Cool or heat up to 1000 Sq. Ft. (92m²).


No AC Power of Grid Connection Required!

ACDC18C Solar Air Conditioner Heat Pump

Click here to download to ACDC18C 18,000 BTU solar AC Manual

The HotSpot engineering team created the world’s first DC solar air conditioner in 2007 and has led the world in solar AC design and quality manufacturing for more than 10 years. The ACDC18C blends solar DC power directly with AC power (optional) to deliver a seamless cooling or heating experience while making the best use of free DC solar power. But unlike previous versions, the ACDC18C does not require an AC backup connection to operate during good sunlight conditions. During the day it can operate on 100% solar power.

ACDC18C Solar Air Conditioner Overview

No batteries needed. Like all DC-Inverter air conditioners, the ACDC18C compressor runs on DC power, which may at times be converted from AC power.

This special solar air conditioner can accept DC power directly from solar panels, without needing an inverter, charge controller, or batteries.

The solar DC power directly replaces AC power from the power company and can cut daytime energy costs for air conditioning or heating by up to 100%. No power is exported and no net metering agreement or special meter is needed. Can be used with all-DC, all-AC, or AC-DC whereby the unit can seamlessly blend both power sources with a bias towards using all available DC (solar) power first

How the ACDC18C Solar Air Conditioner Works

Compatible with all types of solar panels & 50Hz and 60Hz power, use it anywhere in the world.

The system is designed for hybrid operation with solar providing most or all of the energy needed during daylight hours, supplemented by AC power (optional) at night or during times of cloud cover. 

During the day the ACDC18C can run exclusively on solar power with no AC power or grid connection when solar is strong enough. The maximum speed/capacity will be based on the level of available solar power available. If also connected to AC power source, the unit can run at full speed whenever needed, and will add in just enough AC power, if/as needed, while still primarily using available solar DC power.

When connected to both solar and an optional AC power source, the ACDC18C only uses small amounts of power from the utility company, if and as needed. Hybrid operation eliminates the need for batteries and allows use of the system 24 hours per day.

The system primarily uses solar power, and mixes it with normal AC power, if available, at times when solar availability is reduced due to clouds, overcast sky, or at night. If the sun conditions are poor and no AC connection is available, the ACDC18C calculates the amount of solar power available in real time and reduces its speed to match the available solar power. Of course, the unit will not run without an AC connection in very low sunlight conditions, or at night.

The unit can be connected with up to 8 panels for running on 100% solar power with no AC connection or when the sun is not at full strength.

The ACDC18C includes a digital power display so you can get an idea of how much AC and/or DC power is being used in the system.

The ACDC18C Solar Air Conditioner SAVES MONEY

  • Can cool/heat an area with 100% solar energy
  • No batteries required
  • Uses 4-8 solar PV panels
  • Mini-split design
  • SEER 75 rating!!!
  • Ductless System

Your air conditioner needs the most power when the sun is shining, a coincidence you can take advantage of with our ACDC18C solar air conditioner. It can keep an indoor area cool during the day for free, or for just pennies, at times when solar power is not sufficient to carry 100% of the load.

In addition to cooling, the ACDC18C solar heat pump will provide solar powered heating, operating all the way down to an outside ambient temperature of 5 F. No matter how far north or south you are, this is the right system for you. No net metering needed. Single indoor unit.

No need for batteries. Even when the sun is not shining at all, with an AC connection this ultra high-efficiency (SEER 22 without solar) heat pump will keep you comfortable and save you money using far less electricity than a normal AC or heat pump unit of the same capacity. Calculated using only paid-for energy, the ACDC18C produces an equivalent SEER above SEER 75.

This solar mini-split air conditioner design allows you to put solar cooling into the area where it’s needed the most and avoid the security issues of an unsightly and noisy window unit.

If your location needs heat during the winter, take a full 1-ton of the daytime heating load off of your main heating system for free and get a head start on evening heating requirements.

Since the ACDC18C is a ductless system, it allows 100% of your heating or cooling to be delivered where it’s needed without the loss that occurs in a ducted system.

Note – this is not an “off-grid battery powered” unit, although adding batteries is possible, it is not the recommended use. If you have no AC power and need a 24×7 off grid solar air conditioner, contact us

Solar Air Conditioning Cooling & Heating Augmentation

Augmenting a space heating or cooling system with solar makes perfect sense. In addition to heating or cooling a small area, it allows you to add capacity to an existing system, or reduce the load on an existing system, either or both of which can save you money and add comfort.

Solar augmentation also allows offsetting of higher daytime electricity rates and reduces the amount of early evening catch-up required by the normal system. The ACDC18C hybrid solar air conditioner allows you to add comfort without adding energy cost, and can sharply cut your daytime heating and cooling bills.

Get up to 100% of your daytime cooling (or heating) free from the sun. Plug-N-Play solar connections make installation simple. Over SEER 22 on normal AC power. Calculated SEER equivalent net of DC power is >SEER 75. Requires min. 4x solar PV panels.


The ACDC18C installs just like a normal mini-split air conditioner, then you connect the solar panels using industry-standard MC4 connectors.

You can use 4 or more normal solar panels (recommended 72 cell panels) of 290w-375w each and wired in series. You can order the panels, etc. from us or purchase them locally. Note the panels should be minimum 36vmp rated, please review the specifications.

If you use 60 cell panels (30vmp), use a minimum of four 60 cell panels. For off-grid operation during the day with no AC connection, with either type solar panel you may wish to add at least one additional panel.

The ACDC18C is shipped pre-charged with R410a, an ozone-friendly refrigerant and we recommend hiring a professional HVAC installer. If self-installing, you will need a licensed HVAC technician with a vacuum pump to do the final commissioning and to comply with US federal law.

The units include a 3M lineset, if a longer one is needed, you may use a standard lineset which can easily and quickly be made onsite by the installer. You can also order various length linesets (1/2″ x 1/4″) from various online sellers such as Home Depot, Amazon, etc.


Product Specifications

Indoor Unit:

Packing   (W*D*H) mm 36.2×14.6×21.3
Gross weight Lb. 16.4

Outdoor Unit:

Packing  (W*D*H) inch 36.2×15.6×23.8
Gross weight lbs. 79.3

Please Note, PV wire, etc., are not included by default, they must be added on above.



For a smaller 12,000 BTU unit check out the ACDC12C



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