12V / 24V Electric Air Conditioner & Heater Kit – Universal Under Dash or Hidden (Heat & Cool)

12V Electric Air Conditioner & Heater Kit – Universal, Fits Almost Any Vehicle

Heating and cooling in one unit. Cooling is electric; heating uses your engine's hot coolant through a built-in heater core, exactly like a factory heater. Cooling-only version here.

This is a complete 12v car air conditioning and heating kit. The air con runs straight off your battery. There is no belt, no pulley and no engine-driven compressor, so the compressor can mount anywhere – engine bay, boot, under the floor or inside a canopy. That is what makes it work in hot rods, classic cars, 4WDs, vans, trucks, tractors and machinery that were never built to have air con – and because the heater core replaces or adds to your old heater box, it's the one to pick if your car has no heater, or a tired one.

Not for caravans or trailers – there's no engine coolant to run the heater from. Use the cooling-only kit for those.

Available as a 12V or 24V system, with your choice of an under-dash evaporator (vents and controls on the front) or a behind-dash evaporator (hidden, with ports for ducting to your own vents).

Will it fit my car? The two-minute check

The kit is three parts. If you have room for these three, a 12V or 24V battery, and an engine with a coolant circuit to tee the heater into, it fits – make, model and engine don't matter.

Part	Size	Where it can go
Compressor	22 × 13 × 16 cm (about a shoebox)	Engine bay, boot, under the floor, inside a guard or canopy. Must sit horizontal (any rotation is fine, never on its end). Within 1.5 m of the condenser.
Condenser with fan	44.5 × 34.5 × 12 cm	In front of the radiator, in the boot, under a ute tray, in a spare wheel well – any angle, anywhere it can draw air through the coil and the hot air can escape. If enclosed (e.g. boot), duct the hot air out.
Evaporator – under dash	40 × 35 × 14 cm	Under the dash. Vents, fan and temperature controls on the front.
Evaporator – behind dash	40 × 32 × 14 cm	Hidden behind the dash or in place of the old heater box. Four 60 mm ports duct to your existing or custom vents. Two heater hose connections tee into the engine's heater lines.

The two long hoses are 3.5 m, so the evaporator can be a long way from the other two parts. Compressor and condenser mount close together (within 1.5 m) – boot or under the floor with the evaporator under the dash is a common layout.

How many amps does it draw? What alternator do I need?

• 12V: about 45A on average. It drops a bit lower once the cabin has cooled, and may use a little more when first cooling down a really hot vehicle.
• 24V: 10–40A.
• Aim for a 100A alternator or larger on 12V. Early Holdens, Fords, VWs and Datsuns with small factory alternators usually need an upgrade – your auto electrician does that in an afternoon.
• The compressor has soft start (no voltage spike) and low-voltage shutdown to protect your battery.
• The engine does not need to be running – it runs off the battery. With a good battery it will cool a parked cab or canopy, and the low-voltage cut-off (10.5V) stops it before it flattens the battery.
• A heavy-duty relay is included so the system is only live with the key on – no standby drain on a stored classic.

What's in the kit

• 20cc variable-speed brushless inverter compressor (650W on 12V, 850W on 24V), pre-oiled, with upgraded heavy-duty main power cables and a universal L-shaped mounting bracket (replaces the old U-bracket that got in the way)
• Condenser with fan and receiver dryer already fitted, plus a mounting bracket and bolt pack
• Evaporator with built-in heater core – your choice of under-dash or behind-dash. Both front faces are included so you can change your mind during the install
• Three A/C hoses in three different sizes so you can't mix them up – 5/8" suction 3.5 m, 1/2" discharge 1.5 m, 3/8" liquid 3.5 m – plus all fittings, with both a straight and a 90° option for every hose end so you can route around whatever is in the way, all dual O-ring for a better seal
• Digital control panel and wireless remote
• 4 m heavy-duty power cable (16 mm² on 12V, 10 mm² on 24V) with heavy-duty ignition relay, plus the pre-wired evaporator control cable – plug it together on the bench and see it work before it goes in the car

Not included: refrigerant and heater hose (standard coolant hose from any parts shop). Once you've cut the hoses to length they need crimping by an automotive air conditioning shop or auto electrician (A/C fittings need their own dies – not a hydraulic shop), then the system is vacuumed, leak-tested and charged with about 500 g of R134a. Budget a couple of hundred dollars for both.

Vehicles our customers have put these in

HQ, HG, HZ and WB Holdens, Kingswoods, LJ and LX Toranas, VK to VS Commodores, 57 Chev, C10, Impala, F100, XY Falcon, Mustangs, Ford Escort and Cortina, Valiant Charger, VW Kombi and Beetle, Datsuns, Subaru Brumby, Land Rover Perentie, 4WDs, vans, trucks, tractors and machinery. If it has a battery, a coolant hose and room for three boxes, someone has probably already done it.

We keep a running demo unit at Pimpama on the Gold Coast. Come and see and hear it before you buy – by appointment.

How the electric compressor works

It's a variable-speed inverter compressor, driven purely by 12V or 24V DC – the inverter changes the compressor speed to match how much cooling the cabin needs, instead of running flat out and cycling on and off like a belt-driven unit. It starts fast (around 4500 RPM) to pull the temperature down, drops to around 3000 RPM as the cabin cools, and idles around 1500 RPM to hold your set temperature. That variable speed is why the real-world power draw is well below the peak figure most of the time – and why it's quieter than an old belt-driven unit cycling on and off.

Heating and cooling in one box

The evaporator has a cooling coil and a heater core side by side. Cold comes from the electric compressor; heat comes from engine coolant, so it costs you nothing electrically and gives proper factory-style warmth and demist once the engine is up to temperature. Because the two share one housing, the cooling coil is a little smaller than the cooling-only kit's – still plenty for a classic, 4WD or van, but if you're cooling a big cabin in the tropics and never need heat, the cooling-only kit cools harder. Blower moves up to 440 m³/h.

Installing it

1. Pick your three mounting spots using the size table above.
2. Mount the parts (compressor horizontal) and run the hoses. Cut to length and have them crimped by an A/C shop. Keep the caps on the fittings until the last minute – dirt or moisture in the circuit will kill a compressor.
3. Wire it: the 4 m power cable runs battery to compressor controller (via the relay), the control cable runs evaporator to compressor controller, and the fan plugs into the controller. Every terminal is labelled – B+, B-, F+, F-, XH, TX. Everything else is pre-wired.
4. Tee two lengths of heater hose into the engine's heater lines and run them to the evaporator's heater core – same as plumbing any aftermarket heater.
5. Have an A/C tech vacuum, leak-test and gas the system with R134a. Never run the compressor before it's charged.

Full wiring pinout, hose routing and error codes are in the installation manual (PDF).

A capable DIYer with an auto electrician and an A/C tech for the last two steps is the usual path. Any auto sparky or air con shop can do the whole job – it is a standard A/C circuit with an electric compressor instead of a belt-driven one.

Frequently asked questions

Will this 12v air conditioner fit my car?

If you have room for the three parts in the size table above and a 12V or 24V battery, yes. It's not made for one model – it's a set of parts you place to suit your build.

Is it easy to install? Are there instructions?

Yes – download the installation manual here. It covers mounting positions, hose sizes and lengths, the wiring pinout, relay setup and error codes. Most installs are a weekend for a handy owner plus an A/C shop for crimping and gassing.

Do you install, or who can fit it?

We supply the kit. Any auto electrician or car air conditioning shop can install it – it is a normal A/C system with an electric compressor. We're happy to talk to your installer if they haven't fitted an electric compressor before.

How many amps does a 12v air conditioner draw?

About 45A on average on 12V (10–40A on 24V) – a bit lower once the cabin has cooled, and a little more when first cooling down a really hot vehicle. Plan on a 100A or larger alternator and a good-sized battery.

Does it come pre-charged with gas?

No. Because you cut the hoses to length for your vehicle, the system is vacuumed, leak-tested and charged by an A/C tech after install – about 500 g of R134a, adjusted for your hose lengths. The compressor comes pre-oiled.

Can the compressor go in the boot?

Yes. Mount it horizontal (it can be rotated any way, just not stood on end) within 1.5 m of the condenser. The 3.5 m hoses reach from a boot to the dash.

Can the condenser go under the floor?

Yes, at any angle, as long as the fan can draw air through the coil and the hot air can get away. Under a ute tray, in a spare wheel well or in the boot with a duct out are all common.

Can I use the behind-dash unit with my existing vents?

Yes. The behind-dash evaporator has four 60 mm ports. Standard 60 mm ducting, Y-pieces, dampers and vents (the same ones sold as diesel heater accessories) fit straight on, so you can run it to factory or custom vents.

How does the heating work? Is it electric?

No – it's engine heat. A heater core inside the evaporator connects to your engine's coolant lines, so you get strong heat and windscreen demist once the engine is warm, with no extra load on the battery.

My car has no heater box. Can this replace it?

Yes. That's the most common use – the behind-dash unit goes where the heater box was (or would have been) and ducts to your vents. You get heating, cooling and demist from one unit.

Will it work in a caravan or trailer?

No – there's no engine coolant to heat with. Use the cooling-only kit for caravans, trailers and canopies.

Does it cool as well as the cooling-only kit?

Nearly. The cooling coil shares the housing with the heater core so it's a little smaller. For a normal car, 4WD or van you won't notice. For a very large cabin in a hot climate where you'll never use heat, choose the cooling-only kit.

Can I buy just the compressor, or the kit without an evaporator?

Yes – see the standalone 12V/24V electric compressor and the kit without evaporator if you're keeping your existing evaporator or heater box.

Does the engine need to be running?

No. It runs off the battery. With the engine off it will run until the low-voltage shutdown protects your battery.

Is it noisy?

The compressor is a variable-speed inverter unit. At idle speed it is much quieter than a belt-driven compressor cycling on and off. The condenser fan is the loudest part, so mount it where fan noise doesn't matter.

How is it different from the cheap 12v ac units online?

We test every batch ourselves and have upgraded the kit based on that: heavier main power cables, receiver dryer fitted, dual O-ring fittings with both straight and 90° options for every hose, an easier L-shaped compressor bracket, digital controller and remote, and both evaporator fronts included. It's in stock in Australia with a local warranty, and you can come and see one running.

What is the warranty?

3 years on the compressor, 1 year on the rest of the kit.

Is it in stock? Can I pick up?

Yes, stocked in Pimpama QLD. $79 flat-rate shipping Australia-wide (metro and regional), or pick up by appointment.

Specifications

Voltage	12V or 24V DC (select at order)
Compressor	20cc variable-speed brushless inverter scroll, 650W (12V) / 850W (24V), 1500–4500 RPM, soft start, low-voltage cut-off, pre-oiled
Heating	Engine-coolant heater core built into the evaporator; two heater hose connections
Blower	up to 440 m³/h
Cooling capacity	slightly below the cooling-only kit (shared coil housing)
Current draw	About 45A average (12V) · 10–40A (24V)
Refrigerant	R134a, approx. 500 g (charged after install)
Compressor size	220 × 130 × 160 mm
Condenser size	445 × 345 × 120 mm incl. fan and receiver dryer
Evaporator size	Under dash 400 × 350 × 140 mm · Behind dash 400 × 320 × 140 mm (4 × 60 mm ports)
Hoses & fittings	5/8" × 3.5 m, 1/2" × 1.5 m, 3/8" × 3.5 m; straight and 90° dual O-ring fittings for every hose end
Controls	Digital panel + wireless remote
Warranty	3 years compressor, 1 year kit
Shipping	$79 flat rate Australia-wide (metro/regional) or pick up Pimpama QLD

Tucks Performance is proudly Australian owned and operated, Pimpama, Gold Coast.