For almost fifteen years, our goal has been to modernise and optimise the control systems on classic Porsche 911s to deliver a simplified, contemporary driving experience allowing Porsche 911 owners to derive maximum joy from their cars.

How we've changed the game since 2010

This began with our CDI+ system, putting modern, mappable twin-spark ignition into the engine compartment of a classic 911 and delivering more power, better throttle response, better economy and the now-familiar 'Classic Retrofit tickover' to these cars.

Product development was further energised with the arrival of our plug-and-play replacement blade fuse panels for 911s that transformed unreliable electrical systems by reducing resistance across circuits and bringing modern fuse technology to the vehicle, including headlamp relays and blown fuse LED indicators.

In 2016, we began work on the true Classic Retrofit game-changer: an electric A/C system that would outperform all other competitors at similar if not lower cost, and with higher efficiency than anything previously seen. Designed to take weight off the rear of the car, our system was 18 kilos lighter than the original and pulled less than 1.5 horsepower from the engine. No bodywork changes were required.

Generating heat from 12 volts - Singer system 1

The logical evolution of this system was to improve power with an upgraded alternator, further drop cabin vent temperatures with a second condenser and then look at ways to delete the outdated and inefficient heating system, where a series of fans scavenged hot air from the exhaust manifolds and blended that heat in a confusing and frustrating way in the cabin.

The first solution to this was seen in our system for Singer models, using ceramic heat blocks and a new design of bespoke dash controller to combine the A/C and heat output into the first fully-resolved aftermarket climate control system for an air-cooled 911.

While the system is still impressive, this iteration increased complexity and the potential retail price was beyond the reach of many enthusiasts. A significant advantage with the Singer Reimagined business model was that it builds cars from scratch, with bespoke bodyshells and wiring looms. The system was not plug and play for owners of original, unmodified cars, which continues to be important to us as a design goal, andto retain the authenticity of the car's original design.

Sustainable Energy Choices

We were early adopters of alternative energy at home, and our interest in sustainability drove many of our business choices, including local UK assembly and manufacture where possible for carbon footprint reduction, increased energy efficiency of our products in a car, a constant desire to work with reduced and fully recyclable packaging and a constant drive to always do better.

Given that our domestic heating has been driven by heat pump technology for almost twenty years, how could we use the same process in our Porsche 911 HVAC systems? This would revolutionise system efficiency, reduce weight, increase simplicity, and take user interface and experience to a new level. The challenge was accepted. We are delighted to say that we have now developed a truly groundbreaking Porsche 911 heat pump HVAC system, including a brand new dash controller that retains the original look.

The Classic Retrofit 12v hot and cold HVAC system

The brand new system works by replacing the existing 12v A/C compressor with our unique 12v heat pump compressor, which can operate backwards and forwards. In A/C mode the system works in the familiar way of cooling warm air but in heat pump mode, the system works in reverse, taking heat from the cold air and sending it into the cabin.

Heat pumps are significantly more efficient than electric heaters, which is why we use them at home. Advantages to the heat pump system on a 911 include:

• Simplification - heating and cooling in one package
• Improved control - distribution and control of heating, removing the existing mechanical cable controls, replacing with new servo-controlled blend valves
• Unlocks performance - net weight saving, and no requirement for heat exchangers opens up exhaust options
• Elegant ‘OEM+’ design - our new digital slide control panel has classic
  looks but modern functionality

The new system integrates the control cold and hot air into one aesthetically familiar but completely redesigned slider panel, deleting the outdated cables and managing servo-controlled valves either side of our powerful Gen 2 blower unit, with hard lines under the hood to deliver maximum system performance. Our system also mounts a smaller lithium battery and the heat pump compressor on one tightly-packaged chassis. It is a significant evolution of the original Classic Retrofit A/C system.

We have already had conversations with clients at the very highest level of classic air-cooled Porsche restoration who can't wait to incorporate this technology into their premium builds. Expect to see it in the very best classic Porsche 911 builds through 2025 and beyond. The game-changing heat pump system will launch on ClassicRetrofit.com in Summer 2025.