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As mentioned in the previous blog, I couldn’t find any reviews online for the Thermopro 90 but I did find some video/review (actually is just one) regarding the Air Top EVO 55. Beside the wrong description in the video (he calls it Webasto Air Top 40/55), they actually are two completely different model as far as power and fuel consumption. The only way to tell them apart, is from the manufacture label on the actual unit.

While from the outside they look the same, the Air Top Evo 40 only produce 3.5 Kw of heat and require 360 grams of fuel and 40 Watts of power.

The Air Top EVO 55 on the other hand produce 5.0 Kw of heat and require 510 grams of fuel and 95 Watts of power. They are both available in either petrol or diesel and in the diesel version there is also the option for 24Volts.

Price wise, the 40 will set you back around the $1,450.00 dollars while the 55 is about $550 dollars more expensive. It pays to shop around as these units are sold worldwide and there can be huge price differences, so don’t quote me on these prices..

Another important thing to remember is that these units do come in different variation kits: truck, marine or just the unit itself.. Base on your needs, you may find it cheaper to purchase one kit instead of the other. In my case I ended up using the marine kit because of the need for a sealed muffler..

Here you can see the difference between the two exhausts. The truck one on the left, has an extra hole for condensation, while the marine one doesn’t. Because of the mounting location, I need it the sealed unit. They also have few variations/options as far as the controller unit.. Just make sure you actually read what the controller unit does before forking out the extra cash.

Now the unit itself is very good and very fuel efficient. Last month, when we went down to 3°, I had it on and within half an hour I was sleeping in a very comfortable 22.5°. With the thermostat controller, once it reaches the preset temperature, it either switches off entirely and goes in standby mode or it goes into the low mode, where it gently continues to blow warm air into the vehicle at a very low speed.

On an average night I set it on at half on the thermostat around 10pm and it goes into low mode about half an hour later. It then stays in low mode all night until 6 am the next morning. So, a quick calculation reveal that it uses about 0.250 grams for the first half an hour plus another 1.125 grams for the rest of the night, giving me a total daily consumption of about 1.375 grams of diesel (1.65 litre) or around $2.00 per night.

That, to me is good value if compared to a Gas or electric unit of equivalent output. Let’s take a 5Kw electric heater. At the current .26c per Kw, you would only get about one hour and 20 minutes for the same money. With Gas, at $3.00+ per Kg, even a small 3.3Kw (13MJ/h) unit will consume a 1 kg of gas in just about 3 hours.

Now, the Evo 55 when at full speed I won’t lie, it is noisy.. Even at the last air outlet, that is nearly 6 metres away from the main unit, you can still hear the turbofan spinning at what it sounds like a very small jet engine. Like I said, is not a big sound, but it is definitely a high pitch sound. Good news is that, once the temperature is reached you can barely hear it.

You will also need to have some space available for both the unit and also all the 90 mm pipe duct that need to be routed around the vehicle, so in a new vehicle conversion shouldn’t be a problem, but in an existing RV you may be limited in where the duct can be installed..

There is no smell inside the vehicle what so ever as the burner is completely isolated from the air moving into the vehicle. The only noticeable smell of diesel is when the unit is turned off. Then you do smell a bit of diesel but only for a minute or two max.

In the kit you get everything you need less the ducting and the fuel pickup from the tank (if you need one). Everything else is there. The only other thing I needed to buy was the remote temperature sensor as my controller did not have the one builtin.

Finally, as per Webasto standard, the installation instruction are not that good, but luckily the few distributors online, have extra documentation that does help with the installation of the system.

I’m very happy with this unit in both the heat and the cost involved in running it at night and definitely recommend it in particularly for people starting a new conversion..