Not only are urban heat islands increasing the temperature of our cities, that in combination with our technology fueled lifestyle and explosion of urban areas has increased human discomfort in more ways than one. Unfortunately, we equate it all in terms of how hot it is.
My 25 year old house used to be fairly comfortable throughout the year till 2016 when the small bungalow in a large plot next door was demolished to make way for a five storeyed apartment building. The trees were intact and there was sufficient space for air flow between the two buildings. Then why was I suddenly feeling hotter than usual? It's because our new neighbours installed air conditioners in their house and the outdoor units were facing the small window of my room which throw out hot air all the way into my room.
I don't have an air conditioner at my house. And I don't want to ever get one. I believe in cooling the natural way by respecting the climate and building spaces which makes a person comfortable if not supercooled (That's what being comfortable has become.) During summers, I sleep on the terrace at night under the stars (and a mosquito net obviously) where I need an extra blanket as it gets quite cold before dawn. One can say I am privileged to have a terrace and a house surrounded by trees and I would agree with them. Then Why do I complain about my neighbours and their air conditioning?
Say I got fed up of my neighbour's hot air throwing air handling unit, shut off the window and installed an air conditioner in my house... Then I will have installed an air conditioner since the air conditioner installed by my neighbour because it's too hot is making it even hotter.
But that's easier said than done. So if push comes to shove and you don't hire me to design an energy efficient house and want to install an air conditioner... What do you do?
I have a recommendation:
Most ACs these days use R410A or R32 (Freon) refrigerants- both hydrofluorocarbons (HFCs)rather than the Ozone destroying hydrochlorofluorocarbon (HCHC)R22 refrigerant which was used earlier. We're not even talking about CFCs which were banned much before.
Scientists have come up with a very complicated term to compare gases based on their potential to cause global warming.
It's called GWP (Global Warming potential.) read about it here.
Let us compare the GWP for different refrigerants:
For reference, the GWP of CO2 is 1
1. Isobutane (R600A) = 3
2. Propane (R290) = 3
3. Freon (R32) = 675
4. R22 = 1810
5. R410A = 2088
Why, you may ask are R32 and R410A still used in ACs then? Because unlike R22, they do not have any Ozone depletion potential.
So let's talk about Propane: The first thing that came to my mind when I heard it can be used as a refrigerant is it's high degree of flammability. But one company in India has been able to develop an air conditioning system using Propane and has been manufacturing AC units using this since 2012. It's Godrej. The NXW series. As per their statistics, they have sold more than 1,00,000 units in India. So why don't more international brands going the Godrej way?
Ans: Difference in safety standards.
International brands have to follow stringent standards for their ACs which are American and European mostly (I'm guessing First world Asia i.e. Japan and South Korea follow those same standards)
Godrej operates a quality database that includes service feedback and where complaints and faults are systematically recorded. From this database Mr. Godrej has calculated that their R290 AC has a really tiny fault rate which sounds great unless you're part of the tiny bit.
Obviously as more people start using it, the tech and safety does gets better. There'll be more regulation in place for it and more companies can port to R290 in the future.
Chinese companies too have gotten support from their government to develop R290 Air conditioning systems.
On the other hand, maybe I'm missing something and there's still a case for not using Propane based Air conditioners because we still haven't explored all possible scenarios and materials yet. But some self-research for an informed decision is the way to go ahead.
P.S.: In case you're wondering... Godrej hasn't paid me to write this post. In fact, no one has.