Ever notice on all cars there is a temperature setting? What this does is control the on time for the AC compressor and also the flow of hot engine coolant into the heater core located in the dash.
An interesting fact of thermal flow is that even with the temperature set at the lowest and the flow valve closed, due to conduction there will be heat Leeching into the heater core.
For those of us living in hot climates and never use the heat function, this thermal fact is basically reducing the efficiency of the car air conditioning system.
This an after-the-fact instructable and my car has been running very well in this configuration since 2006. Here is how I helped out my car's air conditioning!
Step 1: Locating the Heater Hoses in the Engine Bay.
It's easy To find by just watching the heater hose connections at the firewall. I deemed these are unnecessary and removed all.
Step 2: Capping Those Heater Hose Ports.
I used size 15 rubber caps with hose clamps to close off all heater hose ports. It's important to monitor these every 6 months or so to check for swelling, cracks and softness. Replace immediately should these symptoms appear. Don't worry the caps are cheap and I actually stockpile a dozen in my trunk tool bag.
Step 3: Completed Works!
Without those hoses the engine bay is less cluttered and has better air flow (like if that matters). The air conditioning system however is significantly colder!
Again don't do this is you need the heater but I recommend for hot only climates!