I have an answer for you that might be worth your while. I am a construction man myself having more than 2o years of work experience in the middle east. ONLY ONE WAY TO BOOST PRODUCTIVITY IN THE FIELD IS ENDURING THE WEATHER WITH YOUR WORKERS. I NEVER STAYED MORE THAN 15 MINUTES IN MY AIRCONDITIONED WORK SITE CABIN, AND I MAKE SURE THAT MY WORKERS ARE WELL FURNISHED WITH COLD DRINKS AND LOTS OF ICE. I ALSO FURNISH THEM WITH SHADED BREAKROOM WITH OPEN SIDES AND WELL INSULATED ROOF, THAT GIVES COMFORT FOR THEIR WELL DESERVE BREAK., BY BEING WITH YOUR WORKERS ENDURING THEIR SUFFERING, THEY TEND TO FEEL THAT YEAH, WORKING UNDER THE HARSH CONDITION IS TOLERABLE AND ONCE IN A WHILE DONT BE ASHAME TO GET YOUR HANDS DIRTY BECAUSE YOU GAIN YOUR WORKERS RESPECT. BY THE WAY I AM THE PROJECT MANAGER OF MY COMPANY....