People are funny when it comes to limitations. If a motorist drives 30 mph in a closely patrolled school zone with a 15 mph speed limit, they will likely be given a speeding ticket. On the freeway, however, going 10-15 mph over the speed limit will probably be ignored. This just proves that speed laws have some flexibility depending on the circumstances. Nature is not that flexible with its limits. The speed of light is about 186,000 miles per second. Absolute zero is −459.67 F, water freezes at 32 F, and it boils at 212 F at sea level. There is nothing anyone, including traffic cops, can do to change those limits. There are limitations that people may not be aware of with a home’s HVAC system. Furnaces will have an upper limit of about 200 F so the unit will shut off if that temperature is reached. For air conditioning, the cooling limit depends on the outside temperature. The limit of cooling is about 20 degrees F between the outside air and what the AC system can cool your home’s interior to. This means that on an extremely hot summer day when the temperature is near 100 F your house will be at a balmy 80 F at best. The reason for this involves a lot of technical chatter about the heat cycle and thermodynamics. It all comes down to the compressor not being able to transfer heat as efficiently to the outside during hot weather. The best thing a homeowner can do is keep their system well maintained and clean with regular service by a qualified HVAC technician. Being at 80 F inside is still better than living in 100 F heat with an HVAC system that does not work due to neglect.