I just talked to my ac guy and here’s what he suggested:
Most residential AC units are designed to handle about a 20 degree difference between outdoor and indoor temperatures efficiently. If we try to cool from 101°F to 69°F the AC is pushing the system beyond its designed capacity.
The system may run no stop to try to reach 69 which will cause issues like Coil freezing, Compressor overheating even Premature failure. The coil freeze can cause ice buildup and system shutdown.
So he suggested to run AC temp no lower than 78 during the peak heat like this week. You may use ceiling fan to assist cooling. Blackout curtains will help too. He also stressed to change filter monthly to keep the vents unobstructed.
I can deliver some filtered tomorrow or Friday if you need.
她们总是把温度设在68-72度。这个在我们这里酷热的夏天完全不practical也不responsible。暗示她们几次了都被忽略。她们住了两年我起码带AC公司去小修了三次，当然每次AC公司都会夸大一下问题 把话题往replacement上引。今天气温达101度，tenant又来短信说她们温度设在69度，ac有停机的迹象。我这次把话挑明了：
I just talked to my ac guy and here’s what he suggested:
Most residential AC units are designed to handle about a 20 degree difference between outdoor and indoor temperatures efficiently. If we try to cool from 101°F to 69°F the AC is pushing the system beyond its designed capacity.
The system may run no stop to try to reach 69 which will cause issues like Coil freezing, Compressor overheating even Premature failure. The coil freeze can cause ice buildup and system shutdown.
So he suggested to run AC temp no lower than 78 during the peak heat like this week. You may use ceiling fan to assist cooling. Blackout curtains will help too. He also stressed to change filter monthly to keep the vents unobstructed.
I can deliver some filtered tomorrow or Friday if you need.
刚刚给她们renew了lease 现在后悔怎么没把这个写进新lease里！
如果租客喊热，检查机器最关键的第一步是测量出口处的温度，55度是标准，但实际考虑机器使用年数，60度以下也能接受。温差18度就是房间温度73度，有些地方政府要求节能，要求屋内温度75度，温差就是20度。
理论上，只要时间够，屋内的温度总能降下来，除非机器制冷功率太小，热源大于制冷量。
炎热夏天就有来临，如有人抱怨机器不好，先测量机器出口温度，55到60度，超过60度的“凉风”，当然没有55度左右的“冷风”好。汽车空调的冷气出口温度是35度左右。