Discussion on Payment for Air Conditioner Installation

Hello. My wife called an air conditioner installer, Reuven, whom we received recommendations for, and asked for a quote to replace an old air conditioner with a new one, stating that she wanted to know the total price, specifying that the air conditioner's motor is on the fourth floor while we live on the third floor. Reuven gave a quote, and she agreed with him. I was not involved in the negotiations and only knew that Reuven was supposed to come to install the air conditioner. Then a young man named Shimon appeared at our house and announced: I am the installer. I called Reuven and told him: I heard good things about you and ordered you, I don't know Shimon. Reuven replied: he works for me, the responsibility is mine, as far as you are concerned, you only know me. Shimon, a good and honest guy, it should be noted, started the work and asked me whether to replace the air conditioner's piping or leave the old piping, emphasizing that over 2 meters, each meter of piping costs 150 shekels. I asked if he thought it was worth replacing, and he said yes, and he indeed replaced it, saying the length of the piping is 8 meters. When my wife arrived, she said: I agreed with Reuven that the price includes everything. Shimon replied to her: but your husband approved me that I deserve an addition. I said: I didn't know there was an agreement, and in general, financially, I have no business with you, I ordered Reuven, and he sent you as a worker. All your discussions should be with him and not with me. We called Reuven, and he said: why did Shimon need to replace the piping? When the piping is good, it is not replaced. But he admits that when he agreed with us, he did not say that the old piping would be left, and this issue was not discussed at all. Regarding my wife's claim that she told him in advance that the motor is located a floor above, Reuven answers: I thought 3 meters of piping were needed, not more, I didn't think it was about 8 meters. Reuven and Shimon are God-fearing Jews, and we also try to be God-fearing, and the three of us decided to present the matter before the teachers of the law — and what they decide, we will gladly fulfill. The phone numbers of all three of us are attached so that the rabbis can clarify details.

Hello 

I presented the question before the judges of the rabbinical court under the leadership of our teacher, the Gaon, Rabbi Avraham Fried, shlita.  Here is their response:

In this case, it is necessary to check if the replacement of the piping was indeed needed; if it was needed, it is clear that payment is required. If not, payment is not required.

It is possible to call Reuven and ask him, in light of the data, whether it was necessary.

Even if it was not necessary, but if the replacement improved the air conditioner, payment is required [like one who improves his friend's field].

Although the installer said the piping was on him, if it concerns a length more than usual, he can say that this was not his intention.