Equipment right sizing versus customer demands, need your input.
Have a client with a large new home (3560) being built that I bid 6 months ago and listening to the customer requests I sized the systems at 84kbtu total like every other company and got the job. It is now time to do the install and I have since learned the value of right sizing equipment and not using the ol' 500sqft method anymore.
The issue is that I have now taken a closer look at this home and title 24 (prepared by an independent company) calls for a minimum of 36kbtu. I now want to revise the system down for efficiency and longevity issues to 72kbtu which will only change the condensers down a half ton each, no change on the furnace coil to stick with the same seer/eer ratings and maintain proper airflow. I have of course explained in great detail the benefits of doing this and the customer does not like the fact of having a rightsized system versus one that will cool down faster when the want. I have never had this be an issue for me because my customers go with my recommendations. They have a family member who has built homes in the past influencing their decisions to stick with the bigger system because in his opinion that is better. I have spent some time trying persuade both of them to leave the practices of the past and accept something new that is better for them.
Rather than getting in a pissing match with this family member which may cost me the job, the advice I am looking for is that if they do not go with my revised recommendations do you make your customers sign anything that they are aware that the systems are over-sized and may cause humidity, efficiency and longevity issues?