The contractors will tell you what size air conditioner you need in your home but they don’t always agree.   They cannot just look at your house or go by what unit was already in home previously.

What size air conditioner do I need in my home?

Getting a load calculation is very important to ensure you will get the proper dehumidification and cooling/heating of your home.  Our home’s unit needed to be replaced we had done some improvements and our unit was short cycling.  (Turning on and off frequently).

Our home was cooling and we had dehumidification but our electric bill skyrocketed and our unit was breaking down.

Every contractor that came out told us we needed a different tonnage unit.   We had from 3 tons to 3.5 tons and no one did any calculations they just stood in our home telling us what we needed.

Now, don’t get me wrong there are some contractors that will do their own load calculations but this is not their trained speciality and I truly believe you need to have a third party perform these calculations.

Let me expain why…

The installation

After having multiple estimates we chose an air conditioning contractor to install our new unit according the specs of the manual J that was performed by Pro Calcs.  We also had a manual S,  and manual d performed by Pro Calcs and the blower door and duct leakage test by 15 lightyears.

The manual S assists with system selection and design.  The manual D designs the ductwork to work with the unit you are having installed.

I can tell you I am so thankful we had these calculations and designs completed by Pro Calcs.  The Air conditioning contractor that installed our unit did a very poor installation and did not follow duct design at all.  We hired them to install a system that was to the specifications of the design.  Within the two months after installation the unit broke down three times, it tripped a breaker, it was quite a nightmare.

The day unit was installed the thermostat did not work.  The supplier had to order a thermostat that took a week to come in and then once thermostat was installed we were getting faults that the blower motor was faulty.  It took 3 weeks for ArcoAire to send a new blower unit.  The first blower motor that was sent was damaged in shipping and then finally after 3 weeks we received another blower motor.  (Remember, we just had this unit installed)   I kept calling the installer to let them know that the unit was not working properly.  He told me that he called the manufacturer and that he was waiting on the manufacturer to come and look at unit to see what could be done.

In meantime, I was feeling like we were getting the run around and I called another air conditioning company to come out and take a look at the system.

Another Contractor cleaning up the mess

We were blessed to have Jerrahian Cooling come and assist us with this issue.  I honestly cannot express enough gratitude to Mike for coming out and helping us with this situation.  He came out and initally noticed that the common wires in unit were not hooked up properly for a communicating system.  Then after numerous trips back and forth to our home he found that the static pressure was low on system and that ductwork was not installed to the specs of the plan we hired A1Air Solutions to complete.  Then we find out that the wrong breaker and wire run to air handler were not correctly sized.

Mike came to our home first thing in the morning after our unit broke down for the third time and got that system up and running until we could figure out our next steps.   A1Air Solutions  installed the unit  and decided it wasn’t their problem anymore and just texted me back, sorry when unit broke down again.

We had to call the original installer’s A1Air Solutions supply house and ask them what was going on.  They let me know that they were not refunding this contractor’s costs for the unit because the unit was installed improperly.  I explained to him that we had all of these calculations done and they did not follow any of the design specifications.  Plus, they didn’t know how to properly install an inverter system.

So why were these calculations important?

The load calcuations and duct design importance

When unit wasn’t working properly I had 15 lightyears come back out to our home.  They had completed a blower door test on our home.  This test helps test the leakiness of your home  and ductwork currently installed.  They worked together with Pro Calcs by providing them the numbers necessary to perform Manual J, D, and S.

15 lightyears also came back to our home when unit wasn’t working properly and performed testing and wrote report showing that the ductwork was not installed properly nor were the ducts sealed properly.  15 lightyear’s tests showed the static pressure was low and system could not ramp up to full speed and/or specifications of manual j . 15 lightyear’s findings were poor duct installation and possible equipment malfunction.

The load calculations were important because it got us our money back.  A1Air Solutions tried to offer us a partial refund and I let him know that all the work they performed, duct work included would all have to be re-done because nothing was done to specifications.

A1Air Solutions didn’t have a leg to stand on and had to give us our money back.  We gave them $400.00 towards the costs of new registers, copper, and cement pad for compressor.  After months of aggravation and research on air conditioning I had to do to realize what was going on I should have sent him a bill.



We received a refund from the contractor because we had our “ducts” (he,he) in a row.  The manual D was proof that they didn’t complete the duct work properly for the new system to run optimally.

The manual S helped us because system wasn’t running to specifications required for my home.

I would recommend Pro Calcs again and again because throughout this process they stood behind their calculations and helped us throughout this difficult process.

It should not be this hard to have an air conditioning/heating system installed in your home.  However there are many a/c contractors but not many professionals in the industry.

I also have to say thank you to Jerrahian Cooling for sticking by us.  Mike at Jerrahian Cooling installed our new unit and worked closely with Pro Calcs to get our system working optimally and to design specficiations.

These new units have to be installed by a professional there are so many settings to adjust to the conditions in your home.

Too many contractors just throw these units in our homes and don’t bother with the specifics.

Thank goodness for Pro Calcs and Jerrahian Cooling for standing by your clients and bringing superb service.

As for our original installer A1Air Solutions  thank you for giving us our money back.

As for ArcoAire you should have stood by your contractor.  If you showed up in the beginning when the unit was broken on day one.  A1Air Solutions reached out to you for assistance and you did nothing.  So now you have an installer that still does not know what went wrong with installation, a contractor that is out money for a unit you sold him and didn’t support him when install went wrong, and an upset customer that didn’t see the hassle free in your “Hassle Free 10 year warranty.”

To those of you reading this post make sure you have a competent installer installing these units.  It is hard to tell who is and who isn’t but have your calculations done.  I see now that it covered our butts in this situation.  You need a contractor that is going to continue to research something until it is right.

You also need to go with a brand that will stand behind their warranty.   It is important that a manufacturer allows the contractor to make the call when a part is bad and it is under warranty  If not, you are waiting months for the manufacturer to decide what to do.  A broken system that is draining your wallet with high electric bills is something you receive from poor workmanship and a manufacturer that doesn’t support their contractors and doesn’t follow through quickly for the customer.

Thanks again to Pro Calcs and Jerrahian Cooling