HVAC or Roof, who goes first?

I’m a homeowner and I’m remodelling a '60s house that needed new HVAC, and new roof. I had the rooftop HVAC installed first, because the installer recommended to install it BEFORE the new roof is installed.

Now when I hired a roofing company, they were horrified that the AC unit was installed first, and they said the roof ALWAYS goes first, and I need to pay extra to lift the AC unit and the conduit for the electrical. He said he had 30 years experience and the roof ALWAYS goes before the new AC.

But when I went back to the HVAC installer, he was pissed that I questioned his recommendation, and that the roofer he works with ALWAYS installs the roof after the AC.

Who is right?

If given the choice I would have the ac installed after the roof every time.


The roofer is right.

Unless the Hvac unit is built on its own curb for the roofer To roof around

But if it is sitting on top of a couple 4x4s
Your air conditioner guy doesnt have enough experience with roof-top work.

The unit has to be removed to roof under it.

So you do call the AC guy first… to remove the unit for the roofer.
Then the roofer does his job.
Then the AC comes back and re-installs the unit or installs a new one.
Then it would be wise to call the roofer again to make sure it is water-tight and they didnt mess anything up.

The roofer and the HVAC should be working together , scheduling with each other and keeping their commitments.