Hello, I am in the process of building a new home. I am planning on having the home foam sprayed. My hvac contractor is trying to sell me a 17 seer unit which he says will eliminate the need for the fresh air ventilation unit. The cost of this unit Is also much greater than a 14 seer to the tune of 3K. I am leaning toward going with a 14 seer single speed heat pump and put in the fresh air vent system with the money saved. Any help is much appreciated as I don't have any experience with the foam and what it takes to keep mildew out and good quality air in. Thanks, Luke

Why are you insulating with spray foam if you are concerned with cost? That has to be the most expensive option available.

More info is needed to provide any useful help. Where are you located? How big is the home? How is the home constructed, i.e. basement/crawlspace/slab? 2x4, 2x6, or what? Exterior sheathing / siding material? How will the ceiling be insulated?

Posted By Luke on 03 Jan 2015 01:15 PM
Hello, I am in the process of building a new home. I am planning on having the home foam sprayed. My hvac contractor is trying to sell me a 17 seer unit which he says will eliminate the need for the fresh air ventilation unit.

Don't listen to your HVAC contractor he doesn't know what he is talking about. The SEER rating of an AC unit has nothing to do with it.

Mechanical ventilation is required in any modern air-tight home. The 2012 IBC requires it in new homes. The ERV/HRV unit should ideally be ducted on its own duct work but it can be done on existing HVAC duct runs.

I can only guess that you are comparing a premium to a economy package. There are code minimum systems and then premium systems that include things like higher efficiency equipment or better ventilation etc. We presume that your contractor knows that efficiency doesn't eliminate ventilation requirement so there is something missing in the narrative.