Mike

Thanks so much for the feedback. Our home is located in deerfield IL. The house has 2 floors and the first floor is roughly 2100 SF and second floor is 1600 SF. We have 2 zones of HVAC. Insulation is pretty strong as our village has very strict requirements. I can send you the insulation quote if that helps you i just need an email address to send. I really appreciate the help!

Thanks

Rob

Every new build should have a load calculation done in order to determine the proper size of the furnace and AC condensers. Equipment that is too big is often a bigger problem that equipment that is too small. If your contractor does not want to do a load calculation than find someone else.

You have a big two story house. You need a furnace and AC for each floor. The alternate solution is to have a single furnace and AC and to install zoning. Most HVAC contractors do a poor job when it comes to zoning. I can't image the zoning will ever work properly with a single stage 120K BTU furnace. If this is what he has proposed then I foresee problems.

If you plan to live in this house a long time spend the extra money and get two separate systems installed by a reputable HVAC contractor who will provide you with his load calculation. I would recommend at a minimum a 2-stage furnace. If the area has high humidity then a 2-stage AC would be nice if the budget allows it.

what is the typical equipment layout for 2 units? Side by side? I look at the ducts for air in/out on my setup and wonder how they would add a 2nd furnace and 2nd set of ducts. Just put it in a bigger room?

Well, the duct system has to be designed for 2 systems. If the ductwork is already in, you are SOL. The AS and Carrier system specs are comparable. I'd just go for the less expensive of the two.

Ignore online reviews. A system is only as good as the installer. Bad reviews come from poorly installed systems; good reviews come from well installed systems. Note that brand doesn't enter into the equation!

An HVAC system is typically measured by the sum of it's parts what it is designed to do. When you cut costs you typically cut functionality and in some cases the comfort that the system will be allowed to deliver.

When it comes to HVAC systems, builders are typically not known for quality, they are more frequently known for quantity.

A zone system, when designed properly can work fine with single stage equipment. There is another active thread on this board dealing with problems of a builder installed zone system.... it's good that you're aware of that because it does happen quite often.

Multiple stage equipment works better with zone systems: You have to realize that a zone system when operating the system from one zone is cutting the needed system resource in half or a fraction there of. This can cause debilitating problems for your HVAC system if it is not designed to work properly given various instruction sets from your controllers. (thermostats) in the zones they are designed for.

If you have multiple stage equipment (AC and Heat) a zone system will typically function that much better and more efficiently. But due to the scope and often complexity of such systems, do not expect anything but trouble if design and proper installation are not performed adequately. This is typically a huge problem for a builder.

There is some good advice and info already contained in this
thread. I would further suggest taking the HVAC out of the contract with your
builder, getting an independent heat gain/loss calculation (Manual J) &
ductwork layout calculation done (Manual D), speak with HVAC contractors
yourself and educate yourself.

You’ll likely get a better result and be glad you took
control of this aspect of the build yourself. HVAC is too important to leave to
others, in most cases.

IMPO

SR