Is the first floor furnace being installed in the basement? If it is, then my recommendation is to install two gas furnaces in the basement. The second option is to give up some space on the second floor and install a utility closet. Installing HVAC in an attic and duct work in the attic is the worst place in my opinion.

Gas furnaces are installed in attics all the time. Some contractors will not install a 90% efficiency furnace in an attic because they produce a water condensate which could freeze on a very cold night. In order to avoid that problem a 80% efficiency furnace in installed. Your contractor for some reason is not offering that choice. A good installer can install any gas furnace in a cold attic. It is not not that costly or difficult.

I believe Virginia has fairly high electric rates. Heating withe even an 80% efficiency furnace will less costly to operate compare to a heat pump. There are many furnace choices in between what you have been offered. His choices are not the best.

You should think about hiring your own HVAC contractor and get the equipment and design that are more appropriate. Most builders know very little about HVAC. Based on what you have posted makes me believe this builder falls in that category.

Because this is new construction there are building requirements above that of what a normal retro fit change out would allow. Your local building code requirements could also weigh heavily on what is offered.

If the furnace was a retro fit (existing construction / not new), you could go back with 80% gas furnace. Because this is new construction, an 80% furnace will not pass building code.

Efficiency Standards fact sheet

The table you posted states the a minimum SEER rating of 15 for areas with <5000 HDD. Is that what is required for new construction?

The note below the table says 81% AFUE furnaces are allowed if additional efficiency measures are installed to compensate for differences in energy use. So it is possible to install an non-condensing furnace in new construction.

I thought residential building codes are set at the state or local municipality level. I was not aware there is a federal new residential building code for HVAC. Can you point to a document that contains this code?

The option to install a NG furnace as either primary or as a hybrid in the upstairs zone was my first question to the builder. The answer was a firm no. I have NG now, and I am very happy with it. This is what happens when working with the semi-custom cookie cutter home builders. They are only so flexible before it gets really expense to make changes. By looking at the spec above, it appears the HVAC vending is trying to comply with the minimum govt spec. Good enough?

VA energy rates I thought were on the lower side from a national perspective. I believe the aggregated average rate of power is about 12 -13 cents per KW/h. While I am interested in the cost trade between the two, the other big item for me is cold weather performance of the HPs. VA is cold but not that cold. How does an entry level heat pump perform in below freezing temperatures, especially compared to the Greenspeed from a comfort prospect? Will the output temperature be noticeably different? Does the defrost cycle work differently? It is not uncommon for the temperature to drop below freezing during night of the winter months here.

Mike, I am not apart of the new construction market. I am merely offering an opinion as to why they are offering certain things.

There is no such thing as 81% AFUE furnace. They start at 80%. The home builder would have to take more steps to hit the 81% threshold, it would be far easier with less headaches to just put in and 'sell' a more efficient furnace to the home buyer.

EPA / DOE set rules nationally, You can have additional local codes added to those.

The Greenspeed will produce heat down in the mid teens. The 14-SEER Comfort will not. It will probably be ok down to 28F or so, using the strips when in defrost.

From a theoretical standpoint, the Greenspeed will save you something like 20%-25% on electricity over the Comfort. Right now, you don't have a way to gauge this to know what that means. For a 4-ton unit, maybe $150/month for the comfort, $115 for the Greenspeed (SWAG). $35/mo x 12mo x 20 yr is $8400 over the life of the unit (SWAG).

It's really stoopid they won't do gas.

But if there was a market for 81% AFUE furnaces, don't you think manufacturers would tweak their designs to make the numbers?

The document you posted are federal standards. I could be wrong, but it does not mean states must adopt these standards into their building codes. Everyone should always check with their local code official for the latest building code. They will determine whether you pass inspection or not.

The output temperature of both the low end and high end heat pumps should be about the same. In both cases the backup electric heat strips will supply the additional heat when the temperature drops. However the Greenspeed has better low temperature performance. That will reduce the time the electric heat strips will operate and save money on operation. The Greenspeed is also variable speed which will be more comfortable for winter heating and summer cooling.

But if there was a market for 81% AFUE furnaces, don't you think manufacturers would tweak their designs to make the numbers?

I suppose they could, just as much as the government tweaking their requirements.

As an example: The manufacturer's make 13 SEER air conditioners. For my climate (location) it is against the law to install a 13 SEER air conditioner here (south region) as a retro fit or existing AC system change out.

(New Construction is different in many ways)

That law is a federal law. There are differences in local codes, but typically the efficiency requirements come from EPA / DOE which ever you prefer.

Inventory is costly. The more SKU's you have the more costly it is. An 81% furnace is in the range of a cheaper model. The manufacturer's want to sell higher end.

In the construction industry, many times people buy a new home for the higher efficiency standards.

So all these things would weigh on a decision for a manufacturer to delve into what is known as a limited market?

Current SKU's that I know of: 80% | 90% | 92% | 95% | 97%

then they come in different sizes 40K BTU | 60K BTU | 70K BTU | 80K BTU | 90K BTU | 110k BTU | 120K BTU

This amounts to one heck of a lot of inventory.

What I see happening in the future is that SKU's are reduced because inventory is costly. The models of the future (I suspect) will probably be multi staged devices you might have 2 or 3 different sizes. The equipment is designed to run via load matching and so equipment sizing issues are no longer the issue as long as ducting is adequately designed and installed.

It may take another 10-20 years. Much of this will also depend on efficiency requirements imposed by EPA / DOE. That's what is driving it.