Sounds about right for a quality job in such a big home. And it won't even provide cooling..

Yikes! Can it really be worth that? We will have bedrooms in the basement, is it worth it to spend $6000 on putting foam insullation under the basement? Thanks for your help.

Electric, hydronic, what kind of heat?

We have hydronic under two north-facing rooms, and it's very cozy, but I wouldn't want to do without the central forced air system for providing cooling in summer and humidity in winter.

Sounds a bit low to me for that square footage in hydrionic and I'm presuming 3 levels in the home. Insulation under the slab and footers is absolutely required whether or not you choose radiant.

Only 2 levels, thanks for the input. Thoughts on comfort of forced air in lower level? Will likeley have a lot of tile other than bedrooms. Thanks

A forced-air system, just like a radiant floor heating system, should be sized and probably designed by a professional third party other than the hvac contractor. With 2012 or current levels of energy code for the building envelope, you may not even notice the operation of a forced-air system if it's designed and installed well.

The major comfort advantages of forced-air, is the ability to cool if it's the usual heat pump, and you can make faster changes to indoor air temperature with the thermostat. If you can feel the warmth of a radiant floor by touch, it typically indicates a poorly built building envelope (leaky and under insulated).

So should I expect to wear slippers in the main floor and basement if we go with forced air? Just hate cold floors in the winter. Thanks again.

You can buy a lot of house slippers for 50K. 24K gold ones.

Our builder quoted us $13k additional to add hydronic radiant heat for 5,000 sqft. This would be in addition to the forced air cooling. He kind of talked us out of it.

I think insulating under the entire slab as in this GW thread should address most your concerns. But yeah, slippers will be a good move if you keep your thermostat at normal levels during cold weather.

Springtime you said, "A forced-air system, just like a radiant floor heating system, should be sized and probably designed by a professional third party other than the hvac contractor."

So who should we ask for as a professional third party?

cpartist, you could ask your builder for a recommendation. Or maybe Springtime Builders or others know of folks in your area. Maybe someone who also is a HERS rater or Florida Green Building Coalition certifying agent?

We got a "green building consultant" based on builder recommendation. In our case the consultant did not design but had input on the HVAC; consultant, builder, and HVAC sub were in agreement on the final design/specs.

denalidadeb, good luck with your house!

My statement there cpartist was over sweeping. More of an opinion pertaining to custom homes built to current energy codes. Better performance and unique designs especially deserve it but I think more people are recognizing the benefits of Energy Star certification, HERS ratings and professionally designed systems. As people adopt current energy codes, these services are valuable for navigating the complying software that avoids certain prescriptive requirements with appropriate tradeoffs.