SS in therory you are right but this type of heating is used in Colorado and quite effectively. Similar cold winters to NE and longer too. The system in Maine is a hot water system vs hot air which is typical out west. My brother has the hot air system in his Estes Park CO home. (It is rented for part of the year for the tourists who come to visit Rocky Mountain National Park in Estes Park so it needs to have good heat for the colder times.)
The engineering study done for the Maine home proved the effectivness and efficiency compared to propane gas, oil and electric. The naysayers, builder, architect and others, involved with the build in ME were won over. When my brother arrives in Maine in a few weeks, he is currently driving east and visiting along the way, I will post links to the system he uses. He is thrilled with its performance and comfort using the radiant floor heating. It is a newer technology and you have to study up on it to learn the benifits.
It actually saves fosil fuel costs as compared to other the methods even in getting its source from the power company. An off peak meter is used providing a good savings off regular rates.
BTW I have not heard a good word about geothhermal heat in cold climates where electric costs are high such as NE. I did do my homework on geothermal last year and decided no way I would use it.
On a side note an "Energy Star Rating" tag does not tell you how well a product performed or rated in testing. Always look for "Energy Star Certified" which means the product met or exceeded the standard for that product category for energy efficiency. Very few products meet the "certified" category requirements.