Radiant floor. About 30-30000.00 BTU

What are your fuel options (and prices)?

Electric would be best though I just got this summers propane fill rate and it is1.40 a gallon( way down for us). Electric is Energy Charge per KWH: $0.05063

Condensing propane in a 95% efficiency burner would deliver (91,000 x 0.95=) 86,450 BTU to the water for $1.40. or (86,450/1.4=) 61,750 BTU/$

An electric boiler at 100% heating efficiency would give you (3412/0.05063=) 67,391 BTU/$

...provided that's the delivered retail cost of electricity (includes delivery charges) not merely the energy charge.

In that case the electric boiler would be cheaper now, and probably cheaper into the future, since propane prices tend to track the somewhat volatile and rising world price for #2 distillate oil (heating oil and diesel), whereas electricity is a local regulated-monopoly in most of North America, and has a historically low price inflation.

I am looking for recommendations for models that others are happy with.

I have used these with good results. The benefit of an electric boiler is that they are quite reasonable in cost and if you later put in a heat pump, they make a good back up. Not sure if i am allowed to show products links here.

http://www.thermo2000.com/content/en-US/s2_produits/chaudieres/DTH_ultra.aspx