I am not sure what you consider a high initial cost and in allreality the only one that can answer the "is it worth it" question is you.
With thatI would recommend that if you are still undecided, now would be the time toinstall the PEX piping in case you decide you want to try it later. Justmake sure while they are pouring that the system is pressurized with a gaugeleft on it so any accidental punctures can be dealt with now.
Pluses of radiant heating
I am sure you know about many of the pros:
- it is an efficient means ofheating a space,
- there is no air movement resulting in reduced dusting &increased IAQ,
- the ever popular warm toes,
- along with having very fewcomponents that can fail.
As for costs, one of the biggest things I would mention is that you areapparently building a very tight and highly efficient house. What this meansis that:
- you don't need a huge boiler, but
- instead you can probably just use atankless water heater or a water heater.
All this leaves you needing is the pex lines, a mixing valve, and a pump. I am not adding thefoam under the slab as part of the initial cost as that is already requiredby code.
Minuses of radiant heating
On the con side, many in the home performance world are worried about"over-heating" and it not being as efficient as claimed, etc.
Theefficiency depends a lot on the getting the system designed properly fromthe start and how you use it. Please remember that unlike forced air system,this system relies on radiating the heat from the floor so turning it off orusing lower set points during the night is not only not a good idea but willtake longer for the spaces to heat up.
As for the overheating - this getsback to the proper design, sizing & using a lower set point for the waterentering the system.
For more information:
I would recommend you read my radiant heating FAQandfind a qualified and knowledgeable individual in your area that will do anaccurate Manual J & layout for you.
Also, read "Is hydronic radiant flooring better than electric in terms of cost, heat generated, and installation ease?" a Q&A answered by Randy Potter.