Greetings,

I have a very novice question on radiant floor heating.

About 1/3 of the flooring on the first floor in my house (Chicago suburbs) is ceramic tiles, which includes kitchen, bathroom and a hall area.  The problem is the following: while we keep the house fairly warm (68C during the day), the ceramic floors are very uncomfortable during winter months.   We also have a single-thermostat for central AC, which makes it challenging to keep an even temperature throughout the house.

While in a perfect world I'd love to install a really green solution with GSHP... that doesn't seem possible in today's economic environment.  Thus I was thinking about a high efficiency water heater that can support radiant flooring (something like AO Smith Vertex 100) and a simple staple-up solution to keep the ceramic portions of the floor warm.  We have a full unfinished basement in the house (it is unheated, but gets fairly warm due to open ductwork + water heater + furnace being there), so the access should be fairly simple.

I am NOT looking for the heated floors to replace the existing furnace, which does a fairly decent job keeping our house warm - instead I am looking for an auxiliary solution to (1) make the floors more comfortable and (2) assist with more even heat distribution between the first and second floor in the house.

I came across several possible options:

1. Onix staple-up
2. PEX Staple-up with heat transfer plate
   
3. PEX suspended
   
4. PEX Suspended with UltraFin
5. PEX attached to joists
   

There seems to be many opinions about pros and cons of each, including too localized heating with heat transfer plates (people feeling exactly where the joists are) and concerns about Onix costs.

Any help / advice / recommendation you can provide will be greatly appreciated.

Nick

Heat transfer plates are to increase output. They can, with thin floor coverings, result in noticeable patches of heat, but that is secondary in most cases to the increased output.

In your case, do it cheap and effective. Floor sensor/air sensor thermostat, suspended PEX, regular water heater (assuming you are only floor conditioning), with heat exchanger if you use the water heater for potable use. No need for plates just to do floor conditioning.

If it's a small amount of area, electric radiant might do the trick as well.

Thanks for your comments, Rob.

Is there any guidelines why a separate heat exchanger is required?  Assuming we don't drink hot water.

I have to replace the water heater in any event - the I looked at indicates:
SIDE-MOUNTED HOT AND COLD RECIRCULATING TAPS
Allows Vertex to be installed as part of combination space heating/water heating applications or any system requiring a recirculating hot water loop, including radiant floor heating.

Thank You!

Only use a heat exchanger if the water heater is heating potable (drinkable/showering) water. If it's dedicated for radiant heating, you won't need it. but unless you are doing a huge amount of floor warming, I doubt you need the Vertex.

I was hoping to use Vertex as a combo-device for both flooring and potable. Frankly speaking I didn't realize additional heat exchanger would be required. Do we introduce something "undesirable" to the water with radiant flooring, which makes it unacceptable for potable use?

search any internet forum on radiant or heating for "open system" and you'll likely get lots of discussion on it. Basically, it's not a good idea for the system or for you. It's not a death sentence or anything, just not a good idea.