Make sure you invest in a high efficiency tankless water heater.
Can you use a tankless water heater for radiant heat.
Because the slab installations will require less than 140 deg f water it is safe to use a water heater to heat the radiant slabs.
You actually have a choice between them as you can use a water heater or tankless for radiant floor heating and not just a boiler.
And i would never recommend the use of a tankless water heater for a hydronic space heating system.
Sample temperature curve for an on demand unit.
However it is important to understand that not all of them are suitable for this task.
The system with a tankless water heater will also be much more responsive have unlimited supply of hot water and clean water running through the floor heating pipes without sediments and other mineral build ups.
If you don t want to use a boiler you may be able to use a tank style water heater but only in some jurisdictions since using a water heater as a boiler may be a code violation.
A tankless hot water heater is ideal for this application since there is no water to be kept hot at all times.
Water heater for radiant heat water heaters are good for radiant floor heating because they maintain a low temperature.
We will also be installing 2 separate water heaters.
Tankless water heater can be used to produce radiant heating.
So using the unit for radiant heating generally has little or no effect on the sizing calculation.