Posted by Harold Kestenholz - Hydronic Network on June 01, 2001 at 08:34:26:
In Reply to: Low temp baseboard posted by Wm. G. Barrett on June 01, 2001 at 04:26:00:
Slant-Fin MultiPak 80 emits about 400 btu per linear foot at 140F. I have long believed that radiant floor heating is best done with about 50% of the heat load taken by the floor at a fairly even temperature and the other 50% of the heat load taken by baseboard or other lightweight radiation. This enables the floors to stay even due to expanding much less and also permits the room temperature to follow the weather closely without the need for control other than a two-stage room thermostat and an outdoor reset control.
Radiant is installed best in a home insulated to modern standards with a heat loss of approximately 25 btuh per square foot. The usual output of radiant floor surface per square foot is about 25 btuh.
The use of 1/2 the heating by floor would mean selected areas of the room could have the tubing, the rest of the heat would be by baseboard. If 1/2 the heat is to be done by baseboard, then standard baseboard could be used as the output of baseboard at 140 is about 1/2 that of at 180. The baseboard is not affected by the temperature of the water other than output so one baseboard is not any more useful than another for radiant applications unless you want really short lengths in the rooms.