Bath heating – Hydronic systems
This is a popular type of heating system for many good reasons. Fewer drafts and generally quieter than forced air systems, hydronic baseboard heat also has less of a tendency to dry out the air and is easily divided into separate thermostatically controlled zones. But there are a couple of problems with the baseboard heating in the bathroom. The first is the problem of wall space for convectors. Space is generally at a premium in a bathroom, and proper lengths of baseboard convectors must compete with fixtures for wall space. Sometimes you will find lengths of skirting convectors extending behind the toilet, which in my general experience is a mistake. That’s a pretty humid environment, with splashing and condensation from the toilet, and it doesn’t take long for the steel baseboard housings to start corroding and rusting.
Also, many fin tube convectors, to be brutally honest, look pretty clunky. In a larger room they are not so annoying, but in a small bathroom they are very noticeable. An alternative is to use a slim profile socket like the one from Runtal, which is only 2 inches long. deep and ranging in height from 3 in. to 12 in. from the ground, depending on the heat output of the unit. With a heat output of approximately 900 BTU / hour per foot of stroke for the 12-inch tall 4-pipe unit, this socket is well suited for the limited free wall space of a bathroom. Another solution is to use a wall mounted panel radiator; some of them can double as towel warmers.
If there is a vanity in the bathroom, another option is to mount a compact fan-coil convector underneath, in the leg space. These units are related to the existing hydronic system; They have a small electrically powered fan, which circulates the air around a heating coil before blowing it into the room. They put out a lot of heat, they usually have an adjustable fan, and the hot air they exude feels good on your feet without being so hot that it can burn them.
In my experience these fans can be quite noisy and also require a working water temperature of about 140 degrees F to put out adequate heat, so they don’t work very well with lower temperature systems (like heat pumps). Another problem is the lack of a filtration system. Fans draw air along the toe, usually a very dusty place, and it doesn’t take long for the blower fins to become clogged with dust, reducing blower performance. And its longevity hasn’t impressed me much; Replacing or repairing a unit mounted under a cabinet is no fun, even with an access panel cut into the bottom of the cabinet.
Hydronic systems are also suitable for providing radiant heat, an increasingly popular way of heating a home. Instead of passing through convectors, radiant hydronic systems send hot water through flexible plastic pipes buried in floors, walls, or ceilings, turning these surfaces into heating elements. Although more expensive than regular hydronic convection heat, radiant systems offer invisible mechanical presence, quiet operation, and even, predictable heat.