"Neil" wrote in :

The ceramic heater is not a lamp, it will in 15 minutes defrost all the
glass in a Mercedes Estate car and raise the interior temperature to
acceptable before starting. Trying to source an appropriate thermostat to
operate it in the boat's water tank compartment.

Neil



100 watts is 100 watts is 341.29 BTu/hr no matter what the resistive
element looks like. The bulb does convert a small amount of it to light
because it gets hot enough to incandesce, but the heat from that light is
absorbed by anything it lights up.

In spite of the ad hype, the BTU output of a cheap nichrome heater is
exactly the same as the same wattage amazingly expensive ceramic heater.
Buried inside the ceramic, by the way, is a nichrome wire, which is what
heats it. The ceramic heater does concentrate its BTu output into a nicer
stream of hot air, making it feel like it's putting out more heat, which
it's not. My old "milk house heater" has a metal case that gets warm, but
it heats the room just as good.

Oil heaters that look like old radiators heat the same, too, once the oil
get warmed up. Go figure...nostalgia?

All these heaters with open thermostats will make a boat explode in the
presence of gasoline or propane fumes in explosive concentrations.
Luckily, I've seen some upper-end heaters coming out with solid state
thermostats that have no contacts, but triacs to control them.

To convert watts to BTu, the formula is:

BTu/hr = Watts x 3.4129

Find other interesting conversions on:
http://www.simetric.co.uk/sibtu.htm

Any heater whos outlet gets hot enough to ignite cotton, like those damned
radiant heaters, should be BANNED with the kerosene heaters. People are
too stupid to use these heaters.

The leakage from the boat is lots more than 341 BTu/hr, I'd bet raising the
temperature only slightly and just killing the batteries.

--
Larry