last newsletter we discussed the different types of heat
transfer: Conduction, Convection and Radiation. Each of
these can be your friend when heating a home but they can
also be your enemy when storing or transferring the hot
water in a WaterStove. Proper insulation of the WaterStove
and its plumbing is essential when building an efficient
Insulation is any material that slows the rate of heat flow
from a warm area to a cooler one. The more the rate is
slowed, the better the insulative qualities of the material.
Its ability to resist heat flow is measured as an R-value
(resistance), the higher the R-value, the more the material
will resist the flow of conductive heat.
Foil backed foam
totaling R-60 are often used to totally surround a
WaterStove. Blown-in insulation
(rock wool, fiberglass, etc.) is also popular as long as at
least an R-60 rating can be established.
Protecting the loss of radiant heat
is done with reflective materials
like aluminum foil or special reflective coatings. These
radiant barriers are used to redirect radiant heat back
toward the source. In a WaterStove environment these
reflectives are used under the hydronic heating tubes in the
floor (both poured and in rafters) and on the insulation
panels used to surround the WaterStove reservoir. Radiant
barriers are most efficient if they do not come in direct
contact with the heat source.
Convective heat loss can be a factor if there is moving air
around the uninsulated heated WaterStove parts (the door, the control
panel, some connections, etc.). It is important to protect
these parts from air currents (fans, the outside wind,
will always be some heat loss in any furnace environment but,
by paying attention to the details during installation, this
heat loss can be minimized.
upcoming issues of the WaterStove Newsletter we will discuss specific insulation products and
techniques that have shown extraordinary results.