The inside of the box is lined with a thin sheet of aluminum to ensure that radiant heat from
the sun is distributed evenly throughout the box when the sun hits it at an angle early in
the morning and late afternoon.
Further along in the construction process the inside of the box will be painted with Hi-Temp
flat black spray paint to increase heat absorption and a sheet of Plexiglas will cover and
seal the front of the box.
Not all manufacturers of solar space heaters use the baffle/metal lining system but instead
substitute vertical half pipes or recycled aluminum cans as combination collector/circulators.
Most, but not all indoor window heaters are thermostatically controlled. Those that aren't
usually have a digital display showing the air temperature inside the collector.
The 4" intake fan runs on 12 volts with a 120 volt adapter and requires very little power to
operate. You could even eliminate the expense of running the fan with a small 10 watt solar
electric panel and own a system that heats for free.
Solar Window Heater | Solar Space Heater
|Solar Window Heater
(32"H x 20"W x 5.5"D)
If you live in a home or apartment with southern exposure you
have the perfect opportunity to transform day long sunshine into
free heat with an inexpensive, portable solar window heater.
Manufacturers of solar window heaters state they provide
supplemental heat for up to 1,000 square feet or can function as
a primary heat source for smaller areas less than 400 square feet.
How a solar window heater works
Using the picture on the left as a reference, the air from the room
is drawn into the box by the small fan located in the bottom right
corner of the back panel.
Within the box are baffles configured to look like a maze. As the
air flows around the baffles it is heated to a temperature of
around 120 F (49 C) and then returned to the room through the
exhaust port in the upper left corner of the back panel.
Solar Window Heater Installations
The heater pictured on the left is installed inside the window and is
constructed with a metal components instead of wood. It is slightly
larger than the first example, measuring 42"H x 23"W x 4"D.
The amount of heat generated by this style of solar heater relative to
its size makes it a popular choice for boat and RV owners.
The next photo shows an outdoor installation of a solar window
heater. This unit has vent at the top to channel the heated air into
the room. A flange on the vent is used to secure the heater to the
inside of the sash.
Depending on the width of the window frame, it might be necessary
to fill the gap between the vent and the window jamb much like you
would with a window air conditioner.
The outdoor version produces the same amount of heat as the indoor
model but doesn't obstruct the view, or the natural sunlight which is
also a source of free heat.
Another type of installation is engineered specifically for double hung
windows. (Sorry about the picture quality, it's the best one available.)
They're lightweight, easy to install, and available in sizes ranging
from 27" x 18" to 32" x 26".
The intake air from the room is heated up to 130 F (54 C) and
redistributed by the fan at a rate of 70 cfm (cubic feet per minute).
Build Your Own Window Heater
Instead of buying a ready made window heater you could always
build your own. Solar window heaters are a popular DIY project and
the results vary according to the imagination of the builder.
There are many DIY solar window heater videos on the web but the
following video shows you how it's done by a pro.
Outdoor solar heater
|U S Solar indoor
|Solar window heater for
double hung windows