Solar heater panels: Solar Air Conditioning?

Solar Heater Panels: Why don’t we all have them?


Free energy falls on us from the sun every day.

In our global culture, and in particular in American culture, we don’t make use of the solar energy coming to us every day.

Think “solar panels”, and they still carry some sort of “geeky” (not in a good way) connotation for most people.

That’s really very sad.  On sunny days, the best choice is to make the most use of the sun however we can.

Why don’t we all have solar heater panels?  I don’t know.

There are a few places where it doesn’t make sense to have solar heaters, because they just don’t get enough sun.

However, in most of the United States, Australia, New Zealand, India, Europe (excluding the northern parts of the UK), South Africa, and definitely throughout the middle east, having solar heater panels makes sense economically and ecologically.

We covered yesterday that there are two major categories of solar technologies.

These are:

  • Solar Electric: Making electricity directly from sunlight using photovoltaic panels; and
  • Solar Thermal Applications: Solar Thermal is what we’re concerned with when talking about solar heater panels.  Solar thermal is directly heating something (in our case heating the air) for purposes of turning the heat into a desired benefit (in our case for heating a structure).

Solar Thermal can include solar water heating, but we’ve talked about that at other points.  Solar air heating is the focus of this week.

Solar Thermal is great because it’s easy to get started.  Solar heater panels aren’t very expensive, and are very efficient at absorbing the sun’s light and infrared and converting that energy into heat.

Water heating can also include space heating (having radiant floor heating run by heated fluids). But we’re just concentrating on direct air heating with a solar thermal collectors (solar heater panels) this week.

Why should nearly everyone with a house have solar heater panels?

  • The fuel is free.
    Once you install the collector/panel, there’s no added fuel cost.  The exception to this is, depending on which model of solar heater panel you build/buy, you may need power to run the fan. Sometimes, the panels you build/buy include a photovoltaic panel, which is used just to produce electricity to power the internal fan. Some solar heater panels are plug-in models (to run the fan inside the panel, you simply plug the panel into the wall).  However, generally speaking, the actual thermal energy that you’re using to heat your house is from the sun, so it’s free.
  • Reduce the cost of your other bills:
    Depending on where you live, solar heater panels won’t always be enough to heat your house.  However, using the sun for heating will absolutely offset the costs of heating.
  • The fuel is renewable:
    It’s sunlight.  How renewable is sunlight?  In Colorado, we get 300 days of it every year, pretty much guaranteed.  Whatever you would have used to heat your house (natural gas, heating oil, woodstove) is now taken care of by the sun.  Carbon offsetting?  Yep… Every major building in every major city that experiences sun, but cool temperatures, should have solar heaters on it’s roofs as a supplement to whatever heaters are installed in their buildings.
  • Independence, patriotism, balanced trade:
    How much sun does the United States import from China/Saudi Arabia/Iraq every year?
    The question seems ridiculous.  But why does the question seem ridiculous?  It’s because the sun is free.  By focusing on solar heaters for your home, you’re actively contributing to the reduction of reliance on foreign sources of energy.
  • Quick return on investment:
    Although water heating can be very close in return-on-investment time, solar electric usually takes many more years to recover the cost.  Solar panel heaters however can pay themselves back in a very short timespan (if you do-it-yourself, it can be as little as 1 year, depending on cost of materials, labor time, and how much sunlight you get).
  • Federal and State rebates:
    (You’ll have to check on your state’s laws for this year, but you may be able to get a rebate on the cost of your solar heater panel, thus making your return-on-investment time even less).

Who should not have solar heater panels?

  • People living in apartments might find this difficult to implement in a cost effective way.
  • People living in places that don’t have much sunlight.  No sun = no heat.
  • People who get annoyed with having two systems to heat their house.  Solar panel heaters can’t be used at night.  You can’t consider a solar air heater as a primary heating source. In fact, in some areas, the code requires that a household have a primary heating source of a certain type and this definitely would not qualify as a primary type. However, using one of these as a supplemental heating source can definitely offset how much you need to use your primary source.
  • People who don’t want to put a panel in a place that gets sun.  Solar heater panels must be installed in sunny areas, such as south-facing walls and rooftops.
  • People whose homes don’t circulate air.  Most decent commercial solar heater panels are rated to heat areas as large as 1,000 square feet.  However, you need ways to circulate that air into all of the rooms to take advantage of the heat you’re creating.  This may take some creative placement of your panel(s).
  • People who whine (‘cuz no one likes a whiner).

Solar heater panel basics

Ever gotten into a car that’s been parked in sunlight for a long time?  The car is very warm inside, especially in the summer! In the winter, it may be a nice cozy place to retreat if the sunlight has been falling directly in through the windshield.

That’s the basic principle here.

Under direct sunlight, anything gets warm.

A typical solar air heater is a framed box.

It usually has a heat-absorbing metal plate.

That plate is covered under glass or another clear material.

The clear material lets the sunlight in and traps the hot air.

We then can pull air from inside the room, passing it over the sun-heated metal plate, and send it back into the room where it will have been warmed up as much as 50 degrees Fahrenheit.

Solar heater panels are most often mounted on outside walls of a home, but they can also be quite effective when mounted on rooftops.

Depending on the type of solar heater panel you get or make, you will have thermostats installed into your panel.

Generally speaking, the best heaters will have at least two thermostats.

One thermostat will be located inside the collector itself.

The purpose of the thermostat inside the collector/panel is to know when the panel reaches a certain preset heat.

When the panel reaches that heat, the panel thermostat communicates with the thermostat inside the home.

That thermostat is then allowed to turn on the collector, heating the air based on whatever you have set on the thermostat dial inside the house.

If you build your own solar heater panel, these thermostats can be whatever you want them to be.

If you buy a commercial panel, the thermostat will likely be similar to one you would recognize from previous experience with thermostats in most homes you’ve lived in.

That’s probably enough information for today.

What you should know after today:

Passive solar heating comes from heating materials and letting those materials naturally warm the air without forced air currents.

Active solar heating comes from heating materials, forcing air over those materials, and causing the air to be heated directly.

Active solar heater panels for homes (and structures) operate by:

Drawing interior air into a panel/collector (which has been heated by the sun),

passing it over a heated surface under glass.

Heating the air

Blowing it back into the same space it came from.

Some solar heaters have multiple fans in each collector, but most often there is just one fan in each collector.

Some people chain multiple panels together, but for an active solar heater panel, at least one fan is necessary in order to move the air and cycle it through the collector.

Stay tuned this whole week to become an expert on solar panel heaters, because by the end of the week you’ll be saving money on your heating bills just by following the links and steps we’re outlining this week.

Until tomorrow, think about heat from the sun and how you can get more of it into your home.


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