Solar Furnace is Here!

solar_furnace_1Okay, our solar furnace is actually installed!  Now if only it were cool enough to want to use it…  Still, that will come in time and for now we’re excited to show it off.  Here are some basic pictures of the final product; we’ll post pictures of the actual construction further down the road when we have caught up with ourselves (ha!).

It’s a lot flatter than I expected, about a handsbreadth deep.  I think it looks pretty good on the side of our house and Michael B. did an excellent job with the flashing around the edges.  So what you can’t see is that there are two holes in the back of the panel that continue through the wall of the house and into the living room.  One hole has a fan attached (that unfortunately sticks further into the room than we had envisioned) for pulling air from our house through the panel.  The fan is controlled by two thermostats.

solar_furnace_4One thermostat is mounted on the wall and lets us decide how hot we want our house to be (it cranks up to 90!).  The other is located inside the panel and makes sure the panel is hot enough to heat up air as it passes through.  We had it on for an afternoon right after it was installed and it gets amazingly hot.  We could totally set up a sauna in our living room if we wanted.

So here is my very crude graphic rendition of air flow through the panel heating our house.  We were a little surprised that the panel has no channels or grooves on the inside to direct air flow; it’s just one big black box.  The advantage is that you can cut the openings wherever you need them so if your house happens to have a phone jack or an electrical outlet right where you were going to install the fan, you can move it over a few inches and just put the hole in a different place in the panel.

We’ll keep you posted on results as the weather cools down. this!

11 Responses so far »

  1. 1

    Emily said,

    September 24, 2010 @ 4:27 pm

    Actually, I’d love an update while it’s still hot. How good a job is it doing keeping the super-heated air OUT of the living room just now?

  2. 2

    Will said,

    September 25, 2010 @ 12:40 am

    We haven’t had any trouble with hot air coming in through the fan intake or outtake (there’s a valve on it so that air can only pass through when the fan is on). The wall doesn’t feel any hotter either, which isn’t surprising because, in addition to the insulation in the wall, the back of the solar furnace has significant insulation.

    However, it does radiate some hot air vertically above the unit. This wouldn’t be a problem except that the window is right there, so the breeze we get through there isn’t as cool as normal. Next summer, I think we’ll plant some climbing vines so that they shade the window and the solar furnace.

  3. 3

    Emily said,

    September 30, 2010 @ 4:55 pm

    Sweet. That was one concern I’d had about getting one. Hadn’t thought about the heat radiating off the top, either! Good to know…

  4. 4

    Will said,

    October 12, 2010 @ 11:49 am

    Since I wrote my comment, they added a white metal strip above the solar furnace to protect it better from the elements (and, more importantly, keep rain from getting behind the unit and into the walls). That actually made a huge difference in how much heat radiates off the top. I think now it mostly radiates to the sides and front.

    Now that I have my IR thermometer, I was able to check the actual temperatures on a warm, sunny day. The air inside the outtake duct gets to about 90 degrees, but the wall next to it is at ambient temperature, so any extra heat it provides dissipates quickly behind the vent cover.

  5. 5

    Freeze Yer Buns Challenge | said,

    November 15, 2010 @ 6:31 pm

    […] although in a rather unique way.  We have our thermostat set at 52 degrees and are relying on our solar furnace to heat us up to a more comfortable temperature during the day.  Our main motivation is keeping […]

  6. 6

    JOE WERLE said,

    November 18, 2010 @ 11:34 pm

    I want to know what the thermostats are and where you get them. I’d call it a differential thermostat with two sensors. For example the one in the unit must reach 90 degrees before it turns on the fan; and that is only if the interior temperature of your home is less than 70. So the first turns on the fan and the second turns it off so it doesn’t get too hot.

  7. 7

    Maggie said,

    November 19, 2010 @ 9:19 am

    Joe –
    I’m not sure what the thermostat is called exactly. You might try contacting RREAL (the manufacturers of our panel) to ask about the components. All I know is that there is an extra temperature probe for the panel that measures its temperature so it only kicks on when it’s at least 95 degrees (we think that’s the cut off) and shuts it off if it drops below that.

  8. 8

    Darrell said,

    December 22, 2010 @ 7:09 pm

    My experience with a similar system operating more than 20 years in southern Indiana is that it is most effective in spring and fall seasons when our gas furnace can be turned off for several weeks. It’s especially nice to open the windows after a long winter and the house stays warm without a big gas bill. All the cloudy days in December and January don’t allow much solar heating. That may be why these systems work better in Wisconsin or Minnesota where winter skies are often clear.

  9. 9

    Emily said,

    June 9, 2011 @ 7:46 pm

    So, it’s June! What’s the verdict – how did you like the solar heater over the winter?

  10. 10

    Solar Furnace Verdict: We Like It A Lot But Our Savings Are Minimal Because We Live in the Cold | said,

    June 17, 2011 @ 9:15 am

    […] has passed, giving us time to sit and review how our solar furnace worked.  It’s a bit tricky to evaluate exactly how effective it was since we made several […]

  11. 11

    Open House Feb 26th | said,

    February 16, 2012 @ 3:30 pm

    […] furnace (that big black box shown behind us).  For a sneak preview, check out our post about how it works and our more recent post about our experience so far.  We have enjoyed the extra heat a lot and […]

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