Tuesday, August 7, 2012

Calling all Sunspace Owners

I think that home attached sunspaces may be the most cost effective and sensible approach to adding solar to your house -- attached sunspaces offer:
  • Space heating for the house 
  • Additional living space that can be very pleasant
  • A place to grow plants
  • A place to hang the laundry for solar drying
  • A good place to locate a solar water heater
While direct gain to the house through south facing windows can be an effective solar heating scheme, the direct gain approach has the not so good feature of quite a bit of heat loss on cloudy days and at night through the large windows.  Sunspaces allow you to harvest the same heat through their large, south facing glazing, but the susnpace can be closed off from the house at night or on cloudy days to avoid the big glazing heat losss.
A nice sunspace
Compared to traditional active solar space heating (with collectors, tanks, pumps, ...) sunspaces can be better looking and more cost effective (when you consider all of the benefits).
Doug's sunspace
For space heating, low thermal mass sunspaces collect heat quite efficiently, and it is relatively easy to transfer this heat to the house.  A good writeup on the low thermal mass sunspace design...

While having a sunspace to hang laundry in bad winter weather may seem like a small thing, clothes dryers are are the largest single electricity use in many homes -- on average about 900 KWH a year!  Even more when you consider that the dryer is pulling in cold outside air as it vents its hot air outside.  The sunspace gives you a good, sheltered, efficient place to dry clothes.

Sunspaces make a good, protected enviroment to add a solar water heater to -- the water heater will be more efficient because it does not see outside temperatures, and may need less or no freeze protection.

I've got a section on Sunspaces, but it has few examples of good, attached sunspaces used as described above.

Sooooooooooooooo, I would REALLY like to hear from folks with sunspaces -- how well do they work for you?  What's good?  What's bad?  What do you consider good design features?  
A writeup on your sunspace with lots of pictures would make my whole week!


Nick's multi-story solar space heating sun space
Or, if you have some thoughts, experiences, or questions on sunspaces, how about passing them on in a Comment below.

Gary



16 comments:

  1. If you go to:
    http://altbuildblog.blogspot.com/search/label/Solar%20In%20New%20Mexico
    there are several examples of sun spaces or go to:
    http://altbuildblog.blogspot.com/
    and scroll down the right side bar to LABELS- ELEMENTS and click on Solar In New Mexico for the same list of posts on solar.
    We have built and lived with three sun spaces in the last 20 years in two houses and now own a fixer upper we recently bought with a 6' x 80' sun space. In much of the world it is a no brainer. But you don't need a sun space to dry your clothes, all you need is a clothes line outside (although we do use both the clothes line and the sun space). The first thing I did in our new house was to take out the dryer. This is a great topic, thanks for bringing it up. I hope to blog on this much more in the future.

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  2. Hi Ches,
    Great projects -- thanks!

    I mentioned the laundry in the sunspace because for a lot of people in northern climates, its pretty challenging to hang laundry outside in the winter -- also gets around picky Home Associations.

    Will keep an eye on your blog for more.

    Gary

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  3. Like you said, Gary, they can heat a room nicely when there is sun. I do hang some clothes in mine and allow it to heat the upstairs during the winter. Mine was built on a deck. Nice view, but I'm running into weight issues with any large tanks, grow beds, and that kind of thing. That wouldn't be a problem for ground level structures. They seem to make a great environment for aquaponics setups. I may place my tanks on the patio below. I recently built 3'x6' metal [corrugated roof] awnings for the 3 east windows. It absorbs too much heat in the summer otherwise. They were about $20-25 each, so very cheap and effective. I used door hinges so the angles can be adjusted. This is in my backyard so I don't have to worry about neighbor complaints. -Taylor

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    Replies
    1. Hi -- Like the idea of adjustable awnings -- especially for east facing windows where the sun can come in low in the summer.

      Speaking of aquaponics, did you catch Nathan's sunspace based tank heating/cooling scheme: http://www.builditsolar.com/Projects/Sunspace/LowCostHtStorageNathan.pdf

      Gary

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  4. Hi - We had a "solar" room on one of our houses. And it did generate heat! One problem we had was dumping the excess heat. The other was also related to the excess heat. We set up a drying rack for clothes and it worked but the drying was so hot it wrecked elastics in socks and underwear. I would have set up a thermostat controlled exhaust fan if we had stayed longer. Chris

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  5. I do have a sunroom attached to my house. It is used to dry laundry all year long if it cant be hung outside. Here in Canada winters are cold, so I use this to heat the house, I have a fans that blows cold air from the basement into the sunroom, as another fan blows hot air into another section of the basement. On sunny winter days, it heats my house all day long.

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    Replies
    1. Sounds good -- any chance of getting some pictures?
      gary AT BuildItSolar DOT com

      Gary

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  6. Just a note that clothes washed in a front-loading washer come out almost completely dry already so... especially in a dry house in the winter... they will dry quickly anywhere they are hung.

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  7. The Philips house is an ICF built with a center solarium. In the Fall heat is collected from pex in the floor and stored in a large insulated tank. He has been heating His New Hampshire house for 10 year. www.rphilipstech.com
    Thanks for great web site! I use it often. Dean

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  8. are there more details on the photo at the end of this post??

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  9. Hi -- That is Nick's most impressive sunspace that also uses the "deep mesh" absorber to increase efficiency. I'm hoping to get Nick to provide more info on it. I have a few more pictures Nick sent, but it really needs the description, and I don't understand it all well enough to do it myself.

    Gary

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  10. I generally don't like to be a buzzkill, but...

    Sunspaces are fine for what they are... don't forget that they actually block passive radiant solar energy from directly entering your house.

    So if you are designing a new home, use direct gain passive solar methods which work much better than a sunspace. There have been a lot of studies that back this up, but of course I can't find one right now.

    A sunspace is a lousy solar collector because it gets cold every night. So then you have to wait a long time the next day before it's hot enough to send heat into the house, assuming you have s good fan system or passive method for that.

    They are also lousy living spaces because no one likes to spend time in a place that is always too hot or too cold. So you are spending money to build a room that you can't really use except to grow things (which is fine but costly). In the worst case you might even be heating it just to keep those plants alive.

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  11. Hey Kevin -- Guess we have to agree to disagree on this one, but if you run across those studies I'd like to get the links.

    The low thermal mass sunspaces as described in the Shurcliff article listed above have little mass and heat quickly, and it seems like the reduction in heat loss from large windows directly in the south wall make up for the more indirect heating.
    Agree that there is going to be a lot of the time when the temperature is not right for being in, but during the times when the temperature is good, its a great place to spend time with the more outdoor feel and lots of sun, and the cost per sqft can be low.

    All pluses and minuses to weigh, but if I were doing a new house (which we are thinking about), it would have a sunspace as a key part of its solar design.

    Gary

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    Replies
    1. If the glazing area were equal I would agree with Kevin, but the number I have read is that direct gain is four times more effective than indirect gain. So, my eight by 18 attached greenhouse pictured above has several times more South facing glazing than four times the glazing it covers. After living with it for 26 years, I feel confident that it can introduce more heat into the house indirectly than the two windows it covers would directly. Doug
      http://www.builditsolar.com/Projects/Sunspace/DougSolarGreenhouse.htm

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  12. My wife and I really enjoy our attached solar greenhouse. We use it to grow fruiting tomato plants all winter, we also grow lettuce, onions, over winter houseplants, and we fill it with seedlings for our bedding plant business in the spring. With 4 55 gallon drums of water and dark colored brick pavers it has enough thermal mass to get through cold nights without backup heat. It serves us as a handy place to keep dry firewood, a doghouse for cold winter nights, added heat to the house, and more. I think it's is the best low-cost solar addition a person can put on a house. Doug
    http://www.builditsolar.com/Projects/Sunspace/DougSolarGreenhouse.htm

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  13. Thanks Doug.
    Doug has done a number of really nice projects and put the results up on Build It Solar: http://www.builditsolar.com/Projects/SolarHomes/Doug/DougsProjects.htm

    We have a new article coming up in Home Power that goes into low thermal mass sunspaces vs sunspaces with mass, and with some good descriptions of actual sunspaces from Mike, Bill, and Nick.

    Gary

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