Passive light and heat will it help? : LUSENET : TimeBomb 2000 (Y2000) : One Thread

Should i install skylights in my home and will it add heat by direct sun light and how expensive is it? Any input will help.

-- Bubba (, January 25, 1999


Skylights will add light but minimal heat. Heat rises, so any heat you get from the skylight will hover at the ceiling top. We have cathedral ceilings in our home with skylights. We have two ceilings fans running continuously in the winter to direct the heat back down to the floor. In the summer, we reverse the fans to direct the heat back up to the ceiling so the lower portion of the house stays cooler. The ceilings in our house will be the main draw back if we don't have electricity. However, we have southwestern solar exposure which heats our home to 70-80 degrees in the winter. We're all dependent on the sun to shine for any solar power. We also have backup energy sources, but will use them only on an emergency basis (in other words, we'll be bundling up and I'm thankful to be living in California).

-- bardou (, January 25, 1999.

Skylights will also be a heat sink in winter, unless they're triple glazed, very well constructed, and perfectly installed.

-- Tom Carey (, January 26, 1999.

uh? Heat sink? I don't think so. A heat sink is something that will absorb and retain heat. A skylight will actually permit heat loss to the night sky.

For the money, the best you can do are the following:

1. Insure that you have good, insulated covering for all windows. This can range from expensive double or triple insulated accordian blinds (roughly $250 per large window)down to 'do-it'yourself' window coverings made from inexpensive silver coated mylar (reflect heat) tacked to an insulating cloth. The key is to cover the entire window and not to let air flow over the window surface (to be cooled).

2. If you want to provide passive solar (and it works well), pick a South facing wall and add windows -- wood framed, modern, with insulated glass. You can get gas filled windows that provide further insulation. The window will provide much better heat input during the winter when the sun is low on the horizon than any sky light. You can get a lot of benefit from upgrading old windows (especially metal framed windows that seem to operate to transfer cold into a heated room)and using well built insulating windows.

But, the key is to retain any heat that you have -- insulation in the ceiling, the walls, the crawl space if you have one, and good, tight, non-heat conducting windows.

-- builder (, January 26, 1999.

However - the mylar (reflecting) covers you mention will "blackout" the sunlight as well from outside.

Your answer is exactly right - if heat retention were the sole criteria. If light is desired, double insulate (as mentioned) but with either permanent windows (best if removeable for claening and ventilation) or with clear plastic (temp solution.)

Fir light into the interior - yes a sky light will work in daytime hours, reduce the need for candles inside. They are not "cheap" byt affordable in the long run id insulated and properly installed. Try to get one with "moveable" outlet covers so hot air can escape in summertime.

Much further north - your needs will differ - heat loss is much more important - and there is less natural light available from the sun for fewer hours per day in the winter time. That (your lattitude)should affect your planning.

The latitude of your other half towards spending money at the hardware store is equally important.

-- Robert A. Cook, PE (Kennesaw, GA) (, January 26, 1999.

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