29 Features Off The Grid Homebuilders Should Consider

Daox · 11-09-10, 12:00 PM

While I see absolutely no reason to limit these suggestions to off the grid home builders, it is a good list of ideas for conservation in any conditioned building.

29 Features Off The Grid Homebuilders Should Consider

RobertSmalls · 11-09-10, 05:10 PM

They say that all windows (incl south-facing windows) increase heating and cooling loads. What about double- or triple-glazed south-facing windows at 42°N?

>Plant or maintain deciduous trees on south side of home – evergreen trees on other sides.

That's really clever.

Overall, it's a very nice list, though I have to suspect that a fireplace is a really bad idea.

strider3700 · 11-09-10, 06:03 PM

I'm pretty sure that even triple glazed windows will have a very low R value compared to even a 2x4 wall insulated with fiberglass so they are good sometimes bad others.

Traditional fireplaces (open fire, straight up chimney) are usually a net heat loss but better ones can be great. My airtight insert does a wonderful job of heating the house as would a woodstove. If it had an outside air supply it would be even better but it's very very hard to add one since it wasn't planned for in the first place.

RobertSmalls · 11-09-10, 07:20 PM

Quote:

Originally Posted by Wikipedia

Properly designed triple glazed IGUs with low emissivity coatings on surfaces #2 and #4 and filled with argon gas in the cavities result in IG units with R-values as high as R-5. Certain vacuum insulated glass units (VIG) or multi-chambered IG units using coated plastic films result in R-values as high as R-12.5

And since you can't afford VIG glass, it's R5, versus about R20 for a 2x4 wall with proper sheating, drywall, &c.

You'd lose about 60W/m² through conductive losses 24/7 (barring curtains), but the sun puts out 1000W/m² (perpendicular area, before losses to low-emissivity glass) on a sunny day. With intelligent curtain management, I'm pretty sure even we R-3 double-glazers benefit from the windows.

Also, I never run lights when the sun is up, because I painted the interior of the house the second-lightest shade of each hue available at the Depot.

Daox · 11-10-10, 06:30 AM

I agree, south facing windows are a must and do add more heat than they release. Didn't the article say only to limit east/west/north windows though? BTW, seriouswindows have an R rating of up to R13 I think for a non-opening window and R11 for a casement window. I have no idea what price they command though.

The thing that puzzled me was this:

Quote:

Place fireplace on second floor...

Why the second floor?

I do know you can get high efficiency fireplace inserts that are great for heating. However, like strider mentioned, traditional fireplaces can actually cool the house instead of heating it since they use the warm air from the house to burn the wood which pulls in cold air from outside.

Ryland · 11-10-10, 12:01 PM

Apparently it's pretty much a toss up between using low-e and non low e glass on the south side as low-e glass blocks some of the solar gain but keeps more heat in and non low-e lets more heat in and is cheaper but allows for a greater loss, this is according to an engineer who's house I spent about 6 months working on.

And the fire place cooling off the house as much as it heats it... it really depends on the fire place, one of my other part time jobs is cleaning chimneys and I've seen alot of fire places that have an outside air source right in to the fire box, some people think it's a place to sweep ash and that the ash will to go to some far off magical place, but it's for bringing in combustion air, combine that with a good dampener on the chimney top and you'll keep all that warm air inside your house as the mass of the fire place and chimney should soak up the heat and the smoke should exit just barely warm.

strider3700 · 11-10-10, 12:21 PM

Quote:

Originally Posted by Daox

Why the second floor?

I wondered about that too.

I have a traditional open fireplace upstairs and the insert downstairs. I've never lit the upstairs as other then for mood lighting it would be pointless and the 50ish year old chimney has a few cracks in the liner. The first thing I did when I bought the house was install the insert downstairs and it's connected to a metal liner that runs right to the top of the chimney. I use it for the majority of my heating even though I have a reasonably efficient air source heat pump. I've always used the basement woodstoves/inserts for heating and upstairs fireplaces were rarely used other then a quick shot of direct heat.

The chimney has 3 flues, up, down and originally the oil furnace. it's roughly 4' x 7' x 2 stories tall and pretty much centered in the house. It takes a long time to heat up but it does radiate heat out for a day or two after the fire goes out. If it backed onto the outside most of that stored heat would be transferred out.

My old house I had a wood stove with outside air directly plumbed into the bottom of it. It was wonderful. I have no way to get outside air to this insert short of carving a hole through that chimney. I don't see it happening.

TimJFowler · 11-10-10, 01:04 PM

Arrgghh! Articles like this drive me up a wall!

I think this piece should have been titled 29 Over-Simplified and Under-Explained Features That Off and On The Grid Homebuilders Might Consider Depending on their Latitude, Climate and dozens of other factors. I suppose that doesn't roll off the tongue though.

Here are two examples:

Quote:

3. Eliminate windows, or install a limited number of small fixed windows on north, east and west sides. All windows, regardless of the design, and even with shutters, increase the heat and cooling demand.

Item 3 completely ignores the use of passive solar heating and passive cooling strategies.

Quote:

5. Install a passive solar trombe wall on south side attached to a green house on west end. This is the primary source of passive “solar gain” heating for the home. The trombe wall also hopefully, provides most of the heat for the greenhouse.'

'18. Provide an extended eave on south side of roof.
During the summer the extended eave on the south side shades the south wall and reduces direct heating by the sum. During the winter the sun is lower in the sky and permits maximum passive heating using the trombe wall coupled with operation of the window shutters. This is an important factor in passive solar home design.

Items 5 and 18 recognize passive solar design, but over-simplify it and recommend only one possible strategy.

Any time I see an author put a PhD after their name but no explanation of WHAT their PhD is in I tend to read very carefully with my BS meter turned up.

FWIW,
Tim

Daox · 11-10-10, 01:15 PM

Haha, good points Tim.

gasstingy · 11-11-10, 07:57 AM

The window size and overhang ratio for passive solar heating in winter without too much heat gain in the summer should never be mentioned in an article like this without giving a clue as to what that may be.

I spent waaaaay too much time trying to find the formula and was really frustrated by people who wrote about it as if everyone would know what it should be. In my garage / workshop project thread, I listed all that out after I finally found the information. It's on page 10, post #91. This link will take you to it.

http://ecorenovator.org/forum/new-co...roject-10.html

Most of these articles are so generic / basic that they must be done to whet your appetite for information. If that's the case and you are willing to do some research, it's done its job.

11-09-10, 12:00 PM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	29 Features Off The Grid Homebuilders Should Consider While I see absolutely no reason to limit these suggestions to off the grid home builders, it is a good list of ideas for conservation in any conditioned building. 29 Features Off The Grid Homebuilders Should Consider __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-09-10, 05:10 PM	#2
RobertSmalls Journeyman EcoRenovator Join Date: May 2009 Location: Buffalo, NY Posts: 344 Thanks: 3 Thanked 17 Times in 15 Posts	They say that all windows (incl south-facing windows) increase heating and cooling loads. What about double- or triple-glazed south-facing windows at 42°N? >Plant or maintain deciduous trees on south side of home – evergreen trees on other sides. That's really clever. Overall, it's a very nice list, though I have to suspect that a fireplace is a really bad idea.

11-09-10, 06:03 PM	#3
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	I'm pretty sure that even triple glazed windows will have a very low R value compared to even a 2x4 wall insulated with fiberglass so they are good sometimes bad others. Traditional fireplaces (open fire, straight up chimney) are usually a net heat loss but better ones can be great. My airtight insert does a wonderful job of heating the house as would a woodstove. If it had an outside air supply it would be even better but it's very very hard to add one since it wasn't planned for in the first place.

11-10-10, 12:01 PM	#6
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	Apparently it's pretty much a toss up between using low-e and non low e glass on the south side as low-e glass blocks some of the solar gain but keeps more heat in and non low-e lets more heat in and is cheaper but allows for a greater loss, this is according to an engineer who's house I spent about 6 months working on. And the fire place cooling off the house as much as it heats it... it really depends on the fire place, one of my other part time jobs is cleaning chimneys and I've seen alot of fire places that have an outside air source right in to the fire box, some people think it's a place to sweep ash and that the ash will to go to some far off magical place, but it's for bringing in combustion air, combine that with a good dampener on the chimney top and you'll keep all that warm air inside your house as the mass of the fire place and chimney should soak up the heat and the smoke should exit just barely warm.

11-10-10, 01:15 PM	#9
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Haha, good points Tim. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-11-10, 07:57 AM	#10
gasstingy Journeyman EcoRenovator Join Date: Feb 2010 Location: Arab, AL Posts: 491 Thanks: 109 Thanked 49 Times in 43 Posts	The window size and overhang ratio for passive solar heating in winter without too much heat gain in the summer should never be mentioned in an article like this without giving a clue as to what that may be. I spent waaaaay too much time trying to find the formula and was really frustrated by people who wrote about it as if everyone would know what it should be. In my garage / workshop project thread, I listed all that out after I finally found the information. It's on page 10, post #91. This link will take you to it. http://ecorenovator.org/forum/new-co...roject-10.html Most of these articles are so generic / basic that they must be done to whet your appetite for information. If that's the case and you are willing to do some research, it's done its job.