View Full Version : Green Houses
I'm very interested in alternate way's to make a houses efficient, by using renewable energy source's, and different building material's. I was wondering if anyone had first hand experience, or knew of something that wasn't common knowledge.
I would like to build a house when I retire that is completely independent for all it's energy needs. If a blizzard comes in, and knocks out power for a week, I want to be able to go about my daily routine as if there was no difference. I would also like to have to spend zero dollars on electricity or any public works.
Some of the things I have researched so far is
1. Geothermal heat pump, for cooling and heating the house.
2. Wind Mills
3. Solar panels
4. Triple pain windows, with some kind of gas on the inside (can't remember exactly what kind of gas)
5. One interesting idea I saw, was to build your home with 2x6's, instead of 2x4's. Instead of running a stud every 18 inch's, you ran one every 24 inch's and that gave you 2 more inch's to put insulation in, increasing your R factor.
There is a lot of experience on this board, and an incredible amount of knowledge, on all sort's of differant subjects. Any idea's will go down in my little book, for my future house.
Thanks
Kyobanim
11-19-2007, 08:41
I haven't a lot of experience with this but I have read about the new solar panels that are coming out now that produce more energy and are lighter and flexible like a film. The example I read about produced enough energy to sell back to the grid and keep the house running at norm.
I'll try to find the article for you.
On the studding, think about metal studs. That seems to be the trend here in Florida for new construction. Don't know why but for some reason it makes sense.
You might want to also look at the new construction method of the walls that go up as a single section that have foam insulation incorporated into them. There are specialty companies that use these.
Radiant heating in the floors is another good one. They can be powered and heated with thermal means. I don't know how well this works with carpet but it's great with tile and wood.
That's pretty cool that you want to do this. I'll keep my eye out for more info.
Team Sergeant
11-19-2007, 08:53
5. One interesting idea I saw, was to build your home with 2x6's, instead of 2x4's. Instead of running a stud every 18 inch's, you ran one every 24 inch's and that gave you 2 more inch's to put insulation in, increasing your R factor.
Thanks
Using 2X6 instead of 2X4 is what is done here in the Phoenix area for those reasons. We just built a guest house and maxed out the insulation, including 2X6, Tyvek wrap, thermal doors and windows etc. On this sort of project the internet is your friend.
There's hundreds of website home insulation advice sites among them some real good ones. They even have Insulating Paint.....
http://www.hytechsales.com/questions.html
Look at the hottest places and how they build home or the coldest places..... remember most contractors will use the very least they can get by with when building a house, do your own research.
Don't forget Tyvek.;)
http://www2.dupont.com/Tyvek/en_US/index.html
bricklayer
11-19-2007, 09:18
Wind Power is one of the biggest investments in the area I live in wich has proved itself over and over again. You can install a wind turbine with several back up battery packs to store electricity. Not only can you utilize this power, but you can also sell it back to the power company.
When your turbine is spinning from natural resources like the wind it generates power to your batteries wich stores electricity for a power outage or when the turbine is not spinning.
Say you buy your wind turbine and it pays for itself in 8-10 years. After that initial investment has been paid off, all of the power you generate is profhit!
http://www.renewableenergyaccess.com/rea/news/story?id=44708
Have a look, but im sure you would be on a much smaller scale!
The parents of a close friend of mine live in an "off-the-grid" house in Colorado, and there are a lot of drawbacks that I wasn't aware of. First, they have an entire room dedicated to energy storage (in the form of car batteries run in series/parallel). I don't know how many batteries there were, but 500 probably isn't an exaggeration. Also, construction was incredibly expensive, and the panels are huge eyesores.
Lastly, the solar panels themselves are awfully toxic to make, and their manufacture does a lot to offset any "green" benefits they might produce... not to mention the cost of all those batteries.
I've always thought that the best course was to make the highest efficiency house possible, and just be a good steward with your energy (i.e. turning off lights, using as as few TVs as possible, etc).
bricklayer
11-19-2007, 09:26
Another idea that came to mind since im in the business is a house built out of CMU (concrete masonry units) with grouted and insulated cells. This is seen alot in states like FL. wich proves too keep either heat or AC from escaping.
http://www.gis.net/~mason/benefits.html
Rumblyguts
11-19-2007, 09:36
Things that I know of, but you might have already stumbled across:
Besides looking at the construction of your house itself, don't forget about the position and landscaping as well. Do you want deciduous trees to shade the house during the summer, yet let the sun hit during winter? Do you want a major surface exposed to the south which would be a large heat gain? Can you build down a slope in order to collect/store any sort of water above with pressure for activities?
A few more house related things, but more related to living in the north:
Build a cistern to collect roof run-off
Extend your eves to shade the windows in the summer, but allow the low sun to shine in in the winter.
Slate tile (especially on the lowest floor) as a passive solar heater
If you're wood heating, put the unit in a central part of the house, and keep the building design as open as possible. Also, transom were used for a reason.
Garage on the west side to act as a wind break for your living area if you have cold winds.
Think about where you spend your time, and how wam you want various areas to be when you're in them. That can help with passive solar heating and lighting.
Other ideas:
If you are looking to go off the grid with a windmill, check wiht your local energy supplier to see if you can sell excess power to them.
Be careful to insulate and seal things up, but remember that houses still need to vent.
See if there are any grants out there from the DOE or energy companies for effeciency.
Ask university archetecture/engineering/environmental departments for pamphlets or leads.
And have fun?
Edit: Bah, I got interrputed while posting, so sorry for any redundancy
A number of weeks ago I was watching a show, on Discovery Channel I think, about an inventor who has invented a machine and i think it was the Newman machine. The patent office won't give him a patent because whatever and he can't get it mass produced until he does and he insists it be affordable. Anyway, a number of engineering professors have insisted this works. It has to do with magnetics and batteries and produces about a 1000 times more energy than it uses and recharges the batteries from the energy produced. He says you can supply the average home using his machine with I think it was 12 car batteries which should last 5 years. It may be one of those "nut stories" but the testimonials were pretty impressive. Maybe it could be googled. He travels around the country promoting it.
MT - Is this for state side or OCONUS??
GratefulCitizen
11-19-2007, 11:56
I've seen many designs in this area, inside and out.
For off-the-grid power generation, the solar and windmill are pretty common.
Most of them either have a connection to the local utility or a backup generator, even if it's rarely used.
For heating/cooling and reduction in initial capital there's straw bale and rammed earth construction.
The best for heating/cooling I've seen is a passive design.
IIRC, this is how it's constructed and how it works:
It's a "box inside a box" construction.
It's usually 3 stories, making roughly a cubical shape.
(with a single-slope roof tilting towards the north)
Ideally, it's built into the south slope of a hill.
The "inside" box shares east and west walls with the "outer" box.
The south side of the outer box has plenty of windows and is about 6 feet from the south side of the inner box.
The north sides of the inner/outer box are separated by about 2 feet (no windows).
There is space in the attic between the boxes and deep crawlspace between the inner box and the ground.
There is a narrow crawlspace under the (vented, non-insulated) floor in the south-side space.
The north, south, upper, and lower spaces are all connected.
The south side space has vents near the roof, to the outside.
Large vent tubes are buried north of the house which connect to the deep crawlspace and come up, if possible, in the shade on the north side.
(these tubes have removable caps)
The inner box has closable vents connecting with the spaces (hereafter referred to as "interior vents").
Some sort of thermal mass needs to be placed in the narrow crawl space (south side).
A high-school classmate had a house like this, they used several hundred plastic milk-jugs filled with water for their thermal mass. It was quite effective.
How it works:
For heating:
The large vent tubes are capped. The exterior vents on the south side are closed.
During the day the sun warms the air in the south side space and energy is stored in the thermal mass under the floor. At night, the thermal mass warms the air.
The warm air on the south side rises.
The air on the north side cools and falls.
This creates a convection cycle which keeps a layer of warm air circulating around the inner box.
(Interior vents can be opened as needed.)
For cooling:
The large vent tubes are uncapped. The exterior vents on the south side are opened.
During the day, the sun heats the air in the south-side space and the attic space, causing it to rise. At night, the thermal mass heats the air.
This warm air escapes out the exterior south-side vents.
The pressure differential pulls air through the large vent tubes. These buried tubes cool the air due to the cooler ground temperature.
This creates a cool air layer around the inner box.
(Interior vents can be opened as needed.)
Max_Tab,
Depends on the area (country/state/county/city) that you want to build in....
Stay safe.
LibraryLady
11-19-2007, 12:37
Back in the 80's I was housecleaning my way through college, one of my clients had a home off the grid over in Yakima WA, very hot summers and very cold winters. The temp inside their house was always perfect no matter what it was like outside.
Their storage for the excess solar energy was an indoor swimming pool. I don't know the specifics of the energy transfer etc. I do remember the house was designed from the ground up for this. It was situated on a steep hillside facing south, the panels were unobtrusive - on the side of the garage, with the pool behind the garage and the house rising above the pool.
LL
MT - Is this for state side or OCONUS??
Stateside. Ideally it would be in CO, but definitely in the Midwest. Somewhere like NE.
bravo22b
11-19-2007, 18:31
There's a wealth of information out there if you know where to look. Believe it or not, there are web sites where people talk about insulation and heating systems instead of weaponry and HSLD gear. :rolleyes: Go figure.
With regard to wall construction, there are a few good basic systems. As far as 2x4 vs. 2x6, most people feel it is only a marginal improvement, due to the thermal bridging effect in any conventional wall. A 2x6 wall is, however, a better and stronger wall, IMHO. An alternative idea is using a wider plate (top and bottom horizontal member) with narrower studs alternating on the inside and outside (think 2x6 plate with 2x4 studs) to cut down on thermal bridging. This is another marginal improvement but makes construction and insulation potentially more difficult.
Another system mentioned already is SIP's (Structural Insulated Panels), which come in many different flavors but a very common one is two sheets of OSB (similar to plywood) with a solid slab of foam insulation between them. SIP's are very stiff and can easily span several feet. You get virtually no thermal bridging and a very high R-value due to the solid foam. Usually thinner panels in the neighborhood of R-21 are used for walls, and thicker panels in the R-30 to R-40 range are used for roofs. SIP's can also be had with OSB on one side and drywall on the other, so that the finish face of the wall is already there. They can be used as a skin over a timber frame building or on their own. It is a fairly specialized type of construction, and it requires a lot of thought about how to run mechanicals in the exterior walls.
A third system is ICF's (Insulated Concrete Forms). These also come in many different flavors, but are basically hollow foam blocks which are built like Lego's to form the exterior wall. They are then filled with concrete. You get a very strong (and more bulletproof, I mean, windproof) wall, also with high R-values.
These actually can be a DIY project (a big project) for someone who has good basic construction skills and is willing to do a lot of research and planning.
If using a more conventional approach, your choice of insulation is crucial. The most common and IMHO worst is fiberglass. You can get high R-values, but this assumes an airtight building envelope, which is very difficult to achieve. There is a reason they use fiberglass for air filters, because it passes air freely. A typical 2x4 wall with fiberglass insulation experiences a great deal of air transfer, which moves warm moist air from inside the home to the outside, wasting energy and causing moisture problems as the moisture condenses as is meets the cold dry air outside, usually on the interior of your outside wall and roof sheathing. Cellulose insulation and spray foam insulation both help eliminate air movement to a much greater degree. Cellulose also has the added advantage of helping to minimize flame spread in a fire situation.
Heating systems: geothermal is probably the most energy efficient where possible ($$$). Someone also mentioned radiant heat, which is a system of heat distribution, not generation. Radiant works well with geothermal, since geothermal is best at providing relatively low temperature heat, and radiant heat makes the best use of low temperature water. You can also create a system where the geothermal can be backed up with wood/coal/propane boiler.
All these systems require some electrical input to run, but the pumps for a radiant systems can be run fairly efficiently off of a car battery with an inverter. Suffice it to say that if you want to design a heating system that will work off the grid in the middle of the night in January, you can. Of course, there is something to be said for designing a house that can be heated with a central wood or coal stove with no electricity.
It's a fairly complex subject, and the law of unintended consequences always applies in construction, so a lot of thought has to go into it. I'm happy to share some links to websites dealing with this stuff as well as contributing my own expertise if it's wanted. There is a lot of arcane construction knowledge going mostly unused in my brain housing group.
You can also look into an outfit called Davis Caves....They specialize in subterrainian dwellings....If you're thinking NE, for God's sake remember the WIND!
bravo22b
11-19-2007, 19:26
Just to expand a little more:
You mentioned triple pane windows. Windows and doors are major source of heat loss. I don't have the technical specs at hand, but most "insulated" windows only have an R- rating of about R-3 or less, so there is an inherent trade-off between the desire to have a lot of natural light and nice views and energy efficiency. One way to take advantage of windows is through various passive solar techniques, for instance large south facing windows which shine down on a large, dark high mass floor material to store solar energy during the day. These and all windows will require insulated shades or curtains to prevent that same heat from be radiated right back outside at night. However, one of my primary concerns with "fancy" insulated windows is longevity. Typically, the best sealed glass (double or triple pane) have argon gas inside which helps cut down on heat transfer between the panes. These and all sealed units are basically caulked together with fancy caulk, and the metal spacers used between them contain dessicant to help remediate any moisture trapped between the panes. All of these units have a relatively short life span and a fairly high failure rate. Most units are warranted for somewhere in the neighborhood of ten years, and the cost of the window includes the cost of replacement glass in a certain percentage of them due to failure. I have personally seen and replaced quite a few sealed insulated glass units. Once they fail, they fog up on the inside, and there is no fix (at least not a reliable one). Unfortunately, there are not a lot of good options. I can go into more detail if needed.
The best building practices are always site-dependent. One way to find some of the best building practices for your area is to study closely the native architecture, particularly pre-Industrial revolution. Most places have specific details of building and site that make the best use of the environment. A good example is to look at old farmhouses surrounded by fields, like in the Midwest. The house typically is surrounded by trees, and if you look closely you may even see a distinct pattern. Large, deciduous trees were planted close to the house to provide shade from the hot (and directly overhead) summer sun. In the winter, the trees lose their leaves and allow the lower-angle winter sun to reach the house and gain passive solar heat. Evergreens were then often planted farther away and in a direction to block the prevailing winter winds.
If you are terrain that lends itself to it, you can always do a partially buried house which will cut down dramatically on heat loss in the winter and heat gain in the summer. It is crucial to plan these very carefully, since you will only have access to those walls (or roof) if you dig them back out. There are not many materials and techniques that can be relied on to be water, insect, etc. proof for 40 or 50 years. IMHO, most people do not take these factors into account carefully enough, and end up with substantial problems later on. A "belt and suspenders" approach is best. This is an area where ICF's can shine, since they are basically safe from deterioration (but not waterproof in and of themselves).
The more specific concerns you have, the better I can target the information.
Thank you everyone. I am keeping everyone's idea's on a seperate document, so I can put it in my good idea book. There is so much out there, that I didn't even know about. Thank's again, and if you have more idea's websites, or places to look, let me know.
bravo22b
11-20-2007, 18:03
Here are links to some websites that have a VAST amount of information on general construction practices, and both have a great deal of information that deals with building energy-efficient houses:
The Journal of Light Construction: http://www.jlconline.com
Fine Homebuilding: http://www.taunton.com/finehomebuilding
Both of these sites have a fair amount of information that is available to anyone, both have forums where people argue about the best practices, and both require at least some level of registration to access the majority of their online content.
They both represent everything that is both right and wrong with the internet. The amount of good, hard information is staggering, so finding what you need can be challenging.
Best of luck with your research, and let me know if I can help in any way.
dmgedgoods
11-20-2007, 19:02
Max_Tab,
Depends on the area (country/state/county/city) that you want to build in....
Stay safe.
Location, location, location.
I am in the business of building high-end "green homes". Straw bale construction is a hot commodity out here. Relatively inexpensive for the insulating factor, not to mention the "green" factor. We recently did a live-in granny unit with straw-bale, OSB/Foam insulation on exterior, all plastered. The windows were low-e double pane with Argon gas. Simple, yet highly effective. As far as zero reliance on utilities, how much money do plan on spending? Do you plan on doing the work yourself? The sky is the limit as far as design. The pocket book has set the standard on all of our green homes. Count on at least 20% increase in cost for trying to go green over conventional construction.
bravo22b has laid out some great websites. He makes a good point about alternate types of layout (2x4 vs 2x6, etc.) With straw bale construction, you typically frame a skeleton of a house, lay your bale in the walls flush, and frame 2x4 on the flat inside. Done correctly with substantial structural members, we managed a 4 foot layout, saving thousands of dollars in material. An open floor plan helped even more. How big you plan to go? Do you have a design in mind; anything on paper? Have you considered earthen shelter with CMUs and foam? Waterproofing earthen-shelters is hard. I have seen 20 year warranty on some EPDM products. It's a tough sell. The possibilities are endless...
With my short time remaining here before I deploy back to Benning, I would be happy to help in anyway possible. This is my bread and butter. Guy knows what I'm talking about. :D The hardest thing is sorting through the advertising, and finding the right companies that produce the products you need, and then having a solid, laid out plan to build from. Feel free to pm if you want anymore help design/production wise.
Shawn
This is a most interesting thread - I'm bookmarking this one.
dmgedgoods:
Well said!
Max_Tab:
I'm on the "commercial" side of the construction world.:cool: I gather you are looking at the Nebraska area?
Stay safe.
dmgedgoods:
Well said!
Max_Tab:
I'm on the "commercial" side of the construction world.:cool: I gather you are looking at the Nebraska area?
Stay safe.
Yeah, more than likely. At least that area, is good for wind, and sun. :D
Yeah, more than likely. At least that area, is good for wind, and sun. :DSolar and wind-mills for generating power seems the logical direction to take...
CMU (block) exterior walls w/foam for insulation, with the cells of the CMU filled...insure the rebar is installed at the same time as the foundation.
I'd also go with "steel" studs for strength, durability and longevity, they're even manufacturing trusses out of light-wieght steel nowadays.:cool:
Stay safe.
Since you are looking at NE, I say you are more interested in heating the home than cooling. As has already been mentioned a geothermal heat pump would be you best bet for energy use. There are two types ground sourced and water sourced. I recommend the water sources over the ground sourced. The main difference betwwen the two are the ways that the energy is transfered in the refrigerant.
With a true ground sourced system the condenser is burried in the ground. Basicaly long pipes have refrigerant flowing through them and the heat transfer is between the ground and the refrigerant. Some draw backs to this are: expense system $10K plus installation, special underground piping and fusion of joints, leaks in the underground system, Tree roots breaking the underground system.
With a water sourced system, water is used as the heat transfer medium. The system works the same as a regular heat pump with its condensor above ground. Instead of the finned coil and fan used as a condenser a water coil condensor is used. A seperate water sysem is connecetd to this coil and water is flowed through it. The water lines can be burried in the ground or sunk into a lake of sufficent size. A seperate pump is used in this system. There is no high pressure refrigerant flowing underground in special piping as in a ground source. The installation is not as expensive and basically any standard heat pump can be converted over to this system.
Either system should give you a SEER rating from 18 up.
Yeah, more than likely. At least that area, is good for wind, and sun. :D
Don't forget the F5 Tornado Safe Room. Much cheaper to add it while the house is under construction.
Just in case - :D
Pete
Don't forget the F5 Tornado Safe Room. Much cheaper to add it while the house is under construction.
Just in case - :D
Pete
I'm already planning a reinforced safe room below the basement....for tornado's yeah, that's it. :D