How do you design an energy efficient home?

35 years ago I was looking at underground homes with a southern or soutwestern exposure for solar energy in the winter time.

But life took me in different directions.

I still keep my heat turned way down in the winter and try to not use the Air conditioner in the summertime. Being under a shaded tree in 90+ F is quite pleasant.

I hope you get a lot of input.

I hope people apply your ideas.

James

Mr. James,

I am a freelance Consultant for " Energy Conservation and Management" Normally I should charge you to answer this query.Still some free tips here.When you say energy efficient home it means conservation of all types of energy used for domestic purpose. So it will depend on which locality you want to make the home.I hope you live in Georgia. The climate of that place is "Summer temperatures average 20° C to 24° C, winter temperatures 2° C to 4° C. Humidity is lower, and rainfall averages 500 to 800 millimeters per year. Alpine and highland regions in the east and west, as well as a semiarid region on the Iori Plateau to the southeast, have distinct micro climates".Now you need heaters in winter and coolers in summer.The heating can be electrical/ heating or gas The house has to be properly insulated for heat transfer for which various methods are available in US . This includes special glass windows and double doors and special PVC covering over the wood walls. . Use heating equipments of certified energy efficient equipments for heating and cooling. Design the rooms with ample natural lighting.In Texas I have seen Houses with glass openings at roof for natural light .This can be adopted in Georgia also.Use all light points with energy efficient CFL lamps. Garden lighting can be solar lighting. There are many more such important area where energy can be saved for domestic use.

I'd love to have the time and money to build my own home...

I think the basics are fairly obvious...I think the key is to design in versatility, plenty of potential for light and ventillation...no point going mad capturing loads of solar energy then finding the North facing rooms are all depressingly black and the whole thing is too hot in summer.

A huge ammount depends on location...and bubget...I've seen some brilliant home builds on TV..very organic.. straw bale walls, looked cosy enough for a hobit.

I'd go for timber, for it's versatility and ease of modification.

Give me a plot of land £75,00 and my youth whilst retaining my experience....

Wouldn't we all take that?

Del

I'll say...

Hi James BASF built a near zero energy home in Patterson New Jersey. The largest energy saver was the building envelope I believe it accounted for 85%. They used ICF's built off footers which insulated the floor and drew the earths temp below frostline into the mass 6" concrete walls enclosed in polystyreen ( an ICF ) to this they used SIPS for the second floor and roof, 75 to 85 % less air transmition into the home than a typical 2x6 const energy star rated home. Check it out when I reasearched ICF's in 2004 I found 90+ manufactures. There easy to build with (like leggos), the more reputible ones blow away building codes and are pre enginered for most applications. Having been a sub contractor in another field from 84 to 2004 I sold that business and as far as I know am the first ICF sub contractor in my state. Dont get me wrong having a building background sure helps keep the nightmares away.

It has been my experence as people begin to understand the building process of ICF's and the like, convential construction is something I would never do again.

Think about an insulated cave without burriowing into the earth.

Good luck read, talk, look at both sides. And remember all roads lead to rome

Your question is solution for human to be. We can approach your question:

You can use electric (other) energy with minimum consumption and safe health.

The next question is what you will do for minimum energy consumption?

Check out the zero heat house designed and built by archtect Gokay Devici in Scotland.

http://nickw.worldonline.co.uk/House/index.html

Pretty close to what you're looking into although you'd want to implement some other ideas for energy generation I think.

There have been a lot of great components already written by others...natural light, energy efficient appliances, building envelope, etc. so I'll focus on a couple of ideas not out there yet.

Geothermal heat pump for both heating and cooling. There have been several succesful desings of this system here in the bay area. On-demand solar water heating is another measure.

If we look at this from a broader scope, we not only should consider the energy we use within our home but the energy used to supply our home and businesses. For instance, it takes a lot of energy to provide potable water and to treat wastewater. With that, consider a grey water system for landscaping.

I have friends with a cellar where food is kept and a fridge/freezer, they put a heat pump and storage for hot water and central heating in there and it keeps that cellar room COLD and supplies a good part of the heat needed elsewhere!!!

Seems like a good idea to me......

There's no limit to "maximum", just a limit to your budget. If this is for a homework assignment, then you can "max out" your design with artistic license.

If this is for a real home with a realistic budget here's some tips.

1. 2x6 or staggered 2x4 walls with blown-in insulation.

2. Heavy ceiling insulation; double the 'minimum-code' requirement.

3. Double pane windows.

4. Heat pump.

5. Deciduous trees on the south side

6. Programmable heat/cool times (that's a cheap $50 item)

I've designed 4 homes and built 2. They were standard construction (ie not underground or dome or....) and my heating bills have been very low.

Basically the problem is that the question isn't specific enough.

What would 'fit' in the gulf of Mexico would not work inthe highlands of Scotland or in the African Veldt.

Quick rule of thumb though.

1) Insulate; this helps isolate from heat. Go way over code on this and it'll benefit you.

2) Look at sustainable materials, locally sourced. This keeps you costs lower (as well as the carbon footprint) which increases your budget for other technological solutions.

3) Look at the enviroment where you're going to site the house. This is crucial 'cos in this area one size definately does not fit all.

Good luck.

One thing I have not seen so far on this thread is that once you super insulate you can have air quality problems from lack of air exchanges. Air movement needs to be considered in any efficient home. Air to air heat exchangers are usually needed in really tight well insulated homes.

One thing I have not seen so far on this thread..???

Well you didn't read my post then!!! (#4)

Del

I build 20 years ago. My wife and I build 1200 square foot, semi-underground home. It was dried-in (contractor built shell) as time passed and money was available we sheet rocked the walls, added doors to the rooms and so forth. When my daughter was born we added a split level and finished it out over time also. Slow but inexpensive. We insulated the s--- out of the walls and attic, used good windows, ECT...

Most of my questions on CR4 are intended to get the younger brains to think and create something better for everybody else. I claim to be a provocateur! Oh, by the way, when the canary dies, we open a window.

James

Please send dead canary, urgent....

Follow through the link I attached. Devici included a mechanical ventilation system to address exactly this issue (and others) but it was initially not used correctly by the client.

Read on dude.

Friends,

1. Make sure that the energy saving features you use fit the needs and lifestyle of the homeowners--they are much more likely to be used or kept working.

2. Try to make as many of the energy saving features function independently of the homeowner (example is to avoid shutters which have to be installed or removed frequently).

3. Keep the total space small but include a sense of spaciousness such as a somewhat taller or cathedral ceiling. Good lighting helps here.

4. Insulated Concrete Forms (ICF's mentioned by another post) are very helpful, because they isolate the interior from the exterior's temperature swings, weather, noise, and vibration. They typically add 10-25% to the cost of the shell in normal conditions, but are far less expensive when you look at storm resistance, fire resistance, mold and pest resistance, etc. With them you don't need the set-back thermostat and the eventual problems they raise with programming, remembering to use them, or over-riding them. Their biggest environmental cost probably is in the CO₂ produced in making the portland cement.

5. Use low-e glass in the window glazing. Depending on the local climate the window manufacturers have different low-e coatings that will perform best. Double-glazing was already mentioned.

6. Use trusses for the roof, then an unbroken film of 6-mil or thicker polyethylene sealed at all edges, then 2x2 or similar stripping at right angles to the trusses. Wiring and even water supply pipes can all run in the space below the poly without any need to seal holes afterwards. Interior walls are not load-bearing and can be set up after the 2x2's are installed--they will not touch or damage the poly.

7. Put in an earth-tempered tube (or two) for bringing makeup air into the house, with a smooth inside, sloped to drain condensate to an appropriate spot. Bring its inside end to the return plenum of your heating/cooling air handler. This will create a slightly pressurized house and guarantee sufficient fresh indoor air to avoid the "sick house" syndrome, as well as to minimize risk o radon entry. (See 15 below).

8. Include passive solar design ideas, with appropriate summer shading (mentioned by others).

9. Insulate under any concrete floor slabs. If you are in a cold climate, insulate them well and embed hydronic heating tubing in them. This will allow a cooler air temperature with no discomfort.

10. Plan and include solar domestic water heating. (I planned it but didn't include it.)

11. Energy efficient lighting, of course. Also energy efficient appliances.

12. Insulate your water heater as much as possible (I prefer well-insulated storage tank units to the instantaneous ones because of lower electrical demand). Arrange your floor plan to minimize piping distances.

13. If you need a lot of heat, install a very small wood-burning stove with a outside combustion air supply. Be careful, because your design heating load will be less than 20,000 Btu even with a temperature differential of 70-80 degF on the walls.

14. Down-size your heating and cooling equipment and make sure it has a variable-speed fan on it. Nearly all HVAC contractors use software which does not account for the thermal mass of the ICF's, so their answers will be very over-sized. The "R-value" type of calculations are based on the assumption of light-weight construction, so they are unreliable.

15. Look at including a small thermal chimney to passively draw air out of the house if you don't have a central heating/cooling unit. Include a Gore-Tex type fabric damper on it to avoid backflow conditions. Have it exhaust air from bathrooms or the kitchen area.

16. Don't bother with an air-air heat exchanger (also called a heat-recovery ventilator) if you have done the things above. They require maintenance such as filter changing, and are one more mechanical thing you won't need.

17. If most of your HVAC needs are cooling, a zoned ductless system is pricey but may be worth using.

18. Design for your local climate, as others have mentioned!

These are most of the things I would do again. My daughter's house was built to these standards and costs less than $350 per year for heating and cooling in a climate zone with 4000 degree-days of heating load and 2000 degree-days of cooling load. I would add a modest-sized photo-voltaic array with battery storage for supplying some lighting and perhaps the refrigerator. In the future, LED lighting will be better than fluorescent.

--JMM

This is true energy efficient home.

Very good suggestions. Depending up on budget and cost benefit analysis all the recommendations can adopted. The points for energy conservation are all practical.

Our previous home was built the post war as part of one of the first 'new Towns' to accomodate those bombed out of the East End London.
They used poured 'no-fines' concrete to build 'em real quick... the walls were solid (no cavity) but because the concrete was more like a honeycomb (the smalles pebbles about the size of a pea, and no sand at all) it was surprizingly warm!

The down side was it was an absolute pig to try and attach any fixings to an outside wall .

Dunno why I told you guys this..dunno if it has the slightest relavance???

Del

It all comes down to the way you want to live: Do you want to move to a terrain which is sun faced opportunity? This is completely limited to the availability.

We must face reality and accept that 95% will have to live in towns and on terrains which are not perfectly oriented.

This zero energy homes is a ridiculous evolution in my eyes: OK a small portion want's to live in a house where you have to calculate each step as it may implicate a loss of energy. But the vaste mayority does not want this and is accepting to pay the cost of heating.

My solution is to harvest the free energy surrounding us and use this to heat the house and feed the hot water supply.

There is no such thing as free energy; it all has a cost somewhere down the line. Aiming for a 'target zero' load allows us to limit the costs applied to heating/cooling/living.

No, we can't all live in on the perfect site but as already mentioned previously by myself and a number of other posters, we can all work to mitigate our enviromental load and live in a more energy efficient way.

Oh, and before you assume I'm some sort of tree-hugger, I work in the oil and gas industry, believe that there will always be a need for hydrocarbons, just hate waste in any form and would like to offset my personal impact as much as possible.

To this end, add one more factor to the mix when thinking about energy efficency.

Drive a 4 cylinder turbo diesel car. Works our far more enviromentally sound in pretty much every way than any of the mass market elecrtic cars or hybrids. And most can run on vegetable oil without any modification.

Nice post, especially about the car.

I am a diesel fan since the late 80's....and what people forget is that in an accident, diesel can of course burn sometimes, but it does not explode like petrol does over a hot exhaust!!!! It gives you a slightly longer period to get out of the car generally speaking!!! Flash points are a long way apart temperature wise!!!

You walked in the trap with your eyes open: The free energy I mention is wind, tides, waves and sun. Sorry for it, but I like to confuse and unplug big statements.

People tend to look way to distant when looking for energy: we need to heat our house, let's start drilling in Alaska, build a pipeline and transport the crude over thousands of Km, process it and drive it round in trucks. Now we have oil to heat the house.

What amount of total spend energy is really getting into your house? 10% perhaps

But installing a windmill to generate some energy which can be stored as heat in a thermal accumulator, that is way to complex. No, we need inverters to make AC from the generator output, which can be sold to the community (oh those nasty thieves, I only get 25% of the money I need to pay for the same amount of energy)

You are oh so right on hydrocarbons: we will alway's need them. there is no energy storage system which is so simple, reliable, safe and (the most important) dense.

Imagine a plane running on hydrogen, no way thet you will store the hydrogen in the wings as we do now with the kerosene. You will need a pressure vessel of deep cooled solution. Will the same plane take the same cargo/payload?