There are several secrets to an energy efficient home design. And utilizing these secrets does not have to cost much money. Sometimes there is no extra cost, if you do them when building. I’m not talking about “Green Building,” where we’re concerned about sustainable resources, recycled materials, the energy consumed in producing the building materials, and such. That is an important subject that I talk about on other pages in this website. Here, I am talking about ways to make your house use less energy to remain at comfortable temperatures, stay bright naturally, and simply use less electricity, gas, oil or other energy sources.
Let’s look at a few of the most effective ways to create an energy efficient home design. There are five secrets to making your house more energy efficient:
1. Design the house so it naturally tends to stay at comfortable temperatures without mechanical assistance (heat and air conditioning)
2. Design the house so it retains heat in winter and repels heat in summer
3. Use low-energy fixtures and appliances
4. Design the house to take advantage of natural light
5. Design the house to naturally ventilate
In my opinion, the most important of these five secrets to good energy efficient home design is this first one. If you design a house that simply by the characteristics of its design, will “want” to stay cool in summer and warm in winter.
It is critical to place your house on the land with the proper orientation. If you are in a northern, cold climate, you will want your house to have the majority of the windows on the south side to maximize the heat gain when the sun is shining. In energy efficient home design, you will want fewer doors and windows on the north and northwest sides of the house because that is the direction the harsh weather usually comes from.
In the south, you would want to have few windows on the west side where the hot afternoon sun would overheat your house and the majority of windows should be on the north where they will remain shaded. Of course, I am referring to houses in the northern hemisphere. In the southern hemisphere the orientations would be reversed.
Orienting the house on the land properly will cost virtually nothing extra. It is only a matter of thinking things through at the outset and not simply plopping the house down on the site with no thought about the sun angles.
Next, design proper roof overhangs. Overhangs are surprisingly missing in many house styles. But, in energy efficient home design, a properly sized overhang can keep exterior walls and windows in shade for much of the day, even on the south side of the house.
This equates to significant energy savings because if the windows don’t let in direct sunlight and the walls don’t heat up, there is much less heat gained inside the house. And that means your air conditioner will run less. Sun screens will do a similar job and potentially preserve more natural daylight.
The second secret in energy efficient home design is to create a house that retains more heat in winter and repels heat in summer. The basic shape, orientation, roof overhang and such all contribute to a house retaining heat and repelling excess heat. But there are some additional, “nuts and bolts” things you should do.
First is to properly insulate the house. If you want to stay warm in winter, you need a good, warm coat. Your house needs a good coat, too. That is what insulation is. Of all the building materials that go into a house, one of the least expensive is insulation. The more you have, the more your house will tend to stay at a steady temperature. Don’t skimp here. Additional insulation will pay for itself through lower energy bills in a very short time. Be aware that not all insulation is the same. There are several methods and materials to choose from. Do your homework and select the best one for your energy efficient home design. Just make sure you increase the R-value as much as practical.
Second, position the house so it is protected from the winter wind. A hill or a group of trees can do this nicely. The arrangement of rooms will do this, too. Place the garage and other service rooms on the windward side of the house so they can naturally buffer your living spaces from the cold wind.
Third is to utilize window coverings. Just as roof overhangs shade your windows to limit heat gain, so do window coverings. These can be in the form of blinds or curtains. Blinds have the advantage of being adjustable so as to cut out the direct sun while still admitting indirect daylight. Curtains have the advantage of insulating the cold glass of the window in the winter. In energy efficient home design, a nice compromise between the two are the insulating pleated shades with an enclosed edge.
The third secret to an energy efficient home design is to use appliances and fixtures that use less energy. Energy Star ratings can help you do this. Energy Star is a guide that will let you know the real cost of operation of a fixture or appliance so you can compare and choose the most efficient ones.
Remember, your lights are fixtures that consume a lot of energy. With the continuing drop in the cost of LED lights, LEDs are now clearly worth the investment. Generally speaking, they will use about one-eighth the electricity of a comparably bright incandescent fixture and they will last up to ten times longer. An added benefit is they give off much less heat. So your air conditioning costs will go down, too.
Of course, the largest appliances in your house are your hot water heater and your heating and air conditioning system. For an energy efficient home design, select a water heater that is highly insulated. A water heater’s efficiency is in its ability to store hot water and not in its ability to heat the water. Simple physics tells us it takes the same amount of energy to heat water, regardless of the fuel. But only a well-insulated water heater will hold the temperature of the hot water efficiently. Check the water heater’s label for comparative projected energy costs.
Heating and air conditioning systems are given energy efficiency ratings. Furnaces are rated with an AFUE rating, air conditioners get a SEER rating, and heat pumps get an HSPF rating. Standard furnaces might have an AFUE rating of 80 which means 80% of the fuel goes to heat while the remaining 20% goes up the flue. You will want a high efficiency furnace with an AFUE rating of over 95.
The SEER rating (Seasonal Energy Efficiency Ratio) for air conditioners typically ranges from 13 to 18. Choose a system with a SEER rating of 15 or higher. You can go higher, but the initial cost goes up fast. I would suggest that the extra money you might have spent on a higher SEER air conditioner would be better spent on more insulation. The payback will be quicker, using this energy efficient home design.
Heat pumps are really air conditioners that are reversible. They take heat from inside and move it outside in summer and then reverse and take heat from outside and move it to inside in winter. Yes, there is actually heat outside in winter. But in northern climates, there is a lot less. So a heat pump cannot efficiently move that heat indoors. This is why you only see heat pumps in regions with more moderate winters. And like the other types of equipment, the higher the HSPF, (Heating and Seasonal Performance Factor), the more efficient the unit.
LED lights might be the most efficient electric light, but natural sunlight is completely free and abundant. So it makes sense to use as much natural daylight as possible in your energy efficient home design. But the challenge it to get the light where you want it, block it from where you don’t want it, and keep it from overheating your house.
Natural light comes in two forms, direct sunlight and indirect sunlight. Direct sunlight is wonderful to sit in on a cold winter day, but most of the time, direct sunlight is hot, glaring, fades fabrics, and makes seeing electronic screens tough. It is generally a good idea to limit direct sunlight unless you are developing a passive solar design and you have appropriate sun-spaces to accept the direct sun.
Indirect sunlight is what we all like. Light through north windows has been cherished by artists for centuries. The even and accurate color is unmatched. If your energy efficient home design uses roof overhangs properly, you will gain natural sunlight through most of your windows with only occasional direct sunlight entering your house.
Keep in mind that sunlight reflects off of light colored surfaces. For your energy efficient home design, a light colored patio or wall can reflect the indirect light into a room even if the windows are on the north side of the house.
Skylights and solar tubes can introduce natural light deep into a house where windows cannot be placed. But place skylights carefully. They can also bring in a lot of excess and unwanted heat while also being a “hole” in your insulation. Skylights are usually best if the direct sunlight that comes through them is then reflected off of a light-colored surface before it can reach the furniture and people below.
And of course, the orientation of the house and windows is critical to optimizing natural light. Consider your climate and place windows and skylights accordingly.
Long before houses were air conditioned. Great attention was paid to ventilating houses. Windows were placed at opposite ends of halls. Proper overhangs were built so windows could remain open during rains. And whole-house fans were common. And just as we’ve already seen, the placement of the house on the land is important. When developing your energy efficient home design, you need to pay attention to the direction of the prevailing breezes.
Old southern houses often had a whole-house fan in the attic. The fan would blow air out and each room in the house would have a hatch or opening to the attic that could be opened or closed. The windows around the house were opened only a little and the hatches were opened. Then when the fan was blowing air out of the attic, it would pull air in through all of the windows and hatches to replace the exhausted air. The result was that the house was evenly ventilated and a gentle movement of air through the house would keep everyone cooler.
This whole-house ventilating would be best done during the night when the air was cooler. Then as the day warmed, the windows were actually closed so that the hot, midday heat would not come in. when you think of southern houses, you think of porches. Those porches served a purpose by shading the exterior walls and providing cooler air around the house.
Unfortunately, we have become so dependent on mechanical air conditioning, we no longer design houses with ventilation in mind. That is a shame, since proper ventilation will keep your house cooler with very little energy consumption and it will greatly improve the quality of the air in your house.
If you want to dig deeper into ways of cooling your house by natural ventilation, read up on solar chimneys. These induce a flow of air through the house by means of a solar activated convective air current. Combined with an earth-cooled intake pipe system, solar chimneys are wonderfully effective in hot locales with low humidity.
One other item we can borrow from southern houses for are ceiling fans. These are very helpful in energy efficient home design. By keeping the air moving, we can feel comfortable in air that is slightly warmer. With the air conditioner set at a higher temperature, you will save a substantial amount of energy and thus, money.
In my opinion, these five secrets are the most cost effective and practical steps toward energy efficient home design. Start out making use of these and add in things like programmable thermostats, radiant barrier roof sheathing, good weather-stripping, sealing cracks, energy recovery ventilation systems, and many of the long list of energy reducing building products, and you will greatly reduce your energy consumption while making your house a more pleasant place to live.