Home Energy

Conventional Home Energy

Before the industrial revolution, wood fire provided the heat and cooking for homes. The artificial light was provided with candles or gas and oil lamps. In the early 1880’s, Thomas Edison invented the incandescent bulb, and built the first power plant. By 1908, 8% of American homes had electricity, and by 1925 that number rose to 53%. In the 1930’s, natural gas began to compete with wood and coal as a heating fuel. [1]

Over the past 60 years, Americans have embraced air conditioning, replacing earlier attempts at low-energy cooling. Evaporative coolers appeared in the 1920’s followed by window air conditioners in the 40’s. Central air followed in the 1950’s. Today at least 70% of existing homes and 80% of new homes have air conditioning. [1]

Apart from our heating and cooling needs, we also consume quite a bit of energy through our use of water heaters, televisions, stereos, computers, swimming pools, spas, and all types of electric gadgets. This makes the American household among the most energy consumptive in the world. [1]

Where does the energy come from?

The majority of our electricity is generated by coal, followed by nuclear, with natural gas not too far behind. Natural gas is our major source of home heating, followed by petroleum:

Primary Energy Consumption by Source and Sector, 2010  (Quadrillion Btu)

source: U.S. Energy Information Administration / Annual Energy Review 2010

What do we use the energy for?

 

source: Krigger, John., Dorsi, Chris., “Residential Energy,” April 2004.

 

Improving Home Energy Efficiency

The Building Shell (Air Sealing)

All homes have an air barrier, but some are, of course, better than others. An air barrier basically helps to reduce the amount of conditioned air that is lost and replaced by unconditioned air. The faster a building exchanges air with the outside, the more energy is needed to maintain the structure at a comfortable temperature. There are always holes in your air barrier, because otherwise you would suffocate in your home. The trick is to keep the number of holes to an acceptable level without compromising safe and healthy ventilation. [4]

Energy auditors use a blower door, which is essentially a door frame, tarp, and fan that goes in an exterior door, hooked up to a pressure manometer. Basically, this test tells the CFM leakage of the structure at 50 pascals of pressure. While the fan is running, the auditor can typically find leaks using various techniques and equipment. Based on the structure, the leakage number, and the subsequent tests, they then determine if it is safe to seal up the house further, where to seal, and what potential savings are to be gained. [4]

It is not recommended to perform air sealing on a house without having a blower door test done by a BPI certified Building Analyst. For example, maybe your house is right on the border of allowing mold to develop. You proceed to seal the house too tight, and mold begins to develop in the bathrooms or kitchen. Perhaps you have many pets and odors that are tolerable with your leaky house when they are quickly exchanging with the fresh outdoor air, but then you seal the house up to a point where the smells become unbearable. Or you might encounter the biggest fear of any building analyst, the possibility of a backdrafting flue causing carbon monoxide poisoning. [4]

Older homes tend to be leakier than new homes. Air sealing in the attic is typically the best place to start. Recessed lights, plumbing chases, wire intrusions, open wall cavities, and attic hatches are common leakage points. If you are sealing a recessed light, make sure you follow local fire code. [4]

If you would like to learn more about specific air sealing techniques, the Department of Energy link below has some good information at this site. [5]

Common Air Leaks in a Home via Stack Effect

house-leaks.jpg

source: Energystar.gov [6]

ROI on Air Sealing – AVG 18%

(It really varies on the structure, energy prices, how difficult the air sealing techniques are, and how good your contractor is at finding and sealing the biggest leaks. The materials are usually inexpensive, but can use a lot of labor) [4]

Insulation

Your thermal barrier, or insulation, will determine the ability of your home to retard heat flow. The slower your heat leaves your home, the less energy your heating system will use. Your air barrier and thermal barrier should be together and continuous for maximum efficiency. It is very important that you air seal before installing new or additional insulation. Insulation is another job where it is recommended to hire a BPI certified building analyst before tackling. [4]

The typical insulation install in an existing home is installed in the attic. Sidewalls and rim joists can also be done in certain homes. It is important to do the proper attic prep before adding any insulation. This may include the following:

  • Determine amount (In most States, code is R-38: about 11 inches of blown cellulose or fiberglass.)
  • Check electrical (Watch out for knob and tube wiring, or any frayed wires or overburdened junctions.)
  • Make insulated boxes to go over any non-IC-rated recessed lights
  • Metal flashing with fire-safe caulk to keep insulation away from chimney or flue
  • Air sealing all intrusions into attic (If air sealing is not done, condensation can occur in attic, leading to mold, derated insulation, and ice dams.)
  • Ventilation (Make sure soffit vents have proper vents to train air flow to ridge vent and also make sure blocking is installed to prevent new insulation from clogging vents. Installing insulation without proper vents and blocking can lead to wind washing that will derate your insulation.)
  • Dams may need to be installed to prevent insulation from spilling over attic hatches, air handlers, and vents
  • Any roof leaks must be addressed
  • Watch out for vermiculite, as it has been known to contain asbestos, which can cause cancer. It should be removed by an asbestos-removal contractor. [4]

(photo: vermiculite)

Blowing sidewalls and floors can be a very difficult job, and the only houses that typically make sense to do this in are those without insulation that have large wall cavities and balloon framing. This is definitely a job for the professionals. [4]

Rim joist insulation can be an effective install for those homes with un-insulated rim joists. Below is a nice video that shows where the rim joist is. A homeowner or even a contractor can simply use rigid board insulation friction fit and foamed on the edges with cans of spray foam, for sufficient improvement. [4]

[7]

There are many different insulation materials and application methods. The most common are rolled fiberglass batts, blown loose fiberglass, blown loose cellulose, and closed cell foam. Loose blown cellulose insulation is essentially recycled newspaper. Unlike fiberglass it is non-toxic, resists air, and will seal small air leaks, where fiberglass will not stop air and is quickly derated when windwashing is present. Despite its shortcomings fiberglass is still an effective form of insulation with a low cost. Closed-cell foam insulation is the "new kid on the block." It is a perfect air barrier with a high R value, but it is expensive. It is a good to use if you are insulating a roof deck where you are bringing the entire attic inside the thermal envelope; for example, when you have ducts and an air handler in the attic. Some contractors combine the perfect air barrier of the closed cell insulation as the base of an attic, with the low cost of loose fiberglass to provide the bulk of the insulating inches. [4]

A more complete list of insulating materials and applications can be found here.  http://www.insulation-guide.com/insulation-types.html [8]

(photo: Cellulose Insulation)

ROI on insulation: AVG. 17%

(Varies depending on difficulty of the install, and how much insulation there is. The less existing insulation there is, the higher the ROI.) [4]

Combustion Analysis (Furnace or Boiler analysis)

A combustion analysis can be done on Oil and Gas systems to determine efficiency, draft, CO, O2, among other things. Typically the 80% efficiency + systems and below will progressively lose efficiency after they have been tuned. It is a good idea to have your system professionally maintained. It really does make a big difference. [4]

Oil boilers and furnaces: The best systems are typically 85% efficient. If you have an older system, it could be around 60% or 70% efficient. If you have an older system, it is recommended to discuss replacement with your HVAC professional. If no natural gas is available and you have the funds, switching to a geothermal heat pump is a great way to go. It is on the pricey side, with systems for 30K, but paybacks can approach 10%, depending on how much oil you are using. [4]

Gas Furnaces or Boilers: Natural gas is inexpensive in 2012, and the high efficiency 95% + units are affordable and extremely efficient. This is a nice option if you have a natural gas line that you can tap into. If you have an older 70%+ unit, a high efficiency replacement unit can give you a 10-15% payback, and with the sealed combustion, CO is no longer a major concern. [4]

Electric Resistance Heat: This is by far the most expensive way to heat a house. It is a great idea to switch to natural gas if you have access to a gas line, or to geothermal if you have the funds. High-efficiency natural gas units can yield a 20% ROI, while a geothermal heat pump can yield a 10% ROI. [4]

Size really does matter: One problem in almost every home is that the heating systems are oversized. Does your system frequently turn on and off? Or does it run constantly? A perfectly sized system will run constantly on a cold day. A perfectly sized system will not be able to heat your house to 72 degrees on the coldest day of the year. Combustion heating systems run at their maximum efficiency at steady state. When a system starts and stops, it runs at a much lower efficiency than the unit’s rated efficiency. Fantastic savings can be gained by air sealing and insulating, thereby reducing the heating load on a home, and then the heating system can be replaced with a smaller, more efficient system. [4]

(photo: 90% + condensing furnace)

ROI on heating system replacements: 7%-25% 

(Varies dependent on how inefficient the current system is what fuel source, rebates, and cost.)

ROI on tune up for combustion equipment: 50% 

(Possibly more depending on how out-of-tune your equipment is.) [4]

Duct Sealing and Insulation

If your ducts are entirely inside the thermal envelope, or conditioned area, this is typically not a problem. You can seal ducts in this situation to help balance your furnace. This becomes critical when you have ducts in a crawl space or attic. Any leaks in the ducts will help to heat that attic or crawl space. This can, of course, waste energy, but it can also lead to condensation issues, as the conditioned warm air hits the cool roof deck or crawl space. A very easy fix for sealing your ducts is to use duct mastic to seal up all the joints and connections on metal ducts. Mastic is good because it does not come off like tape and can expand and contract. It is a paste that can be spread with a brush or just an old glove that you are willing to sacrifice. Approved foil tape, not duct tape, can be used on fiberglass ducts. [4]

Ducts in unconditioned spaces should be insulated to R-11. It is possible to lose 10-30% of a home’s heating and cooling energy through the conduction of un-insulated ducts. [4]

ROI on duct sealing: AVG 14%

(Varies on fuel type, prices, accessibility, but also offers many residual benefits to the HVAC.)

ROI on duct insulation: AVG 22%

(Varies on fuel, prices, job difficulty.) [4]

Water Heaters

The first thing to look at is the temperature. 120 degrees usually works well. Make sure your water is not hotter than that. You can check the water heater, as some do have settings, but you may have to put a thermometer under hot water to find out. Constantly keeping a tank at too high a temperature is extremely expensive. [4]

The second thing to be concerned about are the water pipes. Are they insulated? If not, insulate starting from the tank, 6’ on the cold side, and as much of the warm side as you can reach. This will help you reduce standby loss, and it is super easy and cheap also. In some situations water heater tank wrap can also be installed, but be careful because in some water heaters, a wrap will void the warranty. Make sure to check the manual to find out if a wrap is appropriate. Most new water heaters are already insulated. [4]

Should you consider replacement? If you have an electric water heater, it is strongly recommended to consider the new air source heat pump water heaters. They use less than half the electricity of a traditional electric water heater. Solar hot water is another nice option, especially those that are concerned about steady supplies of traditional energy in the future. On-demand tankless systems work well if you use natural gas for your water heating, especially if you are moving from an inefficient tank model (non-condensing unit, atmospherically vented). However, with natural gas so cheap, the ROI is not great, and if you have a heavy hot-water need, you may need more than one. [4]

(image source: www.energysavers.gov)

ROI pipe insulation- AVG 27%

(Big ROI because improvement is so cheap)

ROI new air source heat pump water heater- AVG 23%

ROI Solar hot water- 7%-15%

(Varies based on fuel, can be higher with rebates)

ROI tankless Gas- 4%-7%

(Varies based on type replacing, fuel prices) [4]

Lighting

Incandescent, CFL’s, or LED’s are the predominant lighting choices available to most homeowners. [4]

Type

Pro’s

Con’s

Incandescent

Dims well; cheap; most people like the quality of the light

Not efficient; emits waste heat. Does not last long.

Compact Fluorescent

Affordable; uses 20% of the electricity of an incandescent

Mercury inside if broken. Some people do not like the quality of the light. Does not dim well, even those labeled as dimmable.

LED

Extremely long-lasting; uses 1/3 the electricity of a CFL

Very expensive; some people feel the light is too dim or the quality of the light is poor (due to spectrum/color temp)

It is fairly simple to determine the energy usage of a particular light bulb in your home. For example if you had a 90 watt incandescent light bulb that you used approximately 12 hours per day as a dusk to dawn fixture, and you wanted to find out how much electricity you would save by switching to a CFL, here is the formula.

Incandescent- 90 Watts x 12hrs per day x 365 days per year= 394,200 Watts / 1000= 394.2 KWH

CFL replace- 23 Watts x 12hrs per day x 365 days per year= 100,740 Watts/ 1000= 100.7 KWH

Energy saving= 293.5 KWH per year

Electricity @ .15 per KWH = $44.03 saving per year minus the cost of the bulb

ROI CFL’s- AVG 96%

(Depending on how many hours per day the light is used)

ROI LED’s- AVG 16%

(Depending on how many hours per day the light is used) [4]

Appliances

There are only a couple of appliances that you should be concerned about considering replacing, as far as efficiency goes. The number one appliance is the fridge/freezer. The second would be the washing machine, which would not include the dryer. A distant third and fourth would be the dishwasher and the non-energy-star dehumidifier. [4] Here is a link to a nice database for refrigerators and freezers  [9] to give you an idea of how many KWH of electricity your current unit is using. Compare that to a new unit’s yellow energy sticker to determine the savings you would receive by replacement. Then, based on the cost and potential energy savings, you can easily decide if replacing your appliance is a good investment. Stay away from side-by-side fridges with built in icemakers, as they are more expensive and less efficient than typical top-freezer models. [4]

Front-load washing machines use a lot less water, water heat, and electricity than top-load washers. Whenever replacing a top load, pick an energy star front load. Dishwashers should only be replaced for an energy-star model if you have a pre-1994 model. Otherwise, use it until it breaks. Non-energy-star dehumidifiers are a good item to replace, but it would be even better to remove the source of the moisture so that you do not need the dehumidifier whenever possible. [4]

Fridge Replacement: AVG 21%

Washer Replacement: AVG 11%

Dishwasher Replacement: AVG 8%

Dehumidifier Replacement: AVG 9% [4]

Water Conservation

Low-flow showerheads, faucet aerators, and low-flow toilets are a great way to save water, along with whatever fuel you are using to heat your water, as well as your sewer bill. Most showerheads will tell you on the head how many GPM they allow to flow. Low-flow showerheads typically allow 1.5 GPM. A showerhead with 2.0 GPM of flow or higher, is a good candidate for replacement with a low-flow showerhead. Bear in mind that you will have less pressure and water with a low-flow head, although the new designs do a good job of aerating the water. Low-flow faucet aerators are also 1.5 GPM. It is a good idea to replace the aerators that are 2.0 GPM or higher. The aerators are super cheap, and you will not sacrifice anything to achieve the water savings. [4]

Low-flush toilets typically use 1.6 gallons per flush, although there are lower GPF units, while older toilets can use 3.5 GPF. There are also dual-flush toilets that allow even lower GPF for liquid waste. Switching to a low-flow toilet can save 20,000 gallons of water per year. Composting toilets are a good solution for those off the grid, or who want to remain independent of the public sewer. [4]

(photo: Aerated water)

ROI low flow showerhead: AVG. 50%

(Varies, dependent on fuel source, water prices, GPM of former head, and water use)

ROI Faucet Aerators 1.5GPM: AVG. 70%

(Varies, dependent on fuel source, water prices, GPM of former head, and water use)

ROI low flow toilet 1.6 GPL: AVG. 28%

(Varies, dependent on water prices, former GPF amount, and sewer) [4]

Health and Safety

CO and moisture/mold are important concerns, as far as health and safety, when looking at a house. You can always tell who has a wet basement when you drive by a house and see relatively new paint peeling off. This is from the vapor pressure of the moisture. Excess moisture will literally take years off the life of your home. Below is a list to help keep your house safe, healthy, and durable. [4]

Living in a healthy home and avoiding mold and mildew:

  1. Avoid unvented space heaters
  2. Don't overcool the house in the summer
  3. Don't hang drying clothes inside
  4. Don't dry wood indoors (no storing firewood inside)
  5. Use kitchen and bath fans at least 3x the duration of shower or cooking
  6. Enhance room circulation with fans to avoid cold spots
  7. Avoid storing items against cold outside walls or in damp basements
  8. Avoid storing vulnerable materials in damp basements
  9. Run a humidistat equipped dehumidifier during summer in damp basements
  10. Additional pets and people add moisture; be aware of increased ventilation needs if adding occupants.
  11. New construction adds tremendous moisture to home for the first 2 years as materials are drying
  12. Make sure dryer is always vented outside
  13. Never store the following inside: paints, solvents, grease, oil, pesticides, gas equipment, kerosene space heaters
  14. Don’t warm your car up in the garage, if garage is attached to the house.
  15. Beware of too many house plants, as they can add a lot of moisture to the home
  16. Make sure drain pipes are functional and sent away from the foundation (also keep gutters clean)
  17. Have heating equipment professionally maintained [4]

(photo: mold in a bathroom)

Phantom Loads

Many appliances will draw electricity while plugged in but not in use. The trick is to find out which ones are drawing enough power to be concerned about either unplugging them or putting them on a power strip that you turn off. A handy tool called a watt meter can be used to determine this. You can buy one for about $40. You plug the appliance into the watt meter and the meter into the outlet. Then read the results after it has had enough time to make a good yearly projection. Older televisions tend to be the biggest offenders. People also tend to have these old TVs plugged into areas where they never use them, like the exercise area in the basement that they use twice a year. There are old TV’s that can use 400 KWH just sitting there plugged in for a year. [4]

Items that tend to use a lot of power at rest

Items that do not use much at rest

TV’s, especially older ones

Toasters

DVR’s, cable boxes

Phone Chargers

Older Computers

Printer (must be turned off)

Old Fashioned Jukebox

Microwave

TV/ VCR combos

Playstation 2

Clocks [4]

ROI phantom load removal: 200% AVG

(Does require some occupant discipline to turn off power strips when not in use) [4]

Doors and windows

Typically, a new window or door job has a terrible ROI. The window industry certainly has some great advertising, because more often than not people think they need new windows. If you have old wood-frame single-pane windows, you are better off caulking, weather-stripping, and adding storm windows. If you already have double-pane or better windows, then simply caulking and weather-stripping, if needed, are sufficient. Doors are in a similar situation; just weather-strip and make sure the door sweep is in good condition. The only time it makes sense to replace a door from an energy saving standpoint, is when an interior door is used as an exterior door, but even then the ROI is not great. This is sometimes true if you have a door to the attic or to the garage. New window jobs are typically not done if ROI is a consideration. See below: [4]

ROI new windows: 3% AVG [4]

On Site Home Power Production

Renewable energy is a form of energy capable of being regenerated by natural processes at meaningful rates. Sunlight, wood, wind, and flowing water are all forms of renewable energy. [3]

Solar Photovoltaic

Solar photovoltaic cells convert light from the sun directly into electricity. PV cells are essentially transistors or integrated circuits on steroids. It’s a silicon wafer about the size of your thumbnail that holds several million transistors and other electronic parts. PV cells start out the same way as chip circuits, but they are kept in the oven until they’re much larger. [2]

Solar PV is the backbone of renewable energy systems for homeowners. [2] Solar electricity is typically the most expensive means (not including any subsidies) by which humans generate electricity. However, there are some instances where it can be much cheaper than conventional electricity. For example, when building a new home more than a couple of tenths of a mile away from a power line, it is often cheaper to install solar in an energy efficient home, then pay to hook up to the electrical grid. These “hook up” charges can run in excess of $50,000. [3] Off-grid systems use batteries, typically lead acid, inverters, charge controllers, and of course the solar panels to convert, store, and produce usable electricity. In other instances, for example to take advantage of subsidies, or net metering it may make sense for a homeowner to be grid connected. Grid connected systems do not require batteries, however without batteries any power outage will leave these homeowners without power. A third option is available for the grid connected to also have a battery backup. This is a nice option for those homeowners who would like to take advantage of subsidies and net metering, but would also like the resiliency of having access to power during outages. [10]

Most solar PV manufacturers provide a written guarantee of 20-25 years, although the modules should last well past the guarantee. Modern PV modules do lose power production each year; however it is typically less than 1% per year. Maintenance is pretty simple and can be summed up in three words. Let it rain. [2]

Solar PV systems are a great way to insulate homeowners from future electricity price increases, and grid failures. Solar PV systems are expensive, but they can payback over time, given their long life span. Below is an example of the 2012 ROI on a 10 KW system without a battery backup in PA: [4]

(photo: roof mounted system ~10KW)

  • $7.00 per watt
  • cost = $70,000
  • Federal Tax Credit= $21,000
  • Adjusted Price= $49,000
  • PA power production: Appx. 12 MW per year (Provided full sun site, good pitch, and direction)
  • Electricity saved= $1800 per year at .15 per KWH
  • AEC’s: $600 per year
  • Savings: $2400 per year

ROI: 4.9%

Solar Water Heaters

Most domestic solar hot water systems are designed to provide 40-80 percent of a households annual hot water needs. Domestic solar hot water systems are usually integrated with conventional storage or tankless water heaters. (Be sure to purchase a tankless system that is designed to operate with a solar hot water system.) The conventional tank or tankless system becomes your backup hot water supply for when the sun is not shining. [3]

Illustration of an active, closed loop solar water heater. A large, flat panel called a flat plate collector is connected to a tank called a solar storage/backup water heater by two pipes. One of these pipes is runs through a cylindrical pump into the bottom of the tank, where it becomes a coil called a double-wall heat exchanger. This coil runs up through the tank and out again to the flat plate collector. Antifreeze fluid runs only through this collector loop. Two pipes run out the top of the water heater tank; one is a cold water supply into the tank, and the other sends hot water to the house.

(image source: www.energysavers.gov)

Energysavers.gov is an excellent source of additional information on solar hot water systems.  [11]

Passive Solar

Passive solar heating is a heating system with only one moving part: the sun. Passive solar design relies on ordinary visible light from low-angled winter sun, which penetrates south-facing windows during the heating season. Inside our homes, the sun’s visible light is absorbed by floors, walls, and other solid materials. Here it is converted to heat and warms our homes. [3]

For cool climates, installing the bulk of your windows on the south side of your home, while limiting the windows on the other sides, especially the north side will greatly contribute to passive solar heat gain in the winter. Limiting windows on the shady sides will also help to keep conditioned air from exiting quite as quickly; therefore reducing heating and cooling loads. Thick walls can also be of some help. Thick walls such as insulated concrete forms or ICF’s will soak up heat during the day to be released at night. This will also reduce heating loads. A light colored roof is a nice trick for the summer. The light color will reflect the sun and keep the attic from heating up. This is extremely important if you have ductwork in the attic. It will also help to extend the life of your roof. [10]

(image source: www.passivehouseandhome.com) [12]

Wind Generators

Wind isn’t for everyone. In fact, if you live in a city or town, chances are wind energy is not an option for you. Although the wind certainly blows in the cities and suburbs, the wind flows are very turbulent. The wind does not blow smoothly given the many obstructions in cities and towns. Turbulence is very hard on the wind turbines, especially smaller models suitable for home use. Space can also be an issue, as well as city ordinances, not to mention difficult neighbors. [3]

Wind power is primarily useful in rural areas of at least one acre, where ordinances are not prohibitive. This does limit sites in the US to about 10% of homeowners. This number of course is actually smaller given that not all of these sites will have sufficient wind to make it a viable option. For a map of the wind resources available in your area, the following links are good options. [3]

Most home wind machines are horizontal-axis consisting of three blades making up the rotor, a generator, a shaft, a tower, and a tail. The rotors capture kinetic energy from the wind and convert it into rotating mechanical energy, notably a spinning shaft. The spinning shaft is attached to the generator, where it converts mechanical energy into electrical energy. [3]

Wind power has the same options as solar as far as off grid, grid tied, or grid tied with a battery backup. Many off grid power generators will use a solar system in conjunction with a wind turbine. This is an efficient set-up as wind tends to blow more in the winter and at night when the sun is not shining. [10]

image source: www.allwindenergy.com [15]

Hydropower (Micro Hydro)

Humans have been tapping the power of flowing water for centuries. For example, in the early history of North America, New Englanders tapped the power of water flowing in streams that ran through their towns by installing small dams and water wheels. The water wheels in turn powered the machines of textile factories and grain mills. Hydropower continues to be the biggest source of renewable energy in the United States today. [3]

Hydroelectricity for the home is typically called micro hydro. In a micro hydro system, moving water turns a turbine. The turbine spins a generator or alternator that produces electricity. From there, like solar and wind you have your inverter and battery bank. Like solar and wind you have the option of being off grid, grid tied, or grid tied with a battery backup. [3]

For those fortunate to have a good site, hydro is really the renewable energy of choice. System component costs are much lower and watts per dollar return are much greater for hydro than for any other renewable source. Micro hydro, given the right site, can cost as little as a tenth of a PV system of comparable output. Battery banks also do not need to be quite as large as wind or solar systems given that the hydro system is constantly charging the batteries. No worries about windless cloudy days. Moreover, hydropower users often are able to energy consumptive appliances that would bankrupt a PV system. [3]

Micro hydro is typically installed in remote mountainous terrain in small streams or rivers near the home, the closer the better. [3]

image source: www.tsgtek.com [16]

Heating with wood

For those living in rural woody areas, heating with wood can be a great option. Fire places are typically what most people think, when thinking about heating with wood. Fire places are actually the worst way to heat a home. The majority of the heat is lost up the stack. They are only 10-20% efficient. An insert can be installed in an existing fireplace boosting the efficiency to 70%. A fan can also be installed on an insert to improve circulation and heat adjoining rooms more evenly. [3]

There are three types of wood stoves. Radiant wood stoves are very similar to an insert except they are stand alone, and would need a flue pipe. Like an insert, they are rated at 70-80% efficiencies. Circulating wood stoves are double walled and can be equipped with a fan. They are also rated in the 70-80% efficiency range. Finally the traditional combustion wood stove, which is very similar to the radiant stove except the door can be opened when the fire is burning like a traditional fireplace. This does bring the efficiency down to 50-60%. [3]

Wood stoves are great for one or two rooms, but if you would like to heat a large modern home with wood, a wood furnace makes a great option. Wood furnaces are typically installed in basements, garages, or even outside. Wood furnaces can be used in conjunction with conventional home heating systems such as: radiant floor heat, baseboard, or forced air systems. Some wood furnaces are designed to also preheat the domestic hot water. During the winter these furnaces not only heat the home, they also provide water heat, greatly reducing natural gas or electricity consumption. [3]

Wood furnaces are pretty efficient, clean burning, and easy to operate. Also with an outdoor unit, you can have your woodpile nearby to avoid excessive hauling of wood. On the downside they are costlier than a wood stove, and are more difficult to install. Also, wood needs to be constantly reloaded and the ashes periodically cleaned. [3]     

If cutting and hauling firewood isn’t your cup of tea, then a pellet stove might be a good compromise. Instead of firewood, the fuel is dry compressed wood pellets that are made from sawdust, a waste product of the timber industry. Pellets are packaged in 40 pound bags and sold in most hardware stores. Because pellets are dry, and because they are fed into the combustion chamber at a controlled rate with plenty of air, these stoves burn very cleanly and efficiently. On the downside you will spend more money in pellets than you would with firewood, and pellet stoves require electrical energy to operate the auger and the blower fans. [3]

Outdoor Wood Furnace

(image source: www.showroom411.com)

Battery Backup

https://encrypted-tbn2.google.com/images?q=tbn:ANd9GcROuVNwwIIIT_Wy3_WjazRZ7OU7QXaEDXj_gANUZ4CpewEfCp_gDeep cycle lead acid batteries are still the most economic choice for renewable energy storage. If you would like power during an outage or to be off grid, they are a must. They are not without maintenance, as they need to be periodically refilled with distilled water. Also, it is important that they are stored in a climate controlled area with ventilation for the hydrogen. Hydrocaps can be used to limit some of the hydrogen venting, but it will not prevent it all. A good deep cycle lead acid battery that is maintained well can last 15-20 years. [10]

(image source:  www.windsun.com) [18]

Backup Generators

A backup generator with a reciprocating internal combustion engine is more correctly known as a genset (a generator and motor set). There are many shapes and sizes and a variety of fuel types. A genset could be considered renewable if the feedstock was from biodiesel. However, most gensets are powered by gasoline, natural gas, propane, or diesel. Gensets are an inexpensive way to provide power during a short term blackout. [2]
 

Zero Energy Homes

The holy grail of the home performance industry and eco-builders are zero energy homes. A zero energy home is a home that produces as much or more energy than it uses. This is not that complicated if you have a lot of money to throw at power production. We have to be very clever to perform this feat economically. [10]

Efficiency First

It is always cheaper to reduce your energy usage first, before calculating how many BTU’s of energy you will need to produce to net zero in terms of energy usage. If you are building a new house it is important to incorporate a passive solar design. For existing homes it is important to tighten the thermal envelope, insulate as much as possible, install LED or CFL light bulbs, install energy star appliances or remove them altogether where possible, and install a solar hot water heater or an air source heat pump water heater. Then you work on the behavior of the occupants. Basically common sense behavior such as turning things off when not in use, drying clothes outside, and reducing unnecessary electronic gadgets. [10]

Choosing the Right Power Production

Now the fun part! The top of the list is of course a micro hydro system, if you are lucky enough to live next to a running stream. If not solar is a great option for those with good true south facing exposure without shade. Wind can also be a good option in conjunction with solar if you have the space and wind resources. Wood heat can be a great option for those with a woody property. This will greatly reduce your energy needs, as heating in cool climates tends to be the biggest draw of energy by a home. [10]   

[20]

(image source: www.ecofriend.com)

References

1. Krigger, John., Dorsi, Chris., “Residential Energy,” April 2004.

2. Kemp, William H., “The Renewable Energy Handbook,” 2005.

3. Chiras, Dan., “The Homeowners Guide to Renewable Energy,” March 2006.

4. Williams, Phil., “How to Increase the Energy Efficiency of Your Existing Home,” April 2011.

5. http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/

6. http://www.energystar.gov/ia/partners/publications/pubdocs/DIY_Guide_May...

7.

GreenDreamGroup.com

8. http://www.insulation-guide.com/insulation-types.html

9. http://www.kouba-cavallo.com/refmods.htm

10. Williams, Phil., BPI Building Analyst, and Energy Auditor, February 2012.

11. http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850

12. http://passivehouseandhome.com

13. www.awea.org  

14. www.nrel.gov/wind

15. www.allwindenergy.com

16. www.tsgtek.com

17. www.showroom411.com

18. www.windsun.com

19. www.powergeneratorsandportablegenerators.com

5 Comments

worldtrav's picture
worldtrav
Status: Member (Offline)
Joined: Aug 16 2010
Posts: 10
location, location, location

I've read many of these articles over the years and the majority are written from the perspective of the cold(er) northern states.  Folks living in the south (particularly the humid south) need to get up to speed on what is applicable to them.  Here's one that seems rigorous: 

http://www.buildingscience.com/websiteinfo/atw-website

http://www.buildingscience.com/documents/reports/rr-9302-humidity-contro...

Wendy S. Delmater's picture
Wendy S. Delmater
Status: Diamond Member (Offline)
Joined: Dec 13 2009
Posts: 1535
water conservation

This s a home checkup calculator on how much water you use. http://www.csgnetwork.com/waterusagecalc.html

It seems fairly accurate since it matched our water meter.

Cherihuka's picture
Cherihuka
Status: Member (Offline)
Joined: Jun 18 2012
Posts: 22
The way things are going

The way things are going, I think I should pe-warn folks that there are likely lots of tricks coming our way that can penalize the efforts made toward going off-grid, in many ways but including energy-wise. I've heard rumors about laws that may stop people from using wood burning stoves (it creates CO2 you know...) and what happens in one country could well happen in another -especially if it looks like it works to bring in revenue!

Check this out:



Spain Privatizes the Sun



Via Google translate from El Pais:

 If you get caught collecting photons of sunlight for your own use, you can be fined as much as 30 million euros.

If you were thinking the best energy option was to buy some solar panels that were down 80% in price, you can forget about it.

“Of all the possible scenarios, this is the worst,” said José Donoso, president of the Spanish Photovoltaic Union (UNEF), which represents 85% of the sector’s activity.

Before the decree it took 12 years to recover the investment in a residential installation of 2.4 kilowatts of power. Following the decree, it will take an additional 23 years...

Read more at:

karens2020's picture
karens2020
Status: Member (Offline)
Joined: Jan 21 2014
Posts: 2
energy tips

I have 8 solar panels and am on net metering. So far my bill is for what is called a "distribution" fee of about $5-6/month. In the winter, I use, and in the summer, I generate, especially in the hours when others use AC. Because of net metering, those panels have been sufficient to avoid an energy bill. But I notice that the panels have lower output since installation in 2005.

I have a propane tank for heat, but use it only to warm up the house. A Holmes electric heater keeps it warm the rest of the day. I found a circulating fan online with a motor at the bottom of a PVC tube. It sucks in the warm air at the top, and puts it out on the floor. Ceiling fans are supposed to do that, but don't. I only keep one room warm. Bathroom and bedroom are closed. I only fill this propane tank every other year

I use a small propane tank for the shower. It's hooked up to a battery operated point of use water heater. All I have to do is refill the tank once a year and change the battery.

I have a Prius which has a running average of 50.5 mpg. Brand new it was 52. I go into town 25 miles away once a week to do all my errands and appointments. I try to keep miles under 12000 to avoid an increase in insurance. Gasoline is my nemesis. I do wildlife rescues which use about half of my mileage. If it weren't for that, my total gas emissions would be under 2 tons. Supposedly 2 tons is sustainable.

Boomer41's picture
Boomer41
Status: Bronze Member (Offline)
Joined: Nov 30 2008
Posts: 67
Standby Generator in the Suburbs

During a power outage in an urban or suburban area the noise made by even a quiet generator is excessive at night. However, during the day the ambient noise increases and a quiet (<60 dB(A)) generator will not be objectionable and might even pass unnoticed.

I suggest that a system which uses a battery and inverter to provide backup to essential loads in the home (such as central heat, lighting, refrigeration etc), with a quiet generator to recharge the battery during daylight hours, can be a viable solution.

Such a system can also provide some important advantages:

At night the generator is shut down and the house powered by the battery and inverter thus avoiding annoyance to neighbors and drawing unwelcome attention to the fact that you have a generator and they do not.

A battery/inverter can supply peak power to start motors and run short term high power loads in excess of the generator capability.

The generator is only running during daylight hours to charge the battery. It is also running at full load and thus operating at peak efficiency. This cuts fuel consumption drastically.

The battery can be maintained on float charge from utility power until needed. A properly sized battery will run the essential services for up to two days and nights before the generator must be started.

The disadvantage of such a system is mostly a relatively high initial investment and some minor battery maintenance. Otherwise it makes standby power in a densely populated area a practical reality.

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