Another look at energy efficient computers HERE.

Hard review of the Ecobutton HERE.

South Carolinians to get tax breaks for buying energy efficient HERE.

Masonry heaters in the news HERE.

Like all water heaters, demand water heaters have advantages and disadvantages. For now, we’ll consider some of the advantages.

Advantages: low standby losses, as stated above; low operation costs–a possible 10-50% decrease in energy consumption for heating water; hot water is always available; long life expectancy; good for do-it-yourselfers; no tank to maintain or leak in the future.

Concerning energy savings, for homes that daily use no more than approximately 40 gallons of hot water, demand water heaters can be 24-34% more energy efficient than conventional storage tank water heaters; for 86+ gallons-a-day households, 8-14% more energy efficient; up to 27-50% more energy efficient if a demand water heater is installed at each hot water outlet.

Hot water is always available as long as your water supply lasts and the energy to heat it is available, though the low flow rate may take away some of the appeal of this. This will be discussed in a later article on the disadvantages of demand water heaters.

The life expectancy of a demand water heater is 20+ years, as compared to 10-15 years for a conventional storage tank water heater. These 20 years can be extended for many more years by having easily replaceable parts and by periodic maintenance, which also helps maintain efficiency.

Although, as one would expect, it is not suggested, it is possible for the do-it-yourselfer to install a demand water heater. Of course, the manufacturer should be consulted and should be able to provide you with installation and instruction manuals. (If you are considering a gas unit, you will need to consult with an experienced contractor to find out if your gas supply is sufficient and proper venting is possible.) And don’t forget to check with your local government concerning a permit, if needed, and local water heater installation codes.
(Source) (Source)

Stand-by heat-losses associated with conventional storage water heaters are eliminated with demand (or instantaneous) water heaters, which heat the water as it is needed.

With a demand water heater, when a hot-water tap is turned on and water begins to flow, a heat exchanger is activated. The water runs into the water heater unit, passing through the heat exchanger, where it is heated by an electric element or a gas or propane burner, and is then sent to the tap.

This type of water heater generally has a higher purchase price than a conventional storage water heater, but lower operating and energy costs which could offset the purchase price¹.

Demand hot water heaters perform better when you take steps to use water efficiently, such as installing modern low-flow faucets and showerheads. Also, hot water locations in your home should be close together, and close to the demand water heater; if they are spread out, multiple heaters may be called for, thus raising initial costs.

For a slightly different slant, rather than being your primary source of hot water, a demand water heater can be used as a booster for washing machines, dishwashers, solar hot water systems, or wood-fired hot water systems².

We’ll learn more in future posts about advantages and disadvantages of demand water heaters.

¹Source
²Source

The life of a conventional storage water heater is generally determined by the tank, which usually rusts through within 10 to 15 years, thus calling for a replacement. (Source #1)

Previously, tanks were made of copper, were very resistant to corrosion, and could last decades. They are now made of glass- or porcelain-lined steel, and can rust and leak. Sacrificial anode rods made of magnesium or aluminum alloy are installed in these to help prevent this. These rods undergo galvanic corrosion to reduce corrosion of the steel tank. The longer the guarantee on a tank, the more anode material in it. The tank will rust, however, when the anode is used up, although you may be able to check the anode, and, when needed, replace it. (Source #2) These should be checked and probably replaced every five years, which is the life expectancy of the anode rods. (Source #1)

Plastic tanks are available in some electric water heaters. These are designed with materials that are corrosion-free and corrosion-resistant. They could, in theory, last as long as the home.

Regular (at least annual) maintenance of conventional storage water heaters involves draining the bottom of the tank of accumulated sediment, helping to maintain efficiency and extending the life of the tank. (Source #2)

Are you ready? China, the world’s largest light-bulb producer, is going to phase out incandescent bulbs. Now, China makes about 70% of the world’s light-bulbs, so this could very well be the beginning of the end of incandescent lighting. (Article)

Everyday is Earth day at the United States Department of Energy website.

European “Technology on Tour 2008″ will highlight energy efficiency. (Article)

State of Michigan to join Climate Savers Computing Initiative. (Article)

Hydrogen-powered vehicles in the near future? (Article)

This is the most common type of residential water heater used in the United States today. It provides a ready tankful—20 to 80 gallons, normally—of hot water, which is drawn from the top of the tank when a hot water tap is turned on. Cold water enters the bottom of the tank to replace the hot water that has been drawn off, so that the tank is always full (although not always of hot water!)

Fuel sources for this type of water heater include natural gas, propane, fuel oil, electricity, and solar energy.

Some energy is necessarily wasted with this type of water heater since the water in the tank is constantly heated, even when there is no hot-water demand. This is known as stand-by heat loss. Newer models have less stand-by heat loss and, therefore, lower operating costs because they are better insulated than older tanks. If you are shopping for a new storage water heater, look for one with an R-Value (thermal resistance value) of not less than R-12. Some have an R-Value as high as R-25.The better-insulated tanks have a higher purchase price, but the price can be quickly recouped, depending on your specific use-patterns and energy costs. To help determine your most energy-/cost-efficient choice, check the Energy Guide label (which is required on storage water heaters) for either the annual estimated system-operating cost or for energy efficiency ratings.

If you currently have an older tank and want to increase energy efficiency, you can add an insulating blanket to the outside of the tank to reduce heat loss. The blanket must be the properly sized for your specific tank and not block safety or drainage valves, controls, or airflow. Adding an unnecessary insulation blanket, particularly in very humid locales, can cause condensation problems, possibly leading to mold or rust.

According to one source, (which I believe is not from the United States, so I’m not sure this is an option in the U.S.), efficiency can be increased if you have an intelligent electrical power distribution, heating the water when the power demand is low and turning off when it is high. “This could be implemented by allowing the power supplier to send load-shedding requests, or by the use of real-time energy pricing.”

Keep in mind that smaller tanks have less surface area, and therefore, less heat-loss, which can be 10-15 percent of the water heater’s operating cost, although, as indicated above, the more insulation, the less the heat loss.

Also, if the storage water heater is located in the home’s heated/cooled space, heat loss from the water heater can actually contribute to heating the home. However, in the months when the home is cooled, it also contributes heat, thus creating a larger cooling load. Often, this type of water heater is located in non-heated/non-cooled areas of the home, and therefore does not affect the temperature inside the home, but instead simply loses the heat to the outside air.

Also keep in mind that the space you have—where the water heater will actually be installed–may limit your choices. However, storage tanks come in a number of sizes and proportions, thus accommodating a fairly wide variety of space considerations.

(Source)(Source)(Source)(Source)

Tubular skylights work by allowing sunlight to pass though an acrylic dome (or light collector) lens on the roof. The light passes through reflective tubing to a diffuser lens. That lens then spreads the light evenly throughout the room. With tubular skylights there isn’t any harmful direct sunlight; however, they don’t provide a view, either.

The initial cost for tubular skylights is much less than conventional skylights, ranging from $150-$600 depending on what kind of model is desired. The installation cost is also lower because little or no additional framing is required. This is a much more “do-able” project than conventional skylights. Like everything though, they will not perform well if they are poorly or improperly installed. They should be mounted where the dome will receive direct sunlight. Also, the shorter the reflective tubing that the sunlight has to travel through, the more effective the sunlight will be. Some tubular skylights can even be fitted with electrical lights to provide light in the evening as well. (Click on the thumbnail to view larger)

(Source)(Image source)

This type of skylight is really good to use in kitchens and bathrooms because it can circulate air and rid the room of excess moisture. Because it is on the ceiling, the ventilating skylight creates an updraft which carries the hot air, and the pollutants that come with the rising hot air, out of the house. This makes ventilating skylights a wonderful option for people with severe allergies and asthma.

Ventilating skylights usually open outward at the bottom. Some have moisture control sensors and automatically close when it rains. Ventilating tubular skylights use whirly vents to circulate the hot air out of small areas.

(Source)(Source)(Source)(Image source)

This is a new technology that allows the operator to control how much light passes through the window at just the touch of a button, flip of a switch, or turn of a knob. Smart window technology also doesn’t need any window treatments such as blinds and curtains.

Several technologies can be used in smart windows: thermotropics, photochromics or photochromatics, liquid crystals, suspended particle displays, electrochromics, and reflective hydrides.

Thermotropics: this is the same technology that is used in mood rings. It is highly sensitive crystals that react to changes in temperature. It isn’t the most practical option for smart windows.

Photochromics: eyeglasses that change according to the light use this technology. The molecules that make this material don’t react to artificial light, but they change shape when exposed to UV light. Obviously this wouldn’t be great for smart windows either. It would react the same for a cool winter light as it would for hot summer sun. This isn’t the most efficient use of windows in the winter.

Liquid Crystals: calculators, watches, and digital clocks use liquid crystal displays (LCDs). LCD smart windows are translucent when an electrical charge is absent.

Suspended Particle Displays: SPDs are sandwiched between two layers of glass or plastic. Those layers are then coated with a transparent conductive material. When electricity reaches the SPDs through the conductive material they line up and allow light to pass through the window. If only some light is wanted, but not all, a lower voltage is applied to the conductive material.

Electrochromic: these smart windows are almost exactly opposite to SPD windows. They are transparent when no electrical charge is applied to it. However, like SPDs, electrochromic windows can be adjusted according to the desired amount of light. Only enough electricity is required for electrochromic windows to change its shade; it doesn’t need a constant charge to maintain the desired shade. That makes this type of smart window very efficient.

Thumbnails of liquid crystal, SPD, and eletrochromic windows.

(Source)

Light emitting diodes, or LEDs, are becoming increasingly popular. It is easy to see why, too: LEDs last up to 10 times longer than CFLs, they are extremely durable with the epoxy exterior, they are designed to operate with just 30-60 milliwatts of power, and they don’t get hot (they create only 3.5 Btu per hour compared to 85 Btu per hour for incandescent light bulbs). They have, in other words, a higher ratio of light to heat than incandescent light bulbs. LEDs are replacing more traditional lights in many cities because electricity costs can be lowered by 80% or more. Because of their greater efficiency, longer life, and minimal power requirements, they are an excellent option for houses and buildings powered by solar panels. However, LEDs are still quite expensive: replacing a regular 25 watt incandescent light bulb with a LED equivalent can cost $40! The price is going down as the price of semiconductor material drops. The savings over time though, are wonderful! If properly installed, LEDs can last for decades.

(Source)(Source)(Source)(Image Source)

Contraflow masonry heaters are the most common type. They are regarded as the most fireplace-like of all the masonry heaters on the market. Contraflow heaters have a raised firebox and a set of down drafting heat-exchange channels that end in a chimney exit at floor level.

Most masonry heaters are designed to utilize wood as their primary fuel. Up to 55 pounds of cord wood can be loaded into the firebox and rapidly burned. If it is burned properly this wood can be turned into 33% combustible solids, 66% combustible gases, and the remaining 1% is ash that can be recycled in the garden. The typical one to two hour burn will slowly heat for a twelve to twenty-four hour period. The faster the wood is burned the cleaner and more efficient it is. When wood is burned slowly it creates pollutants. The gases aren’t completely burned and escape either as wasted heat and smoke or build up in cool chimneys and heat exchange channels as creosote. This inhibits heat absorption, making it much less efficient. These gases will generally burn if the temperature reaches or exceeds 1100 °F.

When building a fire for a masonry heater it is best to place and light the kindling on top. This reduces emissions of atmospheric pollutants. Also using larger pieces of wood provides the best fuel/air ratio; they also give the masonry work more time to absorb the heat from the fire. It is most efficient, for masonry heaters, to have one large fire a day rather than two smaller ones. The more sides of the heater that are exposed to the area you are trying to heat with it, the greater the heater’s efficiency.

(Source)(Source)(Source)(Image source)

Masonry heaters are highly efficient, producing more heat and less pollution than wood stoves and fireplaces. They have the advantage of being able to store a large amount of heat that slowly seaps into the house for the next eighteen to twenty-four hours. They only need to be fueled once or twice a day. If the fire is burned quickly and with dry wood the build-up in the channels is greatly reduced. Efficiency combustion can reach up to ninety percent. Compared with ten percent for a regular fireplace and sixty for a regular wood stove this is excellent! The heating efficiency is increased even more if the heater is exposed to direct winter sunlight. It will absorb the sun’s warmth and emit it into the room just as it does with fire heat. Along with pleasing asthetics and wonderful heating efficiency, some masonry heaters can include bread ovens, cookstoves, and even waterheating. The biggest problem with this type of heater is that it cannot provied heat quickly from a cold start.

(Source)(Source)

Most types of skylights come with flashing that will effectively seal the roof. Flashing is usually aluminum or galvanized steel, most often aluminum. It can be finished to match the frame of the skylight to be more aesthetically pleasing. Below are a few links that show how to install a skylight yourself, and a few things to consider before beginning the installation process:

10 Things You Must Know About Installing a Skylight, from the DIY Network.

Several articles from DoItYourself.com

Installing a Skylight, from Lowes

(Source)

Skylight glazings are usually plastic or glass.

Plastic: This type of glazing is usually cheaper than glass. However, they do scratch easily and sometimes become brittle and discolored with age. Plastic glazing also lets more ultraviolet rays into the room which can sometimes be damaging to the furnishings. The most common types of plastics used are acrylics and polycarbonates. Acrylics are weaker, but they cost less. Polycarbonates have a higher impact resistance, but they tend to discolor with age.

Glass: Glass glazing tends to be more expensive, but it doesn’t discolor. Glass used in skylights have to be made of safety glazing. Tempered glass is more impact resistant, and laminated glass has a thin layer of plastic embedded n it. Both types keep the glass from breaking into large, sharp pieces.

In many cases, skylights are made with both glass and plastic. The exterior panel is glass, and the interior one is plastic. This provides the most impact resistance while at the same time protecting the occupants from shards of glass.

Heat gain in the summer and heat loss in the winter are big factors with skylights. The technologies used to prevent or reduce this are the same as with windows: heat-absorbing tints, insulating glazes (two or more panes), and low-e coatings.

(Source)

There are three main types of skylights: ventilating, fixed, and tubular. Within these types there are nine different styles of skylights: flat, round, polygon, pyramid, dome, hip ridge, ridge, lean-to, and barrel vault. In this post we’ll take a look at what these are. First, the types:

Ventilating Skylights: This type of skylight can be opened for better air flow. It is optimal for bathrooms and kitchens where it will help control the moisture. They are operated either by hand crank, automatic (by temperature), or remote control.

Fixed Skylights: This type doesn’t open, and is installed just for light.

Tubular Skylights: This is really just a very small skylight that is meant to fit places such as closets and hallways where traditional skylights wouldn’t work.

Flat: This is the most common. Made out of a flat (obviously) piece of acrylic or glass, it can be either the ventilating type or the fixed type.

Round: These come up out of the roof looking like half a bubble.

Polygon: Polygon skylights are composed of many pieces of glass or acrylic. It is more expensive, but also much more impressive.

Pyramid: These are sort of like the polygon styles without as many panels of glass. Obviously, for a pyramid, there are only four pieces. It juts out of the roof in the same way though.

Dome: This style is pretty much like the flat style except that is gently “bubbles out, ” if you will, above the roof-line.

These styles are mostly residential; the next few are mainly associated with larger buildings:

Hip ridge: These look like enormous pyramid skylights. Long and rectangular hip ridge skylights come to a peak above the roof surface to a central ridge. The short ends are composed of sloping, triangular pieces of the same material.

Ridge: It is almost the same as the hip ridge, but a little simpler with the short ends being flat rather than sloping.

Lean-to: This is a very simple design. It starts on the roof of one story, and ends on the wall of the next.

Barrel vault: These are sort of like the lean-to styles, but a bit more complex with the upper story part consisting of a half sphere.

(Source)(Image source)(Image source)

Skylights can be a very effective way of lighting your home in the daytime. By doing that they will lower your energy bill. There are three things to consider when thinking about installing skylights:

Micro-Climate: This comes up a lot. As always it is crucial to understand how your micro-climate works. Watch how the shadows move along your property and take advantage of them. Skylights on the east and west sides of the house give the most light, but with that comes the most heat gain. North-facing skylights give some light and minimal heat gain. South-facing skylights will give more light than north-facing ones; they also give more heat gain. However, if the skylights were to be shaded in the summer the heat gain would work for you in the winter.

Selection: Choose just the right skylight for your specific climate, micro-climate, and home for the best energy efficiency. A skylight’s shape, glazing and use all effect how efficient it is. We’ll look into this more in another post.

Proper Installation: As with all things, if skylights aren’t installed properly they won’t be efficient, and will probably be an energy drain. When installing a skylight it’s important to take the slope and moisture control into consideration, but, again, we’ll look at this in more detail in a different post.

(Source) (Image Source)

There are two methods of installing these heating systems: wet and dry. 

Wet: The wet method is most often used on ground floors. It does a better job at retaining heat because it isn’t trying to heat an air space as well as a room. When installing a radiant system using this method of installation, tubing (if the radiant floor system is hydronic; wires if it’s electric.) is laid over insulation and and tied to rebar. All this is topped with a poured concrete slab. This is the oldest method of installation.

Dry: This is a relatively new technique for installing radiant floor systems. However, they are quickly gaining popularity because of their quick and cheap installation. When using the dry method, tubing or cables are suspended in floor joists. Reflective insulation is installed to direct the heat upward.

(Source)(Source)

Radiant heating supplies heat directly to the floor or to panels in the wall or ceiling. It’s more efficient than baseboard heating, and usually more efficient than forced-air heating because energy isn’t lost through duct-work. This type of heating can be very good for people with severe allergies because there isn’t any moving air involved.

There are three main types of radiant flooring: Air-heated, Electric, and Hydronic.

Air-Heated Radiant Floors: This type is not used very often because air doesn’t stay warm enough long enough. It’s not cost effective.

Electric Radiant Floors: These are made up of electric cables built into the floor although there are systems that use mats placed on the subflooring. This option isn’t very cost effective either, but it’s better than the air-heated floors.

Hydronic Radiant Floors: This is the most popular and cost-effective option. Hydronic systems pump hot water through pipes or tubes laid out in a pattern under the floor. The cost of this type of system varies by location, size, type of installation, floor covering, how difficult your site is to get to, and the cost of labor.

(Source)

There are basically four types of GHPs (click on the thumbnails to view larger):

• Horizontal
• Vertical
• Pond/lake (these three are closed-loop systems)
• and open-loop systems

Horizontal: This is generally most effective for new-construction, residential installations. The most common layouts use either two pipes with one buried at six feet and one at four feet or two pipes buried side-by-side at five feet

Vertical: This is often used by comercial buildings when the land area that is required for horizontal GHPs isn’t feasible, and when the soil is too shallow for trenching. Four inch holes are drilled twenty feet apart and one hundred to four hundred feet deep; pipes that are connected to horizontal pipes are dropped into these holes. The horizontal pipes are connected to the heat pump in the building. This type of GHP minimizes disturbance on existing landscaping.

Pond or Lake: Of course this type of GHP is used only when there is an adequate body of water nearby. If that is the case, this can be the cheapest option. The pipes are coiled at least eight feet under the surface of the water to prevent them from freezing. The volume, depth, and quality of the body of water are all factors you have to consider when looking at this type of heat pump.

Open-loop System: This uses a well or surface body water as the heat exchange fluid that circulates through the pump system. After it has circulated the water is returned to the ground through another well. This option is only possible when there is relatively clean water in the area and local regulations are met.

(Source)

Geothermal heat pumps (GHPs), also know as GeoExchange, ground-source, earth-coupled, or water-source heat pumps, have been used since the late 1940’s. This kind of heat pump uses the constant temperature of the earth as the exchange medium. GHPs are more efficient in colder climates than air-source heat pumps. They have a much higher efficiency than air-source heat pumps too, and can, if properly equipped, supply the house’s hot water. Because they are underground they are not susceptible to vandalism, and they are extremely quiet. GHPs control indoor humidity making them very effective in humid climates.

The main reason GHPs are not more widely used than other heat pumps is the high cost. They are quite expensive, but mainly because they are so difficult to install. The average cost is about $2500 per ton. However, GHPs are gaining popularity; approximately 40,000 GHPs are installed in the US every year. Typical anual energy savings are 30-60% which means that it is possible to recoup the initial investment in 2-10 years just through lower utility bills!

(Source)

Energy Star funded a research that shows more than 50% of all heat pumps have problems with leaky ducts,

Low air-flow: There should be 400 to 500 cubic feet per minute (cfm) air-flow for ever ton of the pump’s air conditioning capacity. the pump’s efficiency deteriorates if the air-flow is much less than 350 cfm. Cleaning the evaporator coil and increasing the fan speed can sometimes help here, but modifications to the duct-work is often needed.

Incorrect refrigerant charges: This usually doesn’t occur in the packaged systems because they got charged in the factory, but the split-systems get charged in the field, which often results in too much or too little charge. The system should be checked for leaks every time it is serviced. The air-flow needs to be measured before the system is charged because that changes the amount of refrigerant the system needs. Too much or too little refrigerant reduces the heat pump’s performance and efficiency.

(Source)