Efficient Water Heating Techniques
Posted on Nov 27, 2007 - 02:37 PM
By: Adam Beazley
: : Hot Water Heating Intro : :
The typical home spends 20% to 40% of their annual energy cost to keep water hot. The average home uses electrical and/or gas water heating tanks ranging in size from 20 to 80 gallons. Energy is used to keep the water in the tank at a constant temperature (which the home owner sets) even when the water is not in use. The entire concept and most systems are very inefficient, however there are a few things you can do to increase efficiency of your water heating system.
Adjusting Temperature for Savings:
Most home owners have their hot water heaters turned up way too high (between 120° and 140° F). Granted, by setting the temperature this high, you are not going to run out of hot water during your shower, but you are also wasting so much energy just to keep the water that hot throughout the day. If you were to turn the thermostat down about 10° Fahrenheit, you could reduce your energy consumption by 3% to 5%. That would eliminate about 500 lbs. of CO2 per year and save about $25.
The only problem with doing this, is that you run the risk of running out of hot water while you are in the shower. People will say that even at 120°, your shower will not run out, but I am here to say that if two people take showers back to back, the second person depending on how long, does run the risk of getting a cold shower. The only way to solve this problem is to make your water tank even more efficient or using a tankless water heater.
Insulating for Energy Efficiency:
For water tanks which have an R-value of less than 24, insulation is a very affordable and energy efficient modification which can be done very easily. The best way to tell if your water tank needs insulation is by simply touching the outside of your tank, and if it feels warm then it needs additional insulation.
Hot water heater insulating blankets can be purchases for about $10-$20 from most hardware stores. These blankets will have an insulating value of about an R-8. The way these blankets work, is they wrap around your hot water tank and keep the heat from escaping via “Radiant Heat Loss” thereby increasing the water heaters efficiency and saving you money. The reduced radiant heat loss will be in the 25% to 45% range, which can save you about 4% to 9% of your water heating cost.
Depending on the type of water heater you have (electric or gas) that will dictate how the insulation blanket should be installed.
Electric Water Heaters:
Installing insulation blankets on electric water heaters is very easy and most people can do it themselves. Simply wrap the blanket around your electric water tank, being very careful to leave the access panels uncovered. Use scissors to cut the blanket if needed to clear the electrical access panels, as this will eliminate any fire hazards. You will also need to keep the temperature setting below 130°F (preferably 120°F to 110°F) to keep the electrical wires from overheating and causing a fire or damage to the unit.
Gas Water Heaters:
Installing insulation blankets on gas water heaters is a bit more difficult. I recommend that you have a qualified plumbing and heating contractor install this insulation. This ensures you in case of a fire.
If you insist on doing it yourself please follow the directions bellow very carefully:
Keep the insulation blanket away from the drain at the bottom and the flue at the top. Be sure to cut around the bottom to allow airflow to the burner. Cut holes in the insulation to leave the thermostat uncovered, and do NOT insulate the top of a gas water heater tank. Insulation blankets are combustible and can interfere with the draft diverter.
Additional Insulation and traps:
You should also consider putting a piece of rigid insulation under the water heater tank and additional insulation around the copper piping, for an additional 4%-9% of water heating energy savings. This additional insulation will help eliminate heat loss through the floor and through the pipes. The rigid insulation under the water heater is much easier to do when you are replacing or installing a new water heater, however it can be done on an existing installation, but it should be done by a professional.
The installation of a water trap on your water heater can save you another $15 to $30 on your water heating bill. A water trap prevents convective heat loss through the inlet and outlet pipes on your water heater. These specially designed trap valves come in pairs and cost about $30.
The installation of these traps is quite difficult for the average person and it is recommended that you have a professional heating and cooling contractor install them. However, if you are capable of cutting copper tubing and properly soldering pipe joints, this installation is not that difficult.
Tankless Water heaters for supper efficiency:
Although all of the above techniques will reduce your emissions and your energy cost, none can compare to a tankless water heating system. Tankless water heaters are supper efficient compared to a typical electric and/or gas water heater.
The concept of a typical tank water heater is this; water is stored in the tank, heated to a specific temperature and kept at that temperature until the water is used. This means that energy is being used to keep the water hot even when you are not using it and that’s about 22 hours a day. This wasted energy cost you money and emits an extra 2.5 tons of carbon dioxide into the atmosphere each year.
A tankless water heater allows you to totally eliminate all wasted energy, because it only heats the water you are using, when you are using it. They use what is called a incoloy heating element, which heats the water instantly and to the precise temperature you set. This way you only use electricity while the hot water is being produced and this translates into big savings. Best of all, they are not expensive; in fact the best tankless water heater found here, is only $299 and that replaces an entire 40-80 gallon water heater. So for about the same price as a new electrical tank water heater, you can get a great tankless water heater that can cut your monthly energy cost by 20% to 40%.
Passive/Active Systems for Ultimate Savings & Efficiency:
While tankless water heaters are great, adding a passive component to your tankless system will more than double your energy savings and emission reduction. A hybrid passive/active system gives you the best of both worlds; Huge energy savings, space savings, cost savings and more comfort than a typical hot water heating system.
These passive/active hybrid systems are comprised of a high efficient tankless water heater combined with a passive solar heating component. Each piece of the system does its specific job to make this type of system the most efficient water heating solution. The passive solar component works by keeping the water pre-heated at a high temperature. Unfortunately these passive water heaters are not great by themselves, simply because their efficiency varies with the temperature outside, so you run the risk of taking a cold or warm shower. However, when combined with a tankless water heater, you have instant hot water anytime, no matter what the weather conditions are outside.
Passive systems can be built rather easily and inexpensively. In fact, you can use your old water heater tank and convert it to an exterior solar water heater by building a small wood and glass box and painting the tank black. You could also create a solar water heater by using copper tubing and winding it up inside of an enclosed box with a sheet of glass on top.
There are so many ways you can make a passive solar water heating component. In fact, I wrote an e-book showing how to make three different versions and Ill give it to you for free if you will just tell three of your friends about this site. You will also find a place where you can buy the best tankless water heaters ever made, cheaper than anywhere else.
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Show/Hide Comments (8)
By water tank on 06/20/2008
I think gas water heating tanks are more energy efficient than electrical ones
By Adam Beazley on 06/26/2008
If you are talking about tank water heaters, then yes gas tank water heaters are a little bit more efficient than electric tank water heaters.
But TANKLESS water heaters are by far more efficient than either gas or electric tank water heaters.
By Boiler Installation on 07/12/2008
In contrast to the opinion stated above, I genuinely feel that electric heaters are a cut above gas heaters..!
By Draper Tools on 04/21/2009
I am considering to purchase and install an electric tank less(water on demand) water heater, and I would like to know real life opinions of how well they work, and if they will save money on electric bill.
By heated towel rails on 06/12/2009
Which is the best water heater to buy and why?
By making solar panel on 09/10/2009
space heating and cooling equipment has an enormous potential for improving comfort, reducing energy use, and lowering energy bills. Changing the temperature of air only requires ‘low grade’ energy and it can be done with almost any energy source including electricity, oil, gas, biomass and solar. Good building design can maximize the use of passive solar energy for heating and cooling…
By Rain Water Tanks Business on 12/01/2009
Electric water heating needs more energy.
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By Rain Water Tanks Business on 01/07/2010
Installing a pressure pump will get water to outdoor garden taps, or will allow toilet flushing indoors.
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