Methods to Reduce Home Energy Usage

Update 6-11-2011: I added some information in the Space Heating and Space Cooling sections in order to discuss a different alternative, mini-split heat pumps.

 

Homes are one of the largest consumers of energy in the United States.  The unfortunate part of home energy usage is that a large portion of this energy is wasted because of inefficiencies.  Inefficiencies can range from air leaks to poor heating and air conditioning systems.

Increasing home efficiency will not only allow you to save money but it also reduces the amount of energy needed for your home.  Before you can start reducing the energy used in your home, you need to have a basic understanding of where the majority of the energy is used within your home.

US Department of Energy

Courtesy of U.S. Department of Energy

Looking at the pie chart we see that the four largest users of energy are space heating, space cooling, lighting and water heating.  These four segments account for roughly 66% of all the energy used in your home.  We are going to take a look at these four segments specifically and then cover the remaining segments generally.

Lighting

Typically, a large portion of household lighting uses incandescent light bulbs.  A very simple way to reduce your energy consumption is to use compact fluorescent light bulbs (CFL).  CFLs use about 75% less energy than incandescent bulbs and CFLs are designed to last ten times longer.  With so many benefits why wait to start converting your lighting over to fluorescent.  If you want more information on the available types of CFLs visit the Energy Star CFL search.  Amazon.com also has a decent CFL webpage that contains some good information on CFL bulbs and it is an excellent source to purchase your bulbs too.

Now I know many of you out there probably don’t believe that CFL bulbs are actually cost beneficial so, in order to help get this point across let me do some math for you.  I’m going to compute the total cost of each bulb which includes the cost of the bulb as well as the cost of the electricity used to run the bulb.  Incandescent bulbs have a maximum life expectancy of roughly 1000 hours while compact fluorescent bulbs have a maximum life expectancy of roughly 10,000 hours.  Since compact fluorescent bulbs last up to 10,000 hours I will compute the total cost of an incandescent bulb for the same duration of time, which will require the purchase of several incandescent bulbs.

Below is an example of how I computed this, following the example is the computation for each bulb type.


 

Example

(Bulb Wattage) x (Total Hours in Operation) = Watt-Hours

(Watt-Hours) / (1000) = Kilowatt-Hours

(Total Hours in Operation) / (Maximum Life Expectancy) = Number of Bulbs

(Kilowatt-Hours) x (Cost of Electricity per Kilowatt-Hour) = Cost of Electricity to Run Bulb

(Number of Bulbs) x (Cost of Bulbs) = Cost of Purchasing Bulbs For Duration

(Cost of Electricity to Run Bulb) + (Cost of Purchasing Bulbs for Duration) = Total Cost of Bulb

 


Incandescent Bulbs

(60 watts) x (10,000 hours) = 600,000 watt-hours

(600,000 watt-hours) / (1000) = 600 kilowatt-hours

(10,000 hours) / (1000 hours) = 10 bulbs

(600 kilowatt-hour) x ($ 0.10) = $60

(10 Bulbs) x ($ 0.50) = $5

Total Cost of Bulb = $65

 


Compact Fluorescent Bulb

(15 watts) x (10,000 hours) = 150,000 watt-hours

(150,000 watt-hours) / (1000) = 150 kilowatt-hours

(10,000 hours) / (10,000 hours) = 1 bulb

(150 kilowatt-hour) x ($ 0.10) = $15

(1 Bulbs) x ($ 15.00) = $15

Total Cost of Bulb = $30

So if you look at the computed cost of each bulb you see that a incandescent costs $65 for 10,000 hours of operation  and the compact fluorescent costs $30 for 10,000 hours.  Even though the compact fluorescent bulb costs $15, it is still over half the price to own and operate.

Water Heating

Water heating is the third largest user of energy.  Reducing the amount of energy consumed by your current water heater can be accomplished by:

  1. Reducing the temperature of the water heater, as described here
  2. Installing an insulating jacket over the water heater, as described here
  3. Installing insulation on the hot water pipes, as described here

The other way to reduce water heater energy consumption is by purchasing a new efficient water heater.  There are several different types of water heaters available today, which include:

  • High-Efficiency Gas Storage
  • Gas Condensing
  • Whole-Home Gas Tankless
  • Solar
  • Heat Pump

Gas Condensing and Heat Pump water heaters will have all-new models in 2009.  Both of these water heater types offer an easy replacement and significant energy savings.  A.O. Smith makes a gas condensing water heater that looks very promising, called the Vertex™ 100.  This water heater looks like your typical tank water heater but it offers 96% efficiency and can be used to feed a radiant heating system.

You can also use geothermal heat pumps to heat your water, and as you will see later in this article, to heat and cool your home as well.  A geothermal system that will heat your home, cool your home and heat your water typically cost several thousand dollars.

For some more information on water heaters and what type you may want to consider visit the Energy Star – Help me choose page.

Space Cooling

When you think about cooling systems, the first type you probably think about are air conditioners.  Over the years, air conditioner manufactures have continually increased efficiencies.  In addition to increasing efficiencies of traditional air conditioners, many companies have developed air conditioners that use solar panels or ice.  Solar panel systems use the electricity from the sun to help offset the electricity used by the A/C compressor.  Ice based systems will freeze water at night, when there is cheap excess energy, and then use the ice during the day to cool the air.  This saves energy and money because the ice reduces the use of the A/C compressor and the ice is created during the night, typically, when electricity costs are lowest.  For more information on air conditioner efficiencies visit the Energy Star Central Air Conditioners page.

Air conditioners are the typical cooling system but in addition to air conditioners there are several other alternatives that you could consider:

  • Ventilation
  • Evaporative cooling
  • Absorption cooling
  • Radiant cooling
  • Earth cooling tubes
  • Mini-split heat pump (see Space Heating section)

For more information on the above cooling technologies visit Department of Energy cooling site here.  A prime example of an air conditioner alternative is a geothermal heat pump system.  We will discuss how these systems are beneficial and how they function in the last paragraph of the Space Heating section.

Among these several cooling technologies there are also several methods that can be used to reduce energy consumption of your current cooling system:

  • Install a programmable thermostat
  • Sealing air ducts
  • Reducing air leaks
  • Shutting blinds during the day
  • Turn down cooling system, especially when your not home

Space Heating

Heating your home is vital during cold seasons and generating heat can be much more efficient than cooling your home.  Typically improving efficiency in this category is accomplished by the following methods:

  • Purchasing and installing new heating systems
  • Sealing and insulating your home

Replacing your current furnace with an Energy Star rated furnace can help reduce energy usage and costs.  If you are interested in looking at several alternative heating systems I suggest that you read a good article called, Alternative Ways To Heat Your Home on The Greenest Dollar blog.

The more that I learn about heating and cooling systems the more intrigued that I get with heat pump systems.  Heat pump systems can heat and cool your home.  These systems can either use outside air or groundwater as their heat source. The outside air heat pump systems are cheaper and easier to install than groundwater heat pumps but they are also less efficient.  Groundwater heat pump systems, also known as Geothermal Heat Pump systems, offer excellent efficiencies as well as a combined heating and cooling system.  Geothermal systems have a relatively high up-front cost, about $10,000 for a 1500 square-foot home, and require enough land in order to bury piping full of heat exchange fluid.

Geothermal systems offer high efficiencies for both heating and cooling.  As an added bonus, many geothermal systems can also heat your water.  If you can afford to go this route it allows you to increase your efficiencies in water heating, cooling and heating. For information on how geothermal systems operate visit California’s Consumer Energy Center site here.

Update:

In addition to centralized heat pump systems, there is also a smaller modular type system that can be used.  These systems are called mini-split heat pump systems.  They offer the same type of benefits as a typical heat pump system but these systems are ductless and can be added to an existing system (like wood, forced air, etc…).  Mini-split heat pump systems are primarily intended for retrofits or for installations that are difficult to install a large centralized heat pump system (think old house, or rental property).  These systems use an external compressor/condensor and indoor air-handling units, like your typical heat pump system.  The key difference is that they are linked to the compressor/condensor using tubing or conduit instead of ductwork.  By not using ductwork the mini-split system installation is simplified and the energy loss from the ductwork is eliminated.  For more information about this type of system please visit EnergySavers.gov here.

Computers & Electronics, Appliances, Refrigeration and Other

The remaining four categories would seem like large energy users but when you add the percentage from each of these categories together they equate to 34%, which is only 3% higher than space heating alone.

The three easiest methods to reduce energy in these four categories is the following:

  • Use Energy Star rated products
  • Install smart power strips
  • Unplug or turn off unneeded devices

Computer & Electronics

One of the largest problems with computers and electronics is that they continue to use small amounts of power when they are turned off.  Using smart power strips, like the Smart Strip LCG3, is an easy, relatively inexpensive method to reduce energy in the Computers & Electronics category.  Purchasing Energy Star rated devices when purchasing future devices or replacing existing devices are also ways to reduce energy costs.  When replacing existing devices it is crucial to compute how much your current device costs you per year and how much you could save with the purchase of a new device.  Many times you do not experience savings for several years, in some cases, waiting until your current device is in need of replacement is the beneficial thing to do.

Appliances

This category includes items like dishwashers, microwaves and ovens.

These devices, like all electronic based devices, use small amount of electricity when not in use.  Combating this is slightly harder in this category.  Using smart power strips and turning off these devices are not as easy or convenient as with computers & electronics.  You can unplug items like toasters but you can’t easily unplug a dishwasher.  Typically the only method that can be used to reduce energy consumption in this category is the purchase of Energy Star rated devices.  Replacing your current device may or may not be cost effective depending on the cost and savings of a replacement device, make sure you consider this.

Refrigeration

The refrigeration category does not allow you to reduce electricity consumption by turning off devices.  Just because you aren’t using a refrigerator does not mean the refrigerator will not need electricity at some point to cool itself.  With refrigeration, there are only two options for combating energy usage:

  • Purchase Energy Star refrigeration units
  • Consolidate and eliminate unneeded refrigeration units

Conclusion

Implementing practices that reduce energy waste like turning off lights, using smart power strips, installing CFL bulbs and purchasing only energy star rated products can greatly reduce your energy bill and usage.

Every small thing that you can do to reduce energy usage will save you money and will reduce the amount of energy used.  With many tax incentives available it makes these efficiency upgrades even more affordable.  All you need is a little bit of time and, in many cases, little money.

My next post will show you some of the things that I have done and am considering in order to reduce the energy usage in my home.

3 thoughts on “Methods to Reduce Home Energy Usage

  1. Pingback: Energy Strain » Blog Archive » Post Updated: Methods to Reduce Home Energy Usage

  2. Morgan Negrich

    A lot of people don’t really know too much about alternatives to ac units. We try to go over green methods with our clients and let them know they can still be comfortable using other products too.
    +1

    Reply

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