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Home > Resource Conservation > Heat > Programmable Thermostat  

Resource Conservation: Heat: Programmable Thermostat

thermostats
     Hate coming home to a house that is too warm or too cold? Many people leave their thermostats on 24 hours a day just to avoid this from happening. We will discuss how you can avoid keeping it on 24 hours while still coming home to the correct temperature.

 

Overview:

    A thermostat controls the output of a home or business heating and/or cooling system. When a person sets a temperature to heat to (or cool to), the heat system turns on and stays on unit the "set" temperature is the same as the temperature it measures. When the temperature drops below the "set" temperature, it turns back on.  Therefore, thermostats have a form of thermometer in them.
     The thermometer built into the thermostat are not be like the ones we think of that we put in our mouth to take our temperature. Some of these "thermometers" may be a blob of Mercury, or they could be two strips of different metals.
bimetalic strip from Hustvedt,03/09 This A bimetallic strip is usually a strip of steel and a strip of copper laminated together. Because each metal has a different rate of expansion there is a tendency for the the metal to bend.
     According to a study done by the U.S. Energy Information Administration, in 2005, on average about 50% of the "energy" consumption for residential households goes into heating and cooling a house in a year. This "energy" can be in the form of electricity, natural gas, heating oil, wood and so on.
    This discussion will not analyze which of the "energy" types is the most efficient. We will save that for another discussion.
     We are mainly discussing the viability of having a normal thermostat vs. a programmable one. The feasibility will be determined mainly by how you use your thermostat, the size of your space to heat, and the energy source for your heating/cooling.

Go see our selection of thermostats

Energy Efficient?

     There are a few options to reducing your heating bill without changing the heating method. We will quickly analyze theses options here.
Option 1:
     Change the set point to a little cooler in the winter and a little warmer in the summer. This option is free and with a 2 deg. F change this could save on average 3-7% on your heating/cooling bill. If you spend $1,000 a year on heating/cooling that is $30 to $70 a year. Therefore doing this may help you buy a programmable thermostat after a year of conserving in this manor.
Option 2:
    Change out your regular thermostat for a programmable one. The advantages are very difficult to calculate but basically it boils down to programming the thermostat to control the temperature of the house, apartment or building so that a "set" temperature can be maintained at different times of the day.
Option 3:
     This is mainly for the bigger homes (estates, businesses). Zone heating. This means that you can make your heat/cool system to activate in different zones of the property. This is fairly complicated to do an if there is only one heater and cooler you will need to have the ducting to do this.  However, the system is just like it sounds. You only heat/cool certain areas of the property at certain times of the day. If your home or business is large enough you may want to consider zone heating.
    
Go see our selection of thermostats
    A programmable thermostat does not make your heating/cooling system more efficient. What is does is eliminate the need to constantly manually control the "set" temperature. In the winter, you can program the house thermostat to a low "set" temperature when you are usually gone from the house (at work) and a higher "set" temperature when you are home. In the summer, the opposite would be true.
     How much can you really save? That is going to depend on your situation but we estimate it could be anywhere between 10% to 33% on your heating bill. You can get a closer calculation below with the "Green Calculator".
     Programmable thermostats come in a few flavors. There are the 5-2, 5-1-1 and the 7 day programmable thermostats. 5-2 thermostats have 2 times to put in your program (weekdays and weekends). For those people on a more predictable schedule. The 5-1-1 have 3 times to set (weekdays and your Saturday and Sunday). And of course the 7 day type means you can program every day of the week. Many have 4 or more times (and temperatures) per programmable slot.
     Also, be aware, that different models of programmable thermostat will accommodate different numbers of units. Some will be heat only, some will be cool only. Some will control 1heat/1cool and some will control 2heat/2cool. You get the idea. Please check what type and how many  heat/cool units the thermostat will control before you buy.
     Programmable thermostats will have an override so that when you need extra heat/cool you can override the setting and will have vacation modes as well.
Click here for other energy saving solutions with heat/air in your home.

Installation:

     Installation may be considered a two part process. First step you replace your old thermostat. Second step you program your new thermostat.
     The first step may not be that bad if you are handy around the house. If not, make sure you read the instructions carefully or hire an electrician. Go here to check out electricians in your area.
     The typical steps to installing a programmable thermostat are the following:
  1. Turn off the breaker switch that controls the Heat/Cool system.
  2. Remove the front cover of your old thermostat.
  3. Using small amounts of masking tape, label each wire attached to the base of the old thermostat with the letter you see on the base.
  4. Remove the wires from the old base, and remove the base from the wall.
  5. Stick the wires through the base of the new thermostat and find where you will put in the new mounting holes on the wall (use a level). Remove the base.
  6. Drill the holes for the mounting screws into the walls and put in plastic anchors into the holes.
  1. Put the wires through the base again and screw the base onto the wall. Put the wires on the new base by matching the labeled wire with the letter screw of the new base.
  2. After making sure you have fresh batteries in the new thermostat, reset it and install it on the base.
  3. Turn on the breakers that and cycle the heater and air conditioner to make sure the unit is controlling the two systems properly.
     The thermostat should now be ready to program. If these instructions are unclear, there are several instructional videos on You Tube. Here is a 4 minute one from Home Depot. Here is another video from Howcast. Please, if you are unsure of anything consult an electrician.
     Depending on the thermostat, it is relatively easy to program. Usually they come with a manual telling you how to program them and some have "cheat" stickers on their inside cover to give you programming hints. Since there are a variety of ways to program the different brands we will not try to instruct you here on how to program them. Consult the manual.

Go see our selection of thermostats

Disposal:

    Thermostats contain plastic, metal switches, dials  and some other materials. We will break this discussion into older thermostats and some of the newer ones.
Old Thermostat:
pic of old thermostat   Many older thermostats contain a vial of Mercury, which is usually used as a switch. Mercury is considered a toxic substance (RCRA metal) and great care needs to be taken disposing of this type of thermostat. In some states, like California, it is illegal to throw Mercury containing thermostats into the landfill. Check with your local disposal company for ways to dispose of your thermostat. Some of the other components of the thermostat may be recyclable (like the metal) but the plastic, in general will not be.
New Thermostat:
     The newer programmable thermostat will be more complicated to throw away. It will be made of metal and plastic but the part that is "programmable" is a small circuit board. It will also have a back up battery so that it does not loose its program when the power goes out. They will also have a LCD or other type of display.
    The liquid crystal display (LCD) may contain Indium Tin Oxide. The circuit board may contain some Lead. The battery will also have to be disposed of properly.
     Many states have adopted an e-cycle program. It is worth looking at your states e-cycle program to see if they take this type of electrical device. Unfortunately there aren't many areas that would take thermostats.

Click here to find e-cycling in your area.


Look here to find recycling near you.


     We are finding it difficult to research the disposal of some of the products we recommend. If you have a suggestion for other means of disposal write us and we may post it on this site.

Go see our selection of thermostats

Our Picks:

   According to Consumer Reports: Lux, Honeywell and Hunter are the big winners for the 5-2, 5-1-1 and 7 day programmable thermostats.  
     ENERGYSTAR suspended its approval process of programmable thermostats in 2009 but they do have some things to say about them. Click here to see the ENERGYSTAR view of programmable thermostats.
     Remember, beside the 7-day, 5-1-1 and the 5-2 types of programmable thermostat they are further categorized. Some of the other types are specified by the number of units they control. They are: 1 heater, 1 cooler, 1 heat/1cool, 2heat/1cool and 2heat/2cool. Read specifications carefully before you buy.
     Many programmable thermostats have 4 program set points per time period (some have more).  

Go see our selection of thermostats

Look for specification sheets for these thermostats here.

Look for rebates locally for your programmable thermostat here.


Quick Note On Savings:

    It is very difficult to make a calculation on your savings but we have seen many web sites make a generalization. Most people would have a savings of 20%-30% off of the energy they use to heat/cool their house.
     All of this will depend on your insulation, square feet you are heating, outside temperature, how often and for how long you leave your house, and many other things.
    How can this save so much money? If your heat/cool system comes on many times during a day, this should make the system come on less often. Of course, when the system turns on after being off for a while it will take longer to get to the set temperature. In theory, however, that will boil down to being on 20% to 30% less time.

Go see our selection of thermostats

Green Calculator:

     We will have a calculator soon.

Glossary Of Terms:

BTU: British Thermal Unit. A unit of measure of heat. Defined as the amount of energy required to heat 1 pound of water 1 deg F going from 39 F to 40 F. About 1055 joules.

Programmable: An attribute of a thermostat that means that you can program in temperatures and times of day to control the heat/cool system.

Resource Conservation and Recovery Act (RCRA): This act classifies certain elements and compounds as hazardous waste in the United States.

e-cycle: The practice of excepting composite electronic devices for recycling. Usually T.V.'s, printers, computers, cell phones and readers (like the kindle).
Thermostat: a device that activates or deactivates the heat/cool system based on the temperature it measures and the temperature that is "set".

LCD: Liquid crystal display. Made of Indium Tin Oxide. Used as a display monitor for thermostats.

Return on Investment (ROI): Usually measured in an amount of time to pay back an investment by saving money that you would otherwise spend.

Bimetallic strip: two metals laminated together in one strip. The two metals would have different coefficients of expansion being heated.

References:

http://www.eia.gov/emeu/recs/recs2005/hc2005_tables/c&e/detailed_tables2005c&e.html?ref=bookshelf 2005 Energy usage statistics, taken 7/18/2011, you may look at the 61 pg report here.

http://home.howstuffworks.com/home-thermostat.htm, "How Home thermostats work", taken 7/19/11

http://en.wikipedia.org/wiki/Liquid_crystal_display . "Liquid Crystal Display", taken 7/20/11.

http://www.epa.gov/epawaste/laws-regs/rcrahistory.htm , "History of RCRA", Taken 2/7/12.