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Saving Money and Going Green with Programmable Thermostats
Posted 5/20/2008

With rising energy costs and a dire environmental outlook - it's no wonder that programmable (or "setback") thermostats are gaining in popularity.

Using a programmable thermostat, you can adjust the times you turn on the heating or air-conditioning according to a pre-set schedule. As a result, you don't operate the equipment as much when you are asleep or when the house is not occupied.

The benfits are two-fold:
* Save money on your heating and cooling bills
* Feel good about saving energy resources

How many degrees do I need to set my thermostat back to realize energy / money savings?

You can easily save energy in the winter by setting the thermostat to 68°F while you're awake and setting it lower while you're asleep or away from home. By turning your thermostat back 10°-15° for 8 hours, you can save about 5%-15% a year on your heating bill-a savings of as much as 1% for each degree if the setback period is eight hours long. The percentage of savings from setback is greater for buildings in milder climates than for those in more severe climates.

In the summer, you can follow the same strategy with central air conditioning, too, by keeping your house warmer than normal when you are away, and lowering the thermostat setting to 78°F (26°C) only when you are at home and need cooling. Although thermostats can be adjusted manually, programmable thermostats will avoid any discomfort by returning temperatures to normal as you wake or return home.

Most newer programmable thermostats will have a feature which allows the thermostat to "learn" how long it takes to get to a particular setpoint.  With this feature - the thermostat can start "recovering" early in order to reach the programmed setpoint at a given program time.  Honeywell calls this Adaptive Intelligent Recovery.  White-Rodgers calls it Energy Management Recovery.

EnergyStar ratings on thermostats 

What does the ENERGY STAR rating mean on a programmable thermostat?

The ENERGY STAR program was devised by the United States Department of Energy to recognize a product with certain features that reduce the product's use of energy in normal operation.  Only programmable thermostats can carry the ENERGY STAR rating.  

An ENERGY STAR thermostat doesn't automatically save energy just because it has a sticker on the box.   All ENERGY STAR qualified programmable thermostats include:

* Four default program periods per day, allowing you to save money while you're away or sleeping
* +/- 2 degree accuracy to keep the temperature at an even level, keeping you comfortable

ENERGY STAR qualified programmable thermostats typically come with these features:

    * Digital, backlit displays
    * Touch pad screen programming
    * Voice and/or phone programming
    * Hold/Vacation features
    * Indicators which tell you when its time to change air filters
    * Indicators that signal malfunctioning of heating/cooling systems
    * Adaptive Recovery/ Smart Recovery features - control features that senses the amount of time it will take to reach the next set-point temperature, and reach desired temperatures by the set time

Many thermostats ship preprogrammed with an ENERGY STAR program schedule for ease-of-use.  Below is an example of a programming schedule that meets ENERGY STAR guidelines.

You can see a long list of ENERGY STAR rated thermostats here.

Here are some additional tips from a Department of Energy brochure on getting the most benefit from your programmable thermostat:

In order to increase your energy savings, it's important that you:

* Keep the thermostat set at energy-saving temperatures for long periods of time, such as during the day when no one is home and through the night. ENERGY STAR qualified thermostats come with four pre-programmed temperature settings for typical weekday and weekend routines.

* Resist the urge to override the pre-programmed settings. Every time you do, you use more energy and may end up paying more on your energy bill.

* Set the "hold" button at a constant energy-saving temperature when going away for the weekend or on vacation.

* Install your thermostat away from heating or cooling registers, appliances, lighting, doorways, skylights, and windows, and areas that receive direct sunlight or drafts. Interior walls are best.

Limitations on programmable thermostats

 - If the members of your household (small children and their caretakers, older retirees) are generally home during the day - you are limited to the "sleep" program period for setting back the thermostat.  A programmable thermostat will not be as effective in saving energy in this case.
- If you have a heat pump you may not be able to take advantage of a programmable thermostat in the cold months when the unit is heating.  When a heat pump is in its heating mode, setting back its thermostat can cause the unit to operate inefficiently, thereby canceling out any savings achieved by lowering the temperature setting. Maintaining a moderate setting is the most cost-effective practice.  In the summer, when your heat pump is cooling the home - it acts just like a conventional air conditioner so programming a higher setpoint during the day and while you sleep would save energy and money.

- If you have electric baseboard heat, or any high voltage electric heat source - you may have problems finding a programmable thermostat.  Our selection is limited to two products:
1).  Honeywell LinevoltPro 8000 - TL8230A1003 - Double-Pole 7 day programmable thermostat that supports 220/240 VAC Only
2).  LuxPro ELV1 - PSPLV510 - Single-Pole 5+2 programmable thermostat that supports 110/120 VAC and 220/240 VAC

- If you have radiant floor heat, or steam radiator heat - it may be more difficult to use a programmable thermostats due to slow response time and the "thermal mass" generated by these systems.    The adaptive recovery features of newer thermostats can assist with this issue by initiating heating earlier in order to arrive at the correct temperature at the correct programmed time.  We find that with some trial and error - even a radiant heat system can be programmed via a thermostat to save some energy - though not as much as a conventional forced air system. Of course - radiant heat is generally more energy efficient to begin with.