Geek Money: 7-day programmable thermostat

Project Name: Thermostat Management
Initial Cost: $30 (after tax)
Recurring cost: $3.08 per year
($0.26/month for a 4-pack of AA batteries for the new thermostat)
Time involved: 30 minutes
(remove old themostat, install new thermostat, program thermostat)
Time to pay off initial investment: 6 weeks
(varies, depends on insulation in the house and how aggresive your programming is)

 GEEK MONEY: $22.74/month
(varies, I estimate I'll save at least $23 per month, about 20% on gas, 5% on electricity)

Raining MoneyIt was just winter here in Chicago, and it was cold. If it's winter for you right now, you know that your bills are a lot higher due to the increased heating costs. Whether you heat your home with gas, electric or oil, you can benefit from some thermostat management. Turn the thermostat down.

Whether you like it or not, 68 degrees is a perfectly normal temperature for the human being to be in. It may feel cold at first, but you can survive just fine at 68. If you're cold, that is what clothes are for. You shouldn't be in the dead of winter and sitting in your beach clothes at 75-78 degrees.

Not only are you overheating so you can wear shorts in winter, but the bigger the difference in out- and inside temperature, the more expensive it will be to maintain the temperature. In addition, whether your house is at 50 or 80 degrees, the fridge will have to work to keep itself at about 35 degrees (F) and the freezer at about 30 (F).

Also keep in mind that the human body is about equal to a 175-watt heater. You're supposed to be able to keep yourself warm at a reasonable temperature like 68. If not, see a doctor.

Get a 7-day thermostat
I picked up a deluxe model at Home Depot for $30. It was the cheapest one they had, but allows for the themostat to be adjusted at 4 different times during the day, 7 days a week, plus an extra 'special day program' with 4 times. Here's how it works:

On a given weekday, I know that I'll be in bed from midnight to 6:45AM. I'll be up and about from 6:45AM to 7:15AM. I'll be gone from 7:15AM to 5:00PM. I'll be home from 5:00PM to 10:00PM, and I'll be in bed from 10:00PM to midnight. On Saturday and Sunday, I don't know when I'll be home during the day, but I'm pretty sure I'll be in bed from midnight-8:00AM and 10:00PM-midnight.

Looking at this information, on the weekdays my house sees me in bed for 8 hours, 45 minutes. I'm gone for 9 hours, 45 minutes. I'm home for 5 hours, 30 minutes. If I keep the thermostat at 68, the temp is higher than it needs to be for me in bed or at work. That's 18 hours, 30 minutes per day that I am over-heating my house.

Set the 7-day thermostat
Based on the above information, I know I can have the following settings:


  • 6:30AM: set temp to 68 degrees (I wake up 15 minutes later)
  • 7:30AM: set temp to 55 degrees (I left 15 minutes earlier)
  • 4:40PM: set temp to 68 degrees (I get home in 20 minutes)
  • 10:30PM: set temp to 65 degrees (I fell asleep in a warm bed 30 minutes ago)


  • 7:30AM: set temp to 68 degrees (I wake up 15-30 minutes later)
  • 10:30PM: set temp to 65 degrees (I fell asleep in a warm bed 30 minutes ago)

*Special Day Programming*
(there is a 'SDP' button on the thermostat to put on a daily override for weekday holidays, etc.)

  • 7:30AM: set temp to 68 degrees (I wake up 15-30 minutes later)
  • 10:30PM: set temp to 65 degrees (I fell asleep in a warm bed 30 minutes ago)

As you can see, I can time the heat so that I never notice the lower temperatures, and in the meantime, the heater takes a break during a large part of the day (and the fridge hardly has to do anything all day). That also means I'm not paying to have my house heat itself when it's empty, and have my fridge fight the house to stay cold.

A few very important points

  • The amount you save on your bills will relate to how well insulated your house is, how long you can let it be cold, etc. I can't say you will save $xxx per month, but most people save anywhere between 10-30%, and sometimes as much as 50%+, depending on if you can use the sun to heat your house by opening curtains, efficient windows, etc.
  • Don't forget about the pets! If you have a pet, make sure the temperature during the day is one that will be warm enough for them!
  • The thermostat will pay for itself very quickly. My gas bill is about $100, and the electric is about $60. (I'll explain how I do that later) Let's say I save 20% on gas, and 5% on electricity from the fridge. That's $20 + $3 per month I save!
  • Install the thermostat yourself. It's easy, and comes with easy instructions. If you have an electrician do it, it will take a while to pay off that cost in energy savings
  • The new themostat comes with a function that will tell you to change the filter after xxx hours of furnace operation. You can program the hours. A clean filter doesn't make the furnace work as hard, and reduces risk of fire, in addition to cleaning the air. Bonus!
  • My thermostat had a 'copy' feature, where I programmed Monday and copied it to the rest of the weekdays. A big time saver.
  • Don't forget that the A/C will need to be programmed as well, so flip the switch over to 'COOL' and do everything over again.

One Response to “Geek Money: 7-day programmable thermostat”

  1. [...] For me, this is adding up to about $20 per month, but I’m a light starbucks patron. $20 per month added to my savings of a programmable thermostat and my compact fluoresent bulbs. Overall, that’s about $120 per month saved, and I still have adequate light, heat and coffee!  Try some of these cost-cutting ideas, and have a happy holiday! Bookmark at:StumbleUpon | Digg | | Newsvine | Spurl | Simpy | Furl | Reddit | Yahoo! MyWeb [...]

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