Programmable Thermostats

[JWC86]

Those of you that use your programmable thermostats to have the temp adjusted while your away, what settings have you found to work well?

We've had one for a year now but I haven't bothered changing it for heating, only somewhat for cooling in the summer.

I usually work long days but my wife and kids are gone from 8am - 4:45pm on weekdays.

Thanks in advance for any suggestions.

 

[Klutch9]

Those of you that use your programmable thermostats to have the temp adjusted while your away, what settings have you found to work well?

We've had one for a year now but I haven't bothered changing it for heating, only somewhat for cooling in the summer.

I usually work long days but my wife and kids are gone from 8am - 4:45pm on weekdays.

Thanks in advance for any suggestions.

What kind of heating system does your house have, and how quickly does it heat up when heat is called for?

 

[Hall]

Here's ours

When it comes to heat, our furnace warms the house quick enough, referring to letting it go down to 65º during the day. The central air can keep the house cool and comfortable, which to us is 72º. If it's 95º and over 50% humidity and I let the temperature go up to 78-80º like some people do, the AC would run for way too long to get it down to our preferred temperature. Front of our house faces west, we have no shade, etc so it is what it is.

 

[JWC86]

What kind of heating system does your house have, and how quickly does it heat up when heat is called for?

Forced air NG furnace, the house is a newer build(10 years old) 1800sq ft plus finished basement.
I haven't time it but when I have left the temp get down lower in the past like while were away on vacation it did recover quickly. Maybe 15min to go from 60 to 70deg when its 0 to -10f outside.

 

[CDX825]

As an hvac tech I tell most people to just leave them set at one temperature. If you are going to swing the temperature up or down don't go more than 3 degrees.

 

[wwillson]

If you are going to swing the temperature up or down don't go more than 3 degrees.

Why is that the best option?

 

[CDX825]

Why is that the best option?

You end up running the system harder when its trying to play catch up. Any energy savings you had by setting it back are negated. 3 degrees isn't hard to make up generally but you start going 5 degrees or more that's a big jump. Have had many situations where the customer tries to set them back and the system ends up running for hours trying to catch back up.

 

[wwillson]

You end up running the system harder when its trying to play catch up. Any energy savings you had by setting it back are negated. 3 degrees isn't hard to make up generally but you start going 5 degrees or more that's a big jump. Have had many situations where the customer tries to set them back and the system ends up running for hours trying to catch back up.

The net energy to hold a house at 70°F continuously vs leaving the house for 12 hours/day and turning the thermostat down to 55°F for that twelve hours is not the same. I've done this for a couple decades and I can promise it saves a lot of $ in heating costs. The same for cooling in the summer.

 

[2strokeNorthstar]

The net energy to hold a house at 70°F continuously vs leaving the house for 12 hours/day and turning the thermostat down to 55°F for that twelve hours is not the same. I've done this for a couple decades and I can promise it saves a lot of $ in heating costs. The same for cooling in the summer.

So you left is all in suspense. What is cheaper?

 

[wwillson]

So you left is all in suspense. What is cheaper?

Consuming less net energy by demanding less during the hours you aren't home.

 

[Hall]

You end up running the system harder when its trying to play catch up. Any energy savings you had by setting it back are negated. 3 degrees isn't hard to make up generally but you start going 5 degrees or more that's a big jump. Have had many situations where the customer tries to set them back and the system ends up running for hours trying to catch back up.

That's what I was referring to with the AC in the summer. My AC can keep the house cool just fine, it seems, but when it comes to playing catch-up, I just don't like hearing the outside compressor running for hours straight.

 

[hemitom]

Forced air NG furnace, the house is a newer build(10 years old) 1800sq ft plus finished basement.
I haven't time it but when I have left the temp get down lower in the past like while were away on vacation it did recover quickly. Maybe 15min to go from 60 to 70deg when its 0 to -10f outside.

How big is your furnace (btu's) if its really jumping 10 deg in 15 minutes at those temps your furnace is way oversized.

 

[Slick3914]

How big is your furnace (btu's) if its really jumping 10 deg in 15 minutes at those temps your furnace is way oversized.

Could be a two stage system.

 

[JWC86]

How big is your furnace (btu's) if its really jumping 10 deg in 15 minutes at those temps your furnace is way oversized.

To be honest, I don't know. I'll have to look. I didn't actually time that either that's just a guess, I could be way off.

 

[alarmguy]

So have the heat go down to 62 at 7:30 in the morning and go back up to 72 at 4 o’clock in the afternoon

 

[alarmguy]

You end up running the system harder when its trying to play catch up. Any energy savings you had by setting it back are negated. 3 degrees isn't hard to make up generally but you start going 5 degrees or more that's a big jump. Have had many situations where the customer tries to set them back and the system ends up running for hours trying to catch back up.

This isn’t correct.
The heat savings come from the lower temperature in the house creates less pressure for the heat to escape the house.

So the lower the interior temperature of the house more closely matches with the colder outside air.
Think of a hot air balloon, the hot air inside the balloon, the more pressure to increase in height as the air is less dense.
Energy savings comes from reducing the differential between outside and inside.

You can gather all the hours that the heating system had to run during the day that you didn’t turn down the thermostat at least 10°
Add all those hours up and they will be no more then if you turn the thermostat back up at least 10° once you get back home but the big difference was you had less differential inside the house because the house was 10° or more cooler while you were gone, and that saves energy because less heat is escaping.

There is a lot of information on this, just two small examples in me, trying to put it into words

Best explanation is this link

https://www.paenergyratings.com/blog/is-it-cheaper-to-leave-your-thermostat-at-one-temperature/

Thermostat Savings This Winter

Giving a little attention to your thermostat can help you save energy and money this winter.

www.energy.gov

 

[wwillson]

Energy savings comes from reducing the differential between outside and inside

This is exactly my point said much more eloquently.

 

[greenjp]

That's what I was referring to with the AC in the summer. My AC can keep the house cool just fine, it seems, but when it comes to playing catch-up, I just don't like hearing the outside compressor running for hours straight.

It’s just electric motors, not going to hurt it. It’s harder on it to be turning on and off repeatedly while you’re away than having it run a couple hours straight getting back to the set point.

There is no “working hard“ for these things. They’re either on or off running at whatever speed they’re designed for. Don’t believe me, put an ammeter on it.

jeff

 

[Skippy722]

You’ll have to see how your system responds, up here the furnaces tend to be a bit oversized. I have a 60,000btu 95% furnace and 1.5 ton 14 SEER AC for a mid 1970’s 1,800sq ft tri level. The furnace has no problem if you want to jump temperature quickly but the AC will struggle a bit if it’s real hot out but is otherwise capable of maintaining a decent temperature (73F) even if it’s 100 out, just don’t run the oven.

 

[andrew_j]

I don’t use them with a boiler and forced hot water. The system has to run excessively long to being temp back up. I believe they they work well for forced air systems.