HVAC heating question

[Cdnone1]

Wondering if anyone would know the answer to this. I understand there are more variables involved but would like others opinions
I have a place in the mountains. It is SoCal so not really cold. Maybe 20's at night and 50 during the day. There are two furnaces. One for the house and one for the Master, laundry room and master bath.
Which saves more energy? Should I turn off the furnace to the master and close the doors during the day and then heat it up at night, and do the opposite for the main section of the house? I usually keep the heat at 68.
I tried it last night. The main house dropped to 58. When I turned the main furnace on it seems to run straight for 10-15 minutes. The master only drops to around 61 during the day with the furnace off. Or should I just keep the place warm all the time?
I'm trying to figure out which uses less gas.
Thanks

[1990C4S]

I would shut down the unused systems, then restart when they are occupied. People will argue that uses more energy, I disagree, integrate the operation over time, shutting down is the most economical.

[cabmandone]

Originally Posted by Cdnone1

Wondering if anyone would know the answer to this. I understand there are more variables involved but would like others opinions
I have a place in the mountains. It is SoCal so not really cold. Maybe 20's at night and 50 during the day. There are two furnaces. One for the house and one for the Master, laundry room and master bath.
Which saves more energy? Should I turn off the furnace to the master and close the doors during the day and then heat it up at night, and do the opposite for the main section of the house? I usually keep the heat at 68.
I tried it last night. The main house dropped to 58. When I turned the main furnace on it seems to run straight for 10-15 minutes. The master only drops to around 61 during the day with the furnace off. Or should I just keep the place warm all the time?
I'm trying to figure out which uses less gas.
Thanks

Buy 2 nest or ecobee stats, connect them to wifi, and they'll automatically set the thermostat back with their occupancy sensing when you're not around. Or you can program them to set back at a scheduled time. They'll have smart recovery so when the time comes for you to arrive home, wakeup or whatever, they'll be up to temp

[billybek]

Programmable T'stats are great.
I am a big fan of the White Rogers, now Emerson, Big Blue T'stat.
I like the options for setup and they seem to last for a very long time. Available with different staging options and heat pump operation.

The one thing to remember about set back temperatures is that you are not just heating the air, you are heating up the mass of the structure. If the air is warm and the structure cold, you may still be uncomfortable.

Our night temp for heating is 67 deg F. Cool enough for a good night sleep and an easy recovery for the furnace. If the furnace kicks up to high stage during the morning warm up period, I know that it is very cold outside.

Another thing to consider is the possibility of the house freezing if you have turned the temperature down too low or turned the furnace off.

[masraum]

I don't have any data to back this up, but I think the way to go would be too decrease the temp in the front part of the house at night, but don't completely turn the heat off.

I think to get it right it will require some experimentation. I suspect the appropriate change in temp depends upon some factors: how big the space is that needs to be heated, how well insulated it is, how quickly it cools off, etc...

[cabmandone]

I just ordered an Amazon smart thermostat ($79) for the system in the media room/man cave out in my barn. I'll let you know what I think of it once I've got it installed. I don't have an alexa out there but I'll still be able to use the home, away feature to set the room back when I'm not out there. With an Alexa, it's supposed to set back if Alexa determines you're not home. Not sure how it does that.
Ecobee and Nest both utilize occupancy sensors. The Bryant Connex system control for my home has occupancy sensing that as I understand uses my phone to determine if I'm home or not.

Something else, Check to see if your power company offers any rebates for energy star thermostats. Mine offers up to $100 (can't exceed 50% of the cost) if I replace a standard stat with an energy star rated thermostat. So my $79 thermostat should end up costing me $39... good deal!

[cabmandone]

Got the Amazon smart stat installed. My system in the man cave is gas (propane) forced air heat only and does not have a humidifier just so anyone that might look at this knows the setup. My wifi is Mesh.

Install was easy. I had a five wire stat wire and my old thermostat utilized the C terminal. If you have four or five wires and your furnace has a C terminal, you don't need the C wire adapter. Wiring is simple, just strip back about 1/4" and insert it into the block at the corresponding terminal. Once wired, I energized the stat and started setup. I downloaded the Alexa app and signed into my amazon account. Learning the stat was simple enough with a code that you scan in the app. Where I ran into difficulty was in connecting to wifi. Each time I entered the password, it came back with an error message that the password was wrong. I reset the node in the room, retried wifi connection and it worked this time.

Settings on the stat are a bit limited. You can set home, away, sleep and wake periods. My issue is, it doesn't have any sort of bypass for the schedule. Most modern stats allow the user to bypass the schedule by selecting "hold" if you set the temperature any different than the schedule. So if my schedule is 68 wake, 68 home, 64 sleep and 64 away, if I come home during an away period and set the thermostat to 68, it will revert back to schedule at the next schedule time. For what I'm doing in my media room, I'd prefer having a hold function but I'll get over it.

I'm going to mess around with letting Alexa learn my schedule and see if that's any better. The problem is, my media room has an exercise room. I workout in the morning and then I'm not in the room until I decide to watch football or a movie. I need to look at the ecobee and nest thermostats to see if they have a hold function before passing judgement on the Amazon stat.

[cabmandone]

Couple Updates;
On the Amazon smart stat, The Alexa app lets me set the temp and hold it so it ignores any schedule.

On the Bryant Evolution Extreme heat pump.... WOW. This thing is keeping the house at 70 degrees with an outdoor temp at 16 and a "feels like" temp of 4 with wind. I checked energy consumption and it cost $4.29 to run my heat pump yesterday with a low of 17 and a high of 28. I'm liking this thing.

[Arizona_928]

What’s the btu ratings for each furnace? Which one is used to heat the plumbing?


I would keep my apartment at 50 in the Midwest to avoid freezing the water lines.

[masraum]

Originally Posted by cabmandone

Couple Updates;
On the Amazon smart stat, The Alexa app lets me set the temp and hold it so it ignores any schedule.

On the Bryant Evolution Extreme heat pump.... WOW. This thing is keeping the house at 70 degrees with an outdoor temp at 16 and a "feels like" temp of 4 with wind. I checked energy consumption and it cost $4.29 to run my heat pump yesterday with a low of 17 and a high of 28. I'm liking this thing.

Wow! Impressive. Sounds like you're in good shape.