Turning down the heat at night good or bad?

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machinedave
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Turning down the heat at night good or bad?

Post by machinedave » Mon Jan 04, 2016 9:05 pm

Last week with Christmas eve on a Thursday we had four days without being in the shop. We turned the heater down to 55 degrees. The outside temperature average was about 24 degrees. We came back in on Monday morning at 9:30am and turned it up to 67 degrees. The heater ran nonstop until about 6:00pm. The heater is about 7 years old. We have a lot of machining equipment and engine cores in our shop that also needed to warm up. Our shop is in a building with 5 bays and we are in the center. We have a little over 2,000 square feet and 15' ceilings. The walls on the left and right are mostly heat neutral because our shop neighbors are heating them too. On a normal day our heater usually runs for 14-16 minutes each heat cycle depending on the temperature outside. There are many opinions on this. Some feel the heat being off for that long saved money on gas and some felt that there was so much of an effort to raise the temperature back up that it costed more in the long run. Who is right?

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Re: Turning down the heat at night good or bad?

Post by Splitter » Mon Jan 04, 2016 11:25 pm

Less temperature difference (a colder building) means less heat transfer to outside. You should be saving fuel by turning down the heat. And if your shop is colder than your neighbours, you're causing them to lose more heat to you, driving up their heating costs at the same time.

There will be greater savings in lowering the temperature difference if your building is poorly insulated or has a bunch of overhead doors, compared to a well-insulated airtight building.

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Re: Turning down the heat at night good or bad?

Post by machinedave » Mon Jan 04, 2016 11:57 pm

Splitter wrote:Less temperature difference (a colder building) means less heat transfer to outside. You should be saving fuel by turning down the heat. And if your shop is colder than your neighbours, you're causing them to lose more heat to you, driving up their heating costs at the same time.

There will be greater savings in lowering the temperature difference if your building is poorly insulated or has a bunch of overhead doors, compared to a well-insulated airtight building.
Those are my thoughts as well. There are many people that disagree with me. They have a hard time with the straight 9 hours of run time of the furnace. It would be intersting to note how many times the furnace cycles in an 8 hour period just maintaining the temperature.

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Re: Turning down the heat at night good or bad?

Post by bubbabbc » Tue Jan 05, 2016 7:53 am

machinedave wrote:Last week with Christmas eve on a Thursday we had four days without being in the shop. We turned the heater down to 55 degrees. The outside temperature average was about 24 degrees. We came back in on Monday morning at 9:30am and turned it up to 67 degrees. The heater ran nonstop until about 6:00pm. The heater is about 7 years old. We have a lot of machining equipment and engine cores in our shop that also needed to warm up. Our shop is in a building with 5 bays and we are in the center. We have a little over 2,000 square feet and 15' ceilings. The walls on the left and right are mostly heat neutral because our shop neighbors are heating them too. On a normal day our heater usually runs for 14-16 minutes each heat cycle depending on the temperature outside. There are many opinions on this. Some feel the heat being off for that long saved money on gas and some felt that there was so much of an effort to raise the temperature back up that it costed more in the long run. Who is right?
We encountered a similar situation in a cold climate. When the heat is shut off, the shop stays relatively warm for hours because of the mass of steel and cast iron (machinery and parts/cores). The longer you shut the heat off, the more time required to bring the shop back up to temperature. If you feel the need to set the temperature back, try shutting the heat down at 1:00 or 2:00 in the afternoon, and have it come back on at 3:00 or 4:00 in the AM. That approach seemed to work for us. We never really saved much on heating costs, as our building is fairly well insulated. I leave it set at 64/65 degrees, and it seems comfortable. The hot tank also serves and a nice, big radiator. That helps.

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Re: Turning down the heat at night good or bad?

Post by JoePorting » Sun Jan 10, 2016 3:32 am

I'd focus on trying to insulate the shop better. Is the roll up door insulated? Replacing the roll up door with a heavy insulated door may pay for itself in the first few months. Are there lots of windows? Can you double the windows with another set on the inside, or maybe use plastic sheeting? Can you insulate the roof better? Try and find where most of the heat loss is and find solutions to reducing the heat loss in those areas.
Joe Facciano

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Re: Turning down the heat at night good or bad?

Post by sidestep » Sun Jan 10, 2016 12:19 pm

machinedave wrote:
Splitter wrote:Less temperature difference (a colder building) means less heat transfer to outside. You should be saving fuel by turning down the heat. And if your shop is colder than your neighbours, you're causing them to lose more heat to you, driving up their heating costs at the same time.

There will be greater savings in lowering the temperature difference if your building is poorly insulated or has a bunch of overhead doors, compared to a well-insulated airtight building.
Those are my thoughts as well. There are many people that disagree with me. They have a hard time with the straight 9 hours of run time of the furnace. It would be intersting to note how many times the furnace cycles in an 8 hour period just maintaining the temperature.

From a building engineers point of view, splitter is dead on. It's a waste to try and maintain the same temp over a 24hr period. Where are you grabbing air ? From outside or from the interior space your trying to heat? Does the system have the capability to do both? We as individuals naturally put out about 250 btu/hr just being up and walking around, more if your on the move or working out. Seal all the gaps, I have some literature from a pg&e energy conservation course I attended if your interested. We can talk more too if you know more about your system.

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Re: Turning down the heat at night good or bad?

Post by machinedave » Tue Jan 12, 2016 10:36 pm

JoePorting wrote:I'd focus on trying to insulate the shop better. Is the roll up door insulated? Replacing the roll up door with a heavy insulated door may pay for itself in the first few months. Are there lots of windows? Can you double the windows with another set on the inside, or maybe use plastic sheeting? Can you insulate the roof better? Try and find where most of the heat loss is and find solutions to reducing the heat loss in those areas.
It is pretty well insulated. The building was built in 1981. The Roll up door is insulated and was new in 2011. There are no windows. There is a door in the front and rear and I believe both are the original doors from 1981. They both have some leaks. The rear door we block off in the winter with a sheet of 1" board foam that works well. Even in the coldest winter months my worst gas bill has been $210 per month.

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Re: Turning down the heat at night good or bad?

Post by machinedave » Tue Jan 12, 2016 10:38 pm

sidestep wrote:
machinedave wrote:
Splitter wrote:Less temperature difference (a colder building) means less heat transfer to outside. You should be saving fuel by turning down the heat. And if your shop is colder than your neighbours, you're causing them to lose more heat to you, driving up their heating costs at the same time.

There will be greater savings in lowering the temperature difference if your building is poorly insulated or has a bunch of overhead doors, compared to a well-insulated airtight building.
Those are my thoughts as well. There are many people that disagree with me. They have a hard time with the straight 9 hours of run time of the furnace. It would be intersting to note how many times the furnace cycles in an 8 hour period just maintaining the temperature.

From a building engineers point of view, splitter is dead on. It's a waste to try and maintain the same temp over a 24hr period. Where are you grabbing air ? From outside or from the interior space your trying to heat? Does the system have the capability to do both? We as individuals naturally put out about 250 btu/hr just being up and walking around, more if your on the move or working out. Seal all the gaps, I have some literature from a pg&e energy conservation course I attended if your interested. We can talk more too if you know more about your system.

My furnace is a hanging unit so it recirculates the interior air.

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Re: Turning down the heat at night good or bad?

Post by cspeier » Sat Feb 06, 2016 1:43 pm

I insulted the hell out of my new 40x60.. I have a high efficient heater with round duct.

2 months ago I used 1647 Kwh and 184 Therms in 34 Days. My bill was $315.10

I thought OK, first full month. I will try an conserve.. Last month I used 1521 Kwh and 161 Therms in 30 days. My bill is $305.50

It's cold as hell here. I turn it down to 54 at night and it stays on 62 all day.

I was kind of upset at the cost to be honest. However, three phase converter, flow benches, compressor, it's a full day of work.

I HATE energy companies. They need more competition. 4 less days, less energy, and my bill was almost the same. Those bastards get what they want by adding bogus charges to get it.

I called them. I'm surprised they didn't shut my power off. I was less than nice.

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Re: Turning down the heat at night good or bad?

Post by machinedave » Sat Feb 06, 2016 9:00 pm

Years ago I was renting my spare bedroom out to a friend for many years and when she moved out I thought my utilities would drop a fair amount especially water but none of the bills dropped that much at all. I looked at the itemizations at the bills and sure was surprised at all the taxes, fees, surcharges etc... that make up the bills. The actual usage is not nearly as much as I thought it would be.

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Re: Turning down the heat at night good or bad?

Post by gmrocket » Mon Mar 14, 2016 4:51 pm

cspeier wrote:I insulted the hell out of my new 40x60.. I have a high efficient heater with round duct.

2 months ago I used 1647 Kwh and 184 Therms in 34 Days. My bill was $315.10

I thought OK, first full month. I will try an conserve.. Last month I used 1521 Kwh and 161 Therms in 30 days. My bill is $305.50

It's cold as hell here. I turn it down to 54 at night and it stays on 62 all day.

I was kind of upset at the cost to be honest. However, three phase converter, flow benches, compressor, it's a full day of work.

I HATE energy companies. They need more competition. 4 less days, less energy, and my bill was almost the same. Those bastards get what they want by adding bogus charges to get it.

I called them. I'm surprised they didn't shut my power off. I was less than nice.
your heating with electric forced air?

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Re: Turning down the heat at night good or bad?

Post by Calypso » Sat Jul 23, 2016 6:31 am

Insulation thickness on the inner roof makes a big difference in cold climate. Warm air wants to go up.

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Re: Turning down the heat at night good or bad?

Post by cspeier » Thu Sep 22, 2016 12:29 pm

gmrocket wrote:
cspeier wrote:I insulted the hell out of my new 40x60.. I have a high efficient heater with round duct.

2 months ago I used 1647 Kwh and 184 Therms in 34 Days. My bill was $315.10

I thought OK, first full month. I will try an conserve.. Last month I used 1521 Kwh and 161 Therms in 30 days. My bill is $305.50

It's cold as hell here. I turn it down to 54 at night and it stays on 62 all day.

I was kind of upset at the cost to be honest. However, three phase converter, flow benches, compressor, it's a full day of work.

I HATE energy companies. They need more competition. 4 less days, less energy, and my bill was almost the same. Those bastards get what they want by adding bogus charges to get it.

I called them. I'm surprised they didn't shut my power off. I was less than nice.
your heating with electric forced air?
It has central heat and air. High Efficiency American Standard to be exact.

This summer kept it on 76º and my bill was $225-$250

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Re: Turning down the heat at night good or bad?

Post by cspeier » Thu Sep 22, 2016 12:30 pm

Calypso wrote:Insulation thickness on the inner roof makes a big difference in cold climate. Warm air wants to go up.
I put 12" of shredded blow in paper in my ceiling.

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Re: Turning down the heat at night good or bad?

Post by mk e » Fri Sep 30, 2016 11:58 am

sidestep wrote:
machinedave wrote:
Splitter wrote:Less temperature difference (a colder building) means less heat transfer to outside. You should be saving fuel by turning down the heat. And if your shop is colder than your neighbours, you're causing them to lose more heat to you, driving up their heating costs at the same time.

There will be greater savings in lowering the temperature difference if your building is poorly insulated or has a bunch of overhead doors, compared to a well-insulated airtight building.
Those are my thoughts as well. There are many people that disagree with me. They have a hard time with the straight 9 hours of run time of the furnace. It would be intersting to note how many times the furnace cycles in an 8 hour period just maintaining the temperature.

From a building engineers point of view, splitter is dead on. It's a waste to try and maintain the same temp over a 24hr period. Where are you grabbing air ? From outside or from the interior space your trying to heat? Does the system have the capability to do both? We as individuals naturally put out about 250 btu/hr just being up and walking around, more if your on the move or working out. Seal all the gaps, I have some literature from a pg&e energy conservation course I attended if your interested. We can talk more too if you know more about your system.
Turning down the temp will always use less energy...but not as much less less in a shop as in a house. In a wood construction house there is very little thermal mass so it cools and then re-warms quickly. My house takes about an hour to feel warm in the morning after a 10F drop at night.

A shop with a concrete floor and lots of equipment though has a lot of thermal mass so when the furnace oges off all that stored heat starts heating the shop so the temp drops slowly, then when the furnce comes on the air temp goes right up but the warm air touches all the cold surfaces and cools....so the furnace runs and runs and runs until everything is warm.

Here's the inportant part...the energy svings is becasue the temp is lower so there is less heat going outside. If the air temp come up quick you are lossing at the warn rate, and you continue to lose at close to the warm rate as all that thermal mass cools. So you save but not nearly as much as you save doing the same thing in a house.....plus to me it just sucks walking on a cold floor grabbing cold machines & tools so I used to bring the heat on several hours before I got to the shop to make up a 20F night temp setting....it saved about 10% over-all on heating I figured. My shop is in the basement now so its no longer a concern because pretty much all heat loss in the shop is to the house so I just leave it warm.
Mark
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