I have a 125K BTU or 100 K American Standard gas furnace, Its 11 years old. House is 2 story 2200 sq ft. well insulated. I have been told not to completely cut it off and on, because if its very hot and cools quick it can crack the heat exchanger and I mean if its up to a high setting such as76 78 or 80, If its up there I was told to lower the T stat to a cooler temp 68 before turning it off.

Also if I ran this unit up at 78-80 for days in very cold 20 and under weather will it harm it more then leaving it at 70 and being a bit cool in places in the house. It will use more gas of course and the bill will be higher. I usually run it at 70F but on some of these deep freeze days I turn it up for a few hours then back down and not off.

Your question is difficult to answer because you failed to explain your situation in a manner in which it could be understood.

First of all, all your thermostat can do is turn your furnace all the way on or all the way off.

Turning it to 80 just means that it will run the furnace until the temperature gets to 80.

Turning it from 70 to 80 doesn't make the furnace run harder or hotter.

If the furnace doesn't keep up with heat loss on 20 degree days turning it from 70 to 80 really won't do anything at all.

Turning it down in stages won't do anything like what you are suggesting. Turning the thermostat down will turn the furnace burner off until the temperature drops below the new set point.

On or off. No in between gradual cooling off. It is made for it.

I may have discovered something, I have a lamp on a table right by the thermostat. It has a 200W bulb , and its heat 2 feet away from the thermostat is causing the thermostat to be higher then the actual temp of the house which is 70 measured by a lab thermometer. The thermostat temp is showing 78 which is where I set it so its working but fooled by the heat from the lamp.

My main question therefore is : Does running a furnace at as high a temp as the thermostat can go to heat the house as much as possible "wear out" the furnace more with regard to the life of the heat exchanger or any other parts and if that's the same with a heat pump.

I realize that if its cold or colder the furnace will cycle on and off more often at any temp setting on the thermostat its set at.

I keep the fan on automatic setting

My Jan 18 gas bill was 177.00 paid Jan 1st 2018 and due by Jan 16 2018 .Which covers most of Dec . I expect my Feb 2018 bill to be 250.00 or a bit more . Its been colder then normal here for sure for this time period.

I can afford the gas bill just don't want to damage the furnace if that's possible by keeping the temp up too high.

Slit your wrists, you are an idiot.

Question? Wrote:
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> Your question is difficult to answer because you
> failed to explain your situation in a manner in
> which it could be understood.

Li3sten to me carefully, you failed law student awarded highly by Harvard.

WE ALL UNDERSTOOD, and don't believe your lies

Radon's Daughter Wrote:
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> First of all, all your thermostat can do is turn
> your furnace all the way on or all the way off.
>
> Turning it to 80 just means that it will run the
> furnace until the temperature gets to 80.
>
> Turning it from 70 to 80 doesn't make the furnace
> run harder or hotter.
>
> If the furnace doesn't keep up with heat loss on
> 20 degree days turning it from 70 to 80 really
> won't do anything at all.
>
> Turning it down in stages won't do anything like
> what you are suggesting. Turning the thermostat
> down will turn the furnace burner off until the
> temperature drops below the new set point.
>
> On or off. No in between gradual cooling off. It
> is made for it.

you think you know everything but you didn't know it all in the 80's

I'm guessing if he heard that there may be some truth to it (though not as he describes). (think of iron and flame too fast: it might crack. but i'm unsure any older units were built that way: i'd find the online care instructions)

however I'll 2nd the motion that his 20 yr old unit is not the kind of unit which had the rumored care issues.

You need to get a heat pump to be comfortable.

The worst time to have a heat pump is when temps are really cold. The second worst time is all the rest of them.

IDK bout that. I love my heat pump, warm as hell and much more efficient than gas.

Heat Pumps are for poorfags.

Blech! Wrote:
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> The worst time to have a heat pump is when temps
> are really cold. The second worst time is all the
> rest of them.

Heat pumps are the fucking worst.

pellham Wrote:
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> IDK bout that. I love my heat pump, warm as hell
> and much more efficient than gas.

^^^ Thanks of late to its supplemental electric heating capacity. There's no hard and fast rule here though. In the south, the cooling load tends to dominate, and you see a lot of heat pumps. In the north, the heating load tends to dominate, and you see a lot of furnaces. For a home in the Mid-Atlantic region, it all depends. Heat pumps may struggle here in older homes, with pickier people, and where higher electric rates are found. But they may be a good fit in many applications as well. Tastes great vs less filling. You'll have to figure it out for yourself.

The White House was fitted with heat pumps in 2015.

Too bad powering those with solar panels just got a kick in the teeth.

govt guy Wrote:
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> The White House was fitted with heat pumps in
> 2015.

That is the current trend in municipal buildings. Every school built or updated in Fairfax county is being heated with heat pumps.