Heat Pump in Northern Climates?

10F here and supply temps are 95F (edit: 90.6F - I'm an idiot and was looking at a temp in memory) with no issues but clearly starting to lose the ability to produce maximum temps (previous supply temps were 99-100F). It also almost immediately went into stage 2 and it took about 20 mins to reach set temp. We had 7" of snow yesterday and felt the cold air during a defrost cycle and went to the window to watch. Within 2 mins there was steam coming out of the top of the outdoor unit and you could watch the snow melt within a min or two on the top and sides and even on fan blades inside. Do I dare go to 5F?

The defrost cycle does suck as it is basically turning the AC on in the middle of the winter for 5 mins. The entire house drops 1-2F during that time and you can really feel the cold air during that time which is about 5 mins at 10F. I think it is not timer based but based on temp of the outdoor unit.
Why not? It can handle it.
 
Why not? It can handle it.
We've bottomed out here already and temps are already going up but the low Monday night is going to be 3F, the high Tuesday 8F and Tuesday night's low is -1F. Set it at zero and see what happens? It's technically rated to -5F. If I do this I'll do it while I'm home and if it's struggling I'll discontinue the experiment.
 
We've bottomed out here already and temps are already going up but the low Monday night is going to be 3F, the high Tuesday 8F and Tuesday night's low is -1F. Set it at zero and see what happens? It's technically rated to -5F. If I do this I'll do it while I'm home and if it's struggling I'll discontinue the experiment.
No need to do that. I believe most modern systems are somewhat smart and if it runs the HP at max for a certain period of time without hitting the set point it will turn on the aux heat to bring it up to the set temp. Heatpumps are most efficient that way and it will decrease the amount of gas/oil burned since it only needs to use the aux/emergency heat to make up some of the difference.
 
what are compared energy bills before & after installation ?
i´m not a believer into these reverse fridges. flame was mens best friend for thousands years.
 
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Since mine is dual-fuel there is no auxiliary heat and you can see if "emergency heat" is on.

I will say tonight I did find a bit of an Achilles heel. The temp outside is 27F and the temp inside was set to 62F. I jacked the heat up to 74F and the system did not even attempt to heat with HP and it immediately went to the emergency oil heat. I turned off dual-fuel to force it to use only the heat pump and the following happened.

Mins 1-5 was in defrost and so blowing cold air which brought the temp down to 60F
Mins 5-20 was in second stage heat mode and the temp went from 60F to 66F
Mins 20-25 was back to defrost mode and blowing cold air and so temp went down to 64F
Mins 25-40 was in second stage heat mode and temp went from 64F to 70F
Mins 40-45 back in defrost mode and so temp back to 68F
Mins 45-60 in second stage heating and finally we reached 74F.

I let the upstairs cool back down to 62F and turned dual-fuel back on and set the temp at 74F and the oil heat came on and hit 74F in like 13 mins. So for large heat calls it turns out the HP is less efficient and it seems to do best just needing to maintain a set temp which requires less time than is needed to trigger the defrost mode.

The first 5 minutes your Bosch is actually running heat mode but it takes the compressor awhile to ramp up and start making heat. I have the IDS 1.0 system and its the same way. Ive installed a ton of the IDS 1.0 systems but have yet to do any 2.0 Bosch was supposed to fix this issue with 2.0 but I dont know if they actually did.
 
10F here and supply temps are 95F (edit: 90.6F - I'm an idiot and was looking at a temp in memory) with no issues but clearly starting to lose the ability to produce maximum temps (previous supply temps were 99-100F). It also almost immediately went into stage 2 and it took about 20 mins to reach set temp. We had 7" of snow yesterday and felt the cold air during a defrost cycle and went to the window to watch. Within 2 mins there was steam coming out of the top of the outdoor unit and you could watch the snow melt within a min or two on the top and sides and even on fan blades inside. Do I dare go to 5F?

The defrost cycle does suck as it is basically turning the AC on in the middle of the winter for 5 mins. The entire house drops 1-2F during that time and you can really feel the cold air during that time which is about 5 mins at 10F. I think it is not timer based but based on temp of the outdoor unit.
Is your oil furnace not kicking on during defrost? The heat pump sends a signal to the furnace in defrost mode to kick on the oil to help with defrost and also prevent super cold air from blowing from the vents.
 
Is your oil furnace not kicking on during defrost? The heat pump sends a signal to the furnace in defrost mode to kick on the oil to help with defrost and also prevent super cold air from blowing from the vents.
No, that's not how it works. Defrost is simply the AC going on - the air-handler goes on without the condensing unit fan going on - heat from inside the house is used to heat the refrigerant and it's sent to the condenser to defrost. Once a certain temperature is reached, the reversing valve switches and now the condenser fan goes on and heat is pulled from the outside air and sent to the coil in the AH. The downside to defrost mode is it produces cold air during that time - just like it does in AC mode.
 
The first 5 minutes your Bosch is actually running heat mode but it takes the compressor awhile to ramp up and start making heat. I have the IDS 1.0 system and its the same way. Ive installed a ton of the IDS 1.0 systems but have yet to do any 2.0 Bosch was supposed to fix this issue with 2.0 but I dont know if they actually did.
Again, it's not running in heat mode when it's in defrost mode. The condenser is outside a window and I can see it - normally a heat call turns the condenser fan on immediately and yes, it still takes a min or two to produce heat. The defrost cycle doesn't happen every time but when it does the condenser fan does not turn on but the AH does. If you watch the outside condenser you will actually see steam coming out of it and snow actively melting anywhere it's close to the coil. The AH at this point is producing cold air just like in AC mode. When the consider reaches a certain temp, the condenser fan turns on and the reverse valve reverses and heat is produced.

The baseboard oil boiler in my basement has absolutely NOTHING to do with my heat pump in the attic - there is no relationship or communication between the two at all except through the thermostat but it is HP OR oil boiler - those are the only two options. If the HP can't keep up or the outside temp below the switchover temp then the T-stat shuts the HP down and simply turns on the zone for the oil boiler.
 
The one you have is really advanced. Mine is 10 years old and needs air temps of about 40 degrees F to run.

The temps coming out of the hot air duct are indicative of the plenum temperature where the heat exchange occurs and the blower fan forces return air across the heat exchanger inside the plenum. On mine, when in the auxiliary mode, my blower heats the heat exchanger with 148 F hot water. The air picks up the heat and it comes out at 92 F at the hot air duct in the floor. My return air is 70 F.

I”m going to measure my air temp later this morning when the heat pump will be running by noon and will see what the heat pump exchanger can heat the air to. It’s usually 20 to 30 F more than than the return air according to most sources but I’ll see.

There are more advanced heat pumps that work down to about -10F but the quality of the heat is meh
AKA The colder it gets the more lukewarm your “hot air gets” AKA large volumes of 72F heated air technically is heat but it’s not pleasant not to mention economically unless something dramatic changes in energy prices
heat pumps aren’t economical much below 20-30F

If the cost of a unit is basically the same as AC by all means get one as a furnace backup is always prudent but don’t expect to save lots of money
 
what are compared energy bills before & after installation ?
i´m not a believer into these reverse fridges. flame was mens best friend for thousands years.
You don't believe in physics, thermodynamics.........only chemistry? Hahahhaha I'm kidding of course.

Heat pumps have a place. That place is NOT all by themselves in northern climates. Period. Dual source is the way to go. Shoulder seasons, no need to burn LP/oil on cool mornings or maintain the temp. Need a quick ramp up? Combustion, efficient combustion.
 
what are compared energy bills before & after installation ?
i´m not a believer into these reverse fridges. flame was mens best friend for thousands years.
My electricity is much cheaper than oil at the moment. So far I estimate I'm spending about $200 less in oil per month but spending an additional $100 more in electricity. It is not an easy comparison as this year has been warmer than last year but it's as close I can estimate it.
 
There are more advanced heat pumps that work down to about -10F but the quality of the heat is meh
AKA The colder it gets the more lukewarm your “hot air gets” AKA large volumes of 72F heated air technically is heat but it’s not pleasant not to mention economically unless something dramatic changes in energy prices
heat pumps aren’t economical much below 20-30F

If the cost of a unit is basically the same as AC by all means get one as a furnace backup is always prudent but don’t expect to save lots of money
At 10F my HP produces 91F air.

At 20F it produces 99-100F air.

At 35F it produces 103F air.

That is measured directly at the supply vent after running through an uninsulated attic.

The average run time to reach temp is about 12 mins and I'm spending +$100 less per month on heat this winter compared to last year only using oil.

What's wrong with the quality of that heat? My unit is rated to -5F and it's supposed to be 0F tonight - I'll measure supply temps.
 
You don't believe in physics, thermodynamics.........only chemistry? Hahahhaha I'm kidding of course.

Heat pumps have a place. That place is NOT all by themselves in northern climates. Period. Dual source is the way to go. Shoulder seasons, no need to burn LP/oil on cool mornings or maintain the temp. Need a quick ramp up? Combustion, efficient combustion.
Yes, they are pushing the envelope up north but the technology is evolving. My backup is a propane boiler. In my case, it was that I wanted AC, and for a few bucks more I got a heat pump that carries the load during the shoulder season at less than half the cost of propane. ( no natural gas here).
 
There are more advanced heat pumps that work down to about -10F but the quality of the heat is meh
AKA The colder it gets the more lukewarm your “hot air gets” AKA large volumes of 72F heated air technically is heat but it’s not pleasant not to mention economically unless something dramatic changes in energy prices
heat pumps aren’t economical much below 20-30F

If the cost of a unit is basically the same as AC by all means get one as a furnace backup is always prudent but don’t expect to save lots of money
I encourage everyone to calculate their cost per GJ for types of energy available. Yes, heat pumps have a hard time competeting with natural gas, but compete well with oil and propane. The newer low temp heat pumps have been mentioned on this thread.
 
Modern heat pumps are 3-5x more efficient than gas, at minimum. This is definitely a situation where the "nothing has changed in the last 30 years" mindset sadly prevails. Heat pumps will, in essentially EVERY situation, save money on utility bills over gas unless you are at -30F or below for months on end.
 
There are more advanced heat pumps that work down to about -10F but the quality of the heat is meh
AKA The colder it gets the more lukewarm your “hot air gets” AKA large volumes of 72F heated air technically is heat but it’s not pleasant not to mention economically unless something dramatic changes in energy prices
heat pumps aren’t economical much below 20-30F

If the cost of a unit is basically the same as AC by all means get one as a furnace backup is always prudent but don’t expect to save lots of money

This isn't 1990. Your information is years out of date.
 
Here is my latest gas bill in regard to my past posts, we have natural gas hot air on the main level, heat pump second level that has 4 bedrooms, pretty much keep heat pump off all winter long except for any guests that might stay for a day or two because they close their bedroom doors at night, heat rises so we rely on main floor gas when no one here to heat the second floor simply by keeping the door open to the two "offices" my wife and I use. Our electric bill is under $100 a month this time of year. Here is this months natural gas bill which I think someone asked me to post over the winter since gas is cheap here?

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There are more advanced heat pumps that work down to about -10F but the quality of the heat is meh
AKA The colder it gets the more lukewarm your “hot air gets” AKA large volumes of 72F heated air technically is heat but it’s not pleasant not to mention economically unless something dramatic changes in energy prices
heat pumps aren’t economical much below 20-30F

If the cost of a unit is basically the same as AC by all means get one as a furnace backup is always prudent but don’t expect to save lots of money
that makes sense, i wonder what gas is inside. probably something eco, with high boil temp.

one of our 2 stage temp test systems, big compressors 3phase
r404a + r23 (fluoroform) not very eco friendly. (mandatory annual gas checks.)
heatpump in similar fashion could work in upper canada.
not many gases that are safe in case of leak.
 
Here is my latest gas bill in regard to my past posts, we have natural gas hot air on the main level, heat pump second level that has 4 bedrooms, pretty much keep heat pump off all winter long except for any guests that might stay for a day or two because they close their bedroom doors at night, heat rises so we rely on main floor gas when no one here to heat the second floor simply by keeping the door open to the two "offices" my wife and I use. Our electric bill is under $100 a month this time of year. Here is this months natural gas bill which I think someone asked me to post over the winter since gas is cheap here?

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My last oil fill was $560 and that is going to last about 5-6 weeks which were a relatively warm 5 weeks - highs in the 30's and low 40's and lows in the 20's. When we have a cold snap where highs are in the single digits and lows are negative it's more like 3-4 weeks per tank if we have a few of those. They typically only last 3-5 days and then it warms but sometimes they can happen several times in 6-8 week period.
 
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