Hvac peoples

[dodgedifferent2]

So I have to replace my gas furnace in the near future. House currently has a natural gas furnace and no a/c.
Our politicians have a heat pump rebate thing at the moment. Basically they pay 50% of the cost. (My opinion its to create work for the hvac industry)
I have very little interest in the heat pump idea. However I do want a/c would the heat pump handle some cooling?

The area I live in is very humid in the summer. Enough that there are days you sweat sitting still.

Government rebates won't pay for furnace or a/c, so either way I am on the hook for that. Is it worth it to play the heat pump game? For future reasons I the price of oil skyrockets?

 

[H22A4]

What research/reading have you done on heat pumps? For something as important as how your house is heated/cooled, I’d suggest doing some research on your own first. From there ask away. Google is your friend; we are not talking about buying a crescent wrench.

Heating by oil is more and more of a liability as the years go on. Your insurance company is likely to start jacking up the premiums in future years if your place is heated by oil. Finding qualified people to service oil furnaces is only going to become more difficult too.

 

[QWKSLVR]

Look into heat pumps for sure. Most heat pumps if not all can heat and cool your home. I had one installed almost 6 years ago and don't regret it at all. Get a couple of quotes as prices can be all over the place. Good luck. Bobby

 

[4spdragtop]

We looked into same deal. Gov will cover $6500 towards heat pump(heats and cools). But you have to have backup heat. Our NG furnace is 14 years old and apparently beyond its half life. In order to qualify for the Grant, the furnace has to be on their "qualifying list" and of course ours isnt.
So in order to get "free" heat pump we would have to get a new NG furnace.
Our ac is over 35 years old...works but it's a huge hydro sucker.
Seriously contemplating what you are.
If your concern is ac, imo I wouldnt let it worry you. It's not like we live in Texas or Nevada.
Ps, same program will also help with new windows etc to improve efficiency of house.

 

[fishmens67]

I'd be concerned long term for any rebate the government gives.

 

[dodgedifferent2]

Yes, I have been researching this heat pump thing for the last 2 days.
Need real world experience not propaganda.

The air source heat pump is what I am looking at.

Major question is how much does it save?
It may save on natural gas but do I end up paying in electric bill?

My math has figured by saving $300 a year it would take 16 years to pay it off with the savings. Would I be replacing it before that time?

We have replaced the majority of the windows in this old farm house. Yes, I grew up in this house (family farm)

I filled the attic with insulation last year. We have one room to gut out and replace the horse hair/plaster, windows and put real insulation in the room. That is not in the budget.

 

[dusterbing the peace]

First off, yes, heat pumps provide cooling. It’s called a heat pump because it’s always pumping heat…from inside to outside (cooling) or outside to inside (heating). There’s a reversing valve that changes the direction the refrigerant flows.

Unfortunately you can run into capacity issues as it starts to get down past freezing outside as they were designed for more temperate climates (think SE Asia). So, you need to get a performance run for your climate to make sure it’ll provide the heat you need in the dead of winter otherwise you may not get the heat you want without supplementing with some other form of heat (electric heating coil, or other).

 

[67Dart273]

I spent roughly 12 years doing mostly service, but some installs, on gas/ LP, 80% and 90%+ furnaces, heat pumps and AC, and a few oil furnaces.

Back then, the default setup for an air heat pump was an electric furnace, which provided backup/ emergency heat for when the pump could not keep up, and for defrost, or for when the heat pump failed.

A ground coupled pump, if you can afford it needs no defrost cycle, and very likely does not need backup heat. But you SHOULD have something in case the system failed

I don't care how "improved" heat pump tech is claimed to be, I doubt that in higher lattitudes (I'm in the N end of Idaho, 49 North) that it's improved enough to provide much better heat at lower temps than they used to, UNLESS you can go ground coupled.

The big problem with mating a gas/ oil/ combustion furnace to a heat pump is, you really must, in that case, put the heat pump BEFORE (upstream) of the combustion furnace, which is the opposite of how you want an AC/ furnace situation

This is to help prevent radical overheat of the pump during defrost, which the thing is essentially reversed into AC mode. It also prevents overheating the pump if you need additional heat because OD temps are low enough to need additional heat which the pump cannot provide.

You CAN put the indoor coil before the furnace, but it is highly recommended, and required in some areas (code) for an AC coil to be AFTER the furnace, to prevent heat exchanger rust/ corrosion problems.

Frankly I think the big hype over heat pumps by Bidumb and Trewdope is just that--hype and lies.

On a side not, it is not just low temps which establish the need for additional backup heat. It really is a combo of temp and humidity, known as enthalpy. Low temp dry air has very little heat value, and will cause less defrost problems, but will result in less pump heat output. Warmer, wetter OD, air, even though it has more heat content and will allow the pump to output more heat, will cause more icing and cause more defrost problems.

Deep snow areas MUST have the OD unit mounted on a stand to keep them up out of the snow, and high winds/ blowing snow/ sleet and low temp rain can also cause problems with outdoor coil icing.

 

[Demonic]

I don’t do residential HVAC, but friends and co workers report that the 410a units - heat pumps - are a bit better than R22 as the vapor pressure is higher.

 

[dkamp]

HVAC Service guys always told me, that as a furnace they turn into an Electric Heater when the Temperature gets around 35-38 degrees and lower. There just is no heat to pull from a cold day. so there is no heat pump activity occurring, just an old school expensive electric furnace.

 

[dodgedifferent2]

Lennox el22xpv is what I was quoted for

 

[4spdragtop]

No need for concern, this "program" comes and goes. I've done it twice before, got a free furnace and free windows.

I'd be concerned long term for any rebate the government gives.

 

[Phreakish]

I've got a heat pump in my place. 3 floors, over 4k Sq ft. It's a bargain unit sized for the upper two floors (too small) and there are minimal registers in the basement. It keeps the place no lower than 65 when we hit 0, but really wants to burn propane (no NG in my neighborhood) once it's under 20F. I have way too much glass for as far north as we are, but I didn't design the place and bought it for the land more than the house. Anyway, high ceilings, drafts (too many doors too), and lots of glass means heat loss so the pump always runs. If you oversize to get more heat, then typically it will over cool and that can actually cause damage.. So it is what it is. A good heat pump install relies on above average insulation if you're dealing with low outdoor temps. Heat pumps are primarily good for cooling. They heat as a benefit, not necessarily by virtue of their design.

The coefficient of performance or COP is a measure of efficiency. A COP of 1 is 100% efficient. A good unit will run 1.2-1.8 in its design range which they tend to target unrealistic envelopes like 40-165F. The reason they can go over 100% efficiency has to do with what happens when you compress a gas to a liquid or evaporate it back to a gas and which side of the conditioned envelope the heat exchanger is on.

Fiesr thing I'd be doing is looking at your last couple years of gas bills and try to determine how many btu you're using in a season. Trying to figure out "number of heating days" can help you determine a average btu per day based on weather. From that you can do some math to compare btu to cubic feet of gas to kWh and COP to determine if a pump would benefit you or not. Being 120% efficient is awesome, but not if gas is 40% cheaper per unit energy than electricity.

For example, I did all the math on my place once and found that a kWh is cheaper than a comparable measure of propane, so it makes sense for me to use as much electricity as possible. If I had NG, it would be the opposite. NG came out something like 20% cheaper per energy unit, but since I'm miles away and across the river from a hookup it's moot. Then again, a furnace wouldn't cool my place and in the summer we run the ac pretty consistent for a month or so, and it makes a world of difference.

There are worksheets out there on hvac forums to help with the math on all this stuff. A good hvac company would do the work for you and explain it all. If they can't or won't, then they're not worth working with. Their job is to get the customer what will work best. If you go with the cheapest install, you're bound to regret it.

Also keep in mind that if you're in an older home that was never air conditioned before it may be unwise to install one without significant remodeling. If you get interior surfaces of your home cool enough to go below the dew point in summer, you're bound to get condensation in walls and cavities and you'll have mold and rot rather quickly. Again, a quality installer can help you through these kinds of considerations.

 

[72Dinger]

Conventional air to air heat pump is not effective below about 40F but works efficiently in the range 40-70F. It is just an air conditioning system that also works in reverse.

I would say its worth considering, but strongly suggest you have LP or natural gas as an auxiliary heat source. Heat pumps typically come with an electric heat strip installed inside the air handler that functions as the auxiliary heat - in mild climates this conditions a home in winter at reasonable cost, but gets very expensive in more extreme climates or unseasonably cold winters. All depending on your local price per kW/hr of course.

Building on what Phreakish wrote, you do need to ensure older homes are "tight" - good insulation, good seals on doors and windows, to avoid issues installing AC in homes that previously didn't have it.

And just a tip on the equipment...if you purchased a heat pump with gas furnace as your auxiliary heat, you would be provided with a new furnace not unlike your own, and a case coil to sit on top. The case coil is the same, whether you have a conventional outdoor ac unit, or heat pump. It would be fitted with a different metering device for sure. All that said, you could technically purchase a heat pump, and with some adjustments to the controls, operate it exclusively as a conventional ac unit, cooling only, and rely on your furnace 100% for heat.

 

[mcodecuda]

We run a heat pump with a propane furnace as back up heat. We also have a stove and a tankless water heater that runs on propan. Our monthly utility bill for electricity and propane is about $120 a month and we couldn’t be happier with how everything works.

 

[4spdragtop]

Some real good info here, thanks guys.
Stipulation with the grant is you having backup. My concern would have been using the heat pump for 90% of heating and the hydro bill sky rocketing, but if we can use the backup heat(NG furnace) without any downside, it.kinda makes it a win/win.
Thanks

I've got a heat pump in my place. 3 floors, over 4k Sq ft. It's a bargain unit sized for the upper two floors (too small) and there are minimal registers in the basement. It keeps the place no lower than 65 when we hit 0, but really wants to burn propane (no NG in my neighborhood) once it's under 20F. I have way too much glass for as far north as we are, but I didn't design the place and bought it for the land more than the house. Anyway, high ceilings, drafts (too many doors too), and lots of glass means heat loss so the pump always runs. If you oversize to get more heat, then typically it will over cool and that can actually cause damage.. So it is what it is. A good heat pump install relies on above average insulation if you're dealing with low outdoor temps. Heat pumps are primarily good for cooling. They heat as a benefit, not necessarily by virtue of their design.

The coefficient of performance or COP is a measure of efficiency. A COP of 1 is 100% efficient. A good unit will run 1.2-1.8 in its design range which they tend to target unrealistic envelopes like 40-165F. The reason they can go over 100% efficiency has to do with what happens when you compress a gas to a liquid or evaporate it back to a gas and which side of the conditioned envelope the heat exchanger is on.

Fiesr thing I'd be doing is looking at your last couple years of gas bills and try to determine how many btu you're using in a season. Trying to figure out "number of heating days" can help you determine a average btu per day based on weather. From that you can do some math to compare btu to cubic feet of gas to kWh and COP to determine if a pump would benefit you or not. Being 120% efficient is awesome, but not if gas is 40% cheaper per unit energy than electricity.

For example, I did all the math on my place once and found that a kWh is cheaper than a comparable measure of propane, so it makes sense for me to use as much electricity as possible. If I had NG, it would be the opposite. NG came out something like 20% cheaper per energy unit, but since I'm miles away and across the river from a hookup it's moot. Then again, a furnace wouldn't cool my place and in the summer we run the ac pretty consistent for a month or so, and it makes a world of difference.

There are worksheets out there on hvac forums to help with the math on all this stuff. A good hvac company would do the work for you and explain it all. If they can't or won't, then they're not worth working with. Their job is to get the customer what will work best. If you go with the cheapest install, you're bound to regret it.

Also keep in mind that if you're in an older home that was never air conditioned before it may be unwise to install one without significant remodeling. If you get interior surfaces of your home cool enough to go below the dew point in summer, you're bound to get condensation in walls and cavities and you'll have mold and rot rather quickly. Again, a quality installer can help you through these kinds of considerations.

Conventional air to air heat pump is not effective below about 40F but works efficiently in the range 40-70F. It is just an air conditioning system that also works in reverse.

I would say its worth considering, but strongly suggest you have LP or natural gas as an auxiliary heat source. Heat pumps typically come with an electric heat strip installed inside the air handler that functions as the auxiliary heat - in mild climates this conditions a home in winter at reasonable cost, but gets very expensive in more extreme climates or unseasonably cold winters. All depending on your local price per kW/hr of course.

Building on what Phreakish wrote, you do need to ensure older homes are "tight" - good insulation, good seals on doors and windows, to avoid issues installing AC in homes that previously didn't have it.

And just a tip on the equipment...if you purchased a heat pump with gas furnace as your auxiliary heat, you would be provided with a new furnace not unlike your own, and a case coil to sit on top. The case coil is the same, whether you have a conventional outdoor ac unit, or heat pump. It would be fitted with a different metering device for sure. All that said, you could technically purchase a heat pump, and with some adjustments to the controls, operate it exclusively as a conventional ac unit, cooling only, and rely on your furnace 100% for heat.

 

[ProjectBazza]

Lots of good info here, but some seriously out of date, and incorrect, info as well.

The good (info): Yes, pay attention to COP on any system you are considering, and comparing kWH (electrical service) costs against BTUHs (gas/propane) is always a wise move. But more importantly: Run the numbers and do the math! You're going to be living with the with this equipment for 15-20 years, so you need to make the right move for you. Does the math work? Does this make sense?

Again: Run the damn numbers! If you don't know how, or where to get started, contact your utility company, as they will no doubt have calculators, or links to non-partisan sites that can help you. DO NOT RELY ON A SALESPERSON FOR THIS!

Second, the rebates are just that: Rebates. They're not political, they're nothing to get nervous or paranoid about, and Big Brother isn't doing this to try to "control" or "manipulate" you. Leave that paranoid **** to the politcos and move on.

The bad (info): Current air source heatpumps are orders of magnitude better than they were as recently as 10-15 years ago, so pay no attention to the "no good below (a certain temp)" BS. Yes, you will need back-up/"emergency" heat of some sort with an air source HP, but....

There's a term called a "balance point", and it's simply the OA temperature at which a system will need to switch from HP operation to back-up/"emergency" heat for "comfort heating", and this temperature will differ for every building and configuration. On older, less efficient systems this temperature was often as high as 25-30* F, but some currently offered high efficiency HP systems can generate usable heat as low as 0* F (and minisplits can go to -22* F and even lower). Exactly how this occurs would take-up too much time and space to explain here, but if you can wrap your head around the ideas of -30* dewpoints, or boiling temps of -40*, that's a good start.

Regardless, if you go the HP route your balance point will be based on the construction of your home, the efficiency of the system you purchase, and perhaps most importantly, your own comfort. Also, it's a calculated value, and while it's a good starting point, it's not carved in stone and can be changed, as what works for others may not work for you.

In my opinion: Contact your utility provider, run the numbers, and get the most energy efficient system you can comfortably afford.

Jim

 

[toolmanmike]

Lots of good info here, but some seriously out of date, and incorrect, info as well.

The good (info): Yes, pay attention to COP on any system you are considering, and comparing kWH (electrical service) costs against BTUHs (gas/propane) is always a wise move. But more importantly: Run the numbers and do the math! You're going to be living with the with this equipment for 15-20 years, so you need to make the right move for you. Does the math work? Does this make sense?

Again: Run the damn numbers! If you don't know how, or where to get started, contact your utility company, as they will no doubt have calculators, or links to non-partisan sites that can help you. DO NOT RELY ON A SALESPERSON FOR THIS!

Second, the rebates are just that: Rebates. They're not political, they're nothing to get nervous or paranoid about, and Big Brother isn't doing this to try to "control" or "manipulate" you. Leave that paranoid **** to the politcos and move on.

The bad (info): Current air source heatpumps are orders of magnitude better than they were as recently as 10-15 years ago, so pay no attention to the "no good below (a certain temp)" BS. Yes, you will need back-up/"emergency" heat of some sort with an air source HP, but....

There's a term called a "balance point", and it's simply the OA temperature at which a system will need to switch from HP operation to back-up/"emergency" heat for "comfort heating", and this temperature will differ for every building and configuration. On older, less efficient systems this temperature was often as high as 25-30* F, but some currently offered high efficiency HP systems can generate usable heat as low as 0* F (and minisplits can go to -22* F and even lower). Exactly how this occurs would take-up too much time and space to explain here, but if you can wrap your head around the ideas of -30* dewpoints, or boiling temps of -40*, that's a good start.

Regardless, if you go the HP route your balance point will be based on the construction of your home, the efficiency of the system you purchase, and perhaps most importantly, your own comfort. Also, it's a calculated value, and while it's a good starting point, it's not carved in stone and can be changed, as what works for others may not work for you.

In my opinion: Contact your utility provider, run the numbers, and get the most energy efficient system you can comfortably afford.

Jim

Well said. Yes, contact your utility provider before you contact your contractor. When we needed to replace our old cast iron NG fired boiler, I did some homework, got online and downloaded a Manual J load calculator. With all the information loaded I was able to properly size the unit which was going to be a Weil McClain Ultra (suitcase boiler) I didn't want to pull the trigger on one too small or over pay for one too big. It was funny because the salesman at the PHC contractor wanted a copy of the report and sure enough it was the right sized unit for the job. Knock on wood, it has been flawless for the last many years and easily keeps up when the temps here dip into the -20° range for a week. BTW, it is 94.1 efficient and my Nat. gas bill dropped $100 a month after installing it.

 

[Phreakish]

Lots of good info here, but some seriously out of date, and incorrect, info as well.

The good (info): Yes, pay attention to COP on any system you are considering, and comparing kWH (electrical service) costs against BTUHs (gas/propane) is always a wise move. But more importantly: Run the numbers and do the math! You're going to be living with the with this equipment for 15-20 years, so you need to make the right move for you. Does the math work? Does this make sense?

Again: Run the damn numbers! If you don't know how, or where to get started, contact your utility company, as they will no doubt have calculators, or links to non-partisan sites that can help you. DO NOT RELY ON A SALESPERSON FOR THIS!

Second, the rebates are just that: Rebates. They're not political, they're nothing to get nervous or paranoid about, and Big Brother isn't doing this to try to "control" or "manipulate" you. Leave that paranoid **** to the politcos and move on.

The bad (info): Current air source heatpumps are orders of magnitude better than they were as recently as 10-15 years ago, so pay no attention to the "no good below (a certain temp)" BS. Yes, you will need back-up/"emergency" heat of some sort with an air source HP, but....

There's a term called a "balance point", and it's simply the OA temperature at which a system will need to switch from HP operation to back-up/"emergency" heat for "comfort heating", and this temperature will differ for every building and configuration. On older, less efficient systems this temperature was often as high as 25-30* F, but some currently offered high efficiency HP systems can generate usable heat as low as 0* F (and minisplits can go to -22* F and even lower). Exactly how this occurs would take-up too much time and space to explain here, but if you can wrap your head around the ideas of -30* dewpoints, or boiling temps of -40*, that's a good start.

Regardless, if you go the HP route your balance point will be based on the construction of your home, the efficiency of the system you purchase, and perhaps most importantly, your own comfort. Also, it's a calculated value, and while it's a good starting point, it's not carved in stone and can be changed, as what works for others may not work for you.

In my opinion: Contact your utility provider, run the numbers, and get the most energy efficient system you can comfortably afford.

Jim

Regarding balance point BS: I have one of the super whiz-bang maximum efficiency mini-split units installed in our recently renovated offices. We're talking ~500 sq ft (two small offices).
Worksheet says it should outperform resistive heat down to -10F, and paperwork says will operate to -40. We've found the system won't even kick on at 5F and at 10F it'll run but couldn't get our office above 50F, so I'd take the published numbers with a grain of salt as well. In our case, the cause seems to be our flat roof and the fascia wall that shades the unit. The sun doesn't get high enough in the winter to get the unit into full sun (doesn't help the city built an ugly garage across the road that blocks the sun for 60% of the year), but once it gets any kind of warmth that's when it will run - but won't produce much heat.
I mention this because getting the full operating envelope of any system means ensuring it's installed as intended and knowing what kind of limitations you'll run into if you have to compromise on the install due to other factors.

 

[Phreakish]

Some real good info here, thanks guys.
Stipulation with the grant is you having backup. My concern would have been using the heat pump for 90% of heating and the hydro bill sky rocketing, but if we can use the backup heat(NG furnace) without any downside, it.kinda makes it a win/win.
Thanks

Running the numbers should be able to tell you what your hydro bill will be around, or at least get you started. A good installer should be able to do this kind of thing pretty quick and you should be able to then look up the terms or ask around here to find out how accurate it might be.

Where most folks run into issues is that they're used to NG heat feeling warm, and HP heat really doesn't. Gas furnaces typically have register temps above 100F, where a heat pump might push air at or several degrees below the thermostat setting with a maximum typically around 80F (this varies wildly depending on the install, unit, and tech!).
Some folks wind up turning up the stat enough to get there that they drown out the energy savings. In most cases though, the effiency is high enough that the cost is typically no worse and often still much better. Plus the added upside of air conditioning in the summer.

But again, working the numbers will tell you what to expect.

Keeping a gas emergency heat option is a good idea for preparedness. You never know if a windstorm or other issue might knock power out for extended periods, or your gas utility runs into a problem that causes an interruption in service. Having multiple heating options then becomes extremely important IMO.

 

[ProjectBazza]

Where most folks run into issues is that they're used to NG heat feeling warm, and HP heat really doesn't. Gas furnaces typically have register temps above 100F, where a heat pump might push air at or several degrees below the thermostat setting with a maximum typically around 80F (this varies wildly depending on the install, unit, and tech!).
Some folks wind up turning up the stat enough to get there that they drown out the energy savings. In most cases though, the effiency is high enough that the cost is typically no worse and often still much better. Plus the added upside of air conditioning in the summer.

I think this touches on one of the issues (and maybe misunderstandings) of current heatpumps. Many people have gotten used to programmable setback 'stats, and then relying on Morning Warm-up to get the space up to temp during Occupied Modes (I'm using Commercial buildings terms here, but the idea is the same).

I do this at home as well.

Much like the cooler Discharge Air temps that condensing furnaces put out versus what we all grew-up with, the newer air source HPs don't supply that nice, warm (110* or so ) air that everyone seems to want still. Efficiency just means the Manufacturer is grabbing every last bit of BTU/H out of their equipment as possible, which, in many cases, means lower Discharge Air temps.

We service a couple recently renovated "green" buildings here in Minne-a-no-place with rooftop HPs, and there was a nasty learning curve with the tenants/owners at first, as everyone is used to using standard Night Setback & Morning Warm-up routines in the BMS system. And why not? It saves money, right?

But as you pointed out, and as I mentioned, HPs don't generate that nice 110* air, so the MWU schedules didn't work, and because the end users were cold every morning, they cranked-up up the stats (more is better, right?) in an effort to get the units running hotter, faster. Guess what happens when stats are turned-up too high, and people forget about them?

Anywhoooo....With the building owner's permission our Service Techs removed the Night Setback and MWU schedules from the BMS schedules over the summer, and they're letting the buildings settle out at a constant, 24/7 temp, as the Consulting Engineers feel that not only will this ease complaints, but also will ultimately save some $$$. So far we've had about 10-12 nights where's it's gotten down to 20* or so, and as far as I've heard (knock on wood), no complaints or Service Calls!

We'll see.

 

[Phreakish]

I think this touches on one of the issues (and maybe misunderstandings) of current heatpumps. Many people have gotten used to programmable setback 'stats, and then relying on Morning Warm-up to get the space up to temp during Occupied Modes (I'm using Commercial buildings terms here, but the idea is the same).

I do this at home as well.

Much like the cooler Discharge Air temps that condensing furnaces put out versus what we all grew-up with, the newer air source HPs don't supply that nice, warm (110* or so ) air that everyone seems to want still. Efficiency just means the Manufacturer is grabbing every last bit of BTU/H out of their equipment as possible, which, in many cases, means lower Discharge Air temps.

We service a couple recently renovated "green" buildings here in Minne-a-no-place with rooftop HPs, and there was a nasty learning curve with the tenants/owners at first, as everyone is used to using standard Night Setback & Morning Warm-up roputines in the BMS system. And why not? It saves money, right?

But as you pointed out, and as I mentioned, HPs don't generate that nice 110* air, so the MWU schedules didn't work, and because the end users were cold every morning, they cranked-up up the stats (more is better, right?) in an effort to get the units running hotter, faster. Guess what happens when stats are turned-up too high, and people forget about them?

Anywhoooo....With the building owner's permission our Service Techs removed the Night Setback and MWU schedules from the BMS schedules over the summer, and they're letting the buildings settle out at a constant, 24/7 temp, as the Consulting Engineers feel that not only will this ease complaints, but also will ultimately save some $$$. So far we've had about 10-12 nights where's it's gotten down to 20* or so, and as far as I've heard (knock on wood), no complaints or Service Calls!

We'll see.

What's funny is that I'm pretty sure our office situation would actually work better if we left our doors open to the shop (which is heated to 60F with a huge gas furnace and blower) and let the HP just run all night. I'm pretty sure the lockout under 10F is because the unit is cold, no air ciruclation on the flat roof and it's been in shade for 18 hrs when it tries to kick on in the morning. The boss insists on turning off the split each night which I can't imagine helps it run when the temps plummet, but since it takes all of about 4 minutes to heat our tiny spaces it probably does save some electricity most nights. When it gets below 10F, we just anticipate it and open our doors to the heated shop to take the chill off, then by 11am the pump typically kicks on and it's back to normal.

The tech behind heat pumps is awesome, but to get the most out of them they need to be used in a certain way and the building should be designed to match. Just like our cars, poor combos perform poorly.

 

[mcodecuda]

We run a heat pump with a propane furnace as back up heat. We also have a stove and a tankless water heater that runs on propan. Our monthly utility bill for electricity and propane is about $120 a month and we couldn’t be happier with how everything works.

I need to clarify something. The initial signal for heat is sent to the heat pump. If the thermostat senses that the temperature doesn’t raise a certain number of degrees in a certain amount of time it shuts the heat pump down and starts the gas/propane furnace.

 

[67Dart273]

I don't believe the BS balance point numbers either, and REMEMBER THIS. There is a huge possibility that a heat pump will fail something expensive (like a compressor) compared to typical gas/ LP heat. The economy/ efficiency numbers fly right out the open window when that happens. Payback, is a *****.

The other issue, which has not happened yet, is what is going to happen with electrical rates once the far blues keep pushing this green/ electric agenda?

 

[72Dinger]

I don't believe the BS balance point numbers either, and REMEMBER THIS. There is a huge possibility that a heat pump will fail something expensive (like a compressor) compared to typical gas/ LP heat. The economy/ efficiency numbers fly right out the open window when that happens. Payback, is a *****.

I agree with this premise. My previous point about effectiveness below 40F is based on my preference for low SEER units. My experience is that more expensive high efficiency units necessitate more expensive repairs, wiping out the energy savings in the long run.

I'm in a much milder climate than OP and I would say that those with working knowledge in similar climates to OP will have a more relevant opinion than my own.