extreme cold

[Number_35]

4 degrees here in the mid west. Question for those of you who have a heat pump and are experiencing these unusually cold temps, how is it keeping up? Have your auxilary heat strips kicked in, or are you using another method to get supplement heat?

Heard back from my friend. His system switches over to electric (resistance) heat around -20°C (-4°F).

He has a good rooftop solar array which helps offset the cost.

Our electricity is cheap here - about C10¢/kW-h.

His house is well-insulated, so the occasional pure electric heating is not bad financially.

 

[Dave Hess]

What's extreme cold? Temps are forecast to be in the teens here in North AL tonight, and hopefully that's the last of what we consider extreme cold until next year. We'll be mowing grass here this time next month.

I was mowing grass this past weekend. It’s in the 80’s and breezy.

 

[I<3oil]

Anyone else in the middle of the arctic blast? NWS reports -20F, wind chill of -38F, in my town this morning. It's been this way the past couple mornings, and supposed to be the same tonight, then we'll see a warming trend. Highs in the 50s this weekend!

View attachment 264256

yup, getting down to -16 to -18* tonight with wind chill down to -25 to -30. We're just doing a 2 hr delay tomorrow for school start lol

 

[Wrenchturner44]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

 

[Snagglefoot]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

Using actual data from modern cold weather heats pumps, including my neighbour down the street, such a heat pump can run at 1 degree F before it needs to switch to heating strips.

 

[Number_35]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

Lots of stuff to consider ...

What would be the cost of upgrading to a high-efficiency furnace (c. 96%) vs. his present mid-grade? I went this route when our old furnace died about two years ago. Opted for the DC motor, which I suspect has saved us more in electricity than the high-efficiency gas part.

I would compare that cost to the capital cost of a solar installation.

What does he pay per incremental kW-h of electricity?

How well is the house insulated? Here they recommend upgrading installation first.

How big is the proposed solar array? My friend with rooftop solar sent me a screenshot of his system performance around 1:30 p.m., about an hour past solar noon.

His system was making 3.512 kW of power at that moment, so 64% of the installed capacity of 5.46 kW. To that point in the day it had produced 8.73 kW-h of energy.

Bear in mind that we're just short of 50° latitude; KC is way south, and would do a lot better.

 

[OVERKILL]

Lots of stuff to consider ...

What would be the cost of upgrading to a high-efficiency furnace (c. 96%) vs. his present mid-grade? I went this route when our old furnace died about two years ago. Opted for the DC motor, which I suspect has saved us more in electricity than the high-efficiency gas part.

I would compare that cost to the capital cost of a solar installation.

What does he pay per incremental kW-h of electricity?

How well is the house insulated? Here they recommend upgrading installation first.

How big is the proposed solar array? My friend with rooftop solar sent me a screenshot of his system performance around 1:30 p.m., about an hour past solar noon.

His system was making 3.512 kW of power at that moment, so 64% of the installed capacity of 5.46 kW. To that point in the day it had produced 8.73 kW-h of energy.

Bear in mind that we're just short of 50° latitude; KC is way south, and would do a lot better.

Yup, if electricity is cheap, the solar array is going to take a LONG time to pay back.

 

[Snagglefoot]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

For completeness, how much is he paying for grid electricity per kwhr and how much is he paying for natural gas. Just the amount for volume and not including flat rate charges. Also, how much does the electric company pay for his excess power. The heat pump will probably not be running much during typical solar hours so he will need a good price for the amount sold back.

 

[BrianF]

We are just at the tail end of the cold. Had about two weeks of nothing warmer than -20c ambient at the warmest. Last few days were well into the -30s with upwards of -50 windchills. My poor old mule of a Trailblazer has been daily driving in all this cold. She sure uses the fuel though.

If the wind is minimal and sun out, it's doable. Heck, I put many miles on the sleds. Even the kids were out playing and sledding.

 

[Sedin26]

I have friends in Saskatchewan and Ontario with heat pumps and all are very happy with them. Both of the Saskatchewan friends have Fujitsu heat pumps and say the backup heat strips aren’t needed until it gets down to about -30c (-22f). I believe the COP is around 1.8 at those temps and goes up from there.

The ones in Ontario have a Carrier unit and it uses aux heat around -27c or so.

The actual amount of time it is below -30c anywhere in Canada is fairly minimal until you get further north. Saskatoon, for instance is below -30c 10 days per year, on average, but that doesn’t mean it’s below -30 for the entirety of those 10 days.

A common problem with heat pumps is over-sizing them. It is not necessary or helpful to size them based on the very coldest temps that are seen only a few times per year. Rather, you want them running more often but at a lower level.

As for myself, I live where it generally gets down to freezing at the coldest. The worst I’ve seen here over 35 years is -10c (14f). I have a 17 year old central heat pump and it only goes to Aux at around freezing or below. Even down to -10 it’ll often work in heat pump mode as long as we don’t try to raise the temps more than a degree at a time.

 

[Snagglefoot]

I have heard about the mini-splits go to those really cold temps like -22 F but the central units I’ve come across did not seem to make it quite so low. I drop in for coffee at buddy’s just to see his central heat pump running when it’s 1 deg F.

I took in a webinar on grants for heat pump installations in BC. There are income limited grants for up to $16,000 CDN for a professional installation, however, those of us with existing older heat pumps are not eligible, even though they are only capable of running down to freezing temps and there are at least 60 days when it’s below freezing. The powers to be did say that may be coming.

 

[MrGraybeard]

The literature on my Mitsubishi unit claims it's good to -5. I have it running right now at 5 above, it's doing fine.
It got down to -14 the other night; a wood-pellet fired central heating unit is my alternate heat source. I often run both in the morning.

It's supposed to be in the 40s here on Monday.

 

[Wrenchturner44]

Lots of stuff to consider ...

What would be the cost of upgrading to a high-efficiency furnace (c. 96%) vs. his present mid-grade? I went this route when our old furnace died about two years ago. Opted for the DC motor, which I suspect has saved us more in electricity than the high-efficiency gas part.

I would compare that cost to the capital cost of a solar installation.

What does he pay per incremental kW-h of electricity?

How well is the house insulated? Here they recommend upgrading installation first.

How big is the proposed solar array? My friend with rooftop solar sent me a screenshot of his system performance around 1:30 p.m., about an hour past solar noon.

His system was making 3.512 kW of power at that moment, so 64% of the installed capacity of 5.46 kW. To that point in the day it had produced 8.73 kW-h of energy.

Bear in mind that we're just short of 50° latitude; KC is way south, and would do a lot better.

All good questions that I need him to tell me answers to. I agree, my thought is that a 96% efficient gas furnace would be a better replacement. My suspicion is that there is some environmental sway going on here as his girlfriend feels the need to rid their house of natural gas.

 

[eljefino]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

High-efficiency furnaces can be high-maintenance. I'd keep the furnace you have as a backup; they work well on smaller generators during power outages and what else are you going to do with the space?

2 is 1, 1 is none.

Using 90% less gas but having the pipe run to your house still gives you options, I wouldn't cut anything out.

 

[Nukeman7]

All good questions that I need him to tell me answers to. I agree, my thought is that a 96% efficient gas furnace would be a better replacement. My suspicion is that there is some environmental sway going on here as his girlfriend feels the need to rid their house of natural gas.

That is a very, very poor reason to make a decision on one of the most costly items in home maintenance. Not being chauvinistic here, but I don't know of a single woman who has been happy with switching from a gas furnace to a heat pump due to the change in perceived comfort factor. The lower delta in output air temperature from a heat pump is noticeable by anyone who has switched over from a gas furnace and feels "drafty" in comparison.

As such, I have another suggestion that will keep his options open. I have a Trane 96.8% efficient gas furnace/heat pump dual fuel hybrid unit. It is currently set to run in heat pump mode down to 40 degrees F and then automatically switch over to the high efficiency gas furnace below 40F. I can manually lock out the heat pump mode and run the gas furnace exclusively at any temperature by pushing a button on the thermostat. I had the unit installed 10 years ago and at that time, the cost was $800 more than the Trane 96.8% efficient gas only furnace.

If he needs environmental virtue signalling to please his girlfriend, tell him to get an EV!

 

[Snagglefoot]

All good questions that I need him to tell me answers to. I agree, my thought is that a 96% efficient gas furnace would be a better replacement. My suspicion is that there is some environmental sway going on here as his girlfriend feels the need to rid their house of natural gas.

I see. The same thing goes on in BC. The government wants people off natural gas due to environmental reasons even though they are willing to admit natural gas is not so bad. The thing that usually makes the heat pump installation happen is Air Conditioning. The Heat Pump is essentially an air conditioner run backwards.

 

[Wrenchturner44]

That is a very, very poor reason to make a decision on one of the most costly items in home maintenance. Not being chauvinistic here, but I don't know of a single woman who has been happy with switching from a gas furnace to a heat pump due to the change in perceived comfort factor. The lower delta in output air temperature from a heat pump is noticeable by anyone who has switched over from a gas furnace and feels "drafty" in comparison.

As such, I have another suggestion that will keep his options open. I have a Trane 96.8% efficient gas furnace/heat pump dual fuel hybrid unit. It is currently set to run in heat pump mode down to 40 degrees F and then automatically switch over to the high efficiency gas furnace below 40F. I can manually lock out the heat pump mode and run the gas furnace exclusively at any temperature by pushing a button on the thermostat. I had the unit installed 10 years ago and at that time, the cost was $800 more than the Trane 96.8% efficient gas only furnace.

If he needs environmental virtue signalling to please his girlfriend, tell him to get an EV!

Agree with your POV 120%. The other interesting factor here is the house is owned by my son. The GF has no financial interest or equity sadly.....ughhh

 

[Nukeman7]

I see. The same thing goes on in BC. The government wants people off natural gas due to environmental reasons even though they are willing to admit natural gas is not so bad. The thing that usually makes the heat pump installation happen is Air Conditioning. The Heat Pump is essentially an air conditioner run backwards.

This is also a concern for longevity of the HVAC system. Since the compressor runs in the winter to heat and the summer to cool, you are theoretically doubling the "wear" on the compressor unit and associated components in the outside condenser unit when compared to a central A/C unit paired with a gas furnace for heat.

 

[nickaluch]

My thanks to those of you whom responded about my question regarding heat strip operation with heat pumps. My son lives in the KC area. He is getting solar installed on his house. He currently has a forced air gas furnace 82% efficient. He is planning to replace it when it dies with a heat pump and what I am assuming will be conventional emergency resistance heat strips. He believes that the solar will off set his additional energy load that may be needed to heat his house when he transitions to the new HVAC.

Personally, I have my doubts, knowing how cold most midwest winters can be.

I would love to hear feedback from any of you regarding your thoughts on his HVAC transition plan.

If I was junior I would do it now and just keep the old furnace installed for backup or those really long cold spells or emergency

 

[Wrenchturner44]

This is also a concern for longevity of the HVAC system. Since the compressor runs in the winter to heat and the summer to cool, you are theoretically doubling the "wear" on the compressor unit and associated components in the outside condenser unit when compared to a central A/C unit paired with a gas furnace for heat.

Agreed!