I have a related situation, sorta. I know, from the time of the Big Chill, that my 20kw Generac won’t support both heat strips and much of anything else that draws power. I haven’t shut both strips off yet, and might just shut off one heat strip and see how that works. Of course, if we don’t lose power, all is good and I don’t have to do diddly.

But, I have to wonder how the heat pump will do with no heat strips in action at well below freezing. Please keep us informed on how your setup performs in the low temps. I can learn from you.

My bottom floor won't get above 70, top floor is where all the heat is going, it's like 75 with no heater on upstairs

I turned the heater on upstairs to 78 to see if it will bring up temp on the bottom floor

Most of my downstairs has 20 feet ceilings so all the heat up goes up

Great for summer

2 1/2-ton Trane heat pump for 1800 sq ft home running at 71 degrees. No heat strips in use yet.

Oops, just checked and my auxiliary heat came on for 1/2-hour last night and an hour so far today. Wife just asked about the fireplace, but I told her I'm too lazy right now.

The 2 1/2 - 3 Ton Trane heat pumps installed in TEXAS in the last 5 years are usually set up with 15 KW of resistance heat. That is over 60 amps @ 240 volts for resistance heat, plus another 15 amps for the heat pump. They are set up as three 5 KW strips, but the cheaper units turn all 15 kw on/off at the same time. Genny will not like that.

The unit will have two breakers for the inside unit ( Ours is a 60 amp and a 30 amp), plus the breaker for the compressor outside.
The 60 amp breaker has the blower motor, control board, and two 5KW heat strips. The smaller 30 amp breaker has ONLY one 5 KW heat strip.

An easy change to make your generator happy is to move the power source for the blower and control board from that 60 amp breaker in the air handler housing over to the 30 amp breaker in the air handler housing. You can then leave the 60 amp breaker turned OFF. Your AC and Heat will function normally. One bank of heat strips is still available to prevent cold air from blowing while the compressor is in defrost mode and to assist the heat pump when temps get down in the single digits. This is literally two wires to move, but call an electrician or HVAC guy if you are not confident you can be safe around AC power.

When your generator kicks on, the max HVAC load is limited to about 35 amps (20 amps resistance heat + 15 amps for the heat pump), instead of the 75 amps you would have with all 15 KW of resistance heat working.

If your heat pump fails, you can just flip that larger breaker back on and the HVAC has all 15 KM available.

Today's 10 degree weather and last year's 6 degree weather were just fine this way...but our house is well insulted. So far, the heat strips have only come on during defrost.

Good info! Mine's 12-13 yo. I'm considering having the gen hooked up to the main maybe later this year. Right now, I use a thru the wall plug in with no HVAC accessibility.

That’s real good information. Our HVAC guy told me to flip off one of the two breakers in case of having to run on the generator, but I didn’t know any intelligent questions to ask at the time. Thanks to your comments, I have a bit more insight.

24 degrees and tiny snow flakes here.

Or just stack your heat-pump Evap coil on a propane furnace, and throw those heat-strips in the garbage can;
add a $75 dual-fuel thermostat (auto-switches to propane furnace), and watch a 250-gal tank of propane last about 2 years!

Keeping things warm is all I have done today.

A wood stove is a much simpler way to add extra heat.

You have one of those little heat activated fans. My wife bought us one 2 years ago, thinking it would work with our fireplace. It doesn’t, but I took a hacksaw and cut a slot on the back side of the base. Now it’s a stable fit for the top of the guard screen on a Mr Buddy or a Big Buddy. I need a couple more now.

Gave one to a SiL and told him how to adapt it for a Buddy heater, but the glazed look in his eyes suggests he has no clue.

Got is as a Christmas gift from son and DIL a couple years ago. I think a second one would work great.

We are down at 12F this morning, still running on heat pump only and the house is holding my 66-degree setpoint running pretty much full-time. In other words, I found the balance point. If I wanted it warmer, it needs more heat. Now I am going to enable 5 kw of strip heat to see how high I can get the house. Remember that 5 kw of electric heat almost equals the output of a Big Buddy heater.

My system was originally set up the way NAK described, except with 4 x 5 kw. (1979 house with old leaky windows and substandard insulation throughout) When I upgraded to a heat pump, I disabled one of the 5 kw strips. Then I put a switch next to the T' stat to enable/disable the stage 2 heat control wire. With this switch on, it enables 5 kw only, unless I turn on the circuit breaker that serves the 2 x 5 kw strips.

Adding to my post above: Heat pump drawing 2 kw, plus one 5 kw heat strip brought the house up to 71F after about 90 minutes.

This cold weather stuff is complicated.

Had a new Daikin unit installed for the master bedroom last June. No problems cooling. In October it tripped the breaker when it got cold. 'Did it maybe once after that. I thought about calling the installers to check it last week, but figured they'd be swamped with people panicking. Last night it tripped every couple of hours. Comes right back on. I kept it above 60. It did it once more at about 9am and hasn't done it since.

They're supposed to be here between 4 and 6pm today. 'Already had an electrician check everything else. I have never understood HVAC stuff.

Ran out of propane around 3am, house got to 58. Company came out and installed a monitoring device so now they will automatically fill when we hit 20%. They also gave us $0.10 off per gallon for having the monitoring service which is a free service.

It took us 6 years to ask the right person at Northwest Propane to install monitor.

Good outcome. Heard it said that everything happens for a reason.