My HVAC system is nearing 20 years old. I was already thinking about replacing it soon, and the AC broke down in the middle of that recent heat wave in California was a wake up call that it should probably be replaced sooner rather than later. I currently have what I believe is called a “package system”; the central AC and gas furnace are packaged together as one unit, as opposed to a separate air conditioner and furnace.
I am thinking about electric heat pump instead of another gas furnace. I am in the Sacramento area, where the summers are very hot and dry, and the winters are fairly mild, so heat is less of a concern than cooling. And I keep the thermostat fairly low in the winter anyway. And the fact that the local utility company is offering a $3000 rebate for switching from gas to a heat pump makes that option rather attractive (although I believe it has to be a “multi stage” heat pump to qualify). And IIRC the Inflation Reduction Act offers some tax credits if I wait until next year, as well. So maybe I’ll do it in January.
The only real advantage I see with gas it that it’s what I have currently, so it’s sort of the path of least resistance, so to speak.
You already have electricity also, right? So why not use that for heat? You can still use gas for your stove, outdoor grill, water heater, etc. I’d go for the heat pump because of the A/C.
Heat pumps are fine down to about 40 F. When the temp goes lower than that, they have auxiliary heat strips that come on. Then the cost of heating jumps up.
There are systems available that use a dual fuel system- electric heat pump down to a certain temperature, then gas heat kicks in. They might be worth looking into.
I have a heat pump and it’s efficient as all get out, but it’s a cold heat, by which I mean the air outlet temperature at the ducts is pretty cool, around 25 degrees warmer than the inlet temperature, so if you have your thermostat at 68 deg F the air from the ducts is only 93 deg F. With a gas furnace you can get a 70 degree delta T, so under the same conditions the outlet air temperature would be 138 degrees.
That 93 degree air from the heat pump does a fine job of maintaining the set temperature, but by the time some mixing and cooling take place on the way to the people inhabiting the room, it may be only 75 degrees when it gets there which; while on paper is warm, actually feels like a cool breeze.
I find with a gas furnace I can run the thermostat several degrees lower than with a heat pump . The heat pump’s greater efficiency still makes it cheaper to run but that’s something to consider.
I take it that means if the room is cold you won’t be able to warm it up as quickly with a heat pump as with gas. During the winter I have the thermostat programmed to a cooler temperature at night than during the day, because 1) I like it cooler when I’m sleeping, and 2) I figure I’m conserving energy that way. Then I have it programmed to go back to the daytime temperature 30 minutes before I wake up, so it’s cool for most of the night, but nice and toasty when I get up. So I take it a heat pump wouldn’t be able to warm up the house as quickly?
Because a heat pump transfers heat from the outside environment to the indoors or has an efficiency greater than 100%, you can get 6 or 7 joules of heat for each joule of electricity.
Heat pumps also have secondary heating elements, in the case of mine electric heating strips that come on if the heat pump is unable to maintain the indoor temperature. This secondary heat runs at the efficiency of resistance heating, just about 100%, so one joule of electricity makes one joule of heat.
On my system if the set temperature is more than 1.5 degrees above the room temperature the heat strips kick in, dropping the efficiency.
When I do a setback, like at night or when we’re away, I’ve got to sneak the set point of the thermostat up a degree at a time, because I’d rather lose a limb than have those heat strips kick on. They make the meter whirl.
So I did it – my brand new high efficiency heat pump got installed yesterday. Literally right after I decided to pull the trigger, the utility changed the rebate program – now in order to get the biggest rebate you have to go with the most efficient variable speed model, but they increased the rebate amount to $3500. Like I said in the OP, I purposely waited until after the new year to have it installed in order to qualify for the new tax credits in the Inflation Reduction Act. So that plus the larger rebate should cancel out the slightly higher cost of the variable speed unit.
After less than 24 hours of using it it’s doing a good job of keeping my house comfortable (admittedly, in a very mild climate). One mild annoyance is that with this model you have to use the thermostat that comes with it in order to take advantage of the variable speeds, meaning I had to give up my Nest. The one they provide is still a smart thermostat, but it lacks the home/away feature that was one of the reasons I got the Nest in the first place. And the controls are slightly clunkier than the Nest. But that’s a very small inconvenience. And the cat seems a bit suspicious of it, since it makes different sounds from the old furnace. He’ll get used to it.