Announcement

Collapse
No announcement yet.

A/C experts on Electric "Heat Pump" A/C systems...

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    A/C experts on Electric "Heat Pump" A/C systems...

    Is it true that Electric Heat Pumps don't blow warm air in really cold weather and we need to run Emergency Heat or is my AC man blowing smoke?!
    We purchased a new Lennox system a little over a year ago and the few times it's been cold, it started to blow cold air and we've had to switch to Emergency Air to keep the house warm (E-Heat uses a lot of Electricity)... I'm tired, tired, tired of this and I need some advise and help... I can't afford to buy another system.

    #2
    I have electric heat pumps and don't run emergency heat. Heat pumps don't generate heat so you won't feel hot air coming from vents.

    Comment


      #3
      I had a complete new heat pump system installed this past spring. Yes, heat pumps generally don't blow hot air from the vents. They use outside air that has warmth in it from the existing air if that makes sense. If it's extremely cold out the system should automatically kick to emergency heat. They are a lot more efficient than the standard ac units with heater coils in attic or closet room systems. I also had a heat pump system when I lived in Norfolk, VA area...
      Is your system big enough for your house?

      Comment


        #4
        Back when I was in high school and worked doing that, I was told he heat pump would heat until around 40* outdoors. The unit would call for emergency heat then, which was the heat strips. The air from heat pump operation isn't as warm as the air that gets blown across the coils. We had one and I really wasn't a fan, but I wasn't paying the electric or gas bill either.

        They are most likely a little different now.

        Comment


          #5
          Try a wood stove?

          Comment


            #6
            A byproduct of a heat pump is the need to defrost the outside coils. In colder weather this happens more often. When the heat pump defrosts it turns into AC mode to melt the ice. When this happens it blows cold air inside while the electric heat strips also come on to temper the air. This is very expensive to run with the compress and heat strips running. During the defrost cycle the air coming out of the vents may be 75-80 degrees or so. This is not going to warm a house up. If this is happening many times an hour the system will be very inefficient. I haven't worked on a heat pump in a long time. Many members here that are in the business indicate they are extremely more efficient now but the principles remain the same.

            Comment


              #7
              Originally posted by krisw View Post
              Back when I was in high school and worked doing that, I was told he heat pump would heat until around 40* outdoors. The unit would call for emergency heat then, which was the heat strips. The air from heat pump operation isn't as warm as the air that gets blown across the coils. We had one and I really wasn't a fan, but I wasn't paying the electric or gas bill either.

              They are most likely a little different now.

              This is what I was told as well. Had one back in the early 90's on my first house. Based on that fiasco, I will never own another one. Many problems with that system and it was brand new. I don't remember the name brand, but I had a friend that was in the business and he would have to come to the house and work on it at least once or twice a year. Never again.

              Comment


                #8
                With the weather we are having right now you are going to have to run your heat strips. When heating, the heat pump is just functioning as an air conditioner in reverse.

                When the system acts as as A/C, you will notice that the evaporator coils (in the house) are much cooler than the ambient air going across them. The heat from the house air gets transferred into the refrigerant that is running through the evaporator coils. The larger the temperature difference between the refrigerant and the air, the more heat transfer you will have. The heat is then released into the environment since the compressor heats the refrigerant due to the pressure effect (PV=nRT).

                When functioning in heat mode, the evap and condensor coils are essentially reversed. If the refrigerant temperature in the outside coils is higher than the air moving across them then no heat transfer can occur......heat energy only flows in one direction, hot to cold. When this happens something has to supplement the system and in this case it is usually resistive heating elements.

                Comment


                  #9
                  maybe if it switched to E-Heat automatically.... and didn't require me to get up and switch to E-Heat in the middle of the night and after the house has become frigid it would be more tolerable

                  Comment


                    #10
                    I'm surprised your system doesn't switch to the emergency heat automatically. My Lennox system in my former home did. I have Carrier now and it does also if needed.

                    Comment


                      #11
                      Have someone come look at it, I’ve been in the business a long time sold thousands of them something doesn’t sound right. Could be a charge problem or it’s not going into defrost. Mine cranks right along at 28 degrees with the heat assist you shouldn’t be getting cold air through the vents unles your heat strips are undersized.

                      Comment


                        #12
                        Originally posted by ATI View Post
                        maybe if it switched to E-Heat automatically.... and didn't require me to get up and switch to E-Heat in the middle of the night and after the house has become frigid it would be more tolerable
                        It's supposed to switch over automagically. At least, the ones I helped install did. We never actually had any problems out of them, I just felt like the heat should be hotter, since I was used to using straight gas or electric heat strips for heat.

                        Comment


                          #13
                          heat strips should come on as auxiliary heat automatically when needed. The heat pump will run with auxiliary heat. If you switch to emergency heat on the thermostat, heat pump wont run. Its the same heat strips for emergency and auxiliary. Sounds like you have a control wiring issue or a thermostat set up issue

                          Comment


                            #14
                            I would have the Freon level checked.... Freon determines if it is working at its full capacity or not and the last pound or two is crucial for capacity and efficiency. Next, what have your local night time temps been running?

                            It is true, as it gets colder, the heat pump is able to pull less and less heat out of the outdoor air, so it produces less and less heat.

                            You may need to upgrade to a higher end thermostat, one that will use your supplemental (electric heat) anytime the temp drifts off set point, with out you having to only put it on emergency heat.

                            A heat pump shines in 30-60 degree outside air temps.... this is pretty much average temps for most of Texas... during this range your probably pulling 12-14 amps running your heat pump and saving a ton of money. On the occasional colder night when your running your electric heat strips, average 15 kw heater will pull 65-72 amps.

                            So, make sure Freon is right, make sure unit is running properly, and just remember how much your saving on the average night! Most of my customers tell me that I cut there electric bill in half after installing a heat pump! Doesn't take long to pay for itself!

                            Comment


                              #15
                              Once temps drop below 25 switch to E Heat, when you get up switch back to heatpump mode as temps rise during the day. If I know temps are going to drop that low, I usually heat the house up a little warmer during the day, say 74-75, then turn on heat strips and night and drop therostat to 67.

                              Comment

                              Working...
                              X