I have a 1400sq foot 2 story home built in 2005 with a single heat pump. The thermostat is located on the first floor. During the winter the heat will run and run to try to maintain the temperature on the first floor but the second floor will bake. For example, the first floor may be set to 70 but upstairs gets up into the 80s before I realize and turn the heat off. But then if the heat is off it may stay off too long and become too cold even upstairs.

I have tried to close all vents on the second floor and tried closing doors to rooms that aren't in use on the second floor. The system may be engineered incorrectly because there are only 2 vents on the first floor but one in each of 6 rooms on the second floor.

The best solution I have come up with is to use a small space heater on the first floor to assist the heat pump but the amount of heat that needs to be added to the first floor to keep up with the second floor is different each day depending on what the temperature is outside. I have to guess how to set the space heater and if I am right things work pretty good, if I am wrong then the second floor either gets too hot or too cold.

First question is, am I missing something that I could be doing to improve the way things are working? Should I be doing something else that may be non-intuitive but would help fix the problem?

Second question is, I am thinking about installing a second thermostat on the second floor as a more permanent and accurate fix. Does this sound like a reasonable idea given the problem? What's the best method to go with? Parallel with the first floor thermostat so the heat only comes on if it's cold upstairs also? I was thinking maybe a switch to select which of the two thermostats get power or which control signals go back to the heat pump.

Any thoughts would be great. I just don't want to have to keep waking a few times at night to check the temp so my baby doesn't get too hot or cold.

I am not sure how long you have to make a builder come back and fix it. Might post this to the legal forum here too. Could talk to the lawyer that did you closing.

It could be fairly easy to add at least more returns to the first floor. Often they use the cavity between 2 studs in an interior wall as a return vent. Locate one, cut a hole in the drywall, and screw on a vent. That would skew the heat from the second floor to the first. The supplies would be a little tougher. Usually they go up an outside wall. You might have to cut through a tin duct too. Use some caution chopping holes in walls. Besides ducts, there are wires and pipes in there. I can look in my one vent and see romex.

I don't see how relocating the thermostat to the second floor will help. You will set it at 68 and the downstairs will be 54 degrees. I would add more supplies to the downstairs. Or possibly increase the existing ones. So if they are 6" metal pipe, got to 8", you will also have to relace the take-off, boot and possibly registers. But you don't have to cut new holes in the floor. I'm assuming this is on a basement and registers are through the floor.

Thanks for the replies.

I mistyped in my question, my home was built in 2003, not 2005.

I don't have a basement. My home is built on a slab and the heat pump is located in the attic. This being the case, it seems like it would be difficult for me to add more supplies to the downstairs.

NorthernHeat, I did recognize the issue that you brought up about relocating the thermostat.

I'm starting to think that the only real fix is to add more supplies which is beyond the scope of things which I can easily do.

Thanks for the replies.

I mistyped in my question, my home was built in 2003, not 2005.

I don't have a basement. My home is built on a slab and the heat pump is located in the attic. This being the case, it seems like it would be difficult for me to add more supplies to the downstairs.

NorthernHeat, I did recognize the issue that you brought up about relocating the thermostat.

I'm starting to think that the only real fix is to add more supplies which is beyond the scope of things which I can easily do.

I would bad talk that builder all over town. The only realistic thing you can do is hope some closets on the second floor line up with areas you my want registers on the first floor and just have a few exposed runs in those closets.

Good luck

Yes, let everybody know about the builder. Do you have any building inspection in your area? Who signed the certificate of occupancy? Is the builder politically connected like the one shabby builder in my area?

The closets idea is a good one. Even some exposed ducts might be worth living with.