carl

if the basement is enclosed and tight, you should add a supply. I think most people would not like to mix unconditioned basement air with your living space air. may or may not be a big deal. could make your HP work harder and higher electric bills. if you truly needed more return for comfort and improved air movement, I would have taken it from your living space area.

IMO

tiger I havw a supply in the basement.

carl

in your post you said "no heat in basement". ???

Sorry tiger I have heat in the basement ,I have a supply but I put a return in . What is your opinion. thanks

Carl - your question doesn't make sense. So you have a supply in the basement and you added a return. Well - that is good since they should be in balance. Now what is your question exactly?

If the basement wasn't on the system and now is, your system will work more to heat the house. Is that a problem - probably but really hard to say without more specifics. If it is oversized and the basement is relatively small and well insulated, then you will be fine. Any other situation and your HP may not be able to keep up and you will use supplemental heat more often.

Let me make it more clear, My question since I added the return in the basement when using the heat pump for the winter is the heat pump going to work harder to warm the house, it is cooler in the basement. Should I block the return in the winter and open it in the summer. Hope this is clear to you. Thank you for your help.

If you now have better airflow into the basement and you heat it more, then the HP will work harder. If you have a supply in the basement and no return, then you are overpressurizing the basement - which may have no real consequences. It might increase duct leakage and increase leaks out of the basement - but the actual consequences may be small.

So yes - you should block the return - probably - but impossible to say for sure. It depends on duct location, tightness; tightness of basement etc.

If you have a basement with high humidity one solution is add a supply on one end and return on the other to circulate air and cut humidity. If they need to be blocked in the winter you can either tape across the vents or buy some magnetic vent covers at a home center and tape around them if that is not enough.

This is pretty cheap and no water to drain and mess with... Also most dehumidifiers are not near as energy efficient.