Heat pump question

[Jack]

My heat pump is only 2 years old. It is a Lennox 13 Seer and has a variable speed air handler. It has provided adequate heat for our house but the register temperature has never been higher than 86 degrees. I mentioned this to my HVAC contractor the other day and he sent out a technician to check it. THe technician slowed down the fan by 10% and the result is that my register temperature is not about 96 degrees.

I know that the outside unit can only produce a certain amount of heat energy at the coil. By slowing the fan and allowing the air to spend more time on the coil and, thus, raising the T, will the unit operate more or less efficiently. i. e. is it going to cost more or less to heat the house.

Any thoughts will be appreciated.

[Mo Hoaner]

If it's not about 96 degrees, what is it about? You said it provided adequate heat, but you bitched about it. The tech made the temperature of the air at the register higher. I guess you'll need to read your electric bill to figure the rest out.

[Zyp]

Jack;

A heat pump is considerably more efficient than other modes of heat, but it can be somewhat "drafty."

If it's heating your home adequatly, then good. If it seems drafty, try moveing the diffuser vanes at the supply register to move the air away from places where you sit. That may make it more comfortable.

[Jack]

Sorry, I meant to say that, after slowing the fan 10% the register temperature is now about 96 degrees

[Bubba]

Jack, Believe it or not we Did figure that out. Your unit temperatue should be whatever the performance charts say it should be after you have taken static pressures, temperatures, wet bulbs and superheat/subcooling readings. Its Not Rocket Science, you know? Bubba

[Jack]

Thanks for the reply. I really know nothing about all the things you mentioned. I only know that the tech slowed the fan about

10%(according to him) and the result was that the register temp has gone up from 86 degrees to 96 degrees. Do you know if the result will be more, less, or the same amount of electricity to run the unit? Any thoughts will be appreciated.

[Bubba]

Thats why you leave the "Rockets" to the "Rocket Scientists". Your register temperature will vary with the outdoor temperature, the backup heat and the things I mentioned below. I dont know if it will use more or less electricity. It doesnt matter. What you should be concerned with is that the unit is working within the designed parameters of the equipment manufacturer. Thats why you use THEIR performance charts and instructions. You need to find someone that knows how to do that and can explain it to you. Bubba