Energy Savings. Where are they?

[dash]

May be too soon to tell,but as I remember the install photos ,there is a possiblity of problems.


For years now,we have a 25% saving guarantee,based on the heating and cooling expense,being 46% of the total bill.So 11.5% of your total bill ,for going from a 10 to a 12 or a 12 to a 14 SEER ,usually heat pump replacing heat pump.

There have been a few that didn't save,and everyone of them had a problem.Either a bad TXV,or high Static duct system.

The TXV is obvious,but not everyone gets what happens with high static ducts.When installing variable speed fans the literature usually talks about how little they cost to run,and may even encourage running the indoor fan 24/7.

VS is great ,when the static goes up,unlike a PSC motor they deliver the air needed or close to it.But at a much higher cost in wattage,at .9 or 1.0 static,then at .5 Static,fan watts goes up about 40%.Then if they run the fan 24/7,or switch to restrictive filters like 3M's ,the cost goes up even more.

[kcrossley]

Originally posted by Yellow Dot
Didn't you have it installed by an unauthorized Trane dealer?

The installer is now Trane certified. He has to be in order to sell me the extended warranty, which I'm currently buying.

[kcrossley]

Originally posted by dash
There have been a few that didn't save,and everyone of them had a problem. Either a bad TXV,or high Static duct system.

I'm assuming that the TXV is the air handler. What is a High Static Duct System?

[Gunnery Sergeant Hartman]

An improperly sized duct system.
Too small...

[kcrossley]

Originally posted by Yellow Dot
An improperly sized duct system.
Too small...

No, I don't think that is it. I had another Trane dealer do a comfort analysis and they said the ducting was fine for the system I was putting in.

[Shophound]

Originally posted by kcrossley

I'm assuming that the TXV is the air handler.

TXV stands for Thermostatic Expansion Valve. It is a refrigerant metering device. It regulates the proper amount of refrigerant to the indoor coil in cool mode to produce the refrigeration effect, and anøther one meters refrigerant to the outdoor coil in heat mode for the same purpose. When in cool mode, the outdoor TXV is bypassed and the indoor valve active. In heat mode the roles are reversed, along with refrigerant direction.

A malfunctioning TXV will improperly meter refrigerant. In heating mode the outdoor TXV not working right will affect system performance and capacity. Same holds true in cool mode for the indoor coil valve.

A check valve is often built into heat pump TXVs. If one of these valves are leaking by it could also affect performance. Same if one is stuck partially or all the way closed when it should be open.

Lastly, your system charge may not be right because many installers and technicians are fuzzy on how to charge a heat pump in the heat mode and/or during cold weather, when running the system in cool mode is out of the question.

[kcrossley]

[QUOTE]Originally posted by shophound

A malfunctioning TXV will improperly meter refrigerant. In heating mode the outdoor TXV not working right will affect system performance and capacity. Same holds true in cool mode for the indoor coil valve.

The system charge should be easy enough to diagnose, but how would you check a defective TXV?

[kcrossley]

FYI, I emailed my regional Trane rep and got this response:

SEER is a cooling seasonal efficiency rating.

Not knowing the HSPF (Heating Seasonal Performance Factor) for you old unit, it is a little harder to compare the two electric bills.

Did you old outdoor unit break or was it running when you had it pulled out?

Too many variables for me. *I don’t have time to think up all of the question that are relevant. Please consult your dealer. If [dealer name witheld] has any questions I can assist him.

[docholiday]

Hes got a point with his response, thats one kicker to buying on SEER alone and not considering HSPF, EER, or COP.

[dash]

Originally posted by kcrossley

Originally posted by Yellow Dot
An improperly sized duct system.
Too small...

No, I don't think that is it. I had another Trane dealer do a comfort analysis and they said the ducting was fine for the system I was putting in.

The majority ,wouldn't be able to tell if the duct system is okay.

Did they measure the airflow,or the static pressure?

If you don't measure it's just a guess!!

[Carnak]

It looks colder this winter so more heat demand.

As well to the increased heat demand, the lower average outdoor temperature means a lower heat source and reduced heat output of the unit.

If you never had a humifidifer before, yes you will use more energy now and with this being a colder winter, the home would tend to be more dry.

I am not a big fan of setting back the temps on heat pumps because it CAN cause the auxiliary heat to turn on more than necessary. Would pay more of an energy penalty in a colder winter too.

[marauderx]

Your cost savings will be happening in the summer. If the given CFM and heating capacity are the same for both the old and new units, your bills for heating will reflect how much heat you need, independant of the SEER. Find out how much you save during the cooling then compare.

[pstu]

Kcrossley, I think you should listen to what Dash said. Have somebody measure either ESP or airflow in your system, double-check whether the duct system is carrying enough BTUs to where it is needed.

I know for a fact it is not too hard to measure ESP, and the tech requires only about a hundred dollar instrument. That will be an indicator you can use to troubleshoot.

Also I know that weather effects make it very hard to judge based on one month data -- too many false positives *and* false negative conclusions. Unless of course you have a Master's degree in math and can adjust the weather data to make a normalized year (they used to do that in my department at the old utility job). Several months will be a better comparison. But right now I will assume that your system is failing to deliver the expected results and you need to troubleshoot the reason.

Best of luck -- P.Student