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Amethyst 04-03-2011 09:47 AM

New Heat Pumps: Big, Ugly, Flimsy and Expensive
 
Our home's heating/cooling system (heat pump, 2 outside units) will soon be 21 years old, so we are looking to replace it. We went to a local "home show" to see what's new in the heat pump world. Boy, did we get an ugly surprise.

Our present outdoor units fit nicely on a concrete pad just outside the basement door, are only about 2 feet tall, and we never hear them.

The outdoor units we would need to buy are hideous monsters, made of flimsy metal that you can almost feel crinkle under your fingers. Because the metal is so flimsy, you have to buy a plastic "snow cap" to keep snow off the fan blades (we've had 2 feet of snow here with nary a problem). Unless we want to have a bigger concrete pad poured, we also have to buy plastic "feet" and a plastic pad to keep the monsters off the ground.

Altogether, the new units would be almost as tall as I am, have one-and-a-half-times the footprint of the old ones, and cost $5800 apiece. Plus another $5800 for a new air exchanger. We were told we would also have to have a new breaker installed, since new systems take less current than old ones do.

The seller blamed the huge size on "the freon we have to use these days." He had a slightly shorter unit (but just as wide) that he said was for a townhouse.

Bleagh. I expected new technology would be better, but it's worse. It's not worth the modest savings in electricity - we hardly use the a/c in summer as it is. But we are living on borrowed time with the current units. Bummer!

Amethyst

haha 04-03-2011 09:55 AM

Quote:

Originally Posted by Amethyst (Post 1055188)
We were told we would also have to have a new breaker installed, since new systems take less current than old ones do.
Amethyst

I really cannot understand this part. Amps are what counts, and if your old one was wired for a higher amperage draw (including starting surge) than your new one, you will have more margin of safety with the new one that draws less, not less margin.

The main thing is that the wire must be large enough to carry the current, and the breaker cannot be higher rated than the wire. But if you wanted to connect a lightbulb to a proper 50 amp circuit, no problem, provided of course that you match voltages.

ERD50 04-03-2011 10:22 AM

Quote:

Originally Posted by haha (Post 1055197)
I really cannot understand this part. Amps are what counts, and if your old one was wired for a higher amperage draw (including starting surge) than your new one, you will have more margin of safety with the new one that draws less, not less margin.

The main thing is that the wire must be large enough to carry the current, and the breaker cannot be higher rated than the wire. But if you wanted to connect a lightbulb to a proper 50 amp circuit, no problem, provided of course that you match voltages.

It depends, and I'll side with the installer on this one. Circuit breakers can provide two functions. The one you are thinking of is the most common - to protect the wiring from overheating from over-current. And in that case you are correct.

A second purpose is to protect the device itself if it draws too much current. This is only practical if you have a dedicated line for the device (a heat pump would normally fit this description). IF the old circuit was a 40Amp, and the new one is rated for running on a 30A circuit, you can bet the designers only put in enough safety margin in the heat pump wiring for the kind of overload you would expect on a 30A line.

But it should only mean (in my example) replacing the existing 40A breaker with a 30A one. No big deal.

I actually ran into this with my furnace. The motor has been prone to stalling about once every two years (must be a bad spot on the windings). It draws the stall current, and it was burning up traces on the controller board before the breaker would trip. I was able to repair them, but I thought it odd. This last time, I noticed a sign on a plate inside - "For wiring to 15A protected circuits only", and that circuit was 20A. I added a special 15A breaker on the furnace itself, with a special kind of fuse (not a breaker) that is supposed to have a profile better matched to motors. Fuses and circuit breakers are more complex than one might assume - there are tolerances and time/overload profiles that require a 3-D plot to make sense of.

-ERD50

haha 04-03-2011 10:39 AM

Quote:

Originally Posted by ERD50 (Post 1055214)
It depends, and I'll side with the installer on this one. Circuit breakers can provide two functions. The one you are thinking of is the most common - to protect the wiring from overheating from over-current. And in that case you are correct.

A second purpose is to protect the device itself if it draws too much current. This is only practical if you have a dedicated line for the device (a heat pump would normally fit this description). IF the old circuit was a 40Amp, and the new one is rated for running on a 30A circuit, you can bet the designers only put in enough safety margin in the heat pump wiring for the kind of overload you would expect on a 30A line.

But it should only mean (in my example) replacing the existing 40A breaker with a 30A one. No big deal.

I actually ran into this with my furnace. The motor has been prone to stalling about once every two years (must be a bad spot on the windings). It draws the stall current, and it was burning up traces on the controller board before the breaker would trip. I was able to repair them, but I thought it odd. This last time, I noticed a sign on a plate inside - "For wiring to 15A protected circuits only", and that circuit was 20A. I added a special 15A breaker on the furnace itself, with a special kind of fuse (not a breaker) that is supposed to have a profile better matched to motors. Fuses and circuit breakers are more complex than one might assume - there are tolerances and time/overload profiles that require a 3-D plot to make sense of.

-ERD50

I see your point. Unless your breaker box is obsolete, a very simple job with very cheap part. And it really would be expecting more out of a generic breaker than they are normally designed for, as your solution shows.

Ha

samclem 04-03-2011 11:07 AM

Quote:

Originally Posted by Amethyst (Post 1055188)
Bleagh. I expected new technology would be better, but it's worse. It's not worth the modest savings in electricity - we hardly use the a/c in summer as it is. But we are living on borrowed time with the current units. Bummer!

Thanks for the update and warning.
So, what are you guys thinking you'll do? Options that occur to me:
1) If these are "cutting edge" high efficiency units, see if you can get a lower efficiency model that is smaller and cheaper (cheaper after doing the calcs on energy use, utility and govt tax credits, estimated future utility costs, etc)
2) If you've got another source of heat (especially natural gas), look into getting a simpler AC unit instead of a heat pump and do the heating with natural gas.
3) Ground-source heat pump? Very pricey installation and the big govt tax credit has expired, but if the regular air-to-air exchangers have gone up in price a huge amount it is possible that the GSHPs are more competitive (on a relative basis) than they used to be.

Here's a site with some equipment info prices. A 3 ton 13 SEER heat pump, with a new evaporator coil, would run about $2000. Add another $1000 if you need a new air handler. If you wanted the highest efficiency unit (18 SEER), it would be about $1500 more.

travelover 04-03-2011 11:25 AM

I'd get a second and third opinion from other contractors.

Lakedog 04-03-2011 12:18 PM

Quote:

Originally Posted by travelover (Post 1055244)
I'd get a second and third opinion from other contractors.

+1
Just had my heat pump replaced and the six estimates varied greatly for the same size and brand unit. The highest quote was more than 50% above the two lowest (which were within $100 of one another).

Amethyst 04-03-2011 12:18 PM

Quote:

Originally Posted by samclem (Post 1055238)
2) If you've got another source of heat (especially natural gas), look into getting a simpler AC unit instead of a heat pump and do the heating with natural gas.

We wish! The gas line ends about 3/4 mile up the street from us.

Quote:

Originally Posted by samclem (Post 1055238)
Here's

Quote:

Originally Posted by samclem (Post 1055238)
a site with some equipment info prices. A 3 ton 13 SEER heat pump, with a new evaporator coil, would run about $2000. Add another $1000 if you need a new air handler. If you wanted the highest efficiency unit (18 SEER), it would be about $1500 more.

Thanks! I always assume the first price anyone gives me is inflated, and it's great to have some comparison data to "share" with the price inflaters.

Quote:

Originally Posted by travelover (Post 1055244)
I'd get a second and third opinion from other contractors.

You betcha.

I just hate the way plastic and flimsy metal have taken over everything.

Amethyst

haha 04-03-2011 12:22 PM

Quote:

Originally Posted by Amethyst (Post 1055266)
I just hate the way plastic and flimsy metal have taken over everything.

Amethyst

Tell it to the Chinese.

Ha

Telly 04-03-2011 10:20 PM

Higher efficiency heat pumps and air conditioners have bigger outdoor units. They are larger to allow the use of a condensor coil with more surface area, which is one step of creating higher efficiency.

I agree with ERD50's breaker assessment. Downsizing the 240 volt breaker is common when replacing an existing old AC or heatpump condensor unit with a new unit of much higher efficiency. In fact, it is uncommon NOT to have to downsize the breaker capacity. If the breaker capacity DOES NOT have to be downsized, then I'd wonder if the new unit really was higher efficiency. After all, the increase in efficiency means the power used should decrease.

They may be bigger and uglier, but they do save $$ in power cost.

That said, I have avoided being out on the "bleeding edge" of highest-efficiency.

BOBOT 04-04-2011 02:06 PM

FWIW we replaced our system (outside unit and inside air handler) 2 yrs ago. 3 ton, 16 SEER Trane. Outside unit is somewhat larger than old unit, but way quieter. Air handler has variable speed fan, also quieter. Noticeably lower elec bills. Very satisfied.

Spent ~6500, but qualified for rebate from Uncle Sam that reduced our tax bill to zero that year.


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